Breast-feeding for at least six months reduces the risk of childhood leukemia and lymphoma by 19 percent, according to researchers at the University of Haifa.
The results are based on a meta-analysis of 18 studies done over half a century, covering 28,000 children from around the world. The 28,000 subjects covered by the meta-analysis far exceeded the 5,000 subjects in the largest individual study.
The cause of childhood cancers is poorly understood. Leukemia, though rare, is the most common. Breast-feeding could help reduce the risk of childhood leukemia and lymphoma by bolstering the baby's immune system.
“Breast-feeding should be strongly encouraged,” concluded the lead researcher, Dr. Efrat Amitay of the University of Haifa’s School of Public Health. “Future mothers should be educated about it, and medical personnel should be ... given the tools to help mothers who want to breast-feed or are having trouble breast-feeding.”
A separate analysis of 15 studies found that children who were breast-fed only sometimes as infants still had an 11-percent lower incidence of leukemia compared to those who were not breast-fed at all.
Every year, 400 Israeli children are diagnosed with cancer, 170 to 190 of them with leukemia or lymphoma.
A year and a half ago, the Health Ministry and Israel Cancer Association published a study by Amitay and Dr. Lital Keinan-Boker on the link between breast-feeding and cancer rates.
According to that study, exclusive breast-feeding in the first four months was linked to a 43-percent reduction in childhood leukemia and lymphoma. That study was based on Amitay’s doctoral work.
Amitay then conducted her meta-analysis — an analysis of a number of studies published over a long period. Sampling questions and research questions thus vary.
“For example, researchers in various studies may not have distinguished between full and partial breast-feeding, when biologically there’s a big difference,” said Amitay.
At the first stage, the researchers considered articles published from 1960 to 2014 in which the terms “breast-feeding,” “childhood cancer” or “childhood leukemia” were mentioned.
After articles that did not touch on a direct link between breast-feeding and childhood leukemia were excluded, 25 articles remained, 18 of which met all the criteria the researchers sought to study such as breast-feeding for at least six months, whether exclusive or not. The articles came from a raft of countries including Russia, China, Oman and the United Arab Emirates.
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