A Preliminary Report on the Largest Ongoing Outbreak of Lead Toxicity in Iran.

No countrywide data exists on the patients' characteristics of lead exposure in Iran. We aimed to evaluate the demographic characteristics and blood lead level (BLL) of these patients in the country scale during five consecutive years, including the epidemic outbreak year (2016). Between 2014 and 2018, records of all patients who had referred to two reference laboratories in Tehran, Iran, to check BLL were evaluated. Of 58,642 patients, 48,589 were male. Mean age was 44.9 ± 20.7 years. Males had higher BLLs and were significantly older. Median BLL was 16 µg/dL (0.3 to 263 µg/dL). Median BLL was significantly higher in 45- to 60-year-old patients. The highest median BLL was reported in May 2016 confirming our records about the peak of the epidemic. Although the frequency of high BLL declined after 2016, it never returned to the measures before that. Considering the ongoing high prevalence of increased BLLs after 2016 and similar environmental and occupational exposures as before, lead-contaminated opium still seems to persist in the Iranian opium black market. Substitution of this lead-contaminated opium by Opioid Maintenance Therapy (OMT)-prescribed opium tincture is recommended.