en Meta-analysis Review Meta-analysis Review <aside style="box-sizing: border-box; font-family: Arial; margin-bottom: 10px; font-size: 11px;"> <p style="box-sizing: border-box; margin: 0px 0px 10px; text-align: justify;"><b style="box-sizing: border-box;">Context:</b>&nbsp;Few possible risk factors for childhood leukemia including environmental, genetic, and infectious causes can be explained by epidemiologic studies but the etiology of most childhood leukemia is unknown.</p> </aside> <aside style="box-sizing: border-box; font-family: Arial; margin-bottom: 10px; font-size: 11px;"> <p style="box-sizing: border-box; margin: 0px 0px 10px; text-align: justify;"><b style="box-sizing: border-box;">Objectives:</b>&nbsp;In this systematic review and meta-analysis, we aimed to find the relationship between prenatal and maternal risk factors with leukemia children in Iran.</p> </aside> <aside style="box-sizing: border-box; font-family: Arial; margin-bottom: 10px; font-size: 11px;"> <p style="box-sizing: border-box; margin: 0px 0px 10px; text-align: justify;"><b style="box-sizing: border-box;">Data Sources:</b>&nbsp;Relevant studies published in English databases (PubMed, Scopus, and ISI) and Persian databases (Magiran, Medlib, SID, and Iran Medex)) were systematically searched.</p> </aside> <aside style="box-sizing: border-box; font-family: Arial; margin-bottom: 10px; font-size: 11px;"> <p style="box-sizing: border-box; margin: 0px 0px 10px; text-align: justify;"><b style="box-sizing: border-box;">Study Selection:</b>&nbsp;The study included all case-control studies that estimated the effects of prenatal and maternal risk factors on leukemia children in Iran during years 2004 to 2016, and a standardized manner was used for the extraction of information.</p> </aside> <aside style="box-sizing: border-box; font-family: Arial; margin-bottom: 10px; font-size: 11px;"> <p style="box-sizing: border-box; margin: 0px 0px 10px; text-align: justify;"><b style="box-sizing: border-box;">Data Extraction:</b>&nbsp;After reviewing all searched articles (title, abstract, and entire text), irrelevant studies were excluded and related ones were selected.</p> </aside> <aside style="box-sizing: border-box; font-family: Arial; margin-bottom: 10px; font-size: 11px;"> <p style="box-sizing: border-box; margin: 0px 0px 10px; text-align: justify;"><b style="box-sizing: border-box;">Results:</b>&nbsp;We identified 10 case-control studies. The first relative history of leukemia was associated with four times raises of leukemia in children aged 15 > years (OR = 4.58, 95% CI = 1.16 - 7.99). Other significant risk factors were mothers with birth order 3 &le; and maternal age > 35, ORs for these factors were respectively (OR = 2.39, 95% CI = 0.79 - 3.99) and OR = 2.25, 95% CI = 1.09 - 3.41).</p> </aside> <aside style="box-sizing: border-box; font-family: Arial; margin-bottom: 10px; font-size: 11px;"> <p style="box-sizing: border-box; margin: 0px 0px 10px; text-align: justify;"><b style="box-sizing: border-box;">Conclusions:</b>&nbsp;Our results indicate that among maternal and prenatal risk factors, birth order &ge; 3, birth weight < 2,500 g, and first relative history of leukemia increased the risk of childhood leukemia; in contrast, breastfeeding was a protective factor.</p> </aside> Child Leukemia, Leukemia, Leukemia, Risk Factors, Systematic Review 1 7 http://jpr.mazums.ac.ir/browse.php?a_code=A-10-30-73&slc_lang=en&sid=1 Yousef Veisani 10031947532846002338 10031947532846002338 No Psychosocial Injuries Research Center, Ilam University of Medical Sciences, Ilam, IR Iran Ali Delpisheh alidelpisheh@yahoo.com 10031947532846002339 10031947532846002339 Yes Department of Clinical Epidemiology, Ilam University of Medical Sciences, Ilam, IR Iran