Abstract

Context: 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. Objectives: In this systematic review and meta-analysis, we aimed to find the relationship between prenatal and maternal risk factors with leukemia children in Iran. Data Sources: Relevant studies published in English databases (PubMed, Scopus, and ISI) and Persian databases (Magiran, Medlib, SID, and Iran Medex)) were systematically searched. Study Selection: 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. Data Extraction: After reviewing all searched articles (title, abstract, and entire text), irrelevant studies were excluded and related ones were selected. Results: 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 <= 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). Conclusions: Our results indicate that among maternal and prenatal risk factors, birth order >= 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.