Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25–29, 2009: Poster Presentations
Ireland is not known for having extreme high temperatures, with values above 30oC uncommon. Ireland has significant excess winter mortality compared to summer. The objective of this study is to estimate the impact of nation-wide heat waves on the total, cardiovascular and respiratory relationship, for the period 1981–2003, to determine if there are any periods of excess summer mortality.
A time series model was developed to estimate the temperature-mortality relationship. Temperatures were averaged across all stations to create a national daily indicator. Heat waves were characterized by their intensity, duration and their geographical coverage. The excess mortality attributed to the heat waves was estimated comparing the predicted mortality from observed temperatures and the predicted mortality from reference temperatures.
The best model for total mortality includes time, day of the week, minimal temperature at lag 0, 2, and maximal temperatures at lag 1, dummy variables for influenza and day of week were also included. Four heat waves periods were identified: July 1983, July 1989, July–August 1995, and August 2003. A significant mortality impact for total mortality, respiratory and cardiovascular was observed during all these summers (+69.6% in 1983, +61.7% in 1989, +126.6% in 1995, +9.3% in 2003). The impact was largest for the oldest age group and for respiratory mortality.
Even the relatively low maximum temperatures seen in Ireland have an effect on mortality. The largest cities being on coastal areas, they are less exposed to heat, and showed the least signal. The use of a nation-wide model allows capturing the effect of heat on the population. Facing the risk of climate change, it is necessary to gain a better understanding of the potential health impact of increased periods of hot weather, and to identify prevention strategies.
This work is supported by a research grant from the Irish EPA.