ADMINISTRATION OF VITAMIN-K TO NEWBORN-INFANTS AND CHILDHOOD-CANCER

Objectives-To investigate whether childhood cancer is associated with intramuscular administration of vitamin K to newborn infants. Design-R outines for administration of vitamin K to infants born after normal d eliveries during 1973-89 were obtained from maternity hospitals. Occur rence of cancer up to the end of 1991 was identified by comparing thes e records with the national cancer registry. Adherence to the routine method of administering vitamin K was checked with the medical records of a sample of 396 infants (196 who had developed childhood cancer an d 200 controls). Setting-All maternity hospitals in Sweden. Subjects-1 384 424 full term infants born after non-instrumental deliveries, 1 0 85 654 of whom were born in units where vitamin K was routinely given by intramuscular injection and 272 080 of whom were born where it was given orally. Main outcome measures-Odds ratios for cancer after intra muscular administration of vitamin K versus oral administration after stratification for year of birth. Results-Adherence to routine method of administering vitamin K was 92% in the 235 cases where individual i nformation could be found. The risk of cancer after intramuscular admi nistration of vitamim K was not elevated compared with that after oral administration: odds ratios of 1.01 (95% confidence interval 0.88 to 1.17) for all childhood cancers and 0.90 (0.70 to 1.16) for childhood leukaemia. Conclusions-The alleged association between intramuscular v itamin K prophylaxis to newborn infants and childhood cancer could not be verified in the present study of full term infants born after non- instrumental delivery.