Comparison of birth weight corrected for gestational age and birth weight alone in prediction of development of childhood leukemia and central nervous system tumors.

Background: High birth weight (HBW) is an established risk factor for childhood acute lymphoblastic leukemia (ALL). The purpose of this study was to evaluate if birth weight (BW) corrected-for-gestational age is a better predictor than BW alone for occurrence of ALL and other malignancies in children.

Methods: Birth certificate data of 2,254 children with cancer who were younger than 5 years old at diagnosis and registered at Texas Cancer Registry during 1995-2003 were compared to 11,734 age-matched controls. Multivariable logistic regression was used to compare models with BW corrected-for-gestational age and BW alone.

Results: Compared to children who were appropriate for gestational age (AGA), children who were large for gestational age (LGA) at birth had a 1.66 times (95% CI 1.32-2.10) higher odds of ALL. Similarly, children with a BW > or =4,000 g had a 1.5 times (95% CI 1.18-1.89) higher odds for ALL, compared to children who weighed >2,500 and <4,000 g at birth. Using model diagnostics, the model containing BW corrected-for-gestational age was a better predictor than the model with BW alone [Akaike's Information Criterion (AIC) 4,646 vs. 4,658, respectively]. Odds ratios (OR) were similar for LGA children who were <4,000 g and LGA children who were > or =4,000 g (OR = 1.5, 95% CI 0.97-2.5 and OR = 1.67, 95% CI 1.29-2.16, respectively). BW was not an independent risk factor for acute myeloid leukemia or brain tumors.

Conclusions: BW corrected-for-gestational age is a better predictor than BW alone of risk for ALL. Future studies using BW variable should incorporate gestational age in their analyses.