Breastfeeding offers myriad benefits to mothers and babies. Now a new review of 18 previous studies published in the journal JAMA Pediatricsfinds that breastfeeding may lower the risk of childhood leukemia.
Childhood cancer is a leading cause of death among children and adolescents in developed countries, with leukemia accounting for 30 percent of childhood cancer cases.
For the present study, researchers led by Efrat Amitay of the School of Public Health at the University of Haifa in Israel performed a meta-analysis of available scientific evidence on the association betweenbreastfeeding and childhood leukemia.
After compiling studies examining the association between breastfeeding and childhood leukemia published between January 1960 and December 2014 in the PubMed, the Cochrane Library, and Scopus databases, the researchers identified 25 relevant studies. Studies included in the meta-analysis were case control studies that included breastfeeding as a measured exposure and leukemia as a measured outcome and data on breastfeeding duration in months. Of the total studies, 18 met inclusion criteria.
According to the review of the 18 studies, any breastfeeding for 6 months or longer was associated with a 19 percent lower risk of childhood leukemia compared with no or shorter breastfeeding.
A separate meta-analysis of 15 studies additionally found that any breastfeeding was associated with an 11 percent lower risk of childhood leukemia compared with no breastfeeding. The researchers do note that the definition of no breastfeeding differed between studies.
Overall, the meta-analysis reveals that breastfeeding for 6 months or longer may prevent 14 to 19 percent of all childhood leukemia cases.
The researchers hypothesize that breast milk may influence the development of the immune system, which may then influence the development of leukemia. Explains Amitay:
“Breast milk is a total food, intended by nature to exclusively supply all of the infant’s nutritional needs for the first few months of life. Breast milk is a live substance, containing antibodies manufactured by the mother and other unique qualities that promote a healthy flora in the intestines of the infant and influence the development of the child’s immune system.”
Elizabeth Ward, an epidemiologist with the American Cancer Society who was not involved with the meta-analysis, cautions that the present study does not establish a cause-effect relationship between breastfeeding and reduced childhood leukemia risk.
Regardless, Amitay argues that breastfeeding offers many benefits to mothers and child:
“Breast-feeding is a highly accessible and low-cost preventive public health measure that has been found in numerous studies to be associated not only with lower risk for childhood leukemia but also with lower risk for Sudden Infant Death Syndrome (SIDS), gastrointestinal infection, ear infection, type 2 diabetes and obesity later in life.”
Another recent study found that prolonged breastfeeding during childhood is linked to higher intelligence, longer schooling and greater earnings among adults.