BIRTH CHARACTERISTICS OF CHILDHOOD-CANCER CASES, CONTROLS, AND THEIR SIBLINGS

Reproductive characteristics of childhood cancer cares, controls, and their siblings were examined using data from a case-control study in t he Denver, Colorado metropolitan area. Childhood cancer patients (n = 356) diagnosed from 1976 to 1983 were identified and 242 were intervie wed. Controls were selected by random digit dialing, with 212 intervie ws being completed (60% of eligibles). Extremes of birth weight were m ore common only among brain cancer cases. Patients were more often bor n preterm, particularly those with brain tumors [odds ratio(OR) = 6.1; 95% confidence interval (CI), 1.6-23.4] and were more likely to have birth defects(OR = 2.1; 95% CI, 0.9-5.0). Twins were more common among case siblings (OR = 2.6; 95% CI, 0.8-8.2). Low birth weight and prete rm delivery among siblings were related only to soft tissue sarcoma. B irth defects were more common among case siblings, particularly leukem ia cases (OR = 3.2; 95% CI, 1.3-7.7). Previous reports of elevated bir th weight among cases and increased risk of miscarriage in case mother s were not corroborated, but associations with preterm delivery, high birth order, and birth defects among cases and birth defects and twinn ing among case siblings encourage additional evaluation.