Infant infections, respiratory symptoms, and allergy in relation to timing of rice cereal introduction in a United States cohort

Abstract

Rice products marketed in the USA, including baby rice cereal, contain inorganic arsenic, a putative immunotoxin. We sought to determine whether the timing of introduction of rice cereal in the first year of life influences occurrence of infections, respiratory symptoms, and allergy. Among 572 infants from the New Hampshire Birth Cohort Study, we used generalized estimating equation, adjusted for maternal smoking during pregnancy, marital status, education attainment, pre-pregnancy body mass index, maternal age at enrollment, infant birth weight, and breastfeeding history. Among 572 infants, each month earlier of introduction to rice cereal was associated with increased risks of subsequent upper respiratory tract infections (relative risk, RR = 1.04; 95% CI: 1.00-1.09); lower respiratory tract infections (RR = 1.19; 95% CI: 1.02-1.39); acute respiratory symptoms including wheeze, difficulty breathing, and cough (RR = 1.10; 95% CI: 1.00-1.22); fever requiring a prescription medicine (RR = 1.22; 95% CI: 1.02-1.45) and allergy diagnosed by a physician (RR = 1.20; 95% CI: 1.06-1.36). No clear associations were observed with gastrointestinal symptoms. Our findings suggest that introduction of rice cereal earlier may influence infants' susceptibility to respiratory infections and allergy.

Figure 1

Adjusted Risk Ratios (95% CIs) for Each Month Earlier of Introduction of Rice Cereal According to Outcome Severity, N = 572 infants. RR indicates risk ratio for health outcomes according to reported severity. The circles indicate RR at each severity level for each outcome. The lines indicate the 95% confidence intervals. The grey line represents the null RR = 1. Number of total outcome cases in three repeated measures is denoted by n. Number of observed outcomes can be higher due to repeated events among time points for each infant. Abbreviations: RR risk ratio. Sample size N = 571 for fever analyses.