The association of attention deficit hyperactivity disorder and blood lead level among children less than 10 years old referred to Tehran hospitals between 2007 and 2010

ADHD (attention deficit hyperactivity disorder) is one of the most common psychiatric disorders of children with prevalence of 5.29%, and lead as a neurotoxin is reported to cause abnormal behaviors. Differentiation of presentations of lead poisoning and ADHD may be impossible. This study aimed to compare blood lead level of children with ADHD and normal children. This case- control study was conducted in hospitals affiliated to Shahid Beheshti and Azad University in Tehran. 100 healthy children who had come to the clinic for general growth check up were assigned as control group, while case group were 100 children with the diagnosis of ADHD, by Conner's method that were confirmed to have ADHD by pediatrics psychiatrist in psychiatric clinics. Blood lead level (BLL) was measured in all participants in fasting state. Minimum BLL in control group was 1.8μg/dl, while in children with ADHD was 2.9μg/dl. Maximum BLL were 24.1 and 18.6 μg/dl among controls and those with ADHD, respectively. Mean BLL was 7.189±3.186 μg/dl in controls and 7.2±2.365 μg/dl in cases. There was no significant difference in blood lead level between two groups (p=0.987). Although BLL was higher in ADHD children, but was not proven to be significantly higher in ADHD children.