How are SHBG and Langlebigkeit related?

SHBG (sex hormone-binding globulin) is a protein that regulates the bioavailability of sex hormones like testosterone and estradiol. Higher SHBG levels are often associated in epidemiological studies with better metabolic health – lower risk of type 2 diabetes, metabolic syndrome, and cardiovascular disease. These conditions are linked to longevity. However, the evidence for a direct causal role of SHBG on lifespan is limited. SHBG is strongly influenced by insulin resistance, obesity, liver function, and age – it may be more a biomarker than a causal factor. Genetic variants in the SHBG gene (e.g., rs1799941) have small effects on SHBG concentration, but the association with longevity is weak and inconsistent. In summary: SHBG is an interesting metabolic marker, but not a direct 'longevity gene test'. The predictive power of direct-to-consumer tests for SHBG and longevity is low; lifestyle factors dominate.