Aug. 18 : Deposits of fat on the chest and back indicate an increased risk of insulin resistance, a precursor of type 2 diabetes, say researchers at the San Frnacisco VA Medical Center (SFVAMC).

The researchers claim that their study is the first to demonstrate this sort of an association.

In a study, titled ‘Study of Fat Redistribution and Metabolic Change in HIV Infection’ (FRAM), the researchers found that this association was equally strong in HIV infected subjects as well as HIV negative control subjects.

The presence of visceral fat, which is located between and around the internal organs, was also associated with an increased risk of insulin resistance in both populations.

According to the researchers, each type of fat contributes independently to insulin resistance whether or not the other type is present.

“We knew about the insulin resistance risk associated with visceral fat, which has been shown in previous studies, but no one had ever looked at the contribution of upper trunk fat,” says lead author and FRAM principal investigator Dr. Carl Grunfeld.

“Strikingly, there was very little difference between HIV infected people and controls. If you have fat up top, it’s bad for you,” added the chief of the metabolism and endocrine sections at SFVAMC.

During the study, published in the Journal of Acquired Immune Deficiency Syndromes, the researchers measured visceral and subcutaneous fat deposits in the legs, arms, upper trunk, and lower trunk of 926 HIV infected subjects and 258 HIV negative controls. They divided each population into tertiles, or thirds, based on the amount of fat in each location.

Among the HIV infected patients in the highest tertile of upper trunk fat, 57 per cent showed insulin resistance, half of whom lacked high visceral fat. Among the highest tertile of controls with upper trunk fat, 61 per cent were insulin resistant, and a third of them did not have high visceral fat.

“So, basically, there are people who have a lot of fat in their upper trunk and not so much inside their belly, yet they are at risk for insulin resistance. And there are people with a lot of visceral fat but not upper trunk fat who are in the same boat. But if you’ve got both, it’s a double whammy. Your risk of insulin resistance is quite high,” observes Grunfeld.

Grunfeld says that the researchers looked at all regions of the body where fat is usually deposited so as to investigate abnormalities in fat distribution that have been reported in HIV infection, particularly the presence of so-called “buffalo hump,” a prominent fat deposit in the middle of the upper back.

“But we found that fat in that area was present, and associated with the same risk for insulin resistance, in both HIV infected and control subjects,” he says.

“No matter who you are, if you eat too much and you don’t exercise, you’re going to be at risk for insulin resistance, cardiovascular disease, and every other problem associated with being overweight,” he adds. (ANI)

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