Assessing the Global, Regional, and National Burden of Childhood Lower Respiratory Infections From Nonexclusive Breastfeeding, 1990–2021: Global Burden of Disease, Injuries, and Risk Factors Study 2021 Analysis and Implications for Public Health Stra

BACKGROUND: Nonexclusive breastfeeding is a major risk factor for childhood lower respiratory infections, yet its global burden remains unquantified. Although exclusive breastfeeding is widely recommended, the attributable burden of early infancy lower respiratory infections linked to nonexclusive breastfeeding and cross-country performance gaps have not been systematically assessed. This analysis fills that gap by combining burden estimates with frontier benchmarking. METHODS: Using the Global Burden of Diseases, Injuries, and Risk Factors Study 2021 database, we estimated deaths, disability-adjusted life years, age-standardized mortality rates, age-standardized disability-adjusted life-year rates, and population attributable fractions of lower respiratory infections attributable to nonexclusive breastfeeding across 204 countries and territories from 1990 to 2021. Temporal trends were assessed with joinpoint regression, and frontier analysis was applied to identify efficiency gaps. RESULTS: In 2021, nonexclusive breastfeeding accounted for 37,890 lower respiratory infection deaths and 3.41 million disability-adjusted life years globally, with boys carrying a higher burden. India, Nigeria, and Pakistan had the largest absolute numbers, whereas Chad, Somalia, and South Sudan had the highest standardized rates. Neonates (<28 days old) showed the highest mortality and disability-adjusted life-year rates, indicating greater vulnerability than with infants aged 1-5 months. Globally, age-standardized mortality rates and age-standardized disability-adjusted life-year rates declined significantly from 1990 to 2021 (average annual percentage change -4.87%), although sub-Saharan Africa and South Asia still bore the heaviest burden. Frontier analysis revealed substantial potential for further reduction in low- and low-middle sociodemographic index countries through improved breastfeeding and health system strengthening. CONCLUSION: Despite global progress, nonexclusive breastfeeding remains a major contributor to childhood lower respiratory infections, particularly among neonates and in low-sociodemographic index settings. Strengthening breastfeeding promotion and maternal-child health services is critical to reducing mortality, morbidity, and regional inequities. To achieve this, scaling evidence-based policies, such as Baby-Friendly practices, community lactation support, maternity protection, and strong enforcement of the International Code of Marketing of Breast Milk Substitutes is essential.