What role does TCF7L2 play in longevity?

TCF7L2 is a transcription factor gene with one of the strongest GWAS associations for type 2 diabetes risk. Its role in longevity is indirect: risk variants (e.g., rs7903146) impair insulin secretion and glucose homeostasis, increasing diabetes risk, which in turn can reduce lifespan. However, the effect on overall longevity is modest and heavily modulated by diet, physical activity, and body weight. No direct longevity studies for TCF7L2 were found in the provided context; evidence is extrapolated from diabetes and mortality research. Evidence grade: human-moderate (strong for diabetes, indirect for longevity). A single gene variant does not determine lifespan. Consumer tests reporting TCF7L2 variants offer lifestyle suggestions, not medical predictions. Caveat: without integrating lifestyle and clinical data, individual interpretation is limited.