Type 2 diabetes is more common among Indians who stay in India than in those who migrate to US, study findsBMJ 2015; 350 doi: https://doi.org/10.1136/bmj.h2320 (Published 29 April 2015) Cite this as: BMJ 2015;350:h2320
People of Indian origin who live in the United States have a lower prevalence of diabetes than those who live in India, a study published in Diabetes Care has found.
These differences were seen after adjusting for age, sex, systolic blood pressure, and waist circumference, indicating that other factors may be linked to the high prevalence of type 2 diabetes seen in Asian Indians.1 Previously, when the prevalence of type 2 diabetes in India was lower, studies had shown that Asian Indians had a higher risk of type 2 diabetes after immigration.
Unjali Gujral, lead author of the new study, noted that India has seen many economic and nutritional changes in recent years, along with a rapid rise in diabetes cases. The uniqueness of this study is that it looked at two genetically similar Indian populations living in different environments, she said.
The 757 US residents were participants in the Mediators of Atherosclerosis in South Asians Living in America study (MASALA; 2010-13) living in the Chicago or greater San Francisco areas, while the 2305 residents in India were participants in the Centre for Cardiometabolic Risk Reduction in South Asia study (CARRS; 2010-11) residing in Chennai. Both studies were large, population based studies whose participants had similar laboratory parameters and anthropometric measurements.
The prevalence of age adjusted type 2 diabetes was higher among Indians in the CARRS-Chennai study (38% (95% confidence interval 36 to 40)) than among those in the MASALA-US study (24% (21 to 27)). When participants were grouped by body mass index (BMI) the difference in prevalence of type 2 diabetes was significant (P<0.05) among the normal weight and overweight participants but not among those who were obese.
Conversely, the prevalence of age adjusted pre-diabetes was lower in the India residents (24% (22 to 26)) than in the US residents (33% (30 to 36)). When grouped by BMI the difference in prevalence of pre-diabetes was significant (P<0.05) only in those who had a normal BMI.
To correct for possible differences relating to region of origin the group then compared participants in the CARRS-Chennai study with only those of south Indian origin in the MASALA-US study, and they found the same observations. The authors acknowledged that, since the study looked at specific locations in the US and India, it could not be extrapolated to the countries’ entire populations. However, the prevalence in both the MASALA study and the CARRS-Chennai study aligned with other publications that have individually looked at diabetes in these two countries.
Gujral said that the higher diabetes prevalence among participants living in India could be because the disease is at an early stage of the epidemic, where people at risk would develop the disease sooner. Those living in the US were likely to have better access to healthcare and more awareness about diabetes prevention, she said; however, there was still a need to understand why migrant Indians are at a lower risk than those living in India.
Moreover, migrant Indians in the US still have a higher prevalence of diabetes than the overall US population, Gujral added, and better understanding is needed about the best treatment and prevention practices for this group.
Cite this as: BMJ 2015;350:h2320
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