Blood-lead level in humans and drug addiction: a comprehensive study in Iran

Drug abuse has a high prevalence worldwide and causes many health-related disorders. There are limited human exposure studies on establishing lead exposure levels and their propensity for drug addiction. In the present study, blood samples were tested for lead (Pb) concentrations in illicit drug users together with the related symptoms in comparison with control group of non-drug users. The study was performed on 250 volunteers divided equally in four drug groups, namely, opioids, hashish, methadone, and methamphetamine, and one control group of non-drug users. Participants were recruited from drug addiction clinics and camps in Kashan city, Iran, who were using drugs continuously for more than 1 year. Control group was recruited from companions of the patients with no drug use history. In the investigated groups of drug users, the highest blood-lead level (BLL) concentrations were observed in the opioid group (mean 37.57 µg/dL) with almost 3.7 times higher than in the control group (mean 3.39 µg/dL). In the methamphetamine group, type of occupation had the significant association with BLL concentrations. The positive correlation was revealed in the opioid and methadone groups for BLL concentrations and the duration of drug usage. In the opioid group, the highest BLL concentrations were observed among users who used both methods of drug use: smoking and eating. Also, several behavioral and life-style factors were identified which influence the blood-lead concentration in the drug users. The results of our study revealed that the BLL concentrations in investigated drug users' groups were significantly higher than in the control group (P < 0.001). That can be related with the Pb contents in illicitly used drugs. Apart other adverse health effects, long-term illicit drug use might cause to lead poisoning.