Is APOE useful for longevity?

Whether APOE is useful for longevity is not straightforward. APOE is a well-studied gene involved in lipid metabolism and cardiovascular health. The ε4 variant is associated with increased risk for Alzheimer's disease and cardiovascular disease, potentially shortening lifespan. The ε2 variant may offer some protective effects. However, the effects are modest and heavily influenced by lifestyle and environment. Evidence comes from human observational studies and GWAS, but no randomized controlled trials directly prove a causal effect on longevity. Moreover, a single gene has limited predictive power for a complex trait like lifespan. APOE testing can provide risk information but should not be interpreted as a direct longevity marker. The psychological impact of knowing an increased Alzheimer's risk is also a concern. Overall, APOE is useful as part of a comprehensive risk assessment, but not as a standalone longevity predictor.