All statistical analyses were performed using PASW (v. 18.0 for Windows, Chicago, IL). Hardy Weinberg equilibrium was tested using a chi-squared test. We compared allele and genotype frequencies in cases and controls using the chi-squared test with a set at 0.05. All statistical comparisons were corrected for multiple comparisons using the Bonferroni method, in which the threshold p value is obtained by dividing 0.05 by the number of polymorphisms studied.

The inclusion criteria for young adults (controls) were: (1) Age 50 years, (2) free of any diagnosed cardiometabolic disease, and (3) having no known family history of high longevity (90+ years). We also used logistic regression to analyze the association between alleles and longevity after adjusting for sex. The frequency of the CC genotype in the control group was 0%, while it was 2.8% in centenarians (2 men, 1 woman). This marginal association remained when studying only men in both cohorts, i.e., v2 = 15.696, p < 0.001 for the between-group frequency of CC genotype, but not when studying only women (v2 = 2.940, p = 0.230). We found no odds ratio for any of the genotypes or alleles we studied.

All genotype distributions met Hardy-Weinberg equilibrium in both the control and centenarian groups (p > 0.05), except for TFAM Ser12Thr (rs1937) in the centenarians group (p < 0.001). Figures 1 and 2 show the allele and genotype frequencies, respectively, in the two study groups. When studying men and women together in the two cohorts, we found no significant between-group differences (all p > 0.1), except for the genotype frequency of rs1937 (v2 = 11.440, p = 0.003), with no representation of the CC genotype in the control cohort versus a total frequency of *3% in centenarians, including among them the oldest person in Europe until September 2012 (a disease-free man aged 111 years).

The polymorphisms we studied have been associated with several health/disease phenotypes related to mitochondrial function, notably the variant Ser allele of the PPARGC1A Gly482Ser (rs8192678) variation is associated with risk of type 2 diabetes, insulin resistance, obesity, dyslipidemia, hypertension, and low aerobic fitness. Yet, we found no association of genetic variants in the PPARD-PPARGC1A-NRF-TFAM pathway and extreme longevity. We only found a marginal association for the TFAM Ser12Thr (rs1937) polymorphism when studying the two sexes together or only men separately, with a certain survival benefit existing for the rare, low-risk CC genotype. More research is needed on other genetic variants potentially associated with maintenance of mitochondrial function.The text seems to be a part of a scientific paper discussing the role of genetic variants in the mitochondriogenesis pathway in extreme longevity. Here's the processed text:

Phenotype, with elite endurance athletes showing a higher frequency of the C allele than non-athletic controls. Regarding this, a shift toward a more aerobic phenotype could have a beneficial influence on health-related phenotypes and longevity, with classic studies in rats by Koch's and Britton's groups showing improved mitochondrial fitness may be a common factor linking physical fitness and decreased disease risk. Acknowledgment: This study was funded by the Fondo de Investigaciones Sanitarias (FIS, ref. PS09/00194 and PI12/00914). Author Disclosure Statement: No competing financial interests exist.

The renewal of mitochondria through the process of biogenesis is vital for maintaining mitochondrial integrity, and a diminished capacity for organelle biogenesis has been implicated in the pathogenesis of several diseases as well as in the aging process. A role for mitochondrial dysfunction in aging is evidenced by mtDNA mutator mice that express a proofreading-deficient mitochondrial DNA polymerase gamma. These mutant mice have increased mtDNA mutations and display age-related phenotypes, including severe sarcopenia that is likely due to defects in the assembly of functional electron chain transport complexes. Similar findings of increased mtDNA mutagenesis and reduced mitochondrial enzyme activities have been reported in human skeletal muscle with age. However, our findings and those recently reported by our group with part of the present centenarians cohort do not support a major role of genetic variants in mtDNA or in the PPARD-PPARGC1A-NRF-TFAM mitochondriogenesis pathway on extreme longevity. Other genetic variants not studied here or other non-genetic factors that are known to influence mitochondriogenesis, such as exercise or calorie restriction, might be more influential to extreme longevity.

Because all of the following criteria were met: The phenotype exceptional longevity was properly defined with all cases being centenarians (living 100+ years is still a rare phenotype, i.e., 1 every 10,000 people), both groups of cases and controls were ethnically matched, genetic assessment was unbiased, all genotype distributions were in Hardy-Weinberg equilibrium in the control group, and we adjusted our statistical analyses for multiple comparisons. The relatively low sample size of the centenarians cohort is a limitation. Future research is needed with larger sample sizes, especially with more centenarian men, to corroborate the existence of an association between rs1937 and extreme longevity or whether this association is sex-dependent. The lack of data in a replication cohort of a different ethnic background also limits the external validity (and therefore generalizability) of our results. On the other hand, while keeping in mind the aforementioned limitations, we believe the major strength of our study stems from its novelty and in the rationale for studying genetic variants in the mitochondriogenesis pathway.

In summary, common genetic variants in the PPARD-PPARGC1A-NRF-TFAM pathway (rs2267668, rs8192678, rs6949152, rs12594956, rs1937) are not associated with extreme longevity.The processed text is: