Association of Cow's Milk Protein Allergy Prevalence With Socioeconomic Status in a Cohort of Chilean Infants

Objectives: The aim of the study was to compare the cow's milk protein allergy (CMPA) prevalence in 2 cohorts of children from different socioeconomic strata. Methods: Prospective birth cohort that included patients from 2 hospitals providing care for a low- and high-income population, respectively. Healthy newborns >= 34 gestational weeks were recruited and followed up to 12 months by a monthly telephone survey. If >= 2 predefined symptoms/signs suggestive of CMPA were detected, the patient was evaluated by a pediatric gastroenterologist. Diagnosis was confirmed by exclusion diet followed by open oral food challenge. Results: Overall the prevalence of CMPA was 5.2%, with a 6 times higher prevalence in the high income cohort (9.2%) compared with the low-income group (1.5%; relative risk 6.2; 95% confidence interval 1.8-20.7;P = 0.0005). All the cases were non-immunoglobulin E-mediated with predominantly gastrointestinal symptoms. High-income cohort did have higher frequency of C-section, mother's previous chronic disease, mother's history of atopy/food allergy, older age, and higher educational level of parents. Parent smoking and presence of pets at home were more frequent in the low-income cohort. Multiple logistic regression showed that the high-income cohort did have older age and higher educational level of both parents. Conclusion: In these cohorts the prevalence of CMPA was higher than reported previously in other developing countries and significantly higher in the high-income group. Our findings were associated with sociodemographic characteristics of the parents.