Lead poisoning among asymptomatic individuals with a long-term history of opiate use in Golestan Cohort Study

Background: Recent reports of lead poisoning suggest that people who use opium may be exposed to high amounts of lead. Here, we investigate the association between opium use and blood lead levels (BLL) in a population-based cohort study. Methods: In 2017, we studied a random sample of 410 people who currently (both within the past year and the past month) used opium and 104 who did not from participants of the Golestan Cohort Study in northeast Iran. Participants were stratified by sex and tobacco use history, completed a comprehensive opiate and tobacco use questionnaire and provided blood. BLL was measured by Lead Care® II Blood Lead Test Kit, validated by inductively coupled plasma triple quadrupole mass spectrometry. BLL was categorized as �<5 µg/dL�, �elevated� (5-10 µg/dL), �high� (10-50 µg/dL), and �very high� (above 50 µg/dL). To assess the association between BLL categories and opiate use, route of consumption and weekly use, we used ordered logistic regression models, and report OR (odds ratio) and 95 CI (confidence interval) adjusted for age, sex, place of residence, education, occupation, household fuel type, and tobacco use. Results: In the cohort, participants used only raw (teriak) or refined (shireh) opium, which were smoked (45, n = 184), taken orally (46, n = 189), or both (9, n = 37), for a mean duration of 24.2 (standard deviation: 11.6) years. The median BLL was significantly higher in people who currently used opium (11.4 µg/dL; IQR: 5.2-23.4) compared with those who did not (2.3 µg/dL; IQR: 2.3-4.2), and the highest median BLL was seen in oral use (21.7 µg/dL; IQR: 12.1-34.1). The BLL was