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.
Keywords: Biomarkers; Cadmium; Long-term use; Marijuana.
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