2012 Colorado wildfire PM raised asthma visits
During a 32-day 2012 fire period, modeled PM2.5 associated with asthma/wheeze and COPD ED visits; cardiovascular associations were largely null.
Source
The association of wildfire smoke with respiratory and cardiovascular emergency department visits in Colorado in 2012: a case crossover study
What they did
A grid-stratified case-crossover linked 1-h max and 24-h mean PM2.5 (fire-smoke model) to Colorado ED/hospitalization codes from 5 June–6 July 2012, controlling day-of-week and temperature.
What they found
Asthma/wheeze 24-h mean OR 1.04 per 5 μg/m³; COPD OR 1.05 per 5 μg/m³. 1-h max ORs were 1.01 per 10 μg/m³. Cardiovascular estimates were consistent with no association; model absolute bias was ~13 μg/m³ in Denver.
The limits
What it doesn't show
One fire season and wide CVD confidence intervals (low case counts) cannot rule out cardiovascular effects; exposure model bias was large near fires.
Key terms
- Wildfire PM2.5
- Fine particles in smoke plumes, here modeled on a 12 km grid.
- Case-crossover
- Each grid is its own control across days, controlling time-invariant place factors.
- 1-h max vs 24-h mean
- Peak hourly versus daily-average PM2.5 metrics.
- COPD
- Chronic obstructive pulmonary disease ED diagnoses.
- Absolute bias
- Mean absolute difference between modeled and monitor PM2.5.
Flashcards
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Quiz yourself
Wildfire PM2.5 was positively associated with:
Common questions
Which outcomes rose with PM2.5?
Asthma/wheeze and COPD.
CVD?
Fairly consistent with no association.
Study window?
5 June–6 July 2012 (32 days).
24-h asthma OR?
1.04 per 5 μg/m³.
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