Neonatal vitamin K administration and childhood cancer in the North of England: a retrospective case control study

The authors studied 685 children born in the region between 1960 and 1991 who developed cancer between 1968 and 1992. Babies given oral vitamin K at birth or born after a multiple pregnancy were excluded from the case control study. There were 3,442 controls matched for date and hospital of birth. There was no increased risk for the development of all childhood cancers and all acute lymphoblastic leukaemia but there was a raised risk for acute lymphoblastic leukaemia developing 1-6 years after birth. The authors conclude that it is not possible to refute the suggestion that neonatal intramuscular vitamin K increases the risk of early childhood leukaemia.