Background: Leukemia incidence in childhood has been shown to increase with birth weight. The purpose of this paper is to study whether the incidence of other childhood cancers also increases with birth weight.
Methods: The Norwegian Medical Birth Registry was linked to the Norwegian Cancer Registry. The data consisted of 1.65 million children, of whom 3252 had a cancer diagnosis before age 16 years. The diagnoses were divided into 1010 leukemia cases, 870 cancer cases of the central nervous system (CNS), and 1370 remaining cancers.
Results: The increase in hazard rate for all cancers with a 1 kg increase in birth weight was 1.23 (95% confidence interval = 1.14-1.32) after adjustment. For leukemia the increase was 1.29 (1.14-1.47), for CNS cancers 1.07 (0.93-1.23), and for the remaining cancer diagnoses 1.29 (1.16-1.40).
Conclusions: There seems to be a general relationship between heavier birth weight and cancer incidence in childhood.