Evidence check: FTO in the context of Langlebigkeit

FTO gene variants are associated with obesity risk, but their direct link to longevity is weak. Common risk alleles (e.g., rs9939609) increase BMI by ~0.3–0.4 kg/m² per copy, which may indirectly affect lifespan through obesity-related diseases. However, large longevity studies have not consistently found FTO variants to be significant predictors of extreme longevity. Lifestyle factors (diet, physical activity) can attenuate the genetic effect. Consumer DNA tests reporting FTO should be interpreted with caution: the effect is small, not deterministic, and not validated for longevity prediction. Evidence for a direct FTO–longevity connection is unclear; the indirect obesity pathway is mechanistically plausible but insufficient for clinical use.