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close this bookFood and Nutrition Bulletin Volume 05, Number 3, 1983 (UNU Food and Nutrition Bulletin, 1983, 84 pages)
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View the documentIntegrated child development services (ICDS) in India
View the documentInfluences on infant feeding in Dar Es Salaam
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Integrated child development services (ICDS) in India

Badri N. Tandon
Department of Gastroenterology and Human Nutrition, All-India Institute of Medical Sciences,
Ansari Nagar, New Delhi, India


Indian census estimates for 1983 are 118 million pre-school children, 17 million pregnant women, and 32 million lactating mothers with 48 per cent of the population living below the poverty line. They are at high risk for malnutrition resulting from inadequate food intake and repeated episodes of infection. Infant mortality in India is estimated to be 125 per 1,000 live births, and the malnutrition-infection complex is the most important cause of this high infant and child mortality, as it is for two-thirds of the population in the world living in developing countries.

India has given a special place to children in its constitution. It has established a National Board for Children with the Prime Minister as its Chairman to monitor the progress of the programme for the care and development of children. Several programmes have been established since Independence for Indian children. A detailed review of the health and nutrition programme was undertaken by the Government of India at the beginning of 1970.

Teams comprised of planners, administrators, and technical experts reviewed the ongoing programmes by field visits and study of available records. It was decided to develop an integrated approach to provide essential health, nutrition, and education services to preschool children for their optimal development. A new experimental project, Integrated Child Development Services (ICDS), was launched on 2 October 1975 with the following objectives:

1. To improve the nutritional and health status of children in the age group 0 to 6 years.
2. To lay the foundations for proper psychological, physical, and social development of the child.
3. To reduce the incidence of mortality, morbidity, malnutrition, and school drop-out.
4. To enhance the capability of the mother to look after the normal health and nutritional needs of the child through proper nutritional as well as health education.
5. To achieve effective coordination of policy and implementation among the various services to promote child development.

ICDS is designed to provide services to the preschool children aged from 0 to 6 years, pregnant women in the second and third trimester, and lactating mothers for a period of six months. These include appropriate immunizations according to the national plan of the country, nutrition intervention by supplementary nutrition, vitamin A every six months, and distribution of iron and folic acid tablets, primary medical care for common ailments, health checkups, including antenatal and postnatal examinations. Preschool education for children and functional literacy for women is also included in the programme. Emphasis is on nutrition and health education to the beneficiaries.

The services are delivered at a focal point in the village called the Anganwadi, which implies a courtyard of the village. Beneficiaries assemble at the Anganwadi every day for a period of two to three hours to receive on-the-spot services. The principal functionary who delivers these services is a local village young woman educated up to eighth to tenth grade standards. In difficult, backward areas, young women with even less education may be selected from the same village to be the Anganwadi worker.

This worker receives training for a period of four months through a specially developed curriculum that is directed towards her functions in the programme. Furthermore, on-the-job training is scheduled every month by the medical officers and middle-level supervisors of the health infrastructure of the villages. She is designated as honorary worker and is not bound by the service rules of the government. She receives an honorarium of Rs.175 to Rs.200 - (US $17.50 to 20) per month. Another honorary worker helps with cleaning the space, cooking the food for the children, etc.

The Anganwadi is thus the nodal point established in a village for a population of 1,000 where preschool children, pregnant women, and lactating mothers receive health, nutrition, and education services in a coordinated way. It is linked with the village health infrastructure of the State on the one hand and the Social Welfare Department on the other. Thus, it receives support and supervision for its activities from well-established health, education, and welfare departments. in India, for all administrative and development purposes, about 100 rural villages with a total population of approximately 100,000 people are grouped together to form a block.

At the headquarters of the block, which is located in one of the villages, there is a primary health centre that has branches spread out in the villages as sub-centres. One sub-centre, on average, provides health services to a population of seven to ten villages, i.e., 7,000 to 10,000 people. The work of the sub-centre is carried out by an auxiliary nurse midwife or multipurpose workers, and maternal child health services are provided on a priority basis.

Currently, the Anganwadis of ICDS are located in each village. Thus, the sub-centres have been established at the most peripheral points to deliver effective health and nutrition services to women and children.

A new structure has been developed at the block headquarters/primary health centre for the social welfare and education components of ICDS. A graduate in sociology with special training in child development and nutrition is appointed full-time as Child Development Project Officer (CDPO). In addition three to four middle-level women supervisors with special training for their functions support the Anganwadi workers. This system provides supportive supervision and continuous help to the functioning of Anganwadis at each village.

The officers at the block level, i.e., the medical officer in charge of the primary health centre and the CDPO are linked to their respective departments of health and social welfare for interaction at the District and the State headquarters. The Ministry of Social Welfare of the Government of India at the Centre interacts with the State Social Welfare and Health Departments for proper implementation of the programme.

Involvement of Medical Institutions in ICDS

The original plan of ICDS did not include the involvement of faculty of the medical institutions in this national programme. However, the then Cabinet Minister of Education and Social Welfare, Professor Nural Hassan, an academician in his own right, had the foresight to consider the value of participation on the part of the faculty of paediatrics and community medicine departments in this programme. He asked the All-India Institute of Medical Sciences to organize a two-day meeting of professors of paediatrics and community medicine from the medical institutions located close to the proposed 33 ICDS projects. Twenty-seven medical institutions were identified, and invitations were sent to their staffs requesting them to send one physician each from the paediatric and community medicine departments for the meeting on ICDS at the All-India Institute of Medical Sciences on February 18-19, 1976. The meeting unanimously recommended that the medical faculty should participate in this national experimental project on child development and offer the following services as consultants: evaluation, monitoring, training, and continued education.

The Department of Social Welfare of the Government of India appointed a Central Technical Committee for Health and Nutrition at the All-India Institute of Medical Sciences, and a small biostatistics unit was established at the Institute for data analysis. Members of the Central Committee included representatives from the Ministry of Health, Planning, Social Welfare, the National Institute of Public Cooperation and Child Development, and the All-India Institute of Medical Sciences. Twenty-seven ICDS consultants were appointed from different medical institutions located at a reasonable proximity to the project blocks. The consultants were reorganized on a zonal basis, and five regional convenors from among the consultants were appointed to monitor the work by mutual discussion with each consultant in a given zone.

Consultants were given an orientation course where the objectives of the ICDS, organization, its implementation, budget, accounting, and their own specific functions of evaluation, training, and monitoring were explained in detail. The forms for survey and monitoring and the training curriculum for medical officers of the ICDS block were finalized after a critical discussion by all the consultants.

The survey work is done on an annual basis, and the data are analyzed at the central biostatistics unit. Comments on the data are forwarded to the Social Welfare Department and to each consultant for appropriate action. The conclusions of the data on the flow of services and its impact are provided to this Department.

Regional coordinators monitor the implementation of ICDS through the data collected by the consultants from the block level through regional meetings that will be held by rotation at different project blocks once every two months. The deliberations at these regional meetings are forwarded to the Central Committee for information and appropriate action.

The Chairman of the Central Technical Committee meets with the regional coordinators of ICDS once every four months to review the monitoring, training, and survey work being done by the consultants. The Central Committee meets once every two months to review the progress of ICDS, particularly in the health and nutrition sector. The number of experimental projects has expanded from 33 to 100, then to 150 and 200 during 1978, 1979, and 1980.

During this four-year period from 1976 to 1980, ICDS consultants were able to provide orientation and training courses for nearly 75 to 85 per cent of the medical and paramedical functionaries. Five surveys were conducted and the results of the initial three surveys have been published. Monitoring reports are continuously reviewed and the appropriate actions taken. Overall, it appeared that this system worked quite satisfactorily. For less than 0.6 per cent of the total budget for an ICDS project, experts were able to assist a national programme for training, monitoring, and evaluation.

