Stronger relationship between central adiposity and C-reactive protein in older women than men

Cardiorespiratory fitness and obesity, especially central adiposity, have consistently been associated with circulating C-reactive protein (CRP), particularly in aging women. The purpose of this study was to determine the sex-specific independent relationships between physical activity, fitness, central and whole body adiposity, and CRP in sedentary older adults.

Cross-sectional study on sedentary, healthy, community-dwelling older adults (age, mean +/- SD; 70.0 +/- 5.4 years; N = 132, 47 men, 85 women). Physical activity was determined using a questionnaire, fitness using a maximal oxygen consumption treadmill test (V(dot)O2peak), and body composition via dual-energy x-ray absorptiometry.

CRP tended to be higher in women than men (4.0 +/- 2.9 vs 3.1 +/- 2.3 mg/L, P = 0.07). All measures of adiposity (absolute, relative [%fat], and trunk) were positively associated with CRP in women (r range = 0.22-0.28, all P < 0.05), whereas neither physical activity nor fitness was related. In contrast, %fat was the only measure of adiposity associated with CRP in men (r = 0.36, P = 0.01) and V(dot)O2peak was inversely correlated with CRP (r = -0.31, P = 0.04). Trunk fat was the only independent predictor of CRP in women, explaining 8% of the variance (P = 0.01), whereas %fat (P = 0.01) and anti-inflammatory medication use (P = 0.02) were independent predictors of CRP in men, explaining 13% and 10% of the variance, respectively.

In sedentary, healthy older adults, the relationship between regional body fatness, aerobic fitness, and CRP differs between sexes such that (1) central adiposity was most strongly associated with CRP in women, whereas %fat was the strongest predictor of systemic inflammation in men and (2) the negative association between fitness and CRP was stronger in men.