The association of mortality with high temperatures in a temperate climate: England and Wales
Résumé
Background, It is well known that high ambient temperatures are associated with increased mortality, even in temperate climates, but some important details are unclear. In particular how heat-mortality associations (for example slopes and thresholds) vary by climate has previously been considered only qualitatively. Methods We carried out an ecological time-series regression analysis of daily counts of all-cause mortality and ambient temperature in summers between 1993 and 2006 in the ten government regions, focusing on all-cause mortality and two-day mean temperature (lags 0 and 1). Results All regions showed evidence of increased risk on hottest days, but the specifics, in particular the threshold temperature at which adverse effects started, varied. Thresholds were at about the same centile temperatures (the 93rd, year-round) in all regions - hotter climates had higher threshold temperatures. Mean supra-threshold slope was 2.1%/oC (95% CI: 1.6, 2.4), but regions with higher summer temperatures showed greater slopes, a pattern well-characterized by a linear model with mean summer temperature. These climate-based linear-threshold models capture most but not all the association; there was evidence for some nonlinearity above thresholds, with slope increasing at highest temperatures. Conclusion Effects of high daily summer temperatures on mortality in English regions are quite well approximated by threshold-linear models that can be predicted from the region's climate (93rd centile and mean summer temperature). It remains to be seen whether similar relationships fit other countries and climates or change over time, such as with climate change.
Origine : Fichiers produits par l'(les) auteur(s)
Loading...