Blood and Urinary Metal Levels among Exclusive Marijuana Users in NHANES (2005–2018)

• Type of Material: Article
• Authors: Katlyn E. McGraw, Columbia University; Anne E. Nigra, Columbia University; Joshua Klett, Columbia University; Marisa Sobel, Columbia University; Elizabeth C. Oelsner, Columbia University; Ana Navas-Acien, Columbia University; Xin Hu, Emory University; Tiffany R. Sanchez, Columbia University
• Language: English
• Date: 2023-08-30
• Publisher: EHP Publishing
• Publication Version: Final Published Version
• Copyright Statement: EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted.
• Final Published Version (URL): https://ehp.niehs.nih.gov/doi/10.1289/EHP12074
• Title of Journal or Parent Work: Environmental Health Perspectives
• Volume: 131
• Issue: 8
• Start Page: 087019
• Grant/Funding Information: This work has been funded by National Institutes of Health (NIH) NIH National Institute of Environmental Health Sciences (NIEHS) P30 Center for Environmental Health and Justice, P30ES9089 (T.R.S.), NIH Kirschstein National Research Service Award Institutional Research Training Grant T32ES007322 (K.E.M).
• Keywords: metal biomarker level; tobacco; lead; cannabis; Marijuana; contaminants; cadmium
• Research Categories: Health Sciences, Public Health

Abstract

Background: Marijuana is the third most used drug in the world. Objectives: Because the cannabis plant is a known scavenger of metals, we hypothesized that individuals who use marijuana will have higher metal biomarker levels compared with those who do not use. Methods: We combined data from the National Health and Nutrition Examination Survey (2005–2018) for 𝑛=7,254 participants, classified by use: non-marijuana/non-tobacco, exclusive marijuana, exclusive tobacco, and dual marijuana and tobacco use. Five metals were measured in blood and 16 in urine using inductively coupled plasma mass spectrometry; urinary metals were adjusted for urinary creatinine. Results: Participants reporting exclusive marijuana use compared with non-marijuana/non-tobacco use had statistically significantly higher mean cadmium levels in blood [1.22μg/L (95% CI: 1.11, 1.34); 𝑝<0.001] and urine [1.18μg/g (95% CI: 1.0, 1.31); 𝑝=0.004] and statistically significantly higher mean lead levels in blood [1.27μg/dL (95% CI: 1.07, 1.50); 𝑝=0.006] and urine [1.21μg/g (95% CI: −0.006, 1.50); 𝑝=0.058]. Discussion: Our results suggest marijuana is a source of cadmium and lead exposure. Research regarding cannabis use and cannabis contaminants, particularly metals, should be conducted to address public health concerns related to the growing number of cannabis users.