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

The takeaway

Analysis of nearly 13,000 U.S. adults found current marijuana users had significantly accelerated biological aging by two validated measures, with blood cadmium (a toxin in smoke) explaining about 8-16% of the effect.

Cannabis smokers, aging researchers, public health advocates for alternative consumption methods

Current marijuana users showed significantly accelerated biological aging (p < 0.001)

What the researchers found

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.

Why it matters

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.

The numbers in context

12,806 adults; PhenoAge acceleration: beta = 0.72 (95% CI: 0.41-1.02, p < 0.001); KD-BioAge: beta = 0.36 (95% CI: 0.14-0.59, p = 0.002); cadmium mediation: 15.6% (PhenoAge) and 8.3% (KD-BioAge); additive effects for dual tobacco-marijuana users

How the study worked

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.

What this study cannot tell us

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.

How to read the evidence

Moderate: large nationally representative sample with validated aging biomarkers, but cross-sectional design and inability to separate smoking route from cannabis itself.

When this study was published

2026 publication analyzing NHANES 2005-2018 data.

The bigger picture

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.

Questions still open

Would non-smoked cannabis show the same aging acceleration? Is the remaining 84-92% of the effect unrelated to cadmium mediated through other pathways? Does accelerated biological aging from cannabis reverse with cessation?

Common questions

Does marijuana make you age faster?

This study found that current marijuana users had biological markers consistent with accelerated aging compared to never users, measured by two validated biological age algorithms. However, the cross-sectional design cannot prove cannabis caused the aging.

What role does cadmium play?

Cadmium, a toxic metal found in smoke, explained about 8-16% of the aging acceleration. This suggests that how cannabis is consumed (smoking vs. other methods) may partly determine its aging effects.

Read the original research

Current marijuana use is cross-sectionally associated with accelerated biological aging among U.S. adults: exploring mediating effect of blood cadmium.

The journal of nutrition, health & aging, 30(3), 100778

View on PubMed ↗Publisher’s paper ↗

Citation

Wei, Kai; Chen, Xiaotong. (2026). Current marijuana use is cross-sectionally associated with accelerated biological aging among U.S. adults: exploring mediating effect of blood cadmium.. The journal of nutrition, health & aging, 30(3), 100778. https://doi.org/10.1016/j.jnha.2026.100778