Table 2.
Weekly Weather Patterns and Incidence of Invasive Pneumococcal Disease in Philadelphia.
| Univariable Models | Multivariable Modela, b | |||||
|---|---|---|---|---|---|---|
| Environmental or Meteorological Exposure | IRR | (95% CI) | P | IRR | (95% CI) | P |
| Cooling Degree-Days (°C)b | 0.92 | (0.90 - 0.94) | < 0.001 | 0.97 | (0.94 to 1.00) | 0.054 |
| Maximum Temperature (°C) | 0.97 | (0.96 - 0.97) | < 0.001 | 1.03 | (1.003 to 1.06) | 0.028 |
| Minimum Temperature (°C) | 0.96 | (0.95 - 0.97) | < 0.001 | ... | ... | ... |
| Relative Humidity (%) | 0.98 | (0.97 - 0.99) | 0.002 | ... | ... | ... |
| UV Index | 0.89 | (0.87 - 0.92) | < 0.001 | 0.70 | (0.54 - 0.91) | 0.007 |
| Sulphur Oxides (ppm × 100) | 1.73 | (1.27 - 2.37) | 0.002 | ... | ... | ... |
| Average Wind Speed (km/h) | 1.01 | (1.006 - 1.015) | < 0.001 | ... | ... | ... |
NOTE: Incidence rate ratios (IRRs) reflect change in disease risk per unit change in the meteorological variable in question. CI, confidence interval; ppm, parts per million.
aThe model was also adjusted for seasonal oscillation, cumulative cases during the prior month, calendar year and year-squared.
bModel deviance statistic chi-squared = 3156 on 9317 d.f., P = 1.000.
cCooling degree days are defined as the number of degrees a daily mean temperature is above 24°C. For example, a day with an average temperature of 27°C would have 3 cooling degree-days.