Body composition, not body weight, is related to cardiovascular disease risk factors and sex hormone levels in men

Abstract

To clarify the independent relationships of obesity and overweight to cardiovascular disease risk factors and sex steroid levels, three age-matched groups of men were studied: (i) 8 normal weight men, <15% body fat, by hydrostatic weighing; (ii) 16 overweight, obese men >25% body fat and 135-160% of ideal body weight (IBW); and (iii) 8 overweight, lean men, 136-160% IBW, but <15% fat. Diastolic blood pressure was significantly greater for the obese (mean±SEM, 82±2 mmHg) than the normal (71±2) and overweight lean (72±2) groups, as were low density lipoprotein levels (131±9 vs. 98+11 and 98+14 mg/dl), the ratio of high density lipoprotein to total cholesterol (0.207±0.01 vs. 0.308±0.03 and 0.302±.03), fasting plasma insulin (22±3 vs. 12±1 and 13±2 μU/ml), and the estradiol/testosterone ratio (0.076±0.01 vs. 0.042±0.02 and 0.052±0.02); P<0.05. Estradiol was 25% greater for the overweight lean group (40±5 pg/ml) than the obese (30±3 pg/ml) and normal groups (29±2 pg/ml), P=0.08, whereas total testosterone was significantly lower in the obese (499±33 ng/dl) compared with the normal and overweight, lean groups (759±82 ng/dl). Estradiol was uncorrelated with risk factors and the estradiol/testosterone ratio appeared to be a function of the reduced testosterone levels in obesity, not independently correlated with lipid levels after adjustment for body fat content. Furthermore, no risk factors were significantly different between the normal and overweight lean groups. We conclude that (a) body composition, rather than body weight per se, is associated with increased cardiovascular disease risk factors; and (b) sex steroid alterations are related to body composition and are not an independent cardiovascular disease risk factor.