Independent and combined effects of physical activity and weight loss on inflammatory biomarkers in overweight and obese older adults.

OBJECTIVES: To determine the independent effect of long-term physical activity (PA) and the combined effects of long-term PA and weight loss (WL) on inflammation in overweight and obese older adults.

DESIGN: Eighteen-month randomized, controlled trial.

SETTING: The community infrastructure of cooperative extension centers.

PARTICIPANTS: Overweight and obese (body mass index >28.0 kg/m(2) ) community-dwelling men and women aged 60 to 79 at risk for cardiovascular disease (CVD).

INTERVENTION: Physical activity + weight loss (PA + WL) (n = 98), PA only (n = 97), or successful aging (SA) health education (n = 93) intervention.

MEASUREMENTS: Biomarkers of inflammation (adiponectin, leptin, high-sensitivity interleukin (hsIL)-6, IL-6sR, IL-8, and soluble tumor necrosis factor receptor 1) were measured at baseline and 6 and 18 months.

RESULTS: After adjustment for baseline biomarker, wave, sex, and visit, leptin and hsIL-6 showed a significant intervention effect. Specifically, leptin was significantly lower in the PA + WL group (21.3 ng/mL, 95% confidence interval (CI) = 19.7-22.9 ng/mL) than in the PA (29.3 ng/mL, 95% CI = 26.9-31.8 ng/mL) or SA (30.3 ng/mL, 95% CI = 27.9-32.8 ng/mL) group (both P < .001), and hsIL-6 was significantly lower in the PA + WL group (2.1 pg/mL, 95% CI = 1.9-2.3 pg/mL) than in the PA (2.5 pg/mL, 95% CI = 2.3-2.7 pg/mL) or SA (2.4 pg/mL, 95% CI = 2.2-2.6 pg/mL) group (P = .02).

CONCLUSION: Addition of dietary-induced WL to PA reduced leptin and hsIL-6 more than PA alone and more than a SA intervention in older adults at risk for CVD. Results suggest that WL, rather than increased PA, is the lifestyle factor primarily responsible for improvement in the inflammatory profile.