Human adaptation to cold and warm climatic conditions: A comparison between two geographically diverse Indigenous populations

Objectives: The present study aims to compare body adiposity and blood pressure (BP) in two climatically and ethnically diverse populations, examining whether thermoregulatory adaptive mechanism may protect Indigenous populations from exhibiting adverse consequences of increased adiposity. Methods: A cross sectional sample of 404 subjects, of which 200 were Monpa and 204 were Santhal, from two ethnically and geographically distinct populations of India were studied. Body mass index (BMI; kg/m(2)), fat mass (FM; kg), fat free mass (kg), and percent body fat (%BF) were calculated for evaluation of body adiposity. Multivariate multiple regression analysis was adopted to examine the influence of age and sex of populations under study, on body adiposity and BP variables. Results: BMI, %BF, and FM were found to be significantly higher (p < .001) among the Monpa males and females compared with their Santhal counterparts. In contrast, the prevalence of hypertension among Monpa and Santhal is comparable (3.5%(Monpa) vs. 3.9%(Santhal) for systolic BP; 8.5%(Monpa) vs. 8.3%(Santhal) for diastolic BP). Adiposity, as quantitated by the fat mass index and %BF was significantly (p < .001) correlated to age and sex of study population, explaining similar to 75.3% and similar to 75.4% of total variations of these variables, respectively. Conclusions: Overall the present study suggests that modern human populations follow thermoregulatory mechanism for adaptation to different climatic conditions. Consequently, greater adiposity was evident among the Monpa who adapt to the cold climate, in comparison to their Santhal counterparts who dwell in warm climate.