BACKGROUND

This systematic review was conducted as part of the U.S. Department of Agriculture and Department of Health and Human Services Pregnancy and Birth to 24 Months Project. The goal of this systematic review was to examine the following question: What is the relationship between shorter versus longer durations of exclusive human milk feeding and childhood leukemia? This systematic review examines comparisons of infants who were fed human milk exclusively for shorter durations with infants who were fed human milk exclusively for longer durations. was defined as feeding human milk alone and not in combination with infant formula and/or complementary foods or beverages such as cow’s milk. This definition is inclusive of the World Health Organization definitions of and , which permit limited quantities of (a) drops or syrups containing vitamins, minerals, or medicines, (b) water and water-based drinks such as sweetened water and teas, (c) fruit juice, (d) oral rehydration salts solution, and (e) ritual fluids. was defined as mother’s own milk provided at the breast (i.e., nursing) or expressed and fed fresh or after refrigeration or freezing. Donor milk (e.g., banked milk) was not examined in this review. includes acute childhood leukemia, generally, as well as acute lymphoblastic leukemia, specifically.

CONCLUSION STATEMENT AND GRADE

There is no evidence to determine whether or not there is a relationship between shorter versus longer durations of exclusive human milk feeding and childhood leukemia. : Grade Not Assignable.

METHODS

The systematic review was conducted by a team of staff from the Nutrition Evidence Systematic Review in collaboration with a Technical Expert Collaborative. A single literature search was conducted to identify literature for several related systematic reviews that examined infant milk-feeding practices and different outcomes. The search was conducted in CINAHL, Cochrane, Embase, and PubMed, and used a search date range of January 1980 to March 2016. A manual search was done to identify articles that may not have been included in the electronic databases searched. Articles were screened independently by 2 NESR analysts to determine which articles met predetermined criteria for inclusion. Because no articles were identified that met the inclusion criteria, the conclusion statement and grade reflect the absence of evidence and that no grade was assignable to the strength of the evidence.

SUMMARY OF EVIDENCE

No articles met the inclusion criteria for this systematic review.