Table 3.
Associations Between Acute Environmental Exposures and Invasive Pneumococcal Disease by Case-Crossover Analysis.
| Incubation Period (1-3 Days Prior to Case Occurrence) | Prior to Incubation Period (4-6 Days Prior to Case Occurrence) | |||||
|---|---|---|---|---|---|---|
| Exposure | OR | (95% CI) | P | OR | (95% CI) | P |
| Meteorological | ||||||
| Cooling Degree-Days (°C) | 0.878 | 0.624-1.236 | 0.456 | 0.926 | 0.676-1.270 | 0.635 |
| Maximum Temperature (°C) | 1.036 | 0.855-1.256 | 0.717 | 0.997 | 0.822-1.209 | 0.974 |
| Minimum Temperature (°C) | 0.994 | 0.820-1.204 | 0.948 | 1.039 | 0.858-1.258 | 0.694 |
| Atmospheric Pressure (kPa) | 1.026 | 0.848-1.241 | 0.794 | 1.013 | 0.834-1.230 | 0.895 |
| Precipitation (mm) | 0.954 | 0.783-1.162 | 0.6400 | 0.897 | 0.731-1.101 | 0.300 |
| Relative Humidity (%) | 1.038 | 0.844-1.275 | 0.725 | 0.989 | 0.804-1.217 | 0.916 |
| UV Index | 1.148 | 0.944-1.396 | 0.168 | 1.061 | 0.874-1.289 | 0.548 |
| Average Wind Speed (km/h) | 0.900 | 0.737-1.098 | 0.298 | 1.045 | 0.851-1.283 | 0.6739 |
| Air Quality | ||||||
| Sulphur Oxides (ppm) | 0.747 | 0.603-0.925 | 0.007 | 1.425 | 0.952-1.425 | 0.138 |
| Oxides of Nitrogen (ppm) | 0.918 | 0.735-1.147 | 0.452 | 1.144 | 0.930-1.406 | 0.203 |
| Carbon Monoxide (ppm) | 0.925 | 0.751-1.139 | 0.461 | 0.996 | 0.809-1.227 | 0.971 |
| PM10 (μg/m3) | 0.215 | 0.732-3.999 | 0.215 | 1.199 | 0.523-2.750 | 0.668 |
| Ozone (ppm) | 1.018 | 0.830-1.249 | 0.861 | 0.904 | 0.730-1.118 | 0.351 |
NOTE: OR, odds ratio; ppm, parts per million; kPa, kilopascals; PM10, particulates 10 micrometers or less in diameter. Presented odds ratios are those associated with upper tertile of exposures during incubation period. No significant associations were detected in analyses using raw exposure data.