Parental consanguinity and susceptibility to drug abuse among offspring, a case-control study.

Consanguineous marriage is the union of individuals having at least one common ancestor. It is well established that consanguinity is a potential risk factor for many adverse health outcome of offspring. In the present case-control study we tested the hypothesis of an association between parental consanguinity marriages and risk of offspring substance abuse. The study was performed in Shiraz (Fars province, Iran). Here 156 male drug abusers (case group) and 264 randomly selected healthy blood donors, matched for age and gender as control group, were included in the study. The prevalence of parental consanguineous marriages in the studied sample was 39.1 and 28.0% among cases and controls, respectively. The difference was statistically significant. The substance abusers were more smokers and drinkers compared with the control group. There was significant negative linear trend between drug abuse and level of education. The participants stratified using drinking habits and then the analysis was carried out separately for drinker and non-drinker subjects. Among drinkers, neither before nor after adjusting for smoking status and educational level, parental consanguinity did not show association with risk of substance abuse. Among non-drinkers, after adjusting for smoking status and educational level, parental consanguineous marriage was significantly associated with increased risk of substance abuse. Our study supports a significant relationship between parental consanguinity and drug abuse among non-drinker subjects.