Is longer duration of exclusive breastfeeding associated with decreased risk of childhood cancers? : Study

Despite its rarity compared to adult cancers, childhood cancer remains a significant concern, with various types affecting young individuals. Leukaemia, brain tumours, lymphomas, and neuroblastomas are among the most prevalent forms. According to global statistics, approximately 300,000 children below the age of 15 are diagnosed with cancer each year.

Previous research has suggested that breastfeeding is associated with a reduced risk of childhood cancers, such as acute lymphoblastic leukemia (ALL), the most common cancer in childhood. Meta-analyses and pooled studies have shown that children breastfed for at least 6 months had an approximately 20% lower risk of developing ALL or leukaemia in general compared with those breastfed for shorter durations or not at all.

In the study, researchers used administrative data on exclusive breastfeeding duration from the Danish National Child Health Register. All children born in Denmark between January 2005 and December 2018 with available information on duration of exclusive breastfeeding were included. Children were followed up from age 1 year until childhood cancer diagnosis, loss to follow-up or emigration, death, age 15 years, or December 31, 2020. Data were analyzed from March to October 2023.

The result revealed that among the 3,09,473 children included in the study,332 children (0.1%) were diagnosed with cancer at ages 1 to 14 years. Of these, 124 (37.3%) were diagnosed with hematologic cancers (81 [65.3%] were acute lymphoblastic leukemia, 74 [91.4%] of which were B-cell precursor. Compared with exclusive breastfeeding duration of less than 3 months, exclusive breastfeeding for 3 months or longer was associated with a decreased risk of hematologic cancers, which was largely attributable to decreased risk of BCP-ALL, but not with the risk of central nervous system tumours or solid tumours.

The findings suggested that the association between breastfeeding and childhood BCP-ALL risk, if determined to be causal, could be mediated by preventing this immunologic dysregulation. Specifically, breastfeeding provides passive protection against infections and inflammation through antibody transmission and anti-inflammatory properties and also directly influences the shaping of the infant’s gut microbiome, important for immune system maturation.

Reference: Signe Holst Søegaard, PhD; Mie Mølgaard Andersen, BSc; Klaus Rostgaard, MSc; et al; Exclusive Breastfeeding Duration and Risk of Childhood Cancers; Journal: JAMA Network Open; doi:10.1001/jamanetworkopen.2024.3115