Breastfeeding in infancy and mortality in middle and late adulthood: A prospective cohort study and meta-analysis

Abstract

Background: Breastfeeding in infancy is associated with a lower risk of mortality among children, but the impact on mortality in middle and late adulthood remains unknown. Objectives: To assess the association between breastfeeding in infancy and mortality in middle and late adulthood. Methods: We included 383,627 participants aged 40–73 from the UK Biobank (2006–2010) and followed up until 2021. Hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortality according to breastfeeding in infancy were estimated with Cox proportional hazards regression models. We further did a meta-analysis, including results from our present study and three other cohort studies (PROSPERO; number CRD42022348925). Results: During a total of 4732,751 person-years of follow-up, 25,581 deaths were identified. Breastfeeding in infancy was associated with lower risks of mortality in middle and late adulthood, with adjusted HRs (95% CIs) of 0.95 (0.93–0.98) for all-cause mortality; 0.91 (0.87–0.96) for cardiovascular mortality and 0.94 (0.874–0.999) for respiratory mortality. Specifically, the association with mortality seemed to attenuate with age – stronger in middle-aged adults than in older adults. A similar association between breastfeeding in infancy and all-cause mortality was found in the meta-analysis. Conclusion: Breastfeeding in infancy is associated with a lower risk of mortality – even decades later – in middle and late adulthood.