title: Birth weight as a risk factor for childhood leukemia: a meta-analysis of 18 epidemiologic studies.
abstract: Evidence has emerged that childhood leukemia is initiated in utero. High birth weight is one of the few birth-related factors that has been associated with childhood leukemia, albeit not consistently. The authors conducted a meta-analysis of studies of the association between birth weight and childhood leukemia risk. Study-specific odds ratios for leukemia were calculated, using a cutoff at 4,000 g of birth weight. The authors also evaluated whether the association between birth weight and leukemia followed a log-linear dose-response-like pattern. They calculated summary estimates using weighted averages of study-specific odds ratios from dichotomous and trend analyses. Eighteen studies (published between 1962 and 2002) were included, encompassing 10,282 children with leukemia. Children weighing 4,000 g or more at birth were at higher risk of acute lymphoblastic leukemia than children weighing less (odds ratio (OR) = 1.26, 95% confidence interval (CI): 1.17, 1.37). Furthermore, data were consistent with a dose-response-like effect (OR = 1.14/1,000-g birth weight increase, 95% CI: 1.08, 1.20). Studies of acute myeloid leukemia indicated a similar increase in risk for children weighing 4,000 g or more at birth (OR = 1.27, 95% CI: 0.73, 2.20) and a dose-response-like effect (OR = 1.29/1,000 g, 95% CI: 0.80, 2.06), but results varied across studies. Our findings support a relation between birth weight and childhood acute lymphoblastic leukemia risk and emphasize the need for additional studies of the biologic mechanisms underlying this association.
authors.affiliation: Department of Epidemiology Research, Danish Epidemiology Science Center, Statens Serum Institut, Copenhagen, Denmark. LIH@SSI.dk
authors.forename: Lisa Lyngsie
authors.initials: LL
authors.lastname: Hjalgrim
authors.forename: Tine
authors.initials: T
authors.lastname: Westergaard
authors.forename: Klaus
authors.initials: K
authors.lastname: Rostgaard
authors.forename: Kjeld
authors.initials: K
authors.lastname: Schmiegelow
authors.forename: Mads
authors.initials: M
authors.lastname: Melbye
authors.forename: Henrik
authors.initials: H
authors.lastname: Hjalgrim
authors.forename: Eric A
authors.initials: EA
authors.lastname: Engels
mesh_terms: D000293:Adolescent; D000328:Adult; D001724:Birth Weight; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000453:epidemiology* / Q000209:etiology; D012042:Registries; D012307:Risk Factors