Exposure to lead through sources such as contaminated food, soil, and paint might have contributed to 5.5 million adult cardiovascular disease deaths and 765 million lost IQ points among children younger than 5 years in 2019, according to a new analysis of countries’ blood lead level estimates.
Low- and middle-income countries combined bore up to 95% of the losses. Moreover, the estimated IQ loss and deaths from cardiovascular disease were about 80% higher and 6 times greater, respectively, than earlier approximations for low- and middle-income countries.
One link frequently dismissed is the amount of heavy metals, including lead, found in cannabis. NHANES data suggest that cannabis users have higher levels of lead and cadmium in their blood and urine (1).
Also known is that cannabis is a soil remediator and hyperaccumulator of substances, including lead, which may end up being consumed by the unsuspecting person (2). There are higher blood lead levels in childhood associated with lower socioeconomic status and poorer cognitive functioning in adulthood (3).
It appears that with expansion of marijuana/cannabis programs across the country (and the world), there may be increased exposures to heavy metals, lead in particular, which can impact overall cognitive function, IQ in particular.
References
1. Katlyn E. McGraw, Anne E. Nigra, Joshua Klett, Marisa Sobel, Elizabeth C. Oelsner, Ana Navas-Acien, Xin Hu, and Tiffany R. Sanchez. Blood and Urinary Metal Levels among Exclusive Marijuana Users in NHANES (2005–2018). Environmental Health Perspectives 131:8 CID: 087019 https://doi.org/10.1289/EHP12074
2. Evangelia E. Golia, John Bethanis, Nikolaos Ntinopoulos, Georgia-Garifalia Kaffe, Amalia Athanasia Komnou, Charicleia Vasilou. Investigating the potential of heavy metal accumulation from hemp. The use of industrial hemp (Cannabis Sativa L.) for phytoremediation of heavily and moderated polluted soils. Sustainable Chemistry and Pharmacy, Volume 31, 2023, 100961, ISSN 2352-5541, https://doi.org/10.1016/j.scp.2022.100961.
3. Belsky DW, et al. Association of Childhood Blood Lead Levels With Cognitive Function and Socioeconomic Status at Age 38 Years and With IQ Change and Socioeconomic Mobility Between Childhood and Adulthood. JAMA. 2017;317(12):1244–1251. doi:10.1001/jama.2017.1712
