The study’s goal was to assess the prevalence of cow’s milk protein allergy (CMPA) in two cohorts of children from different socioeconomic backgrounds. Prospective birth cohort of patients from two hospitals serving low- and high-income populations, respectively. Healthy infants 34 gestational weeks were enrolled and surveyed monthly for up to 12 months. A pediatric gastroenterologist was consulted if two specified symptoms/signs indicative of CMPA were identified. Exclusion diet followed by open oral food challenge verified the diagnosis. The overall prevalence of CMPA was 5.2 percent, with a 6 times greater frequency in the high-income cohort than in the low-income group. All of the instances were non-immunoglobulin E–mediated, with gastrointestinal symptoms being the most common. The high-income cohort had a greater incidence of C-sections, a mother’s past chronic condition, a mother’s history of atopy/food allergy, was older, and had parents with a higher educational level. Smoking by parents and the presence of pets at home were more common in the low-income group. Multiple logistic regression revealed that the high-income cohort had both parents who were older and had a higher educational degree.

The prevalence of CMPA in these cohorts was greater than previously documented in other developing nations, and it was substantially higher in the high-income group. The findings were related to the parents’ sociodemographic traits.