Neighborhood disadvantage and the back-to-school epidemic of viral-associated asthma exacerbations.

Abstract

Rates of viral-associated asthma exacerbations typically increase when children return to school after the summer holiday. The effect of neighborhood disadvantage on this back-to-school increase in viral-associated asthma exacerbations is unknown. We aimed to evaluate the effect of neighborhood disadvantage on the back-to-school increase in asthma-related emergency department (ED) visits. Administrative health records were used to define population-based incidence rates of asthma-related ED visits by week and census tract among children aged 5 to 17 years. Using Bayesian regression models of incidence rates, we evaluated additive interactions between a 7-week back-to-school period (relative to a 6-week summer period) and neighborhood disadvantage (eg, captured by the Social Vulnerability Index [SVI]). In census tracts with low social vulnerability (SVI = 2), rates of asthma-related ED visits increased by an average of 378 (95% credible interval [CrI] = 358-398) per 100,000 person years when children went back to school. Relative to the back-to-school increase in tracts with low social vulnerability, in tracts with moderate social vulnerability (SVI = 5) there was an excess of 199 asthma-related ED visits per 100,000 person years (95% CrI = 183-214). Relative to the back-to-school increase in tracts with moderate social vulnerability, in tracts with high social vulnerability (SVI = 8), there was an excess of 303 (95% CrI = 268-339) asthma-related ED visits per 100,000 person years. Greater levels of neighborhood disadvantage were associated with a greater increase in the rate of asthma-related ED visits when children returned to school. Neighborhood disadvantage may modify the back-to-school increase in asthma exacerbations by increasing the risk of upper respiratory viral infections.