Systematic Review and Meta-Analysis of Randomized, Controlled Trials on the Effect of Exercise on Serum Leptin and Adiponectin in Overweight and Obese Individuals

Abstract

Previous reports have shown that exercise improves serum leptin and adiponectin abnormalities in overweight and obese individuals; however, results to date are controversial. Here we performed a systematic review and meta-analysis of the available randomized controlled trials (RCTs) of the possible beneficial action of exercise on serum leptin and adiponectin levels in overweight and obese individuals. We searched PubMed, EMbase, The Cochrane Library, and the Clinicaltrial.gov databases for relevant studies published between January 1980 and September 2015. Two independent reviewers extracted relevant data and assessed study quality and risk of bias. Data were pooled using a random-effects model for leptin and a fixed-effects model for adiponectin. Effect of size was expressed as mean difference (MD) with 95% confidence interval (CI). Heterogeneity was assessed (Cochran Q-statistic) and quantified (I ). Twenty-eight RCTs (40 studies) were identified, of which 24 were on the effects of exercise on leptin (n=1 358) and 31 referred to changes in adiponectin (n=1 774). Our analysis revealed that exercise significantly reduced serum leptin (MD=-2.24 ng/ml; 95% CI, -3.26, -1.23; p<0.001) and increased adiponectin (MD=0.44 μg/ml; 95% CI, 0.13, 0.75; p=0.005) levels compared to no exercise as well as control (who were also overweight or obese). Exercise, particularly aerobic exercise, had a significant effect on serum leptin and a possible influence on adiponectin levels, suggesting its therapeutic implications.

Physical Exercise as Therapy for Type 2 Diabetes Mellitus: From Mechanism to Orientation

“…A recent meta-analysis indicated that exercise, particularly aerobic exercise, significantly increased the ADP levels compared to no exercise as well as control in overweight and obese individuals [68], consistent with the finding in T2DM [69]. However, some studies is contrary to the results presented before suggested that the plasma ADP levels were not altered after 12 weeks' combined training in overweight and obese children [70].…”

Effects of a diet with or without physical activity on angiopoietin-like protein 8 concentrations in overweight/obese patients with newly diagnosed type 2 diabetes: a randomized controlled trial

“…Second, the contribution of exercise has been more difficult to understand, and findings on the effects of increased PA on serum adipokine levels continue to be debated [37]. A few meta-analyses found that there were no statistically significant changes in certain circulating levels of adipokine, such as adiponectin or resistin, in the intervention group with and without exercise [37,38]. Divergent forms of exercise may have varying effects on adipokine levels [39].…”

Effects of Aerobic Versus Resistance Training on Serum Leptin and Insulin Resistance in Healthy Sedentary Men

“…Research results showed that short-term aerobic exercise training caused no significant change in serum leptin level (3). While other studies showed that extreme physical activity may lead to a decrease in leptin concentration due to a decrease in weight and fat mass (4). However, there are insufficient research findings to show that short-term exercise (less than 12 weeks) have any significant effect on leptin unless when the exercise is linked to fat mass reduction (2,5).…”