The impact of "unseasonably" warm spring temperatures on acute myocardial infarction hospital admissions in Melbourne, Australia: a city with a temperate climate

Abstract

The effects of extreme temperatures on human health have been well described. However, the adverse health effects of warm weather that occurs outside the summer period have had little attention. We used daily anomalous AMI morbidity and daily anomalous temperature to determine the impact of "unseasonable" temperature on human health. The "unseasonably" warm weather was attributed to a slow moving high pressure system to the east of Melbourne. No morbidity displacement was noted during either of these periods suggesting that morbidity due to "unseasonable" temperatures is avoidable. An increase in warmer weather during the cooler months of spring may result in increased morbidity, and an alert system based on summer thresholds may not be appropriate for early season heat health warnings. A straightforward alert system based on calculating anomalous temperature from daily weather forecasts may reduce the public health impact of "unseasonably" warm weather.

Figure 1

Percentage difference in mean monthly admission rate relative to base month December.

Figure 2

Monthly percentage differences for males aged 65–74 years.

Figure 3

(a) Daily temperature and AMI anomalies during October 1994. (b) 3-day averages of daily temperature and AMI anomalies during October 1994.

Figure 4

(a) Daily temperature and AMI anomalies during October 2004. (b) 3-day averages of daily temperature and AMI anomalies during October 2004.

Figure 5

Synoptic charts showing mean sea level pressure (MSLP) analyses for the Australian region for the period 15–18 October 1994 (a–d respectively). The locations of high and low pressure and frontal systems are shown on the charts. Data are from the Australian Bureau of Meteorology.

Figure 6

Synoptic charts showing mean sea level pressure (MSLP) analyses for the Australian region for the period 10–13 October 2004 (a–d respectively). The locations of high and low pressure and frontal systems are shown on the charts. Data are from the Australian Bureau of Meteorology.