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

Background

Genetics 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.

Methods

Multi-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.

Results

Gly 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.

Conclusion

Lines 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 abbreviations

A

Asian

ACE

Angiotensin converting enzyme

ACTN3

Alpha (α)-actinin 3

AM

Analysis model

ANOVA

Analysis of variance

df

Degree of freedom

ES

Elevated significance

C

Caucasian

CB

Clark-Baudouin

CI

Confidence interval

CID

Confidence interval difference

E

Endurance

EH

Eliminated heterogeneity

F

Fixed-effects

Fs

Favoring SP

Ds

Disfavoring SP

Gly

Glycine

GS

Gain in significance

Het

Heterogeneity

HWE

Hardy-Weinberg Equilibrium

I2

Measure of variability expressed in %

K

Number designation of the study

Li

Lithuania

Log OR

Logarithm of OR

M

Mixed

maf

Minor allele frequency

M-H

Mantel-Haenszel

N

Null

NA

Not applicable

n

Number of studies

OR

Odds ratio

P

P-value

Pa

P-value for association

Pb

P-value for heterogeneity

Po

Poland

PPARGC1A

Peroxisome proliferator-activated receptor gamma co-activator-1-alpha

PRISMA

Preferred Reporting Items for Systematic Reviews and Meta-Analyses

PRO

Pre-outlier

PSO

Post-outlier

Pw

Power

R

Random-effects

[R]

Reference number

RH

Reduced heterogeneity

RNS

Retained non-significance

RS

Retained significance

Ru

Russia

SD

Standard deviation

SE

Standard error

Ser

Serine

Sig

Significance

SP

Sports performance