After a critical review, Prime Minister Ghandi decided that the programme should expand to 1,000 projects by the end of the sixth Five-Year Plan that ends in March 1985. Furthermore, she declared it a programme of national importance and included it in the 20-Point Development Programme for the country. The Central Committee has devised a new system for evaluation, monitoring, training, and continued education to cope with the expanded ICDS programme. The characteristics of the new system are:

1. The four functions mentioned above are preserved.
2. Each State will have two to three training consultants drawn from medical colleges with wide experience in ICDS. All the medical officers and district health officers (advisers) and other non-medical officials will receive orientation in ICDS at these training centres under the training consultants.
3.There will be about 40 training consultants through out the country who will also help the Anganwadi Training Centres conduct courses for the Anganwadi workers.
4. The survey will be carried out in 20 per cent of all the projects, and each State will have two to three survey consultants who will do a relatively more detailed survey on the 10 per cent of samples under the guidance of the Biostatistics Unit of the All-India Institute of Medical Sciences. They will also do a survey of severely malnourished children and perform other specific functions assigned to them. The data analysis will be done by the survey consultants for their own project and forwarded to the State coordinator as well as to the Central Committee.
5. There will be 10 research consultants who will do the research on a contract basis to provide answers for specific problems related to ICDS and to guide changes or modifications in ICDS in the future.
6. District Health Officers or persons with equivalent rank will be appointed as advisers. Their main functions will be monitoring and continuing education at the level of the project block. They will also receive continuous guidance and supervision from senior advisers.
7. One senior adviser will be appointed for each State. He will be a very senior person with wide experience in nutrition, child development, and ICDS. His main task will be to guide the advisers to discharge their functions effectively and advise the State coordinator on proper implementation of ICDS in each State. These appointments will be on an honorary basis with contingencies and funds for travailing for the project work.
8. The data from training, survey, and monitoring will be analyzed at the first level by the individual officers, then they will be forwarded to the State coordinator. There will be a data analysis cell at the State headquarters to compile all the State data. These data will be sent to the Central Committee that will then prepare the national data report.

Regional meetings are organized for consultants, and State level meetings are organized for advisers to review and continuously monitor the progress of the work. The monthly monitoring system has evolved with a flow from Anganwadis to the apex at the State level and Centre. The training programme has been expanded with greater emphasis on continuous education of the field workers, creating awareness among administrators, voluntary organizations, and the people. A new component of research has been added through a selective group of consultants who will be able to provide answers for pressing questions raised from time to time by the Social Welfare Department, the Planning Commission, and others.

The Ministry of Social Welfare, through its apex institution known as the National Institute of Public Cooperation and Child Development, has been responsible for organizing the training of ICDS staff working as Anganwadi workers, Mukhya Sevikas, and Child Development Project Officers. further, continuing education for these functionaries is arranged through appropriate workshops and seminars. The number of training institutions and training courses has substantially increased during the phase of extension of ICDS. At present there are 200 Anganwadi worker-training institutions, 25 Mukhya Sevikas-training institutions, and 3 regional centres for training Child Development Project Officers who will be spread out in the country.


Data from the expanded programme suggest a significant increase in the proportion of immunized children, vitamin A distribution, and a decrease in prevalence of severe malnutrition.

Severe malnutrition is a serious, life-threatening condition for children. Very high death rates have been reported among such children if they are left untreated for a long time or taken to the hospital in very late stages of their illness. Readily available services at Anganwadis in their own villages improved the prognosis for these children. A follow-up of more than 4,000 severely malnourished children by our consultants at the Anganwadi centres revealed an overall fatality of only 3 per cent after treatment by Anganwadi workers and a significant improvement in the nutritional status of about 46.5 per cent of the children. Diarrhoea, fever, and respiratory infections were the main diseases associated with severe malnutrition, and could be treated satisfactorily at the Anganwadi centre in the majority of cases by the workers.

There are also several research studies by individual consultants that have demonstrated a decrease in the infant mortality rate, an increase in birth weight, and improvement in nutritional and health status of pregnant women in ICDS project areas. Comparative studies in a few ICDS and non-ICDS populations have also confirmed these findings.

The achievements of ICDS can be summarized as follows:

1. A wide network of infrastructure has been established.
2. A good system of continuous education and supportive supervision of the functionaries has been developed.
3. A team approach for the delivery of essential services at the village is in operation.
4. There is unequivocal evidence of progressive improvement in the coverage and utilization of all the essential services delivered through ICDS.
5. The nutritional status of children has improved; in particular, there has been a marked decline in the prevalence rate of severe malnutrition.
6. The language and values of the academic community of medical scientists are being modified to suit the health needs of the community.

There are, however, several shortcomings in this national programme, namely:

1. It is a multisectoral programme and coordination among different departments, e.g., health, education, and social welfare, is not yet up to the desirable level.
2. Participation by the community and voluntary organizations is not as great as it should be.
3. Nutrition and health education, and even preschool and non-formal education, need more emphasis.
4. Younger children 0 to 3 years are receiving proportionately less ICDS services compared to children 4 to 6 years of age.
5. The impact of the programme on morbidity and mortality needs further evaluation.
6. It is often said that ICDS is a costly programme. However, this needs more careful cost-benefit analysis.

(a) The total cost of a primary health centre establishment where ICDS does not exist is about Rs. 350,000 to 500,000 (US $35,000 to 50,000).
(b) The ICDS health component adds Rs.130,000 (US $13,000) to the primary health centre, with a very significant improvement in the maternal-child health services.
(c) The cost of non-medical, i.e., social welfare and education input, in each rural ICDS project is about Rs.397,000 (US $39,700), which covers the management, social welfare activities, and particularly preschool education. This is lower than the cost of sporadic vertical programmes in non-ICDS blocks.
(d) The cost of supplementary nutrition is the major component, i.e., about Rs.800,000 (US $80,000) per project per year. This is the same or less than for other vertical supplementary nutrition programmes in the country.

We have also to answer two other questions when considering the cost of ICDS: What would be the cost of not having a programme like ICDS? Is there another less expensive and successful model? If there is a less costly programme that does not bring the desired results, then it is not really cheap.


Influences on infant feeding in Dar Es Salaam

Han Bantje
Institute of Resource Assessment, University of Dar es Salaam, Dar es Salaam, Tanzania

Olyvia Yambi
Tanzania Food and Nutrition Centre, Dar es Salaam, Tanzania


This paper summarizes the findings from a study of infant feeding practices in Dar es Salaam, the capital of Tanzania, in 1980. It was part of an international investigation entitled, "Rethinking Infant Nutrition Policies under Changing Socio-Economic Conditions", organized by a task force of the International Union of Nutritional Sciences (IUNS) (1). Its broad aim was to identify negative material constraints on breast-feeding, and to stimulate social and political action to remove them. The comparative results have been published in the final project document (2).

The worldwide shift in infant feeding practice has been a cause for concern for some time. An increase in early weaning and reliance on bottle-feeding with breast" milk substitutes have been reported from many countries. These changes are part of the pervasive social transformation taking place in the Third World, involving the breakdown of traditional cultures, rapid urbanization, more intensive communication between countries and social groups, the demographic transition, and the changing position of women. Rapid social change creates insecurity and a quest for symbols of modernity that makes people vulnerable to the promotion strategies of the producers of milk formulas. Health workers are faced with the distressing and sometimes fatal effects of artificial feeding under poor hygienic conditions. Much energy is spent to convince governments, the milk companies, and the public, of the dangers of artificial feeding. Within the wider context of female activism, such efforts sometimes merge with action for women's rights to breast-feed their babies.

Sociologically, the change of feeding patterns as a result of social transformations raises the issue of the linkage between macro-level processes and individual decision making. Individuals do not react to abstract macro-level processes, but to the concrete micro-level conditions that result from them. The aim of the study was to test the assumption that women's behaviour is, to a large extent, determined by material constraints, such as the availability of money, time, and energy that largely depend on female employment status and the socio-economic level of the household. Furthermore, a shift towards artificial feeding can only be expected to occur if people actually have access to formula milks and are exposed to their promotion. Therefore, a second objective was to study the impact of formula milk promotion on mothers' attitudes and practices.

Fortunately, the shift from breast to bottle has not progressed nearly as far in Tanzania as in many other countries. Government policies restricting the imports of milk formulas, paired with an economic straight-jacket that prohibits almost all food imports, have served to retain adherence to traditional breast-feeding habits. A legally enforced maternity leave period of three months enables women to fully breast-feed for at least that long. Nevertheless, the pressures towards a change in feeding practices may also be observed here.

