A case-crossover analysis to quantify the impact of wildfire smoke on hospital respiratory admissions in the Rogue Valley, Oregon

Background

With the increasing prevalence of wildfire smoke in the Pacific Northwest, it is important to quantify health impacts to plan for adequate health services. The Rogue Valley region has historically faced some of the greatest wildfire threats in the state. Health impacts from smoke have been estimated in several recent studies that include Oregon's Rogue Valley, but the results between studies are conflicting.

Objective

The objective is to critically examine impacts of wildfire smoke on health in the Rogue Valley area and translate the results to support hospital staffing decisions.

Study design

The study adopts a case-crossover approach.

Methods

Apply a conditional Poisson regression to analyze time stratified counts while controlling for mean temperature.

Results

Every 10 μ/m³ increase in PM_2.5 is associated with a 2% increase in same-day hospital or emergency room admission rates for respiratory conditions during fire season after adjusting for temperature and time (OR = 1.020; 95% CI: 1.004–1.034); a 10 μ/m³ increase in PM_2.5 lasting nine days is associated with a 4% increase in admission rates (OR = 1.041; 95% CI: 1.018–1.065). In other words, for each 10 μ/m³ single day increase in pollution from smoke, an additional 0.26 respiratory patients would be expected in the area hospitals. With a single day increase from 10 μ/m³ to 150 μ/m³, hospitals could expect an additional four patients.

Conclusions

There are small but significant health impacts in the Rogue Valley. These impacts are smaller than some statewide estimates. We need further research to understand these differences.