title: Variation in vulnerability to extreme-temperature-related mortality in Japan: A 40-year time-series analysis.
abstract: BACKGROUND
  Although the impact of extreme heat and cold on mortality has been documented in recent years, few studies have investigated whether variation in susceptibility to extreme temperatures has changed in Japan.
  
  
  METHODS
  We used data on daily total mortality and mean temperatures in Fukuoka, Japan, for 1973-2012. We used time-series analysis to assess the effects of extreme hot and low temperatures on all-cause mortality, stratified by decade, gender, and age, adjusting for time trends. We used a multivariate meta-analysis with a distributed lag non-linear model to estimate pooled non-linear lag-response relationships associated with extreme temperatures on mortality.
  
  
  RESULTS
  The relative risk of mortality increased during heat extremes in all decades, with a declining trend over time. The mortality risk was higher during cold extremes for the entire study period, with a dispersed pattern across decades. Meta-analysis showed that both heat and cold extremes increased the risk of mortality. Cold effects were delayed and lasted for several days, whereas heat effects appeared quickly and did not last long.
  
  
  CONCLUSIONS
  Our study provides quantitative evidence that extreme heat and low temperatures were significantly and non-linearly associated with the increased risk of mortality with substantial variation. Our results suggest that timely preventative measures are important for extreme high temperatures, whereas several days' protection should be provided for extreme low temperatures.
authors: Department of Health Communication, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors: Daisuke
authors: D
authors: Onozuka
authors: Department of Health Communication, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address: hagihara@hsmp.med.kyushu-u.ac.jp.
authors: Akihito
authors: A
authors: Hagihara
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death; D002648:Child; D002675:Child, Preschool; D002980:Climate; D003080:Cold Temperature; D004781:Environmental Exposure; D005260:Female; D006358:Hot Temperature; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D055815:Young Adult
keywords: Climatic change; Extreme temperatures; Mortality