A prospective cohort study of cutaneous leishmaniasis risk and opium addiction in south eastern Iran.

Opium addiction and cutaneous leishmaniasis (CL) are endemic in different parts of Iran, particularly in Bam, where a massive earthquake occurred. This study was designed to compare the incidence rate and severity of CL cases among opium addicted and non-addicted individuals in south-eastern Iran. This study was carried out as a prospective cohort by active house-to-house visits of 1,481 habitants in Bam. CL cases were confirmed by smear and identification of Leishmania species was performed using nested-PCR. The data was analyzed by χ(2) and t-tests, using SPSS software and also Kaplan-Meier survival curve and long-rank test in Stata 11.2 and P<0.05 was considered as significant. A total of 904 individuals consisting of 226 opium addicted and 678 non-addicted individuals were followed-up for a period of seven years. The two cohorts were similar in terms of age, sex and place of residency. A similar pattern of incidence was observed among the two cohort groups. In contrast, the severity of CL in terms of the number, duration and the size of the lesions in opium addicted individuals was significantly (P<0.001) higher than non-opium addicted individuals. In conclusion, the present findings indicate that there is no relationship between the incidence of CL and opium addiction.