Association between extremely cold weather and ischemic heart disease-related death during 2011–2017, Jinan City

Objective: The objective of the study is to evaluate the acute effects of extreme cold weather and cold waves on the risk of death from ischemic heart disease (IHD) in Jinan city. Methods: Daily meteorological data, air pollution data, and IHD-related death data in Jinan from January 1, 2011, to December 31, 2017, were collected. The extreme cold weather was defined as temperatures below the 10th percentile (−1.6 C), 5th percentile (−3.3 C), and 1st percentile (−6.4 C) of the daily average temperature during the study period, expressed as P10, P5, and P1 respectively. Cold strokes were defined as P10, P5, or P1 temperatures lasting for 3 days or more, and were expressed as Cold stroke I, Cold stroke II, and Cold stroke III, respectively. A time-stratified case-crossover study was used to assess the acute effects of extreme cold weather and cold strokes on IHD-related deaths. Results: During the 1486 days of the 2011–2017 cold months, 50,845 IHD deaths were detected with an average of 34 daily deaths. The relatively cold years were observed in 2011, 2012, 2013 and 2016 during the study, and the coldest was for 2012. The maximum effects of P10, P5, and P1 on IHD deaths occurred on lag6, lag6, and lag2, respectively, and the results were 1.08 (95% confidence interval [CI]: 1.04, 1.12), 1.10 (95% CI: 1.04, 1.15), and 1.20(95% CI:1.09, 1.32), respectively. The maximum effect of Cold stroke I and Cold stroke II on IHD mortality risk was 1.09 (95% CI: 1.04, 1.14) and 1.11 (95% CI: 1.04, 1.19), respectively, at lag6 and lag2. Conclusions: Extremely cold weather and cold strokes in the cold months of 2011–2017 in Jinan City significantly increased the risk of acute death from IHD. It was also found that the occurrence of cold weather and cold strokes after warm years can further increase the risk of acute death from IHD