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
2
). 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.
Key words obesity - overweight - exercise - leptin - adiponectin