The study addressed itself mainly to the question: In what way are feeding patterns influenced by household conditions and specific material contraints on women? Practices related to breast-feeding, the initiation of weaning foods, and current infant diets are related to household income and female employment status, as well as to a number of social and cultural variables covering maternal background, living conditions, knowledge and attitudes, and exposure to formula promotion. The impact of government maternity protection legislation is briefly outlined.

The Field Study

Sample households were systematically selected from four urban wards on the basis of a preliminary census. The sample consisted of 219 mother-child pairs, distributed more or less equally over the four sub-groups resulting from subdivisions by income and employment status (table 1). High-income households were defined as those with a total monthly income of over Tshs 2000/-, roughly three times the official minimum wage at the time of the survey. Women were defined as employed when engaged in some form of formal wage earning. The others were termed housewives for want of a more convenient term. Contrary to expectation, so few informally employed women were identified that they could not be considered as a separate sub-group.

TABLE 1. Composition of the Sample

  Low-income High-income Total
Employed 53 55 108
Housewives 77 34 111
Total 130 89 219

Because low-income employed women were few in the area-based sample, their number had to be supplemented by selection from factories to fulfill objective of having four subgroups of comparable size. As a result, the composition of the sample does not reflect the proportions of those subgroups in the population at large.

Household interviews ware conducted by Tanzanian university students. They were based on a formal questionnaire covering feeding habits, employment conditions, economic status, living conditions, knowledge and attitudes, health-related behaviour, and how women allocate their time. In addition, in-depth studies were conducted in 28 households over a four-week period to obtain detailed activity and feeding records, as well as to gain some insight into the social background of behaviour and attitudes relevant to infant feeding. The household information was put into perspective by background data obtained from site visits to hospitals and retail outlets, key informant interviews, group discussions, and a number of supporting studies covering demographic aspects, health care, female employment conditions, maternity legislation, and the structure of the formula market (2).

In designing the sample, care was taken to assure similarity of the sub-groups in terms of maternal age, as well as number, sex, and age of the index children. The children were evenly distributed over the 0 to 24-month age range, while a few slightly older children were retained.

A few descriptive characteristics of the sample households have been summarized in table 2. A strong association between income level, employment, and marital status is apparent. Single women were more common in the low income group (23 per cent) than in the high-income group (9 per cent). Among the low-income employed women, 41 per cent were single, while only 5.5 per cent of the high-income employed were unmarried. A strong association was also found between education, employment, and income level. Low-income women very rarely had more than primary education, and often less. High income women often had secondary or university education, and rarely less than complete primary education. In both income groups, education clearly promoted employment opportunities.

The variation in social conditions between the sub-groups is also apparent from the interrelations between house. hold size and dependency ratio. Although high-income households are larger, they have a lower dependency ratio than low-income households. This is because high-income households often accommodate relatives who are working or studying in town, some of whom contribute to the household income. Low-income households can rarely afford to harbour relatives, who in any case would be unlikely to contribute to the household income.

The Effect of Income and Employment Status on Feeding Practices Breast-feeding. The start on breast-feeding was found to be strongly influenced by the conditions at the place of delivery. Of the index children, 9.6 per cent were born at home, 58 per cent in government hospitals, 15 per cent in private hospitals, and 17.4 per cent in smaller health units. Low-income women generally deliver in government hospitals, where rooming-in is standard and artificial feeding discouraged. Ninety per cent of the low-income group said they had started nursing within 24 hours after delivery. High-income women often give birth in private units for which they pay fees, where rooming-in is not general and bottle-feeding is routine. Such women reported a slower initiation of breastfeeding: only 64 per cent had started within 24 hours.

About one-third of the mothers experienced various minor problems with breast-feeding, but only six per cent breastfed for less than three months. Of these, half were Asian women (i.e., women of Indian origin) who are well represented among high-income households, and on the whole are more inclined towards artificial feeding than African mothers are. Only two women in the sample did not breast-feed their babies at all. As most of the children were currently breast-fed at the time of the survey, few data were obtained on the total duration of breastfeeding. From the available information, it appears that low-income women, on average, continue longer than high-income women (table 3). With six months as a cutoff point, the difference is statistically significant. Employment status seems to have a minor effect. Among low-income women there is hardly any difference between the employed and the housewives. Unemployed high-income mothers tend to stop even earlier than the employed. This dispels the notion they employment as such necessarily interferes with the duration of breastfeeding.

TABLE 2. Summary of Household Characteristics

  Low-income High-income
Employed Housewives Employed House wives
Single Women (%) 41.5 10.4 11.3 5.5
Household size 5.9 5.6 6.7 7.2
Dependency ratio 2.3 3.7 1.7 3.2
Education of mother        
< primary level (%) 26.4 70.1 0.0 27.7
secondary level (%) 5.7 1.3 77.3 25.0

TABLE 3. Duration of Breast-Feeding by Income and Employment Groups

Duration (months) Low-Income High-Income Total
Employed Housewives Employed Housewives
0-6.* 14.3% 14.3% 47.6% 64.3% 35.5%
7-12 21.4% 14.3% 30.0% 21.4% 22.8%
13-18 50.0% 52.4% 20.0% 7.1% 31.6%
>18 14.3% 19.0% 3.3% 7.1% 10.1%
N = 14 21 30 14 79

* At six months the difference between income groups is significant: X-square = 10.7; P < 0.01.

On the other hand, the duration of exclusive breastfeeding was found to be influenced by employment status rather than income (table 4). High-income women introduce supplementary foods earlier, but the low-income employed catch up before three months, the end of the legally enforced maternity leave period. At that point the difference between employed and unemployed mothers was statistically significant, while the difference between income groups was barely so.

TABLE 4. Percentage of Children Receiving Supplementary Foods in the First Three Months

  Low-Income High- Income Total
Employed 82.0 83.0 82.5
(50) (47) (97)
Housewives 47.8 69.6 53.3
(67) (23) (90)
Total 62.4 78.6 68.4*
(117) (70) (187)

Statistical significance: between employment groups:
X-square = 17.0; P < 0.001; between income groups: X-square = 4.6; P < 0.05 (Numbers in brackets).

Infant feeding. Infant diets consisted of various combinations of breast-milk, formula milk, and other foods. Maize porridge was by far the most common supplementary food in all age groups. More than half of the children were given maize porridge before the age of six months, and one in four received fruit juice, mainly orange juice. Formula milk was used by slightly over half of the index mothers for children of this age, more often in the high-income group. Fruit juice and glucose were also mentioned more often by high-income women. After six months the children were increasingly fed mixed foods from the family pot, mainly cereals with a sauce of meat, fish, or vegetables.

Almost one-third of all mothers stated that they had used formula milk as a first weaning food. High-income women had done so more often than low-income women, and the employed more often than the housewives. The difference between income groups was small, and that between employment groups only significant among low-income women. It appears that low-income employed women use formula milk as a first weaning food even more often than high-income employed women (table 5).

The use of milk formulas beyond a very early age was found to be significantly more common among the high income group (table 6). The difference between employment groups here was only significant at the low-income level, where unemployed women rarely use formula milk. Income is obviously a major constraint here. Low-income employed women are somewhat dependent on artificial feeding because of their absence from home, but our data indicate that, while in the high-income group the use of formulas increases with age, low-income women often initiate formula feeding but soon abandon it.

The use of feeding bottles was reported by 83 per cent of high-income, and 49 per cent of low-income women. In both groups it was more common with the employed.

TABLE 5. Percentage of Children Receiving Formula Milk as a First Weaning Food

  Low-Income High-Income Total
Employed 48.8 32.6 40.2
(43) (49) (92)
Housewives 15.0 34.5 21.3
(60) (29) (89)
Total 29.1 33.3 30.9.*
(103) (78) (181)

The difference between employment groups is significant in the low-income group: X-square = 12.3; P < 0.001 (Numbers in brackets).

Those who use formula milk invariably also use bottles. However, some of the same women feed other liquid foods (tea, juice) from cups, demonstrating the lack of a real need for the feeding bottle. But the mental association of formula and bottle is strong. Ironically, locally manufactured feeding bottles became generally available around the time of the study, although milk formulas were not.

