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Association of Exclusive Breastfeeding Duration With Risk of Childhood Cancers
TAKE-HOME MESSAGE
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This cohort study evaluated the association of the duration of exclusive breastfeeding with the risk of developing childhood cancers, specifically acute lymphoblastic leukemia. Of note, 0.1% of children were diagnosed with cancer during the study period. Exclusive breastfeeding for 3 months or longer was associated with a decreased risk of hematologic cancer, specifically acute lymphoblastic leukemia. There was no association between exclusive breastfeeding for 3 months or longer and the risk of developing solid tumors or central nervous system tumors.
- Clinicians should continue to counsel patients on the benefits of exclusive breastfeeding, including a decreased risk of developing hematologic cancers.
abstract
This abstract is available on the publisher's site.
Access this abstract nowIMPORTANCE
Breastfeeding has been suggested to protect against childhood cancers, particularly acute lymphoblastic leukemia (ALL). However, the evidence stems from case-control studies alone.
OBJECTIVE
To investigate whether longer duration of exclusive breastfeeding is associated with decreased risk of childhood ALL and other childhood cancers.
DESIGN, SETTING, AND PARTICIPANTS
This population-based cohort study 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.
EXPOSURE
Duration of exclusive breastfeeding in infancy.
MAIN OUTCOMES AND MEASURES
Associations between duration of exclusive breastfeeding and risk of childhood cancer overall and by subtypes were estimated as adjusted hazard ratios (AHRs) with 95% CIs using stratified Cox proportional hazards regression models.
RESULTS
A total of 309 473 children were included (51.3% boys). During 1 679 635 person-years of follow-up, 332 children (0.1%) were diagnosed with cancer at ages 1 to 14 years (mean [SD] age at diagnosis, 4.24 [2.67] years; 194 boys [58.4%]). Of these, 124 (37.3%) were diagnosed with hematologic cancers (81 [65.3%] were ALL, 74 [91.4%] of which were B-cell precursor [BCP] ALL), 44 (13.3%) with central nervous system tumors, 80 (24.1%) with solid tumors, and 84 (25.3%) with other and unspecified malignant neoplasms. 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 (AHR, 0.66; 95% CI, 0.46-0.95), which was largely attributable to decreased risk of BCP-ALL (AHR, 0.62; 95% CI, 0.39-0.99), but not with risk of central nervous system tumors (AHR, 0.96; 95% CI, 0.51-1.88) or solid tumors (AHR, 0.87; 95% CI, 0.55-1.41).
CONCLUSIONS AND RELEVANCE
In this cohort study, longer duration of exclusive breastfeeding was associated with reduced risk of childhood BCP-ALL, corroborating results of previous case-control investigations in this field. To inform future preemptive interventions, continued research should focus on the potential biologic mechanisms underlying the observed association.
Additional Info
Disclosure statements are available on the authors' profiles:
Exclusive Breastfeeding Duration and Risk of Childhood Cancers
JAMA Netw Open 2024 Mar 04;7(3)e243115, SH Søegaard, MM Andersen, K Rostgaard, OB Davidsson, SF Olsen, K Schmiegelow, H HjalgrimFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Breastfeeding and childhood cancers
This cohort study from the Danish National Child Health Register followed 309,473 children born in Denmark from January 2005 to December 2018. Of these, 332 children (0.1%) were diagnosed with cancer (mean age at diagnosis, 4.24 years) comprising 37.3% hematologic cancers, 13.3% central nervous system tumors, 24.1% solid tumors, and 25.3% other and unspecified malignant neoplasms.
The primary outcomes were the associations between the duration of exclusive breastfeeding and the overall risk of childhood cancer and by subtype. Findings were mixed. Exclusive breastfeeding for 3 months or longer, compared with exclusive breastfeeding duration of less than 3 months, was associated with an overall 21% risk reduction in childhood cancer, primarily attributable to a 38% risk reduction in B-cell precursor acute lymphocytic leukemia (BCP-ALL). No significant risk reduction in central nervous system tumors or solid tumors was found due to the increased duration of exclusive breastfeeding.
The authors noted that the significant association between longer duration of exclusive breastfeeding and the risk of childhood BCP-ALL is consistent with studies implicating early gut microbiome maturation in the pathogenesis of BCP-ALL and recommended that future studies investigate the underlying biologic mechanisms.
What does this mean clinically?
Exclusive breastfeeding for the first 6 months provides significant benefits for the breastfeeding dyad, which are important to communicate to families. For the infant, these include decreased rates of otitis media, respiratory tract infections, severe diarrhea, asthma, eczema, Crohn’s disease, ulcerative colitis, obesity, type 1 and 2 diabetes, SIDS, leukemia, and overall infant mortality.1 Human milk provides both optimal macronutrients for infant growth and a unique composition, specific to each dyad, of living leukocytes and immunomodulatory, antimicrobial, and anti-inflammatory agents to augment the developing immune system of the child.2
Primary care physicians have an important role to play in promoting breastfeeding during pregnancy and supporting lactation during the initial period of exclusive breastfeeding and from 6 to 24 months or beyond after the introduction of appropriate complementary foods.3 They should familiarize themselves with basic breastfeeding physiology and management,4 local lactation consultants who can provide breastfeeding families with additional hands-on assistance,5,6 and resources for the safety of medications and substances during breastfeeding.7,8,9
They are encouraged to reference the Academy of Breastfeeding Medicine protocols, which provide the most up-to-date evidence-based recommendations regarding breastfeeding and lactation, and to consult breastfeeding and lactation medicine (BFLM) subspecialists for additional clinical support.10
References