Time course of apparent temperature effects on cardiovascular mortality: A comparative study of Beijing, China and Brisbane, Australia

Abstract

Objective: This comparative study aimed to clarify the different characteristics of time course of apparent temperature and their effect on cardiovascular mortality in Beijing, China, and Brisbane, Australia. Design and setting: The present study used polynomial distributed lag models to explore the lagged effects of apparent temperature on daily cardiovascular mortality up to 27 days in Beijing, China (2005-2009), and Brisbane, Australia (2004-2007). Results: The results show a longer lagged effect on cold days and a shorter lagged effect on hot days. The cut-off points in Beijing and Brisbane were 22àand 27ì respectively. In Beijing, a statistically significant association was observed for lags of 0-3 days and lags of 3-18 days on hot and cold days, respectively. In Brisbane, a significant association was found for lags of 3-4 days and lags of 10-21 days on hot and cold days, respectively. Conclusion: The lagged effects extended longer for cold apparent temperature but were immediate for hot apparent tem-perature. Though the cut-off point in Brisbane was higher than in Beijing, the population in Beijing was more resistant to high temperature above the cut-off point than the population in Brisbane. Keywords: temperature, apparent temperature, cardiovascular mortality