Common vaccines, infections not related to childhood leukemia

Intake of vitamin supplements was related to an increased risk for developing leukemia among children aged 0 to 5 years old, according to recent data.

Conversely, children who were breastfed for more than six months or who used immunosuppressant medications appeared to have a lower risk. There was also a nonsignificant inverse association between leukemia and children who received the measles-mumps-rubella vaccine after age 1 year.

Researchers from the Cancer Control Research Program of the British Columbia Cancer Agency conducted a case-control study to evaluate the association between postnatal exposures and the etiology of childhood leukemia.

They identified 399 case-control pairs using information from pediatric oncology treatment centers and population-based cancer registries to identify cases, and provincial government health insurance rolls to identify controls.

Information on risk factors, including childhood vaccinations, illnesses and medication use, was collected through personal interviews with each child’s parents or guardians. Immunization data was taken from vaccination records, if available. Researchers also asked parents about feeding patterns.

Data revealed no association between leukemia and exposure to common vaccines, including the diphtheria-tetanus-pertussis, poliomyelitis, hepatitis or Bacillus Calmette-Guérin vaccines. Researchers also found no association between leukemia and common infections, including measles, mumps, rubella, chicken pox and ear infections. – by Emily Shafer

Am J Epidemiol. 2008;167:598-606.

It has been asserted by several investigators that some genetic changes and markers for leukemia begin to develop in utero. Leukemia in children of this age group is a multi-step process, and there are a number of factors that will introduce multiple genetic changes. This study is too small to come to any firm conclusion, since the study size is inadequate. I am glad that the authors came out and said there is nothing wrong with immunization. In fact, they suggested a protective effect of the measles-mumps-rubella vaccine. They also suggested that breastfeeding for six months offers protection. These findings were also specific to the younger age group. I doubt the etiology is similar between children who develop leukemia before age 5 years, and those who develop the disease later.

– Laurence Boxer, MD

HemOnc Today Editorial Board member