Type 2 diabetes is more common among Indians who stay in India than in those who migrate to US, study finds
BMJ 2015; 350 doi: http://dx.doi.org/10.1136/bmj.h2320 (Published 29 April 2015) Cite this as: BMJ 2015;350:h2320- Cheryl Travasso
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.
Notes
Cite this as: BMJ 2015;350:h2320
