Prematurity, atopy, and childhood asthma in Puerto Ricans

Abstract

Background: Puerto Rican children share a disproportionate burden of prematurity and asthma in the United States. Little is known about prematurity and childhood asthma in Puerto Rican subjects.

Objective: We sought to examine whether prematurity is associated with asthma in Puerto Rican children.

Methods: We performed a case-control study of 678 children aged 6 to 14 years with (n = 351) and without (n = 327) asthma living in San Juan, Puerto Rico. Prematurity was defined by parental report for our primary analysis. In a secondary analysis, we only included children whose parents reported prematurity that required admission to the neonatal intensive care unit. Asthma was defined as physician-diagnosed asthma and wheeze in the prior year. We used logistic regression for analysis. All multivariate models were adjusted for age, sex, household income, atopy (≥1 positive IgE level to common allergens), maternal history of asthma, and early-life exposure to environmental tobacco smoke.

Results: In a multivariate analysis there was a significant interaction between prematurity and atopy on asthma (P = .006). In an analysis stratified by atopy, prematurity was associated with a nearly 5-fold increased odds of asthma in atopic children (adjusted odds ratio, 4.7; 95% CI, 1.5-14.3; P = .007). In contrast, there was no significant association between prematurity and asthma in nonatopic children. Similar results were obtained in our analysis of prematurity requiring admission to the neonatal intensive care unit and asthma.

Conclusions: Our results suggest that atopy modifies the estimated effect of prematurity on asthma in Puerto Rican children. Prematurity might explain, in part, the high prevalence of atopic asthma in this ethnic group.

Keywords: Childhood asthma; ETS; Environmental tobacco smoke; FVC; Forced vital capacity; NICU; Neonatal intensive care unit; OR; Odds ratio; Puerto Rican; atopy; prematurity.

FIG 1

Results of the multivariate logistic regression analysis of prematurity and asthma after stratification by atopy (defined as ≥1 positive allergen-specific IgE). Multivariate models were adjusted for age, sex, household income, maternal history of asthma, and early-life exposure to ETS. Goodness of fit for each of the multivariate models was assessed by using the Hosmer-Lemeshow test (P = .9 for the model in nonatopic children and P = .9 for the model in atopic children).