Ambient ozone concentration and hospital admissions due to childhood respiratory diseases in New York State, 1991-2001

Background and objective

Respiratory diseases constitute one of the leading causes of ill health among children in New York State (NYS). The current project, a component of the NYS Environmental Public Health Tracking Program, investigated a potential association between ambient ozone (O₃) concentration and childhood respiratory hospital admissions over 11 years in NYS.

Methods

We used a two-stage Bayesian hierarchical model to assess the exposure-disease associations within 11 geographic regions and statewide. The data included total daily hospital admissions due to respiratory diseases for children 0-17 years old from 1991 to 2001 in NYS (N=134,099) and daily ambient O₃ level with different single-day lags. These analyses adjusted for particulate matter ?10 μm in size (PM₁₀), meteorological conditions, day of the week, seasonality, long-term trends, and demographic characteristics.

Results

In 5 of the 11 regions, including the Upper and Lower Adirondacks, Upper Hudson Valley, Staten Island, and New York City, positive associations were found between respiratory hospital admissions and ambient O₃ level 2 days prior to the admission. Applying different statistical methods and sensitivity analysis of PM₁₀ did not alter these findings. When region-specific results were combined, no statewide association was apparent.

Conclusions

Geographic differences were found in the associations between O₃ levels and respiratory hospital admissions among children. In addition, we found that the two-stage model may be an appropriate approach for tracking the health effects of air pollution over time in different geographic areas when heterogeneity of risk factors across regions is present.