Increased Prevalence of Insulin Resistance and Fatty Liver Disease in Asian Indian Men
Asian Indian men are at increased risk to develop type 2 diabetes mellitus because of chronic liver disease rather than obesity, Yale School of Medicine researchers report in the November 13 issue of the Proceedings of the National Academy of Sciences.
Diabetes mellitus is strongly associated with obesity in most, but not all, ethnic groups and the study was intended to examine ethnic differences in disease susceptibility. The risk statement is based on the researchers’ finding that insulin resistance associated with non-alcoholic fatty liver disease is three to four times more prevalent in healthy, lean, Asian Indian men than in lean men of other ethnic groups.
“The worldwide prevalence of type 2 diabetes mellitus is expected to double within the next two decades with the greatest increase occurring in Asia and the Indian subcontinent, where it will affect 130 million individuals,” said the principal investigator, Gerald Shulman, an investigator of the Howard Hughes Medical Institute and professor of internal medicine and cellular and molecular physiology. “This might explain why Asian Indians tend to develop type 2 diabetes mellitus without the same degree of obesity found in most other ethnic groups.”
Interestingly, the insulin resistance was not found in Asian Indian women, which might indicate protective effects of estrogen on this process, the researchers said.
In the study an oral glucose tolerance test to assess whole body insulin sensitivity and magnetic resonance imaging measured liver fat content of 482 young, lean, healthy, sedentary, non-smoking Eastern Asians, Asian Indians, Blacks, Caucasians, and Hispanics. The prevalence of insulin resistance was about three-to-four-fold higher in the Asian Indian men compared to other ethnic groups and was associated with an approximately two-fold increase in hepatic triglyceride content.
Shulman said that based on his previous studies it is likely that the increased liver fat content was playing an important role in causing the insulin resistance. He also said that these data have potentially important implications for the prevention and treatment of type 2 diabetes in these individuals.
Co-authors include Kitt Falk Petersen, Jing Feng, Douglas Befroy and James Dziura, of Yale, and Chiara Dalla Man and Claudio Cobelli of the University of Padova, Italy.
PNAS: Online early edition