Effect of PPARGC1A Gly428Ser (rs8192678) polymorphism on athletic sports performance: A meta-analysis
Authors: Tharabenjasin Phuntila , Pabalan Noel , Jarjanazi Hamdi 
Published: July 2018

AbstractBackgroundGenetics plays a role in sports performance (SP) which, in this study, is measured by power and endurance activities as well as a mix between the two. However, variable results from genetic association studies warrant a meta-analysis to obtain more precise estimates of the association between PPARGC1A Gly482Ser polymorphism and SP.MethodsMulti-database literature search yielded 14 articles (16 studies) for inclusion. Pooled odds ratios (ORs) and 95% confidence intervals (CI) were used in estimating associations. Summary effects were modified based on statistical power. Subgroups were SP (power, endurance and mixed) and race (Caucasians and Asians). Heterogeneity was assessed with the I2 metric and its sources examined with outlier analysis.ResultsGly allele effects significantly favoring SP (OR > 1.0, P < 0.05) form the core of our findings in: (i) the homogeneous overall effect at the post-modified, post-outlier level (OR 1.13, 95% CI 1.03-1.25, P = 0.01, I2 = 0%); (ii) initially homogeneous power SP (ORs 1.22-1.25, 95% CI 1.05-1.44, P = 0.003-0.008, I2 = 0%) which precluded outlier treatment; (iii) pre-outlier Caucasian outcomes (ORs 1.29-1.32, 95% CI 1.12-1.54, P = 0.0005) over that of Asians with a pooled null effect (OR 0.99, 95% CI 0.72-1.99, P = 0.53-0.92); (iv) homogeneous all > 80% (ORs 1.19-1.38, 95% CI 1.05-1.66, P = 0.0007-0.007, I2 = 0%) on account of high statistical power (both study-specific and combined). In contrast, none of the Ser allele effects significantly favored SP and no Ser-Gly genotype outcome favored SP. The core significant outcomes were robust and comparisons subjected to publication bias test showed no evidence of it.ConclusionLines of evidence show that the Gly allele effects favor SP. These were observed in the overall, Caucasians and statistically powered comparisons which exhibited consistent significance, stability, robustness, precision and lack of bias, all of which provide good evidence of associations between the Gly allele and SP.List of abbreviationsAAsianACEAngiotensin converting enzymeACTN3Alpha (α)-actinin 3AMAnalysis modelANOVAAnalysis of variancedfDegree of freedomESElevated significanceCCaucasianCBClark-BaudouinCIConfidence intervalCIDConfidence interval differenceEEnduranceEHEliminated heterogeneityFFixed-effectsFsFavoring SPDsDisfavoring SPGlyGlycineGSGain in significanceHetHeterogeneityHWEHardy-Weinberg EquilibriumI2Measure of variability expressed in %KNumber designation of the studyLiLithuaniaLog ORLogarithm of ORMMixedmafMinor allele frequencyM-HMantel-HaenszelNNullNANot applicablenNumber of studiesOROdds ratioPP-valuePaP-value for associationPbP-value for heterogeneityPoPolandPPARGC1APeroxisome proliferator-activated receptor gamma co-activator-1-alphaPRISMAPreferred Reporting Items for Systematic Reviews and Meta-AnalysesPROPre-outlierPSOPost-outlierPwPowerRRandom-effects[R]Reference numberRHReduced heterogeneityRNSRetained non-significanceRSRetained significanceRuRussiaSDStandard deviationSEStandard errorSerSerineSigSignificanceSPSports performance