BODY-MASS INDEX AND ITS ASSOCIATION WITH SOCIOECONOMIC AND BEHAVIORALVARIABLES AMONG SOCIOECONOMICALLY HETEROGENEOUS POPULATIONS OF ANDHRA-PRADESH, INDIA

The nature and extent of relationship between socioeconomic and behavi oral variables and body mass index [BMI = weight (kg)/height (m)(2)] i s studied in a sample of 1119 individuals (456 males and 663 females), aged 18 to 75 years, drawn from socioeconomically diverse populations from southern Andhra Pradesh, India. These populations are categorize d into four groups, with graded lifestyles toward urbanization. The BM I of the participants ranged from 12.6 to 35.1 in males and from 12.3 to 34.2 in females. There is an increasing trend in mean BMI until abo ut 50 years, followed by a decline, indicating nonlinear nature of age effects. Mean BMI also increases with better socioeconomic status of the constituent groups and with decreased physical activity level. A t rend of a decrease in the proportion of individuals with chronic energ y deficiency and an increase in the proportion of obese individuals is also seen from the traditional Yerukala tribe (group 1) to the urbani zed group 4, from the lower to the higher income categories, and from heavy to light physical activity types. Smokers show a greater proport ion of obese cases compared with nonsmokers. The prevalence of obesity (BMI greater than or equal to 25) is 6.6% in males and 10% in females . The results of the analysis of variance suggest that three of the fo ur socioeconomic and behavioral variables (except smoking) show signif icant effects on age-adjusted BMI, and the R-2 suggests that these var iables explain 27.4% of variation in males and 17% in females. Althoug h income explains the largest amount of variation (24%) in males, foll owed by physical activity and group affiliation, in females group affi liation (12.5%), followed closely by income, accounted for most of the variation. Inclusion of age in the model improved explanatory power b y 5-7%. The positive association between socioeconomic status and BMI observed in the present study is qualitatively different from the nega tive association that characterizes contemporary Western populations.