TABLE 6. Prevalence of Formula Milk in Infant Diets (%)

  Low- Income High-Income Total
Employed 30.2 47.3 38.9
(53) (55) (108)
Housewives 13.0 52.9 25.2
(77) (34) (111)
Total 20.0 49.0 40.0.*
(130) (89) (219)

*Statistical significance: income groups X-square = 4.9; P < 0.01; employment groups X-square" 4.9; P < 0.05 (Numbers in brackets).

Social and Cultural Variables

Of the 50-odd social and cultural variables investigated, many showed no significant associations with infant feeding behaviour. The following is a brief summary of those that were found to be relevant, in particular to the choice for or against formula milk.

Mother's background. No significant associations were found with maternal age, tribal background, religion, place of birth, or length of stay in town. Level of education was associated with the current feeding pattern, but not with the start of weaning. An inverse relationship was found between level of education and breast-feeding: both among housewives and employed women, those with more education were inclined to an earlier termination of breast-feeding (table 7), and were also more likely to use formula milk. This finding has to be seen in the context of the interrelations among education, employment, and income.

Economic status and living conditions. Our sample house holds displayed a wide range of economic and living conditions, with concomitant differences in social security and hygienic circumstances. There is no doubt that style of living and the ability to cope with adverse conditions are pervasively influenced by household income, the level of which primarily depends on the type of occupation of the head of the household. Those in the low-income groups were engaged in manual labour, the service sector, and lower level professional jobs, whereas heads of high-income households were in higher and middle level professional, clerical, and managerial jobs. In addition to higher salaries, the latter often had access to various side-benefits such as housing and company transport.

A number of variables related to living conditions of the household correlated with both the start of weaning and current feeding practices. These were expenditure on food, type of house, the number of rooms, the type of water supply, and sanitary facilities. All of these directly depend on income level. Of special interest was the association between the use of formula milk and the presence of a refrigerator. The latter is a status symbol par excellence, but, more importantly, in a hot country the safety of artificial feeding is greatly improved if milk can be stored in a cool place.

Knowledge and attitudes. One of the main concerns of the study was the influence of formula promotion on mothers' perceptions, attitudes, and feeding practices. A distinction was made between direct promotion by means of advertisements, free samples, and spread of information, and indirect or soft informational and attitudinal aspects reflected in opinions about the desirability of certain infant foods and feeding practices.

The promotion of infant formulas has been officially discouraged in Tanzania for a number of years. Moreover, the economic situation of the country has severely restricted the imports of commercial infant foods. No advertisements are heard on the radio or seen in government hospitals, and no free samples are channeled through the government health services.

TABLE 7. Duration of Breast-Feeding by Level of Education(%)

  Primary Education Secondary Education
Employed Housewives Employed Housewives
Duration (Months)        
0-6 30.0 30.0 43.5 75.0
7-12.* 15.0 16.7 34.8 -
13-18 40.0 43.3 21.7 -
> 18 15.0 10.0 - 25.0
N = 20 30 23 4

*The difference between education levels is significant, with 12 months 85 a cut-off point: X-square = 6.0; P < 0.02.

Nevertheless, almost one third of the index mothers reported that they had been directly exposed to advertisements for formulas. The majority of those who did, mention Lactogen, which was also rated the most preferred brand. Lactogen has dominated the market in Tanzania for a long time, and was forcefully promoted in past years.

Advertisements from milk companies are still retained as wail decorations in private hospitals, and free samples are occasionally distributed via that channel. Site visits at health institutions revealed clear differences in administrative practices. In private hospitals there are no rooming-in facilities, and infant formulas are used indiscriminately in the neonatal ward. In government hospitals infants stay with the mother and breast-feeding is on demand. When inevitable, formula milk is fed by cup or tube. Women who delivered in private health units had significantly more often been in contact with direct promotion and specific instructions regarding the use of formula milk than other mothers had.

Thus, it is not surprising that the birthplace of the child appeared to have an impact on feeding practices. Children born in private hospitals received supplementary foods earlier, and much more often these consisted of formula milk. Such children were more often breast-fed for less than six months. However, these differences approached statistical significance only among the high-income unemployed because low-income women very rarely give birth in private hospitals. The high-income employed are induced to early weaning and formula feeding by the demands of their jobs regardless of where they give birth.

Yet, a preference for artificial feeding and early weaning was also expressed by some of the low-income women who had not been directly exposed to advertisements. Such views appear to be a relic of past promotional inputs transmitted by word of mouth and filtering through from the higher to the lower socio-economic stratum. The presence of sizeable Asian and European communities may also play a part. On the other hand, it should be borne in mind that traditional concepts of infant feeding sometimes include notions about early supplementation of breast-milk. No doubt there is a constant flow of ideas and secondary information about such matters in society, but this is difficult to document because of its diffuse, informal nature.

Government Legislation in Support of the Working Mother

Maternity protection legislation in Tanzania provides for 84 days of paid maternity leave once in three years, irrespective of marital status. Our data show near total compliance with this law. In the few cases where employed women had not been granted paid leave it was usually because less than three years had passed since their previous maternity leave. A small number of cases dated back to the time when this leave was restricted to married women. However, our sample included a few cases in which a breach of the law was most likely to occur: in marginally institutionalized occupations such as bar workers and domestic servants.

The law also ensures the right of working mothers to take two half hour nursing breaks a day to feed their babies. This provision cannot easily be put into effect because creche facilities are rare at work-places, and the distance from home is often far. Day care centres care for older children, and only women with access to private transport are able to take advantage of the short breaks. Of 94 respondents, only 11 said they had a chance to breast-feed during office hours.


In this summary article, only a few aspects of the study could be presented. The detailed analysis of variables was not an end in itself, but instrumental to a better understanding of the factors influencing infant feeding practices, to provide guidelines for government policy making. Although less advanced than elsewhere, the trend towards artificial feeding is also present in Dar es Salaam, but could perhaps be curbed by appropriate action.

Because of the lack of a major industrial focus, urbanization in Tanzania has started late. Currently about 10 per cent of the population live in urban centres. Even Dar as Salaam retains a distinctly rural touch. Women often return to their home villages for delivery and spend most of their maternity leave there. Alternatively, relatives may come from the rural area to assist the mother after childbirth. All this encourages the persistence of traditional patterns of child care and feeding. Nevertheless, the dependence on commercial infant foods is already very real in certain sectors of the population. In a group discussion, employed women emphatically expressed the hardships they faced because of the scarcity of baby foods. They have to go to great lengths and pay exorbitant prices to obtain any at ail. In view of this, generalized warnings about the dangers of bottle-feeding are obviously ineffective. As long as formula milks are scarce, their use will be limited by economic factors. In the long run, a well considered national policy will be needed to avoid the adverse side effects of artificial feeding.

The importance of our study lies not so much in the documentation of the negative effects of formula milk promotion on infant diets, which was more clearly evident in the parallel studies in Sao Paulo and Colombo, but in the more refined picture it presents of the conditions surrounding women's lives in a Third World town. Economic and social conditions make it impossible to transfer the Western ideals of female employment and unhampered opportunity to breast-feed without adapting them to the local situation. Women can only be persuaded to change their practices if they perceive this as desirable for themselves or their children, and possible within the context of their lives. The prevailing conditions in Dar es Salaam make the combination of employment and motherhood strenuous, and hardly possible without recourse to some form of non-human milk feeding. Cow's milk being in very short supply, mothers avidly turn to whatever; other milk products are available. It does not help to dismiss such solutions imposed by circumstances, as one member of the project team suggested. There are very real contradictions between the goals of Western activists and the needs of Third World women facing the hard realities of life. Whoever seriously wants to improve those realities cannot avoid facing this contradiction.

In trying to document the current situation and associated factors, our study concentrated on the respective effects of income and female employment status. The findings indicated that overall socio-economic level, epitomized by total household income, is the dominant factor influencing material conditions and feeding practices. Therefore, conditions surrounding the mother-child dyed cannot be isolated from those facing the household and social group. The material and social support mobilized on the basis of social networks was found to be an important source of security, depending to a large extent on where one stands in the social and economic continuum.

