Lead poisoning outbreak among opium users in the Islamic Republic of Iran, 2016–2017

Objective To describe an outbreak of lead poisoning among opium users in the Islamic Republic of Iran and estimate the number of affected people in the country. Methods We used data from the country's largest poison treatment centre to illustrate the epidemiology of an outbreak of lead poisoning in oral opium users. We describe the government's referral and treatment guidelines in response to the outbreak. Based on the number of individuals treated and previous studies on the prevalence of oral opium use we estimated the total number of people at risk of lead-contaminated opium nationwide. Findings In February 2016, we noticed a steep increase in the numbers of oral opium users referred to our poison treatment centre with abdominal pain, anaemia and constipation. Numbers peaked in June 2016 but the outbreak was ongoing in August 2017. The mean blood lead level in a sample of 80 patients was 140.3 µg/dL (standard deviation: 122.6). Analysis of an illegal opium sample showed 3.55 mg lead in 1 g opium. Treatment was exposure reduction with opioid substitutes and laxatives, or chelation therapy if indicated. Over 7 months, 4294 poison cases were seen at main referral hospitals in Tehran out of an estimated 31 914 oral opium users in the city. We estimate more than 260 000 out of 773 800 users nationwide remain untreated and at risk of poisoning. Conclusion Lead-contaminated opium and heroin that has transited through the Iranian markets is a global risk and highlights a need for better monitoring of illegal drug supplies.