|The Functional Significance of Low Body Mass Index (IDECG, 1992, 203 p.)|
|Body mass index values in the Cuban adult population|
The results obtained in this study pointed to BMI as the best index among those examined to evaluate the nutritional condition of adults 20-59 years old in our country. This coincides with what was stated in the conference on 'Implications of obesity on health', organized by the US National Health Institutes (1985). It also coincides with the criteria proposed by, for example, Keys et al. (1972), Cronk & Roche (1982) and Frisancho & Flagel (1982).
The BMI values of the Cuban population had a distribution similar to those of developed countries with a greater tendency towards overweight and obesity than to low weight, especially in females (Table 1).
The range of BMI values considered appropriate for our population and based exclusively on anthropometric data (Table 2) coincided, except in the oldest women group, with those mentioned by Bray & Gray (1988) who based this choice of cut-off points on lower mortality recorded data with either classification (Tables 3 and 4). Only a very small percentage of adults is classified by CED, particularly men. It should be noted that James, Ferro-Luzzi & Waterlow (1988) indicate that those classified as CED 2 with physical activity levels (PAL) 21.4 (4-5 h or more of standing activity) would be shifted to CED 1, and those in CED 1 with PAL values 21.4 would be changed to low weight. It should be inferred that the individuals in this study, because they were almost all workers, expected to spend at least 4-5 h standing -including housewives. They should therefore have a PAL >1.4, for which a reclassification would have to be made starting with group 2 of CED.
Rural individuals were lighter than urban adults (Table 5) as has been found in children and in other adults (Eveleth & Tanner, 1991; Bielicki, 1986). They had higher percentages of individuals classified as CED and underweight. But despite this, rural adults have a higher percentage of normal adults than the urban population because of the smaller proportion of obese individuals in the rural area. Rural women have a higher proportion with CED than the men, even if the men seem to have a higher sensitivity, in terms of BMI, to their environment. In other cultures the apparent lack of environmentally related differences between men and their low response to change may be masked by the preferential treatment that men usually receive in terms of more food and other benefits. This is not the case in Cuba.
Educational level was related to BMI values although its influence was not the same on both sexes (Tables 6 and 7). In men, higher educational levels were linked to greater obesity but in women this was not so. Lower educational levels were related to higher CED percentages in women, but there was not a defined trend in men.
As far as the physical activity demands of work were concerned (Tables 8 and 9) men engaged in light activity were prone to obesity. In women the highest percentages with CED were found in agricultural workers and housewives.
Different findings from ours were reported by Sonne-Holm et al. (1986) and Braddon et al. (1986) who found a relationship between high obesity levels and lower educational and occupational levels. Likewise, Seidell et al. (1986) found (in both men and women) that obesity was inversely related to educational level. Power & Moynihan (1988) too, in the cohort study of British children born between 3 and 9 March 1958, noted that when they were adults there was a direct relation between obesity prevalences and lower socio-economic status.
Lew & Garfinkel (1979) reported weight-for-height data in the study of the American Cancer Society. Having calculated the BMI from these data, it must be concluded that individuals of either sex with higher educational levels have the highest percentage of normal BMI values. Poorly educated men had the highest proportion of both the overweight and underweight. Women with a lower educational level also had higher overweight percentages.
Most of the information that we have about the relationship between morbidity or mortality and BMI values has been gathered in developed countries. The extreme BMI values are associated with high morbidity and mortality but extrapolated; these conclusions applied to populations of developing countries may not be appropriate. In developing countries, the issue is malnutrition and this may enhance morbidity and mortality. Where there is a high proportion of adults with CED low levels of all kinds of resources, including food, may be responsible.
These relationships need to be recognized because actions to solve or paliate the malnutrition is difficult. Nevertheless the issues must be faced because the health of millions and future generations in Asia, Africa and Latin America is at risk. Selecting a tool such as the BMI and choosing appropriate cut-off points is not enough: government and international organizations have to respond with aid and programmes to combat the problem.