Women in Third World societies function as individuals to a lesser degree than in the West. Their behaviour is very largely conditioned by the social groups to which they belong, and from which they have little freedom to withdraw. We came across many instances where women drew on family and neighbourhood groups for support in the struggle for survival. Perhaps the most important factor is the quality of marital relationships. Marital instability is a frequent cause of social and financial insecurity, leading to an emotional instability that may result in erratic child care. Conversely, the social position of the husband in many cases gives the mother access to resources she would not have had otherwise.

Social status was also found to influence the choice of the health care facility for delivery. The practices followed in the maternity wards are one of the strongest influences on the choice of feeding methods. An association was found between the feeding pattern and first food supplements with subsequent feeding. Those who give supplements early also stop breast-feeding early. Those who give formula milk tend to continue doing so. It appears that the start of food supplementation (at what age and with what foods) is the most crucial decision in the whole feeding process.

Thus, there appears to be a typical sequence from a hesitant start of breast-feeding to early supplementation, and early termination of breast-feeding. However, this is not a simple causal chain, but a complex syndrome. Both the start of weaning and current feeding practices have highly significant associations with income level, while the start of supplementary feeding is also associated with employment. Income and employment conditions influence the choice of the health care facility for delivery, the initiation to weaning, and the subsequent feeding pattern.

An inverse relationship was found between breast-feeding and bottle feeding. Bottle-feeders tend to use formulas as the first supplement, and do so at an earlier age. Among families with formally employed mothers, infants who were given formula milk as a first supplement all received less than three months of exclusive breast-feeding. There is also a tendency towards shorter total duration of breastfeeding.

No evidence was found that a mother's employment as such was conducive to shorter breast-feeding, although it encourages earlier supplementation. The maternity protection legislation is relatively progressive. Extension of the paid maternity level has been proposed by some, but serious questions may be raised about its feasibility in view of the present state of the economy. It may even be counterproductive by motivating employers to hire male workers instead of females. It should also be realized that formally employed women constitute only a minute section of the population. No system of formally recognized maternity leave can be envisaged for the mass of rural women, who usually do more physically exhausting work than the urban employed.

As nursing breaks during work hours tend to remain ineffective, a better alternative would be to allow nursing mothers a shorter work day, enabling them to return home earlier. Creches at workplaces seem an attractive solution, but are beset with practical problems. An experiment carried out at the Tanzania Food and Nutrition Centre showed that women are reluctant to bring very young babies. The main reasons are the hazards and inconvenience of travelling to the workplace by public transport with a small baby, and mothers' reluctance to leave their babies under the care of attendants over whom they have no control.

In view of the public demand for infant formulas, and the real need for them in a few cases, a total ban appears neither feasible nor desirable. Those who have become dependent on formulas will continue to procure them by any means. Government policy should aim to maintain the still high rate of breast-feeding by creating the best possible conditions for nursing women, and reducing as much as possible the negative effects of formula feeding There is no easy, clear-cut prescription for doing this.

It is felt that the official attitude against formula promotion, and the restriction of imports of baby foods, are beneficial and should be maintained. There are inconsistencies at the policy level, however, because preparations to establish a formula milk factory in Tanzania itself have reached an advanced stage. The local production of feeding bottles is also a sore point, especially since it began at the very time when awareness of the dangers of bottle feeding was growing. Since the time of our survey, private medical practice has been officially abandoned in Tanzania, although it continues in institutional disguise. It should be possible to put some pressure on private maternity clinic personnel by at least making them aware of the implications of their management of neonatal feeding.

The importance of encouraging breast-feeding should be stressed in the curricula of medical training schools at all levels, to make the health care delivery system instrumental in the promotion of breast-feeding. Generally, more attention should be paid to the role of nutrition in the aetiology of diseases of both women and children.

A secondary finding in our study was that the knowledge about home preparation of weaning foods leaves much to be desired. Improvement of both home-made and commercially produced weaning foods in necessary, as well as education on proper feeding practices. The Tanzania Food and Nutrition Centre has meanwhile undertaken further work on this matter. Thus, there are a number of practical actions possible that would serve the goal of reinforcing or restoring adequate infant feeding practices without involving large financial commitments. The current economic and ideological climate in Tanzania provides a favourable matrix for such actions.


The authors gratefully acknowledge the contribution of the whole project team to the Tanzania country study, in particular those of the methodology coordinator, Dr. Thomas Marchione. However, the views expressed in this paper are not necessarily shared by all team members.


1. T.J. Marchione and E. Helsing (Eds.), Rethinking Infant Nutrition Policies Under Changing Socio-Economic Conditions. Interim report of IUNS-Sponsored Task Force. IUNS Publication No. C36 (1980), Xerox, 107 pp.

2. T.J. Marchione and E. Helsing (Eds.), Results and Policy Implications of the Cross-National Investigations: Rethinking Infant Nutrition Policies Under Changing Socio-Economic Conditions. Project report of IUNS Sponsored Task Force. IUNS Publication No. C41 (1982), 97 pp.


Life table analysis of birth intervals for Bangladesh

M. Kabir and A. J. M. Sufian
Department of Statistics, Jahangirnagar University, Savar, Dhaka, Bangladesh


In nutrition field studies the relationship between maternal and child nutrition, infant mortality, and birth interval is often of interest. Infant mortality and hence birth interval is heavily dependent on the nutritional status of the infant The life table approach employed in the following paper is seldom used, but has distinct advantages for some nutrition field studies.


In recent years the study of birth intervals has acquired added importance because of its relationships to fertility. The mean duration of successive birth intervals is obviously related to the fertility rate; the longer the interval, the lower the fertility. The relation between these two measurements of the same phenomenon is, however, far from simple (1). There are two aspects to the family building process. The first is the parity progression ratio, which is related to the quantum of fertility, and the second is the time it takes to make the transition from one parity to the next for those who continue reproduction, or the distribution of birth intervals, which is related to the timing or tempo of fertility. The main objective of this study is to present the pattern of birth intervals through life table techniques; all data used here are from the Bangladesh Fertility Survey (BFS), conducted in 1975 as part of the World Fertility Survey Programme (WFS)*. The basic principle under-lying the analysis of birth intervals is to view the family-building process as a series of stages where women make the transition from marriage to first birth, from first birth to second birth, and so on until they reach their completed family size.

The Data

Ever-married women between the ages of 15 and 49 years were selected with equal probability so as to yield a self weighted sample of women. In all, 6,515 eligible individuals were interviewed in detail regarding their maternity and marriage histories, knowledge and use of contraception, fertility intentions and preferences, and socio-economic background. The sample was selected by a three-stage sample design. The sample selected represents the country as a whole and allows separate estimates according to various socio-economic characteristics.

The primary problem in analyzing birth history data from developing countries is the accuracy of reporting. Different errors may affect the data and lead to false conclusions. The direction and magnitude of the error are influenced by the number of births displaced by women from one period to another and the total number of children born to them. The tendency for the proportion of both births and deaths that are not reported to increase with the age of the mother is well established (2). Brass has recently documented some of the possibilities for detecting error in birth history (3). According to him, most retrospective survey data are deficient because of faulty declarations about children ever-born and children who died. The magnitude of the deficiency increases as the respondents report farther into the past. In addition to this, birth history data may contain erratic errors and biases in the timing and location of births and deaths. The Bangladesh birth history data are of doubtful quality. Dating of birth has been found to be incomplete, with 85 per cent of dates given in years ago: 3 per cent are reported as year only with the month missing, and 12 per cent report the calendar month and Year (4). However, completeness of date reporting is no guarantee of accuracy because of the unknown amount of interviewer estimation and the possibility of digit preferences and more systematic respondents' errors in the dating of events. There are also reasons for believing that maternity histories frequently suffer from event displacement, particularly in the form of a concentration of births prior to the survey. Detailed analysis confirms that displacement of dates of birth is more prevalent than omission of births (4).

