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close this bookThe Functional Significance of Low Body Mass Index (International Dietary Energy Consultative Group - IDECG, 1992, 203 pages)
close this folderUse of body mass index in the assessment of adult nutritional status in Vietnam
View the document(introductory text...)
View the documentIntroduction
View the documentResults
View the documentEffect of low BMI on health status
View the documentConclusions
View the documentReferences
View the documentDiscussion

Effect of low BMI on health status

In Study III carried out in 1990, we followed the change of food intake and weight gain of the mothers during pregnancy, some biochemical indicators of nutritional status and the weight of newborn babies. Results indicated (Hop et al., 1991) that the average weight gain of mothers during pregnancy in rural areas is 6.4 kg and in Hanoi city 8.5 kg. The study also revealed a relation between weight gain during pregnancy and the weight of newborn at different values of the mother's BMI before pregnancy (Table 10).

Study IV assessed the health status of women at reproductive age in two communes in rural areas in the north of Vietnam. In the sample of 400 subjects, aged 18-49 years, the mothers with a high parity were more likely to have CED than the others (Khoi et al., 1993) (Table 11).

Toan et al. (1992) also carried out studies on the nutritional and health status of 605 adults aged >45 years in Thanh Hoa province and the cut-off point of BMI at 18.5 was used to classify the nutritional status with a systematic subsample for biochemical examination. They found that the older the people, the lower their BMI and that when the BMI value was <18.5 the rate of morbidity was higher and digestive diseases more common.

Table 10. Relation between body mass index (BMI) of mothers before pregnancy and weight gained during pregnancy and birth weight

Weight gained during pregnancy

Newborn weight (g) by mothers' prepregnancy BMI levels

P


<18.5

>18.5


<8 kg

2770

3020

<0.001


(n = 21)

(n = 34)


>8 kg

2880

3050

<0.05


(n = 19)

(n = 40)


We have found that:

1. BMI has a relationship with age, sex, socioeconomic condition and pattern of food intake and is a good indicator of nutritional status and health development.

2. BMI decreases with age in rural populations but increases in urban ones. Such different patterns can be the result of various factors but are linked to the fact that people in rural populations have little fat reserves and the energy balance is often negative due to heavy physical work.

3. Body mass also decreases with the number of pregnancies.

Since nutritional status of adults directly affects productivity, work performance and well-being of the community, it should receive more attention in both methodology and practice.

Table 11. Relationship between the mothers' body mass index (BMI) and the number of their children


Percentage of women in BMI classes

No. of children in family

³18.5

CED I

CED II

CED III

1

55.6

35.5

7.3

1.6

2

51.7

37.4

8.2

2.7

3

40.6

46.9

9.1

3.7

>4

39.3

46.0

12.2

2.6