Vitamin K and childhood cancer

• concern about the safety of i.m. vitamin K surfaced in the early 1990's with the publication of two papers reporting an association between intramuscular vitamin K and later childhood cancer (1,2). An association was found between cancer and drugs given to the neonate, especially intramuscular vitamin K
• a case-control study assessed this association by comparing 195 children with cancer born in the two major Bristol maternity hospitals from 1965-87 with 558 controls - an increased risk of cancer was found in children given i.m. vitamin K around birth (odds ratio 1.97, 95% confidence interval 1.3 - 3.0) but not in those given oral vitamin K
• a retrospective case-control study (3) has shown an association between i.m. vitamin K and acute lymphoblastic leukaemia developing at age 1-6 years

The Committee on Safety of Medicines (CSM) and the Medicine Control Agency (MCA) formed an Expert Working Group to review all the available studies:

• the Working Group concluded that there is no increased risk of solid tumours in association with vitamin K. Also, though an increase in risk of leukaemia cannot be excluded, the group stated that the observed results in studies relating vitamin K and leukaemia were compatible with the play of chance
• the group concluded that there was no basis for recommending a change to the current licensing of i.m. vitamin K.

Reference:

• Golding J et al (1990), Br J Cancer, 62, 304-8.
• Golding J et al (1992), BMJ, 305, 341-6.
• Parker L et al (1998), BMJ, 316, 189-93.
• Current Problems in Pharmacovigilance (1998), 24, 1-4.