Relationships between the seasonality of temperature and ischaemic heart disease mortality: implications for climate based health forecasting

The relationship between the seasonality of ischaemic heart disease (IHD) mortality and temperature is explored for the purpose of evaluating the climate-based predictability of the magnitude and timing of the annual IHD mortality peak for 5 English counties. Seasonality is described by the amplitude (magnitude) and phase (timing) of the first harmonic of the annual cycle of IHD mortality and mean and minimum temperature. Study results reveal a positive association between the amplitude of the annual IHD mortality cycle and temperature seasonality such that years with an exaggerated mortality peak are associated with years characterised by strong temperature seasonality. Overall, the timing of the annual mortality peak is positively associated with the timing of the lowest temperatures. Such findings provide some optimism for exploring the development of experimental climate-based health-forecasting models. This is because the simple climate-seasonality diagnostics presented here provide a fundamental source of predictability of the magnitude and timing of the annual IHD mortality peak.