Air Pollution and Hospitalization for Bronchiolitis among Young Children

Several studies have found higher risks for childhood respiratory illness, associated with exposure to particulate matter (PM) less than 10 μm in diameter (PM₁₀) and PM_2.5 and gaseous pollution.

We analyzed the association between air pollution and hospitalizations due to bronchiolitis, an obstructive pulmonary disorder, commonly caused by respiratory syncytial virus infant infection.

Data were obtained from a local tertiary medical center providing services for a population of 700,000 comprising two ethnic groups: predominantly urban Jews and rural Bedouin Arabs. The latter group includes 30% residing in unrecognized villages in a temporary dwelling. We included all infants (0-2 yr) hospitalized with bronchiolitis between 2003 and 2013. Daily PM estimates were obtained from a satellite-based model incorporating daily remote sensing data and assigned to the family residence locality. Other air pollutants and meteorological parameters were obtained from a local monitoring site. We used case-crossover models with adjustment for temperature.

We identified 4,069 bronchiolitis hospitalizations (3,889 children), with 55.3% being Bedouin Arabs, of whom 16.8% resided in temporary dwellings. An increase in interquartile range of average weekly air pollutants was associated with an increased odds of bronchiolitis (odds ratio [95% confidence interval]): PM₁₀ (1.06 [1.02-1.09]), PM_2.5 (1.04 [1.02-1.06]) and nitrogen dioxide (1.36 [1.12-1.65]). Higher effect-estimates for PM were observed among Bedouin Arabs residing in temporary dwellings (1.14 [1.01-1.30] and 1.07 [1.01-1.15]) compared with Jewish individuals (1.05 [0.99-1.11] and 1.03 [1.01-1.07]) and other Bedouin Arabs (1.05 [1.01-1.10] and 1.03 [1.01-1.07]), and among males (1.11 [1.06-1.16] and 1.06 [1.03-1.09]) compared with females (0.99 [0.94-1.05] and 1.01 [0.97-1.04]).

High PM levels were positively associated with bronchiolitis. The stronger associations among Bedouin Arabs may be related to higher pollution infiltration and exposure in residents of temporary dwellings.