
Univariable Models

Multivariable Model^{a, b}


Environmental or Meteorological Exposure

IRR

(95% CI)

P

IRR

(95% CI)

P


Cooling DegreeDays (°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.

^{a}The model was also adjusted for seasonal oscillation, cumulative cases during the prior month, calendar year and yearsquared.

^{b}Model deviance statistic chisquared = 3156 on 9317 d.f., P = 1.000.

^{c}Cooling 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 degreedays.