Indian men are prone to insulin resistance

Men from India are more likely than those in other large ethnic groups to have a condition that predisposes them to type 2, or adult-onset, diabetes, a U.S. study shows.

The condition, called insulin resistance, arises when a person’s cells fail to respond efficiently to insulin—requiring the body to make extra insulin to move glucose into cells where it’s converted into energy. Insulin resistance is often linked with obesity.

Researchers enlisted 482 men and women in Connecticut from five ethnic groups—East Asian, Indian Asian, white, black, and Hispanic. All were lean, apparently healthy individuals, and most were in their 20s.

When the scientists tested how well each group processed glucose, women showed no difference from each other. However, Indian men were three to four times as likely as the other men to show significant insulin resistance. The findings appear in the Nov. 28 Proceedings of the National Academy of Sciences.

“We’re seeing a very important ethnic difference” that could explain a portion of the type 2 diabetes seen in India’s population, says study coauthor Gerald I. Shulman, an endocrinologist at the Howard Hughes Medical Institute and Yale University School of Medicine.

Magnetic resonance images of the Indian- and white-male volunteers showed that Indian men had twice as much fat deposited in their liver tissue. The condition can cause insulin resistance, says Shulman. The fatty livers probably account for these Asian Indian men developing insulin resistance despite being normal weight, he says.

Why the men develop fatty liver disease is a mystery. Shulman and his colleagues have begun testing a gene in their search for an explanation.