Effect of internal migration on diabetes and metabolic abnormalities in India - The ICMR-INDIAB study.

AIMS To assess the effect of migration (rural-to-urban and vice versa) on prevalence of diabetes and metabolic disorders in Asian Indians participating in the Indian Council of Medical Research-India Diabetes (ICMR-INDIAB) study. MATERIALS AND METHODS The ICMR-INDIAB study is a national study on diabetes and associated cardiometabolic disorders in individuals aged ≥20 years from 28 states and 2 union territories of India. Individuals who moved to a different place from their place of birth and had resided in the new location for at least one year were considered as migrants. Anthropometric measurements, blood pressure estimation and a capillary oral glucose tolerance test were performed. RESULTS Of the 113,043 participants, 66.4% were non-migrant rural dwellers, 19.4% non-migrant urban dwellers, 8.4% rural-urban migrants, 3.8% multiple migrants and 2.0% urban-rural migrants. Weighted prevalence of diabetes was highest in rural-urban migrants followed by urban dwellers, urban-rural migrants and rural dwellers [14.7%, 13.2%, 12.7% and 7.7% respectively (p < 0.001)]. Rural-urban migrants had highest prevalence of abdominal obesity (50.5%) compared to the other three groups. The risk for diabetes was 1.9 times higher in rural-urban migrants than among rural dwellers. Five risk factors [hypertension, abdominal and generalized obesity, physical inactivity and low fruit and vegetable intake] together explained 69.8% (partial population attributable risk) of diabetes among rural-urban migrants and 66.4% among non-migrant urban dwellers. CONCLUSIONS Rural-to-urban migration is associated with increased risk of developing diabetes and other cardiometabolic abnormalities. Adoption of healthier lifestyle patterns among migrants could help prevent/delay onset of these abnormalities in this population.