Unlike visceral adipose tissue, abdominal subcutaneous adipose tissue is not associated with a linear increase in all cardiovascular and metabolic risk factors, according to a report in the journal Diabetes Care.
In fact, the results of human and animal studies have suggested a possible protective role for subcutaneous fat.
Unlike visceral adipose tissue – the fat located in the abdomen surrounding the abdominal organs – subcutaneous adipose tissue is more superficial, located just beneath the skin.
Dr Caroline Fox, with the US National Heart, Lung, and Blood Institute's Framingham Heart Study, and colleagues examined the abdominal subcutaneous adipose tissue in relation to cardiovascular and metabolic (cardiometabolic) risk factors among participants in the Framingham Heart Study who were matched for age.
Among participants with the lowest and the middle visceral adipose tissue amounts, the prevalence of cardiometabolic risk factors increased as the amount of subcutaneous adipose tissue increased, the authors report.
In contrast, the researchers note, in the subjects with the highest levels of visceral adipose tissue, the pattern of increasing risk factor prevalence across subcutaneous adipose tissue amounts was absent for low HDL, fasting glucose and impaired fasting glucose – this despite large increases in body mass index (BMI) across subcutaneous adipose tissue groups.
A protective fat depot
Moreover, the prevalence of high triglyceride levels in men with the highest visceral adipose tissue levels decreased significantly as subcutaneous adipose tissue increased, and showed a similar trend in women.
The findings were similar when the study participants were stratified by body mass index (BMI) levels instead of visceral adipose tissue categories.
"Whereas abdominal adiposity is associated with a higher absolute risk of metabolic and cardiovascular disease, subcutaneous abdominal fat is not associated with a linear increase in the prevalence of all risk factors among the obese," the investigators conclude.
"In the case of high triglycerides, subcutaneous adipose tissue may actually be a protective fat depot in obese individuals."
(Reuters Health, June 2009)