PRENATAL VITAMIN SUPPLEMENTATION AND PEDIATRIC BRAIN-TUMORS - HUGE INTERNATIONAL VARIATION IN USE AND POSSIBLE REDUCTION IN RISK

An international case-control study of primary pediatric brain tumors included interviews with mothers of cases diagnosed from 1976-1994 and mothers of population controls. Data are available on maternal vitami n use during pregnancy for 1051 cases and for 1919 controls in eight g eographic areas of North America, Europe and Israel. While risk estima tes varied by study center, combined results suggest that maternal sup plementation for two trimesters may decrease risk of brain tumor [odds ratio (OR)=0.7; 95% confidence interval (CI)=0.5-0.9], with a trend t oward less risk with longer duration of use (P trend= 0.0007). The gre atest risk reduction was among children diagnosed under 5 years of age whose mothers used supplements during all three trimesters (OR=0.5; C I=0.3-0.8). This effect did not vary by histology and was seen for sup plementation during pregnancy rather than during the month before preg nancy or while breast feeding. These finding are largely driven by dat a from the US, where most mothers took vitamins. The proportion of con trol mothers who took vitamins during pregnancy varied tremendously, f rom 3% in Israel and in France through 21% in Italy, 33% in Canada, 52 % in Spain to 86-92% at the three US centers. The composition of the v arious multivitamin compounds taken also varied: daily dose of vitamin C ranged from 0 up to 600 mg; vitamin E from 0 to 70 mg; vitamin A fr om 0 to 30,000 IU and folate from 0 to 2000 mg. Mothers also took indi vidual micronutrient supplements (e.g., vitamin C tablets), but most m others who took these also took multivitamins, making it impossible to determine potential independent effects of these micronutrients.