Life Table Analysis of Birth Intervals

Life table analysis of birth intervals is not new, However, the method has rarely if ever been systematically used. The WFS enquiry provided a large body of data and thus opened up the possibility of applying the technique more comprehensively. The life table method calculates the probabilities that women who could give birth at the beginning of a month actually do so. The standard life table measures are derived from the series of conditional probabilities. When there is a truncation the life tabir will be incomplete, in the sense that more women will attain the given parity at a later date. Moreover, a full set of life table estimates for every birth interval is a large number of indices that must be summarized for discussion and interpretation. The methodology for constructing life tables from maternity history data is described by Smith (5). The basic information required to construct a life table is a cross tabulation of an ever-married woman by duration of exposure and termination status. By duration of exposure we mean the interval from marriage to either first birth or interview, whichever comes first. By termination status we mean a variable indicating whether exposure was terminated by the lack of further observation or by the first birth. The measure used to estimate the quantity of fertility is the birth function Bx, which stands for the cumulative proportion of women having a subsequent birth by duration x months since the previous birth. We examined Bx in detail and found that the proportions having a birth four, five, and six years later are suitable measurements for adequate description of the results. However, the data from marriage to first birth are quite insufficient for Bangladesh. Since age at marriage is very young, the first birth interval is unusually longer in Bangladesh. Even after six years of marriage, only 70 per cent have had their first child. Besides first births, 90 to 95 per cent of higher order births occurred within six years and the data were available for most tables. We thus conclude that six years is the most suitable indicator of the quantum of fertility. The search for two or three summary measurements that conveyed most of the information contained in the life tables emerged in the choice of B72 because of its availability in most of the tables. Rodriguez and Hobcraft (6) suggest that for each birth interval three summary indices are quite adequate for the interpretation of results: the proportion of women having subsequent births within six years (B72), and the trimean and the interquartile range distribution of intervals to births occurring over the six years.

The trimean is defined as:

(see reference 7) where q1, q2, and q3 denote the quartiles of the standardized distribution derived by standardizing the birth function to make B72 = 1. The inter-quartile range, or the spread: S = q3-8. These indices broadly measure the quantum, average timing, and spread of timing of the movements towards the next birth. From the estimated standardized quartiles, many statistical parameters in addition to those above can be derived for discussion and interpretation of the results, as for example, the median, M= q2 (7).

Table 1 shows an abbreviated life table for interval between first and second births. From this table we find B72 = 0.9331. To derive the standardized quartiles (i.e., q1 q2, and q3) we require the duration by which the cumulative proportions having a second birth within six years of the first event are 0.23333, 0.4666, and 0.6998 (these values being 25, 50, and 75 per cent of 0.9331). The quartiles can be estimated by simple linear interpolation. For example, the first quartile is found by linear interpolation between durations 18 and 24 months as q1 = 20.8 months. Similarly, q2= 29.4 and q3= 40.1. The trimean is thus T = 29.9 months and the spread is 19.3 months. Thus, about 93 per cent of Bangladeshi women have their second child within six years of the first child, with an average birth interval of 30 months and a spread of about 19 months. As is evident from table 2, the proportion of women having a subsequent birth by each duration remains almost stable up to the fourth birth and then declines gradually.

Most of the differences are captured by the birth function (B72), which ranges from 93 per cent for the second birth to 88 per cent for the sixth birth. The mean birth interval is about 29 months and is almost the same from second birth order to the sixth birth order. The first birth interval is high (about 36 months), because women marry at so young an age in Bangladesh. Similarly, the spread of the distribution is about 18 months and is approximately the same for all birth orders. These results reveal the differences in the distribution for first birth intervals compared with other order of births. The other birth intervals are more or less homogeneous. The results also suggest that after the birth of the first child, family size does not seem to have any effect on subsequent birth and timing of the next birth.

TABLE 1. Abridged Life Table for the Interval between First and Second Birth

Duration of Exposure (Months) Number of Women at Risk Number of Births Omitted Cumulative Proportion Who Gave Birth
0-3 5,304 0 56 0
3-6 5,252 0 52 0
6-12 5,128 131 40 .0359
12-18 4,624 334 57 .1561
18-24 3,798 421 41 .3257
2436 2,002 304 28 .6415
3648 937 116 19 .8150
48-60 491 57 9 .8947
60-72 275 21 6 .9331
72-84 180 17 11 .9522
84-96 123 5 2 .9630
96- 108 96 3 0 .9692
108-120 75 3 2 .9745
120-132 59 1 0 .9782
132 + 55 0 1 .9787

The Effect of Age at Marriage on Birth Interval

We have shown that first birth interval is longer in Bangladesh than in many populations. In this section, an attempt has been made to examine this more incisively by controlling the age at marriage, i.e., < 15 and 15+years. The results are shown in table 3.

It is evident from the above tables that birth interval is higher for those who married when less than 15 than for those who married at age 15 and older. Thus, most of the difference in the first birth interval is due simply to the longer reproductive life of women marrying early. The proportion of women married before age 15 who had a first birth within six years of marriage was 0.70 compared to 0.90 for those who married at age 15 and older. Most of this difference in the first birth interval by age at marriage can be attributed to the adolescent sub-fecundity and adolescent sterility. Delay of consummation or irregularity of sexual intercourse for women marrying early is another possible explanation of why the first birth interval is longer than usually expected. Delay of consummation in Bangladesh is generally associated with the fact that the girl, although married in most instances, has not reached menarche. Age at marriage has a pronounced cohort effect on the timing of the first birth, with the trimean being nearly 56 months for women marrying before age 15 compared with 25 months for women marrying at age 15 and above. This difference in the timing of first birth is also revealed by the proportion of women having the first birth since first marriage.

As we move to a higher order of births, the effect of age at first marriage is minimal, since there is no significant difference in the trimean (see table 3). In fact, the trimean varies from 28.5 to 29.2 months.

TABLE 2. Summary Measurements of Birth Intervals

Summary Measurement Birth Order
1 2 3 4 5 6
B12 .0836 .0359 .0393 .0417 .0429 .0364
B36 .2312 .6415 .6443 .6412 .6182 .6178
B60 or Quantum (P) .6152 .8947 .8918 .8878 .8678 .8451
B72 .6943 .9331 .9334 .9208 .9051 .8805
Trimean (T) 35.4 29.9 29.6 29.5 29.5 29.4
Spread (S) 30.2 19.3 19.6 19.3 19.7 19.2
No of cases 6,009 5,304 4,497 3,766 3,113 2,499

TABLE 3. Summary Measurements of Birth Intervals by Age at Marriage

Summary Measurement Age at Marriage
< 15 Birth Order 15+ Birth Order
1 2 3 1 2 3
B 12 .0836 .0349 .0401 .1960 .0407 .0341
B24 .2212 .3241 .3418 .4402 .3345 .3275
B72 .7044 .9328 .9279 .8941 .9556 .9208
q1 20.1 21.0 20.6 13.0 20.2 20.8
q2 36.0 28.5 28.1 24.0 27.8 28.9
q3 50.6 38.9 38.4 37.7 38.0 38.9
Trimean (T) 35.7 29.2 28.8 24.7 28.6 29.4
Spread (S) 30.5 17.9 17.7 24.7 18.3 18.0
No. of cases 5,043 4,404 3,823 1,181 900 674

Birth Intervals by Some Selected Socio-Economic Characteristics

In this section we investigate the effect of some selected socio-economic characteristics on the quantum and tempo of fertility. For our analysis here we consider variables, namely by type of place of residence and level of education, as measured by years of schooling. These two are the important determinants of fertility. Table 4 shows the summary measurements of birth intervals by place of residence and level of education as well as by religion. For the first birth interval we find a higher mean for rural areas than for urban areas (40 months as against 35 months!.

This difference can be explained in terms of difference in the age at marriage between the two areas. As we move on to the higher order of births, we find no significant difference in trimean, although there is evidence that trimean is slightly lower for urban areas for the higher order births compared to rural areas. A similar conclusion can be reached for the two religious groups (Moslem and Hindu women).

We examine the effect of education on birth intervals by constructing life tables by birth order separately for three educational groupings: No schooling, one for four years of schooling, and five or more years of school. These results are also summarized in table 4. Women with no schooling show a slightly higher mean than women with some education or five and more years of school. After the birth of the second child, however, women with higher education begin to show a lower fertility than women with less than five years of schooling. The group with no schooling shows a similar pattern to those with some education, suggesting that a few years of schooling have little effect on subsequent fertility. Examination of the trimean demonstrates that there is no systematic educational differential in the timing of fertility. The question may arise as to whether the observed educational differences in the quantum of fertility can be partly explained by the age of the women at the start of each interval. For instance, the more educated women tend to marry later, and will therefore be relatively older than women with no education by the time they reach the second birth, a fact that should decrease the proportion having a third birth within six years.

