Clinical characteristics and epidemiology of pediatric cow's milk protein allergy: a multicenter cohort study in urban China.

backgroundCow's milk protein allergy (CMPA) is the most common food allergy during infancy. Although the prevalence and natural history of allergic conditions have been well characterized in western populations, comprehensive data from rapidly urbanizing regions such as China remain scarce, limiting our understanding of how environmental transitions influence the developmental trajectories of allergic diseases.

methodsWe conducted a multicenter, cross-sectional survey of infants across five major regions in China between November 2018 and June 2019. Infants diagnosed with CMPA using a standardized protocol were subsequently enrolled in a prospective longitudinal follow-up at 3 years and 5 years after diagnosis.

resultsAmong 10,754 infants, 327 were diagnosed with CMPA, yielding a prevalence of 3.04%. Independent associated factors included higher birth weight, winter birth, antibiotic exposure within the first 6 months of life, formula feeding, a family history of allergy, pet exposure during pregnancy, and maternal use of progesterone and vitamin A. Exclusive breastfeeding and higher parental education were inversely associated with CMPA. At the 3-year follow-up, 94.47% of the children had developed tolerance to cow's milk protein. Longitudinally, the prevalence of food allergy and eczema decreased, whereas that of allergic rhinitis increased significantly after 5 years, suggesting a dynamic evolution of atopic manifestations over time.

conclusionsCMPA affects approximately 3.04% of infants in urban China. Despite the high prevalence of early tolerance development, the progression to other atopic conditions-particularly respiratory allergies-is frequently observed. Our findings highlight the long-term consequences of early-life food allergies and emphasize the need for integrated surveillance and preventive strategies within child health programs in transitioning societies.