New research suggests breastfeeding children for six months or longer could reduce their risk of leukemia.

Leukemia is the most common childhood cancer, but its cause largely remains a mystery, the JAMA Network Journals reported. Breast milk is believed to provide all nutrients essential to an infant's development and health during the first six months of life.

A team of researchers looked at 18 studies on the link between breastfeeding and occurrences of childhood leukemia. All of the studies showed breastfeeding for six months or longer was associated with a 19 percent lower risk of childhood leukemia compared with breastfeeding for a shorter period of time or not breastfeeding at all. A separate analysis of 15 additional studies suggested children who were breastfed were 11 percent less likely to develop leukemia than those who were never breastfed.

The researchers believe several biological mechanisms are at play in the link between breastfeeding and reduced leukemia risk; breast milk contains a number of "immunologically active components and anti-inflammatory defense mechanisms" that have a strong influence on the development of the infant's immune system.

"Because the primary goal of public health is prevention of morbidity, health care professionals should be taught the potential health benefits of breastfeeding and given tools to assist mothers with breastfeeding, whether themselves or with referrals to others who can help. The many potential preventive health benefits of breastfeeding should also be communicated openly to the general public, not only to mothers, so breastfeeding can be more socially accepted and facilitated. In addition, more high-quality studies are needed to clarify the biological mechanisms underlying this association between breastfeeding and lower childhood leukemia morbidity," the study concluded.

The findings were published in a recent edition of the journal JAMA Pediatrics.