Phenotypic age acceleration through a lens of intersectional inequalities in the German National Cohort (NAKO).

PURPOSE: Biological aging differences are linked to sociodemographic characteristics, but how intersecting social dimensions shape these differences remains unclear. Integrating aging biology and intersectionality theory, we examined the joint influence of multiple social determinants on phenotypic age acceleration (biological vs. chronological age).

METHODS

Using data from 173,925 participants in the German NAKO study, we calculated phenotypic age acceleration based on blood-based biomarkers and created 72 intersectional social strata based on sociodemographic factors. We assessed differences across strata using intersectional Multilevel Analysis of Individual Heterogeneity and Discriminatory Accuracy (I-MAIHDA).

RESULTS

All intersectional strata displayed phenotypic age deceleration (biologically younger than chronological age). The advantage was smallest among men without migration background, living alone and with low socioeconomic status. Substantial discriminatory accuracy (7.13%) revealed intersectional inequalities, predominantly driven by additive effects. Modest interaction effects indicated increased risk for individuals with migration background not living alone and medium/high socioeconomic status and those without migration background living alone with medium/low socioeconomic status.

CONCLUSIONS

Our findings suggest that intersectional strata shape biological aging beyond chronological age, potentially through cumulative physiological effects of chronic psychosocial stress. Future epidemiological research should explore the mechanisms linking intersecting social dimensions and biological aging, designing intersectionally-informed targeted interventions.