Impact of breastfeeding on morbidity during the first two years of life

Introduction : Breastfeeding (BF) has demonstrated multiple benefits for the mother–infant dyad, including immunological protection for the child. This study assessed the relationship between breastfeeding patterns and morbidity during the first two years of life. Methods : A secondary analysis of the Lactancia y Desarrollo Infantil (LAYDI) study was conducted. This was a single-cohort trial carried out by the Primary Care Pediatric Research Network (PAPenRed), involving 320 pediatricians. Each pediatrician recruited one newborn per month over one year and followed them up to 24 months of age. Demographic, feeding, and morbidity data were collected at seven visits (<15 days, and at 1, 2, 6, 12, 18, and 24 months). Results : 2046 infants were included. BF showed a protective effect against common conditions such as constipation in the early visits (p<0.001), and against infectious diseases After adjustment for confounders (“having siblings” and “attendance at childcare centers”) (p<0.001 at 12 and 18 months). BF also provided specific protection against the most frequent acute infections—otitis media, conjunctivitis, bronchiolitis, gastroenteritis, and wheezing episodes—with adjusted statistical significance (p<0.005). Exclusive breastfeeding (EBF) for 6 months conferred long-term protection, particularly against acute otitis media (12, 18, and 24 months; p<0.001, <0.004, and <0.036). Confounders acted as risk factors for each of these infections. Conclusions : BF protects against common digestive disorders in infancy (constipation, colic, regurgitation) and against infectious diseases. EBF for 6 months provides sustained adjusted protection (12–24 months) against the 19 conditions studied, particularly the most prevalent ones. These results substantiate the protective relationship between breastfeeding and reduced morbidity, extending at least through the first two years of life.