Exploring Exclusive Breastfeeding and Childhood Cancer Using Linked Data
Menée à l'aide de données portant sur 309 473 enfants nés au Danemark entre 2005 et 2018, cette étude analyse l'association entre la durée de l'allaitement maternel exclusif et le risque de cancer infantile (1-14 ans, 332 cas) par sous-type
Søegaard and colleagues investigated whether prolonged exclusive breastfeeding (defined as ≥3 months) was associated with childhood cancer. Their register-based study included all children in the Danish National Child Health Register who were born between 2005 and 2018 and who had information about exclusive breastfeeding, defined as breast milk supplemented only by water or milk formula (maximum of once weekly). Until 2011, the reporting of exclusive breastfeeding in Denmark was voluntary (data available for 21% of births) but became mandatory in 2012 (data available for 62% of births). These data were linked to other population-based registers (Medical Birth Register, Civil Registration System, Population Education Register, Danish National Patient Register, and Danish Cancer Register). Children were followed up until diagnosis, loss to follow-up or emigration, death, age 15 years, or December 31, 2020 (ie, minimum of 2 years of follow-up). Using Cox proportional hazards regression and based on approximately 310 000 births and 1.6 million person-years of follow-up, the authors found that children who were exclusively breastfed for at least 3 months had a decreased risk of hematologic cancers (based on 124 cases), particularly B-cell precursor acute lymphoblastic leukemia (BCP-ALL; 74 cases), compared with those who were breastfed for less than 3 months. No such association was found for central nervous system (CNS) tumors (44 cases) or solid tumors (80 cases). The study was underpowered to investigate rarer cancers, such as acute myeloid leukemia (AML) or Hodgkin lymphoma.