Birth weight and acute childhood leukemia : a meta-analysis of observational studies /

by Taylor, Jean

The major objective of this study was to determine whether high birth weight is associated with ALL and AML among children and to quantify the strength of the relationships. We conducted a meta-analysis of nine case-control studies (published between 1991 and 2004) encompassing over 6,200 children with ALL and over 12,000 controls. We found that children weighing 4,000 g or more at birth had 24% (OR: 1.24; 95% CI: 1.12, 1.37) higher odds of developing ALL than children weighing less (without consideration to reference weight). Regardless of peer-review status, response rates among cases and controls, or choice of threshold for high birth weight, studies consistently demonstrated a similar overall odds ratio ranging from 1.23 to 1.29. In addition, our data analysis identified possible reasons for inconsistent findings among previous studies that examined high birth weight as a risk factor for ALL. Possible explanations include: use of different reference birth weights, different data source for birth weight (i.e., birth certificate vs. interview), and different ethnic makeup of the study population. Our data supports the growing evidence for the link between high birth weight and childhood ALL. Women who are pregnant or considering pregnancy should know that unbounded weight gain may increase the odds of childhood ALL in their baby. Whether a positive association with high birth weight applies to AML is less clear from our results. Based on a meta-analysis of only three case-control studies (published between 1997 and 2004) involving over 700 children with AML and over 1,900 controls, high birth weight ( > 4,000 g) appeared to increase the odds of developing AML by 14% (OR: 1.14; 95% CI: 0.84, 1.54). Birth Weight and Acute Childhood Leukemia: A Meta-analysis of Observational Studies Doctoral Dissertation March 22, 2005 Jean Taylor, MPH DrPH Candidate Department of Preventive Medicine and Biometrics Uniformed Services University of the Health Sciences Committee Members: David Cruess, PhD (Chair) Robert Lipnick, ScD (Advisor) Michael Feuerstein, PhD, MPH Michele Forman, PhD, MS Jeffrey Jackson, MD, MPH Richard Thomas, MD, MPH