In 8,516 Canadian adults (mean age 62.6), women earning under $20K annually showed metabolomic ages averaging 1.14 years older than women earning $100K+, with a clear income dose-response gradient persisting after adjustment for behavioral risk factors and chronic conditions. Women in middle income brackets ($20K–$50K and $50K–$100K) were 0.90 and 0.70 years older metabolomically, respectively. Interleukin-6 showed a similar dose-response in both sexes, but the metabolomic aging gradient appeared exclusive to women. Six DNA methylation clocks—including GrimAge2 and DunedinPACE—were also assessed alongside CRP and TNF-α.
This finding carries real weight for longevity science. Metabolomic age integrates hundreds of circulating metabolites into a single biological clock, making it arguably more functionally rich than single-biomarker measures. The sex-specific pattern is striking: chronic socioeconomic stress may activate distinct biological aging pathways in women—possibly via neuroendocrine or hormonal mechanisms—that don't manifest the same way in men. This aligns with growing evidence that psychosocial stress disproportionately accelerates female biological aging, though causality remains unproven in cross-sectional designs like this one.
Critical limitations: the cross-sectional design prohibits causal inference, the cohort is Canadian and predominantly older, and reverse causation (poor health reducing income) cannot be excluded. As a preprint not yet peer-reviewed, these results should be interpreted cautiously. Still, the granular multi-clock approach and large, population-based sample make this incrementally important, particularly for sex-stratified public health policy.
