No or only population-specific effect of PON1 on human longevity: a comprehensive meta-analysis

Paraoxonase 1 (PON1) has been suggested as a plausible candidate gene for human longevity due to its modulation of cardiovascular disease risk, by preventing oxidation of atherogenic low-density lipoprotein. The role of the PON1 192 Q/R polymorphism has been analyzed for association with survival at old age in several populations, albeit with controversial results. To reconcile the conflicting evidence, we performed a large association study with two samples of 2357 Germans and 1025 French, respectively. We combined our results with those from seven previous studies in the largest and most comprehensive meta-analysis on PON1 192 Q/R and longevity to-date, to include a total of 9580 individuals. No significant association of PON1 192 Q/R with longevity was observed, for either R allele or carriership. This finding relied on very large sample sizes, is supported by different analysis methods and is therefore considered very robust. Moreover, we have investigated a potential interaction of PON1 192 Q/R with APOE epsilon4 using data from four populations. Whereas a significant result was found in the German sample, this could not be confirmed in the other examined groups. Our large-scale meta-analysis provided no evidence that the PON1 192 Q/R polymorphism is associated with longevity, but this does not exclude the possibility of population-specific effects due to the influence of, and interaction between, different genetic and/or environmental factors (e.g. diet).

PON1 is a longevity gene: results of a meta-analysis

Paraoxonase 1 (PON1) is one of the most studied genes regarding cardiovascular risk, oxidative stress and inflammation. Several lines of evidence suggests that PON1 promotes an atheroprotective effect. Patients carrying PON1 codon 192 QQ genotype display a higher risk of cardiovascular events, the major cause of mortality in the elderly: it can be predicted that gene variants increasing the risk of mortality will be under-represented in long-living individuals. We first reported that PON1 R allele (R+) carriers are significantly more represented in Italian centenarians; subsequently this topic has been addressed by many other groups, and here we report a meta-analysis on 11 studies in different populations selected by a review of the literature available in PubMed and testing the effect of the Q192R polymorphism on human ageing. QUORUM guidelines for meta-analysis have been followed, and a total number of 5962 subjects have been included: 2795 young controls (<65 years of age) and 3167 old subjects (>65 years of age). The Mantel-Haenszel weighting for pooling in presence of a fixed effects model has been applied. The meta-analysis of R carriers showed a significant result with an overall OR of 1.16 (1.04-1.30, 95% CI, p=0.006). The meta-analysis of QR genotype also showed a significant result, with an overall OR of 1.14 (1.02-1.27, 95% CI, p=0.016). The results show that PON1 gene variants at codon 192 impact on the probability of attaining longevity, and that subjects carrying RR and QR genotypes (R+ carriers) are favoured in reaching extreme ages. These results likely represent the counterpart of the effects observed on cardiovascular diseases (CVD), as centenarians and nonagenarians escaped or delayed the onset of the major age-related diseases, including CVD.