Effects of exercise on C-reactive protein, inflammatory cytokine and adipokine in patients with type 2 diabetes: a meta-analysis of randomized controlled trials

Abstract

Objective: C-reactive protein (CRP), inflammatory cytokines, and adipokines contribute to atherosclerosis, insulin resistance, and development of late-onset complication in patients with type 2 diabetes. We performed a systematic review to assess effects of exercise interventions on inflammatory markers/cytokines and adipokines.

Materials/methods: We searched electronic databases (MEDLINE, EMBASE, and Cochrane Controlled Trials Registry) and reference lists in relevant papers for articles published in 1966-2013. We selected studies that evaluated the effects of exercise intervention on inflammatory markers/cytokines and adipokines in adult patients with type 2 diabetes. Weighted mean differences of exercise on outcomes were derived using fixed or random effect models; factors influencing heterogeneity were identified using meta-regression analysis.

Results: Fourteen randomized controlled trials (824 patients) were included in our meta-analysis. Exercise was associated with a significant in CRP=-0.66mg/l (95% CI, -1.09 to -0.23mg/l; -14% from baseline) and interleukin-6 (IL-6)=-0.88pg/ml (95% CI, -1.44 to -0.32pg/ml; -18% from baseline) but did not alter adiponectin or resistin levels; aerobic exercise program was associated with a significant change in leptin=-3.72ng/ml (95% CI, -6.26 to -1.18ng/ml; -24% from baseline). For IL-6, exercise was more effective in those with a longer duration in the program and larger number of sessions during study (p=0.001).

Conclusions: Exercise decreases inflammatory cytokine (CRP and IL-6) in patients with type 2 diabetes. Exercise could be a therapeutic option for improving abnormalities in inflammation levels in patients with diabetes.

Keywords: Adipokine; Diabetes; Exercise; Inflammation.