Table 3 Hazard ratios (95% confidence intervals) of stroke associated with 1-year air pollution exposure at baseline (per IQR increase) in the two-exspoure models
| Â | Single-exposure modela | Two-exposure modelsa, additionally adjusted for | |||||
|---|---|---|---|---|---|---|---|
PM2.5, μg/m3 | SO2, ppb | NO2, ppb | Warm-season O3, ppb | CO, ppm | Temperature°C | ||
Total Stroke | |||||||
 PM2.5, μg/m3 | 1.03 (1.00–1.06) | – | 1.02 (0.99–1.06) | 1.02 (0.98–1.05) | 1.05 (1.02–1.09) | 1.01 (0.98–1.05) | 1.03 (1.00–1.07)b |
 SO2, ppb | 1.03 (1.00–1.05) | 1.02 (1.00–1.05)b | – | 1.02 (0.99–1.05) | 1.02 (1.00–1.05)b | 1.02 (0.99–1.04) | 1.02 (1.00–1.05) |
 NO2, ppb | 1.04 (1.00–1.07) | 1.03 (0.99–1.07) | 1.03 (0.99–1.07) | – | 1.03 (0.99–1.06) | 1.02 (0.98–1.06) | 1.03 (1.00–1.07)b |
 Warm-season O3, ppb | 0.98 (0.96–1.00) | 0.96 (0.94–0.99) | 0.98 (0.96–1.01) | 0.98 (0.96–1.01) | – | 0.98 (0.95–1.00) | 0.98 (0.95–1.00) |
 CO, ppm | 1.04 (1.02–1.06) | 1.02 (1.00–1.04)b | 1.02 (1.00–1.04)b | 1.02 (1.00–1.04)b | 1.02 (1.00–1.0.4) | – | 1.03 (1.01–1.05) |
 Temperature, °C | 1.02 (1.00–1.04) | 1.00 (0.98–1.03) | 1.00 (0.98–1.02) | 1.01 (0.98–1.03) | 0.99 (0.97–1.02) | 1.02 (0.99–1.04) | – |
Ischemic stroke | |||||||
 PM2.5, μg/m3 | 1.06 (1.02–1.09) | – | 1.04 (1.01–1.08) | 1.05 (1.01–1.09) | 1.07 (1.03–1.11) | 1.03 (0.99–1.08) | 1.06 (1.02–1.10) |
 SO2, ppb | 1.04 (1.01–1.07) | 1.03 (1.00–1.06) | – | 1.03 (1.00–1.07) | 1.04 (1.01–1.07) | 1.03 (1.00–1.06) | 1.04 (1.01–1.07) |
 NO2, ppb | 1.05 (1.01–1.09) | 1.02 (0.98–1.07) | 1.02 (0.98–1.07) | – | 1.04 (1.00–1.08) | 1.02 (0.98–1.06) | 1.04 (0.99–1.08) |
 Warm-season O3, ppb | 1.00 (0.97–1.02) | 0.98 (0.95–1.00) | 1.01 (0.98–1.03) | 1.00 (0.97–1.03) | – | 1.00 (0.97–1.02) | 0.99 (0.97–1.02) |
 CO, ppm | 1.04 (1.01–1.06) | 1.02 (1.00–1.05)b | 1.03 (1.01–1.05) | 1.03 (1.01–1.05) | 1.03 (1.01–1.05) | – | 1.04 (1.02–1.07) |
 Temperature, °C | 1.03 (1.01–1.05) | 1.01 (0.98–1.04) | 0.99 (0.97–1.02) | 1.00 (0.97–1.03) | 0.99 (0.97–1.02) | 1.02 (0.99–1.05) | – |
Hemorrhagic stroke | |||||||
 PM2.5, μg/m3 | 0.95 (0.89–1.10) | – | 0.95 (0.89–1.02) | 0.93 (0.87–1.00) | 0.99 (0.93–1.06) | 0.95 (0.88–1.02) | 0.95 (0.88–1.01) |
 SO2, ppb | 0.98 (0.93–1.03) | 0.99 (0.94–1.05) | – | 0.96 (0.90–1.02) | 0.96 (0.91–1.01) | 0.98 (0.93–1.04) | 0.98 (0.93–1.03) |
 NO2, ppb | 1.02 (0.95–1.09) | 1.05 (0.98–1.13) | 1.05 (0.97–1.13) | – | 0.99 (0.93–1.06) | 1.03 (0.96–1.11) | 1.03 (0.95–1.11) |
 Warm-season O3, ppb | 0.92 (0.88–0.97) | 0.92 (0.88–0.97) | 0.92 (0.87–0.96) | 0.92 (0.88–0.97) | – | 0.92 (0.88–0.97) | 0.92 (0.88–0.97) |
 CO, ppm | 1.04 (1.00–1.08) | 1.00 (0.96–1.05) | 0.99 (0.96–1.03) | 0.98 (0.95–1.02) | 0.98 (0.95–1.02) | – | 0.99 (0.94–1.03) |
 Temperature, °C | 0.99 (0.96–1.02) | 0.99 (0.94–1.04) | 1.00 (0.96–1.05) | 1.02 (0.96–1.07) | 1.00 (0.96–1.05) | 0.99 (0.94–1.04) | – |