Global climate change: impact of heat waves under different definitions on daily mortality in Wuhan, China

Abstract

BackgroundThere was no consistent definition for heat wave worldwide, while a limited number of studies have compared the mortality effect of heat wave as defined differently. This paper aimed to provide epidemiological evidence for policy makers to determine the most appropriate definition for local heat wave warning systems.MethodsWe developed 45 heat wave definitions (HWs) combining temperature indicators and temperature thresholds with durations. We then assessed the impact of heat waves under various definitions on non-accidental mortality in hot season (May–September) in Wuhan, China during 2003–2010.ResultsHeat waves defined by HW14 (daily mean temperature ≥ 99.0th percentile and duration ≥ 3 days) had the best predictive ability in assessing the mortality effects of heat wave with the relative risk of 1.63 (95% CI: 1.43, 1.89) for total mortality. The group-specific mortality risk using official heat wave definition of Chinese Meteorological Administration was much smaller than that using HW14. We also found that women, and the elderly (age ≥ 65) were more susceptible to heat wave effects which were stronger and longer lasting.ConclusionThese findings suggest that region specific heat wave definitions are crucial and necessary for developing efficient local heat warning systems and for providing evidence for policy makers to protect the vulnerable population.Electronic supplementary materialThe online version of this article (doi:10.1186/s41256-017-0030-2) contains supplementary material, which is available to authorized users.

Diurnal Temperature Range in Relation to Daily Mortality and Years of Life Lost in Wuhan, China

“…Secondly, we did not adjust for the effects of air pollutants in our main analyses due to data unavailability. However, the results of our study would not be substantially affected, since very close effect estimates were obtained in previous DTR/temperature-mortality studies with and without controlling for air pollutants [ 14 , 49 , 50 ]. Additionally, the findings of this single-city study should be cautious of directly generalizing to other locations because of the great differences in climate conditions, population vulnerability, and life expectancy.…”

Effects of temperature variation and humidity on the mortality of COVID-19 in Wuhan

“…All analyses were conducted using R software (version 3.5.3) with the GAM fitted by the "mgcv" package (version 1. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. The effect estimates were expressed as the percentage changes and their 95% confidence intervals (CIs) in daily mortality of COVID-19 associated with per 1 unit increase in weather variables.…”

“…As the capital of Hubei Province and one of the largest city in central China, Wuhan is located in the middle of the Yangtze River Delta, which has a typical subtropical, humid, monsoon climate with cold winters and warm summers [14]. The average annual temperature and rainfall are 15.8 °C-17.5 °C and 1050 mm-2000 mm, respectively [15].…”

Health impact of climate change in cities of middle-income countries: the case of China

“…Although increased mortality risk occurs in both cold and hot temperatures, larger proportion of temperature-related mortality attributed to cold rather than hot temperatures 8 – 10 . Overall, results indicated that mean temperature was a better predictor of mortality than maximum or minimum temperature, particularly in heat waves 11 – 13 . While heat effects were more immediate, cold effects were found to be more prolonged and long lasting 10 , 14 , 15 .…”

“…Several papers adopted their own best-fit regional definition and found a higher temperature threshold and longer duration of days in more southern cities, e.g. 97.5th percentile of daily mean temperature for ≥2 days in Beijing, 98th percentile for ≥4 consecutive days in Nanjing and 99th percentile for ≥3 days in Wuhan 12 , 13 , 40 , 41 . Their findings also revealed that the group-specific or cause-specific mortality risks were smaller in the best-fit definitions, when compared with the official CMA definition 12 , 13 .…”