Plasma high-density lipoprotein cholesterol responses to endurance exercise training: A meta-analysis of randomized controlled trials

Background: Endurance exercise improves lipid and lipoproteins levels, while low high-density lipoprotein cholesterol (HDL-C) levels are risk factors for cardiovascular disease. There is a lack of evidence for the exercise characteristics in increasing lipids level, irrespective of the fact that endurance exercise increases lipids and lipoproteins level. The aim of this study was to clarify the effect and characteristics of endurance exercise in increasing HDL-C in randomized controlled trials. Methods: A search was performed for published studies between 1999 and 2014. Studies that assessed endurance exercise for ≥8 weeks and also reported the HDL-C levels pre- and post-training were included. The random effects model was used to measure the association between exercise and net change of HDL-C. Univariate regression analyses investigated the correlation of exercise characteristics. Subgroup and sensitivity analyses were performed to explore the sources of heterogeneity and the effect of potential confounders. The influence of pre-exercise lipid profile was assessed by meta-regression. Data were analyzed using Stata SE (12.0). Results: Fourteen studies with a total of 777 subjects were included. The mean HDL-C was reported to be increased and was statistically significant (weighted mean difference: 4.41 mg/dL; 95% confidence interval [CI]: 2.16–6.66 mg/dL, P