Québec, QC - A new study shows that among individuals with the same body-mass index (BMI), men with lower cardiorespiratory fitness (CRF) levels had almost twice as much abdominal fat than their counterparts who were "fat and fit. [1]" The higher levels of abdominal obesity were also associated with poorer metabolic profiles, the researchers found.

"To the best of our knowledge, this study is the first to show that the poorer metabolic risk profile of men with low CRF is associated with more visceral adipose tissue accumulation even after controlling for BMI," note Benoit J Arsenault (Hôpital Laval, Québec, QC) and colleagues in their report in the July 23, 2007 issue of the Archives of Internal Medicine. "This finding supports the notion that visceral obesity is a major correlate of a metabolic risk-factor profile that predicts the development of cardiovascular disease and type 2 diabetes mellitus resulting from poor CRF," they add.

They note, however, that their study was cross-sectional in design and had a limited sample size, "so prospective studies with measurement of CRF, visceral abdominal tissue accumulation, and hard end points will be needed to further sort out the respective contributions of visceral adiposity and CRF to metabolic risk."

Arsenault et al studied 169 asymptomatic men with diabetes mellitus who were participating in the Quebec Family Study, a population-based study of French Canadian families living in and around Quebec. They measured abdominal adipose tissue accumulation, cardiorespiratory fitness, and indexes of plasma glucose-insulin homeostasis and lipoprotein-lipid profiles.

More visceral fat was seen among men in the lowest tertile of CRF than among those in the highest tertile, and those in the highest tertile of CRF also had more favorable lipoprotein-lipid profiles than those in the lowest tertile.

After individuals with similar BMIs were matched, men with low CRF were characterized by more visceral adipose tissue accumulation than men with high CRF (mean 114.4 cm² vs 87.8 cm²; p<0.007) and by a poorer metabolic profile. When matched for visceral adipose tissue accumulation, however, such differences were no longer significant.

"This study underlines the importance of visceral adipose tissue accumulation in the previously reported association between CRF and metabolic complications predictive of coronary heart disease and type 2 diabetes mellitus," say Arsenault et al.

"Our results suggest that visceral abdominal tissue accumulation could be a key confounding factor when the relationship of CRF, coronary heart disease risk, and metabolic syndrome is examined."

Physical activity should be promoted, irrespective of age, sex, or degree of obesity as a measure to reduce adiposity, to increase energy expenditure, and to potentially decrease atherogenic visceral adipose tissue mass, they conclude.