TABLE 4. Summary Measurements of Birth Intervals by Socio-Economic Characteristics

Summary Measurements Socio- Economic Characteristics
Residence Education Religion
Birth Order
Birth Order
Birth Order
1-5 Years'
Birth Order
5 Years'+
Birth Order
Birth Order
Birth Order
2 3 2 3 2 3 2 3 2 3 2 3 2 3
B12 . 041 .044 .031 .039 .037 .038 .030 .057 .032 .025 .035 .037 .041 .051
B24 . 366 .363 .240 .338 .321 .336 .327 .343 .372 .370 .326 .337 .334 .359
B72 .925 .917 .934 .928 .932 .925 .930 .936 .951 .948 .934 .930 .939 .922
q1 19.1 19.4 20.8 20.9 21.0 23.8 20.8 19 9 20.3 20.8 20.9 20.8 20.4 20.1
q2 27.3 26.9 28.4 28.4 29.4 28.4 27.9 28.4 27.7 26.9 28.4 28.3 28.2 28 0
q3 38.0 37.4 38.3 39.0 38.8 38.5 38.5 38.9 38.9 37.8 39.1 38.4 37.7 39.0
Trimean (T) 27.9 27.6 29.2 28.9 29.7 29.6 28.7 28.9 28.7 28.1 29.2 28.9 28.6 28.7
Spread (S) 18.9 18.0 18.1 17.1 17.8 15.3 17.7 18.9 18.6 17.0 18.1 17.6 17.4 18.9
No. of cases 420 349 4,274 4,147 4,203 3,622 592 489 441 339 4,385 3,729 854 717

Cohort and Period Effects

We examine the experience of birth intervals of different cohorts of women using life tables by birth order constructed separately. The results are summarized in table 5. Examining the interval from marriage to first birth, we see that the older cohorts have experienced their first birth with a longer duration compared to younger cohorts. For instance, the trimean for the cohort 20 to 24 is 34.0 months compared to 40 months for the cohort 45 to 49. This may be due to the changing pattern of age at first marriage. Surprisingly, the difference in the trimean for different cohorts becomes insignificant when we compare second and higher order births.

We examined period effects by calendar period. Since the survey occurred in 1975, women in the most recent period have been exposed to the risk of having another child for a shorter period. Thus, the most recent period represents an incomplete experience. Here we find no trend over time in trimean except in transition from marriage to first birth. The trimean is the same for both the periods. The average length of the third birth interval has changed by two months between the periods 1960-1964 and 19651969. These results must be viewed with caution because there is a possibility of the effect of selectivity in retrospective period data. As we move farther back in time we are faced with a progressively younger group of women. The birth intervals for past periods are based on women who, on average, were comparatively younger at the beginning of the interval. Since comparatively young women are more likely to have another birth within a short interval, may yield a spurious time trend.

The Effect of Infant Mortality on Birth Interval

Among many factors that can contribute to the wide variations in completed family size, infant mortality is considered to be one of the important factors in the variation of natural fertility. In societies where breast. feeding is common and extends for more than a few months, its ovulatory suppressant effects result in longer average birth intervals to the next birth if the previous child survives the breast-feeding period than if he dies therein (8; and A.K. Jain, "Lactation and Natural Fertility," paper presented at a Seminar on Natural Fertility, Paris, 1977)

In order to examine this more incisively and to assess the magnitude of the effect of infant mortality on fertility, we have constructed life tables by birth order according to whether or not the previous child survived the first year of life. The results are presented in summary form in table 6. It is evident that for each of the birth orders, the death of the previous child within the first year of life increases the proportion of women who go on to have another child within six years and reduces the waiting time before the next birth. The death of the first child in the first year of life reduces the average birth interval from 30.8 months to 24.1 months. Similarly, the death of the fourth child increases the proportion of having a fifth birth within six years from 92 to 94 per cent and reduces the average interval by 3.6 months.

TABLE 5. Summary Measurements of Birth Intervals by Cohort and Period

Birth Order Summary Measure meets Cohort Period
20-24 25-29 30-34 35-39 40-44 45-49 1960-64 1965-69
1 B12 .1031 .0867 .0731 .0838 .0616 .0438 .0921 .1044
B24 .2645 .2410 .1899 .1881 .1431 .1312 .2387 .2581
B 72 .7784 .7672 .6838 .6491 .6247 .5067 .7130 .7887
T* 34.3 34.5 36.6 36.2 38.9 40.2 33.8 33.7
S** 21.7 31.2 29.1 35.5 29.8 32.1 30.7 29.5
2 B12 .0325 .0333 .0291 .0214 .0190 .0225 .043 .044
B24 .3257 .3629 3132 .2888 .3020 .2493 .358 .387
B72 .0343 .9515 .9461 .9369 .9197 .8991 .953 .938
T 29.4 30.1 28.7 29.2 28.5 31.5 27.5 27.3
S 19.1 20.5 16,9 16.4 17.5 20.2 15.9 17.9
3 B12 .0337 .0310 .0361 .0287 .0339 .0218 .034 .049
B24 .2974 .3768 .3343 .3146 .3331 .2743 .395 .346
B72 9197 .9498 .9375 .9386 .9101 .8845 .953 .923
T 28.2 27.5 28.0 29.4 29.4 30.1 26.8 29.0
S 18.5 17.5 16.1 18.6 20.0 17.5 15.1 19.0

* T = trimean.
** S = spread.

TABLE 6. Birth Interval by Survivorship of Previous Child

Birth Order Summary Measurement Survivorship Status
Survived Died in First Year
2 B72 930 .944
  T* 30.8 24.1
3 B72 .931 .958
  T 29.0 26.8
4 B72 .922 .938
  T 28.8 25.2
5 B72 .907 .920
  T 29.1 25.7
6 B72 .872 .904
  T 28.6 24.3

*T = trimean.


The results presented here reflect the pattern of the family-building process into a series of stages, including marriage and births of successive orders, and investigates the transition from one stage to another. In Bangladesh, age at first marriage is a poor indicator of entry into risk of childbearing and therefore the inclusion of marriage as the first stage in the process may yield doubtful results. In this situation, an analysis of age at first birth would have been more useful than analysis of the interval from marriage to first birth. Differentials in the quantum and tempo of fertility have been studied using life table techniques by birth order separately. The process of transition to each birth order has been examined in terms of birth function or cumulative proportion of women having a birth of a certain order by successive intervals since the previous birth, which was estimated using life table techniques.

Several findings reported here deserve comment. First, the first birth interval is consistently high in Bangladesh, possibly because of low mean age at marriage. In this situation, first birth interval can be studied by controlling age at marriage. There is, however, little difference in the birth intervals between second and higher order of births, although the quantity, i.e., proportion of women having a particular birth order, varies. In Bangladesh child mortality shortened median birth intervals. There is, however, a suggestion that mortality control programmes could reduce fertility through a biological mechanism. Better survivorship of infants would facilitate lactation and prolong the period of postpartum sterility and thus the birth interval (9). It is important to point out that this fertility reducing effect of better infant survival is more complex when viewed in terms of population growth rates. While fertility would be reduced, survivorship, a central element of net reproduction, would be improved.

From the perspective of a population replacing itself in the next generation, reduced mortality of infants would have dual effects: a reduction of fertility but better survivorship of those infants who are born. The outcome of these dual changes would result in a reduction of fertility but an overall increase in net reproduction (9). Perhaps the most important contribution of this study has been that overall birth interval is about 30 months. The birth interval is a useful measurement of fertility. Thus, future studies dissecting out actual components of birth intervals, such as postpartum amenorrhoea, the waiting time to conception, gestation, and the time required for foetal wastage would permit a more precise quantification of mortality effects on fertility.


1. L Henry, Human Fertility: The Basic Components (The University of Chicago Press, Chicago and London, 1973).

2. W. Bass, ''The Assessment of Validity of Fertility Trend Estimates from Maternity Histories'', Proceedings of an International Population Conference, International union for the Scientific Study of Population (IUSSP) Mexico City, August, 1977.

