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.

Exposure of young children to household water lead in the Montreal area (Canada): the potential influence of winter-to-summer changes in water lead levels on children's blood lead concentration.

Drinking water represents a potential source of lead exposure. The purpose of the present study was to estimate the magnitude of winter-to-summer changes in household water lead levels (WLLs), and to predict the impact of these variations on BLLs in young children. A study was conducted from September, 2009 to March, 2010 in 305 homes, with a follow-up survey carried out from June to September 2011 in a subsample of 100 homes randomly selected. The first 1-L sample was drawn after 5 min of flushing, followed by a further 4 consecutive 1-L samples after 30 min of stagnation. Non-linear regression and general linear mixed models were used for modelling seasonal effects on WLL. The batchrun mode of Integrated Exposure Uptake Biokinetic (IEUBK) model was used to predict the impact of changes in WLL on children's blood lead levels (BLLs). The magnitude of winter-to-summer changes in average concentrations of lead corresponded to 6.55 µg/L in homes served by lead service lines (LSL+ homes) and merely 0.30 µg/L in homes without lead service lines. For stagnant samples, the value reached 10.55 µg/L in 'LSL+ homes' and remained very low (0.36 µg/L) in 'LSL- homes'. The change in the probability of BLLs ≥5 µg/dL due to winter-to-summer changes in WLL was increased from <5% (in winter) to about 20% (in summer) in children aged 0.5-2 years. The likelihood of having BLLs ≥5 µg/dL in young children during warm months was reduced by at least 40% by flushing tap-water.