Objective: It has been suggested that low-grade systemic inflammation is associated with obesity and that this association might be modified by sex.
Methods and results: We performed a cross-sectional analysis among 641 men and 597 women aged 55-74 years who participated in the population-based KORA Survey 2000, conducted in the area of Augsburg, Germany. Measures of both total (fat mass, body mass index) and abdominal adiposity (waist circumference (WC), waist to hip ratio (WHR)) were highly correlated with markers of systemic inflammation (C-reactive protein (CRP), serum amyloid A (SAA), fibrinogen (FIB), interleukin-6 (IL-6)) in men and in women. Significant associations persisted when the effect of lifestyle factors was taken into account. In multivariable linear regression analysis, a considerably higher percentage of variability in inflammatory markers was explained by body composition in women compared to men. Furthermore, the relevance of single body composition variables varied by sex. In women, fat mass in % explained the highest percentage of the variability of circulating acute-phase proteins (18.2% for CRP, 7.2% for SAA, 6.1% for FIB, all p-values < 0.001), whereas in men, WHR explained the highest percentage of the variability (6.2% for CRP, 2.3% for SAA, 1.8% for FIB, all p-values < 0.001). For IL-6, WC explained the highest percentage of the variability in women (3.7%, p < 0.001) and in men (1.8%, p < 0.001).
Conclusion: Adiposity is strongly associated with low-grade systemic inflammation in men and in women but the association is considerably stronger in women, especially for CRP. Thus, weight reduction as a means to prevent a state of subclinical inflammation might be particularly effective in women.