the role of lead exposure on attention-deficit/‎‏ ‏hyperactivity ‎disorder ‎in children: a systematic review

objective: attention-deficit/hyperactivity disorder (adhd) is one of the most common behavioral ‎disorders in children effecting the families and society. this systematic review examined ‎the literature on the role of lead exposure in children with adhd‏ ‏symptoms. articles were ‎analytically compared, focusing on the methodology used to assess exposure and‏ ‏adverse ‎effects‏ ‏on children with adhd. ‎ method: using the search strategy from six databases (pub med, psycinfo, web of science, sid, ‎iran medex, iran doc), hand searching in key journals, list of references of selected ‎articles and gray literature, without time and language limitation, articles up to may 2014 ‎were entered into this review. in this review, 1,387 articles were acquired at the primary ‎search. study selection and quality assessment processes were done based on cochrane ‎library guidelines. after assessing the quality and inclusion and exclusion criteria, 18 articles ‎were selected and entered into the data synthesis.‎ results: blood lead level (bll) of less than 10µg/dl in children has been attributed to at least one ‎type of adhd i.e., combined / inattentive / hyperactive-impulsive. the results of this ‎study revealed that in 16 out of the 18 studies, a significant association was found between ‎bll and one of the types of adhd.‎ conclusion : based on the findings of this study, even the bll of less than the action level of 10µg/dl, ‎chosen by centers for disease control and prevention (cdc), may affect children with ‎adhd.‎