title: Association between high temperature and mortality in metropolitan areas of four cities in various climatic zones in China: a time-series study.
abstract: BACKGROUND
  Numerous studies have reported on the associations between ambient temperatures and mortality. However, few multi-city studies have been conducted in developing countries including China. This study aimed to examine the association between high temperature and mortality outcomes in four cities with different climatic characteristics in China to identify the most vulnerable population, detect the threshold temperatures, and provide scientific evidence for public health policy implementations to respond to challenges from extreme heat.
  
  
  METHODS
  A semi-parametric generalized additive model (GAM) with a Poisson distribution was used to analyze the impacts of the daily maximum temperature over the threshold on mortality after controlling for covariates including time trends, day of the week (DOW), humidity, daily temperature range, and outdoor air pollution.
  
  
  RESULTS
  The temperature thresholds for all-cause mortality were 29°C, 35°C, 33°C and 34°C for Harbin, Nanjing, Shenzhen and Chongqing, respectively. After adjusting for potential confounders including air pollution, strong associations between daily maximum temperature and daily mortality from all-cause, cardiovascular, endocrine and metabolic outcomes, and particularly diabetes, were observed in different geographical cities, with increases of 3.2-5.5%, 4.6-7.5% and 12.5-31.9% (with 14.7-29.2% in diabetes), respectively, with each 1°C increment in the daily maximum temperature over the threshold. A stronger temperature-associated mortality was detected in females compared to males. Additionally, both the population over 55 years and younger adults aged 30 to 54 years reported significant heat-mortality associations.
  
  
  CONCLUSIONS
  Extreme heat is becoming a huge threat to public health and human welfare due to the strong temperature-mortality associations in China. Climate change with increasing temperatures may make the situation worse. Relevant public health strategies and an early extreme weather and health warning system should be developed and improved at an early stage to prevent and reduce the health risks due to extreme weather and climate change in China, given its huge population, diverse geographic distribution and unbalanced socioeconomic status with various climatic characteristics.
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Li
authors.forename: Yibin
authors.initials: Y
authors.lastname: Cheng
authors.forename: Guoquan
authors.initials: G
authors.lastname: Cui
authors.forename: Chaoqiong
authors.initials: C
authors.lastname: Peng
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.forename: Yulin
authors.initials: Y
authors.lastname: Wang
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Liu
authors.forename: Jingyi
authors.initials: J
authors.lastname: Liu
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Li
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wu
authors.forename: Peng
authors.initials: P
authors.lastname: Bi
authors.affiliation: Institute of Environmental Health and Related Product Safety, Chinese Center for Disease Control and Prevention, 29 Nanwei Road, Beijing 100021, China. jinyinlong1951@sina.com.
authors.forename: Yinlong
authors.initials: Y
authors.lastname: Jin
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000393:Air Pollutants / Q000633:toxicity*; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D002947:Cities; D057231:Climate Change; D004700:Endocrine System Diseases / Q000209:etiology / Q000401:mortality*; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008659:Metabolic Diseases / Q000209:etiology / Q000401:mortality*; D008875:Middle Aged; D012140:Respiratory Tract Diseases / Q000209:etiology / Q000401:mortality*; D012737:Sex Factors; D055815:Young Adult
chemical_list: D000393:Air Pollutants
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