Association between Change in Body Composition and Change in Inflammatory Markers: An 11-Year Follow-Up in the Whitehall II Study

Context: Obesity is associated with low-grade inflammation, but the long-term effects of weight change on inflammation are unknown. Objective: The aim was to examine the association of change in weight, body mass index (BMI), and waist circumference with change in C-reactive protein (CRP) and IL-6 and to assess whether this association is modified by baseline obesity status. Design and Setting: The design was a prospective cohort study among civil servants (the Whitehall II Study, UK). We used data from two clinical screenings carried out in 1991-1993 and 2002-2004 (mean follow-up, 11.3 yr). Participants: We studied 2496 men and 1026 women [mean age, 49.4 (SD = 6.0) yr at baseline] with measurements on inflammatory markers and anthropometry at both baseline and follow-up. Main Outcome Measures: We measured change in serum CRP and IL-6 during follow-up. Results: The mean increases in CRP and IL-6 were 0.08 [95% confidence interval (Cl), 0.07-0.09] mg/liter and 0.04 (95% Cl, 0.03-0.05) pg/ml per 1-kg increase in body weight during follow-up. Study members with a BMI less than 25 kg/m(2) at baseline had an average increase in CRP of 0.06 (95% Cl, 0.05-0.08) mg/liter per 1-kg increase in body weight, whereas the increase in those who were overweight (25 <= BMI < 30 kg/m(2)) and obese (BMI >= 30 kg/m(2)) was greater: 0.08 (95% Cl, 0.06-0.09) mg/liter and 0.11 (95% Cl, 0.07-0.14) mg/liter, respectively (P value for interaction = 0.002). Similar patterns were observed for changes in BMI and waist circumference. Conclusions: Those who were overweight or obese at baseline had a greater absolute increase in CRP per unit increase in weight, BMI, and waist circumference than people who were normal weight. (J Clin Endocrinol Metab 95: 5370-5374, 2010)