Evidence check: TCF7L2 in the context of Langlebigkeit

TCF7L2 is a well-established risk locus for type 2 diabetes (GWAS, rs7903146). In a longevity context, the evidence is indirect: the variant moderately increases diabetes risk (OR ~1.4), which in turn can shorten lifespan. No direct studies link TCF7L2 variants to longevity beyond diabetes as a mediating factor. Effect sizes are population-dependent and not causal for longevity. Consumer DNA tests often list TCF7L2 as a 'metabolism gene,' but clinical actionability is low – lifestyle factors dominate. Supplementation or specific diets based on this gene are not evidence-based. Beware of exaggerated claims. Evidence grade: gwas (for diabetes), unclear for longevity.