Obesity, dyslipidaemia and candidate gene polymorphisms: a cross-sectional study among the Liangmai and Mizo tribes of Manipur, India

The prevalence of obesity and dyslipidaemia was observed to be increased among the tribal populations, due to globalization. In the present study, data on demographic, somatometric and blood samples were collected from 613 participants of both sex, age 18-60 years, further lipid profiling and genotyping was executed. Multifactor dimensionality reduction (MDR) software was used for gene-gene interactions analysis. Significantly differences were observed with respect to the general characteristic and selected gene polymorphisms in both the tribes. Among the Liangmai tribe, MC4R gene was found to pose significant decreased risk for waist-height ratio (WHtR) (OR = 0.56; 95% confidence interval (CI)= 0.32-0.99; p value = .04) and HDL (OR = 0.58; 95% CI = 0.36-0.92; p value = .02). Similar trends of significant decreased risk (OR = 0.39; 95% CI = 0.20-0.76; p value=.006) for BMI were observed among the Mizo tribe. The gene-gene interaction revealed the combined model of FTO+MC4R genes shows an increased risk for BMI in both the tribes. The independent significant increased risk posed by FTO gene was moderated by interaction with MC4R gene. The observed differences can possibly attribute to both their respective ancestries resulting in different gene pools and the physical environment. The results of the study highlight the importance of gene-gene and gene-environment interactions in adverse phenotype groups. KEY MESSAGE Among the tribal population, the prevalence of obesity and dyslipidaemia has been increased. Differential distribution and associations of selected markers hint towards differential genetic architecture in these populations. MC4R rs17782313 polymorphism was found to show a significantly decreased risk for WHtR and low HDL among the Liangmai tribe and BMI among the Mizo tribe. Significant increased risk posed by FTO rs9939609 gene polymorphism was moderated by the interaction with MC4R rs17782313.