Current marijuana users showed signs of accelerated biological aging, partly explained by cadmium exposure from smoking

Current marijuana users showed significantly accelerated aging versus never users on both PhenoAge (beta = 0.72, p < 0.001) and KD-BioAge (beta = 0.36, p = 0.002). Dual users of marijuana and tobacco showed additive effects. Blood cadmium was a partial mediator, explaining 15.6% of PhenoAge acceleration and 8.3% of KD-BioAge acceleration.

Cross-sectional analysis of 12,806 U.S. adults from NHANES 2005-2018. Biological age calculated using two validated algorithms (PhenoAge and KD-BioAge). Aging acceleration defined as residuals from regression of biological age on chronological age. Survey-weighted multivariable regression with mediation analyses.

This is one of the first large studies to link marijuana use to accelerated biological aging using validated biomarker-based measures, and it identifies a potential mechanistic pathway through cadmium exposure from smoking.

Combined with the Klotho study (RTHC-08700), this represents growing evidence that cannabis use may affect biological aging markers. The cadmium mediation finding suggests that the route of administration (smoking) matters, raising questions about whether non-smoked cannabis would have the same effect.

Cross-sectional design cannot establish causation. Cannot distinguish route of cannabis administration (smoked vs. edible vs. vaped). Cadmium exposure could reflect tobacco co-use despite adjustments. Self-reported marijuana use may be inaccurate.