The various studies looking at the effects of breastfeeding on childhood leukemia have had inconclusive and inconsistent results. Experts, led by Marilyn Kwan at the School of Public Health, University of California, Berkeley, have taken 14 of these studies and analyzed them together as a group. This meta-analysis is published in the November 2004 Public Health Reports (the official journal of the US Public Health Service).
The pooled data suggests that children who are breastfed for 6 months or more have a 24 percent reduced chance of developing acute lymphoblastic leukemia (ALL), and a 15 percent reduced chance of developing acute myeloblastic leukemia (AML). These are the two most common forms of leukemia in childhood.
Those who breastfed for less than 6 months also had lower leukemia rates, but not as low as those who breastfed longer. It’s quite possible that the reduced leukemia rate came from something else in the environment that tended to differ between the breastfed and non-breastfed babies. But it is also possible that protection against cancer will become another in the growing list of proven benefits of nursing.
I’m excited that research in this area is continuing.