Evidence check: FOXO3 in the context of longevity

FOXO3 is a key transcription factor in the insulin/IGF-1 signaling pathway and one of the most robustly replicated genetic markers for human longevity. The most studied variant is rs2802292: carriers of the G allele show increased odds of reaching age 90 or 100 in multiple independent cohorts (German, Japanese, US). The effect size is modest – the G allele raises the chance of exceptional longevity by roughly 10–20 %, which must be viewed in the context of polygenic inheritance and the strong influence of lifestyle, environment, and chance. Mechanistically, FOXO3 is linked to improved stress resistance, reduced inflammation, and enhanced autophagy. Importantly, lacking the G allele does not imply a shortened lifespan; genetics is only one piece of the puzzle. The evidence is based on numerous GWAS and meta-analyses that consistently confirm the association. However, there is no clinical recommendation for a 'longevity gene' – the predictive power of a single SNP is limited. In summary, FOXO3 is a well-supported but moderate predictor of longevity that should be considered as part of a comprehensive health assessment.