Lifetime marijuana use in relation to cadmium body burden of US adults: results from the national health and nutrition examination surveys, 2009-2016.

OBJECTIVES

Low-level cadmium exposure has been linked to chronic diseases, but the importance of marijuana use as a source of cadmium remains unknown. We aimed to determine the association of marijuana use with blood cadmium (BCd) and urinary cadmium (UCd) levels.

METHODS

We abstracted data from the National Health and Nutrition Examination Surveys, 2009-2016. We modeled lifetime marijuana exposure accounting for both duration and frequency of exposure. We used adjusted ratio of geometric means (ARM) and 95% confidence intervals (95% CIs) to compare outcomes among groups of marijuana exposure, relative to never users. The UCd level was adjusted for creatinine excretion.

RESULTS

We included 163,250 adults (mean age, 38.7 years; 50% women). The ARM of BCd was 1.28 (95% CI = 1.04, 1.57), 1.40 (95% CI = 1.11, 1.76), and 1.77 (95% CI = 1.51, 2.09) in current users with <2 uses per week, 2-3 uses per week, and ≥4 uses per week, respectively. Marijuana use for ≥15 years was associated with both higher cadmium burden in adults with <2 uses per week (ARM of 1.30 (95% CI = 1.04-1.62) for BCd and 1.48 (95% CI: 1.05, 2.09) for UCd or ≥4 uses per week (ARM of 1.69 (95% CI = 1.40, 2.05) for BCd and 1.38 (95% CI = 1.11, 1.72) for UCd. In former users, marijuana use was significantly associated with higher UCd levels in those with ≥15 years of use [ARM of 1.39 (95% CI = 1.14, 1.69) for those with <2 uses/week and 1.51 (95% CI = 1.19, 1.92) for those with ≥4 uses/week].

CONCLUSIONS

The BCd level was higher in both current and former marijuana users than in never users. Marijuana use was also associated with higher UCd levels after a long-term use.