Ethnic heterogeneity in body composition patterning and CVD risk factors: a multi-ethnic study of Asian Indian Tribes

BACKGROUND . Indian subcontinent exhibits considerable degree of ethnic heterogeneity in cardiovascular disease (CVD) risks. Given the importance of ethnicity, the present multi-ethnic study was conducted to find out the differences in body composition patterning and its influence on CVD risk variables. OBJECTIVE . Owing to considerable ethnic heterogeneity among Asian Indians the study was performed to determine the association of variability between body composition and CVD risk factors at the micro-level among different tribes by sex, province, and generation. METHODS. Nine tribes from three different states (provinces) were considered. Anthropometric measurements, body composition, adiposity, blood pressure, and fasting blood glucose was measured using standard technique. Body composition was measured using BIA method by means of body fat monitor. Mean differences of the body composition measures were analysed by ANOVA. Stepwise multiple regressions were done with CVD risk variables as dependent and body composition profiles as independent variables to find out the significant predictors. Those were then loaded for principal component factor analyses (PCFA). RESULTS . Tribal subjects of both sexes and from both younger and older generations in Gujarat had significantly higher percentage body fat, subcutaneous fat-whole body, and subcutaneous fat-trunk as compared to tribal subjects of Odisha, and West Bengal, as well as significantly lower skeletal mass-whole body and skeletal mass-trunk. PCFA showed two components: (i) percentage body fat with muscle mass; and (ii) visceral fat with resting metabolism. These two components cumulatively explained 80-90% of the total variance associated with CVD risk variables, across the nine tribes. CONCLUSION . Tribal subjects of Gujarat had higher CVD risks with significantly higher fat mass and lower muscle mass followed by the tribal subjects of Odisha, and West Bengal respectively. The younger generation are equally at risk as their older counterparts. The CVD risks are developing at a much faster rate resulting in a serious public health threat, even in traditional societies. Body composition measures could be considered as a better non-invasive technique for early intervention and proper risk management among the Asian Indians in general and tribal populations in particular.