Prospective study of physical fitness, adiposity, and inflammatory markers in healthy middle-aged men and women.

BACKGROUND: Physical fitness may provide cardiovascular benefits in the obese. OBJECTIVE: We prospectively examined the associations between inflammatory markers and fitness, body mass index, and central adiposity. DESIGN: Healthy men and women (n = 176) were recruited from the Whitehall II epidemiologic cohort. At baseline we measured physical fitness and adiposity, and blood was drawn for the assessment of inflammatory markers [C-reactive protein (CRP) and interleukin-6 (IL-6)]. We subsequently assessed inflammatory markers and adiposity at the 3-y follow-up visit. RESULTS: Body mass index, but not physical fitness, was independently associated with IL-6 and CRP at follow-up. Weight gain was also associated with CRP at follow-up. Compared with fit-lean participants, the unfit-overweight participants had significantly higher concentrations of CRP (adjusted beta: 0.67; 95% CI, 0.31, 1.00) and IL-6 (adjusted beta: 0.28; 95% CI: -0.06, 0.49) at follow-up. In contrast, the fit-overweight and unfit-lean participants did not differ significantly from the fit-lean participants after adjustments for age, sex, smoking, employment grade, and baseline inflammation. CONCLUSIONS: In participants followed up for 3 y, changes in low-grade inflammation were positively associated with adiposity but not with fitness at baseline. Further attention should focus specifically on overweight-obese participants in relation to physical fitness and cardiovascular disease risk.