title: A large change in temperature between neighbouring days increases the risk of mortality.
abstract: BACKGROUND
  Previous studies have found high temperatures increase the risk of mortality in summer. However, little is known about whether a sharp decrease or increase in temperature between neighbouring days has any effect on mortality.
  
  
  METHODS
  Poisson regression models were used to estimate the association between temperature change and mortality in summer in Brisbane, Australia during 1996-2004 and Los Angeles, United States during 1987-2000. The temperature change was calculated as the current day's mean temperature minus the previous day's mean.
  
  
  RESULTS
  In Brisbane, a drop of more than 3 °C in temperature between days was associated with relative risks (RRs) of 1.157 (95% confidence interval (CI): 1.024, 1.307) for total non-external mortality (NEM), 1.186 (95%CI: 1.002, 1.405) for NEM in females, and 1.442 (95%CI: 1.099, 1.892) for people aged 65-74 years. An increase of more than 3 °C was associated with RRs of 1.353 (95%CI: 1.033, 1.772) for cardiovascular mortality and 1.667 (95%CI: 1.146, 2.425) for people aged <65 years. In Los Angeles, only a drop of more than 3 °C was significantly associated with RRs of 1.133 (95%CI: 1.053, 1.219) for total NEM, 1.252 (95%CI: 1.131, 1.386) for cardiovascular mortality, and 1.254 (95%CI: 1.135, 1.385) for people aged ≥ 75 years. In both cities, there were joint effects of temperature change and mean temperature on NEM.
  
  
  CONCLUSIONS
  A significant change in temperature of more than 3 °C, whether positive or negative, has an adverse impact on mortality even after controlling for the current temperature.
authors.affiliation: School of Public Health and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia. guoyuming@yahoo.cn
authors.forename: Yuming
authors.initials: Y
authors.lastname: Guo
authors.forename: Adrian G
authors.initials: AG
authors.lastname: Barnett
authors.forename: Weiwei
authors.initials: W
authors.lastname: Yu
authors.forename: Xiaochuan
authors.initials: X
authors.lastname: Pan
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Ye
authors.forename: Cunrui
authors.initials: C
authors.lastname: Huang
authors.forename: Shilu
authors.initials: S
authors.lastname: Tong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001831:Body Temperature / Q000502:physiology; D001833:Body Temperature Regulation / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D015141:Los Angeles / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009026:Mortality; D011793:Queensland / Q000453:epidemiology; D012306:Risk; D012621:Seasons; D013696:Temperature; D013997:Time Factors; D015854:Up-Regulation / Q000502:physiology