Strict breastfeeding has been linked to reduced risk of blood cancer in children

Scientists from Denmark have found that under certain conditions exclusive breastfeeding can reduce the likelihood of hematologic cancers in children, including acute lymphoblastic leukemia.

It is known from the scientific literature that in Europe one in 350 children under 15 years of age is diagnosed with cancer. Cancer is the leading cause of deaths due to disease in children older than infancy. At least 10% of pediatric cancers are associated with rare germline cell mutations, but the causes of most childhood cancers remain unclear. As a consequence, doctors do not yet have established methods of prevention.

However, new research suggests a possible cancer-protective effect of mother's milk on children. A meta-analysis of previous work in this area showed that babies who were breastfed for at least six months had about a 20% lower risk of acute lymphoblastic leukemia, the most common type of cancer in children, than those whose mothers fed their milk for less than six months or who were fed artificial formula. Researchers also found a link between breastfeeding and a lower likelihood of developing acute myeloid leukemia, Hodgkin's lymphoma and neuroblastoma in childhood.

A new contribution to the topic was recently made by Danish researchers. In the paper, which was published by the medical journal JAMA Network Open, they looked at data from Denmark's National Health System Registry on nearly 310,000 children born in the country between January 2005 and December 2018 for whom information on the duration of exclusive breastfeeding was available. By this term, the authors mean feeding on mother's milk only, with the possibility of drinking water and adding formula to the diet no more than once a week.

Comparing the data with information from other Danish population databases, the experts followed the fate of the children, emphasizing details such as childhood cancer diagnosis and death. Observations continued until these events or until the age of 15 and the end of 2020. In some cases, tracking was discontinued due to children moving out of the country or for other reasons.

Using statistical analysis techniques and a Cox regression model, the researchers assessed the association between the duration of exclusive breastfeeding and pediatric cancer risk - overall and by subtype. It turned out that those who were exclusively breastfed for three months or more were more than one-third less likely to develop hematologic cancers, especially acute lymphoblastic leukemia, than children who were exclusively breastfed for less time.

No such association was found for central nervous system oncopathologies. For solid types of cancerous tumors, the risk reduction was 13%, which, given the 80 cases of such diseases, was considered statistically not very significant.

Pediatric cancer research is complicated by the rarity of such diseases and limited sample sizes. Although the Danish scientists looked at data from more than 300,000 children over 14 years, that was not enough to draw conclusions for some cancers, such as acute myeloleukemia, Dr. Helen D. Bailey of Curtin School of Medicine at Curtin University in Australia said in a commentary on the paper

Nevertheless, the findings are important because they move health professionals forward in finding ways to prevent pediatric cancer. Previously, Chinese scientists have shown that mother's milk not only directly stimulates a baby's immune system, but also acts on it indirectly by regulating the number of gut microbes on which the baby's immunity depends.