3. W. Brass, "Screening Procedures for Detecting Errors in Maternity History Data." Asian Population Studies Series No. 44, Regional Workshop on Techniques of Analysis of World Fertility Survey Data, Report and Selected Papers, Economic Commission for Asia and the Pacific (1980).

4. V.C. Chidambaram, "Some Aspects of WFS Data Quality: A Preliminary Assessment."Comparative Series No. 16,World Fertility Survey, London, U.K.lnternational Statistical Institute, Voorburgh, Netherlands (1980),

5. D. Smith, Life Table Analysis World Fertility Survey Bulletin No. 6, World Fertility Survey, London, U.K. (1980).

6. G. Rodriguez and J.N. Hobcraft, "Illustrative Analysis: Life Table Analysis of Birth Intervals in Colombia." Scientific Reports No. 16, World Fertility Survey, London, U.K. International Statistical Institute, Voorburg, Netherlands (1980).

7. J.W. Tukey, Exploratory Data Analysis (Addison Wesley Publishing, Reading, Massachusetts, 1977).

8. R.G. Potter, Jr., M. New, J.B. Wyon, and J.E. Gordon, "Application of Field Studies to Research on the Physiology of Human Reproduction: Lactation and Its Effects Upon Birth Intervals in Eleven Punjab Villages, India", in: Public Health and Population Change: Current Research Issues, M.C. Sheps and J.C. Ridley (Eds.) (Schenkman Publishing Company, Cambridge, Massachusetts, 1965).

9. Committee for International Coordination of National Research in Demography (CICRED), Seminar on Infant Mortality in Relation to the Level of Fertility, 6-12 May 1975, F.C. Madigan (Ed,) (CICRED, Cedex-14, Paris, France, 1975).


Food allergy and its clinical symptoms in Nigeria

Simeon C. Achinewu
Department of Food Science and Technology, Rivers State University of Science and Technology, Port Harcourt, Nigeria


The frequency of food allergies is not sufficiently appreciated because they are difficult to investigate. This is because the reactions are subjective and hard to verify. Almost all of the reported prevalence rates are from industrialized countries, and they vary from four to 30 per cent. The following paper indicates that food allergies must also be taken into account in nutrition advice in developing countries.


Adverse effects resulting from ingestion of certain foods have been recognized by rural Nigerian people for a long time. Some attributed these effects to poisoning by enemies, others to the anger of the gods, and only a few understood that they could have been caused by constituents in foodstuffs. Abnormal reactions to food may be the result of either food allergy or food intolerance. Food allergy can be defined as hypersensitivity mediated by one or more forms of immunological reaction to certain food components. This is different from intolerance induced by other mechanisms, such as lactase deficiency and milk intolerance (1).

A wide range of illness has been attributed to food allergy. For example, Dohan (2) has shown that psychiatric symptoms, including schizophrenia, could be caused by food allergy. The mechanism by which such adverse effects are mediated is not fully understood. The problems of food allergy are of great public health concern, and hence an investigation was initiated to identify some of the offending foods and the symptoms they cause.


A prepared questionnaire was distributed to fairly literate communities throughout the Rivers State of Nigeria. All age groups in all walks of life were covered. There was no attempt to interview equal numbers of age or sex groups. Individuals were given sufficient time to answer the quest tions asked on the forms. They were allowed to recount previous symptoms of food allergy from childhood, and how many times such food was eaten with definite adverse effects. Individuals were asked whether other family members, including parents, grandparents, children, and other relatives had similar reactions to the same food. Children's questionnaires were completed by their parents. The questionnaire sought to determine whether the reaction was immediate or prolonged, mild or violent, and whether any medical advice was sought. The criterion for confirming suspected allergy to a specific food was occurrence of symptoms more than three times in the same individual after eating that food.


In ail, 972 people responded to the questionnaire and 275 reported allergies to various foodstuffs. This represented about 28 per cent of total respondents.

Table 1 shows the various foods reported to cause allergic reactions. The figures represent the number of people who stated that they were affected by the particular food or food group, expressed as per cent of the total number of people affected by all foods. Foods of plant origin together caused more complaints of allergy than other foods did. This was followed by marine foods, which affected 14.7 per cent of the people. The 9.8 per cent who reported allergic reactions to milk and milk products were mostly children. Meat, especially pork, affected only 1.6 per cent, while eggs caused reactions in 5.4 per cent. Some people reported allergy to more than one food. About 5.2 per cent of those with food allergies reported that other members of their immediate families reacted to the same food in the same manner, an indication that allergic tendency may be hereditary.

TABLE 1. Various Foods that Caused Allergic Reactions

  Per Cent of Total
Marine foods 14.7
Cereals 11.4
Beans (including all legumes) 11.4
Vegetables 7.6
Tubers 9.8
Fruits 7.6
Plantain, banana, coconut 3.2
Mushrooms 2.7
Vegetable oil 1.1
Alcoholic drinks 5.4
Other beverages 4 9
Milk and milk products 9.8
Eggs 5 4
Meat (pork) 1.6
Snails 2.7

Table 2 shows the clinical symptoms and parts of the body affected. About 58 per cent had gastrointestinal symptoms. Some 17.5 per cent developed skin reactions, while the respiratory and central nervous systems were involved in 9.6 and 5.4 per cent, respectively. Fewer people complained of circulatory, muscular, ear, nose and throat, and eye or mouth symptoms.

Only a few of the people who suffered allergic reactions (less than 30 per cent) sought medical advice. The rest had local treatment or put up with the inconvenience. Many simply abstained from eating the offending foodstuffs. Some suffered the same symptoms when they unknowingly ate the food again.


Many different kinds of food caused allergic reactions, and affected various parts of the body. Similar findings have been reported by Denman (1) and Bender and Matthews (3). Several workers have associated other ill health with food allergy. For example, bed-wetting in a normal child over three years old was associated with a food allergy. Gerrard and coworkers (4) showed that the capacity of the bladders of such children to expand was severely restricted by swelling of all layers of the bladder wall. The bladders resumed normal size when allergenic foods were removed from the diet. Denman (1) and Dohan (2) suggested that food allergy might provoke psychiatric symptoms and abnormalities in the heart rate. Dickerson (5) concluded that special facilities are necessary to investigate and treat people with food allergies. The provision of these facilities is necessary for disease prevention and health care.

In the present study, some of the people affected discontinued eating the offending food. However, some of these foodstuffs are staples supplying a wide range of nutrients, and complete abstinence from these foods when there may be no alternatives may lead to malnutrition. Some others who had not much variety of foods to choose from continued to eat some of the allergenic foods and suffered discomfort. This makes food allergy a public health problem and it becomes necessary for affected individuals to seek dietary advice. Food allergy should be more recognized as a problem and should be given adequate attention in a nation's public health programme.


1. A. M. Denman, "Nature and Diagnosis of Food Allergy," Proc. Nutr. Soc., 38: 391 (1979).
2. F. C. Dohan, "Cereals and Schizophrenia, Data and Hypothesis, "Acta Psychiat Scand., 42: 125 (1976).
3. A. E. Bender and D. R. Matthews, "Adverse Reactions to Foods," Brit. J. Nutr., 46: 403 (1981).
4. J. W. Gerrard, B. Jones, and M. K. Shorkier. "Allergy and Urinary Infection: Is There an Association?" Pediatrics, 48:994 (1971).
5. J. W. T. Dickerson, "Adverse Effect of Food on Human Health," Roy. Soc. Hlth J., 101 (No. 5): 200 (1981).

TABLE 2. Clinical Symptoms Caused by Floods.*

Part of Body Affected Symptoms Per Cent of Total
Cutaneous Irritation, rashes, eczema 17.5
Gastrointestinal Irritation, vomiting, diarrhoea, nausea, constipation, abdominal pain 58.7
Skeletal Painful joints, rheumatism, swellings 3.6
Respiratory Difficult breathing, catarrh, asthma, cough 9.6
Central nervous Headache, dizziness, weakness, confusion, restlessness 5.4
Circulatory Impairment of heart beat, palpitation of heart 1.2
Ear/nose/throat Diminished hearing, painful, watery nose, sore throat 1.2
Mouth Irritation, inflamed tongue 1.2
Eye Dimness of vision 1.0

*The figures represent the number of people affected by the group of symptoms expressed as percentage of the total number affected.