title: Excess mortality during the warm summer of 2015 in Switzerland.
abstract: OBJECTIVE
  In Switzerland, summer 2015 was the second warmest summer for 150 years (after summer 2003). For summer 2003, a 6.9% excess mortality was estimated for Switzerland, which corresponded to 975 extra deaths. The impact of the heat in summer 2015 in Switzerland has not so far been evaluated.
  
  
  METHODS
  Daily age group-, gender- and region-specific all-cause excess mortality during summer (June-August) 2015 was estimated, based on predictions derived from quasi-Poisson regression models fitted to the daily mortality data for the 10 previous years. Estimates of excess mortality were derived for 1 June to 31 August, at national and regional level, as well as by month and for specific heat episodes identified in summer 2015 by use of seven different definitions.
  
  
  RESULTS
  804 excess deaths (5.4%, 95% confidence interval [CI] 3.0‒7.9%) were estimated for summer 2015 compared with previous summers, with the highest percentage obtained for July (11.6%, 95% CI 3.7‒19.4%). Seventy-seven percent of deaths occurred in people aged 75 years and older. Ticino (10.3%, 95% CI -1.8‒22.4%), Northwestern Switzerland (9.5%, 95% CI 2.7‒16.3%) and Espace Mittelland (8.9%, 95% CI 3.7‒14.1%) showed highest excess mortality during this three-month period, whereas fewer deaths than expected (-3.3%, 95% CI -9.2‒2.6%) were observed in Eastern Switzerland, the coldest region. The largest excess estimate of 23.7% was obtained during days when both maximum apparent and minimum night-time temperature reached extreme values (+32 and +20 °C, respectively), with 31.0% extra deaths for periods of three days or more.
  
  
  CONCLUSIONS
  Heat during summer 2015 was associated with an increase in mortality in the warmer regions of Switzerland and it mainly affected older people. Estimates for 2015 were only a little lower compared to those of summer 2003, indicating that mitigation measures to prevent heat-related mortality in Switzerland have not become noticeably effective in the last 10 years.
authors.affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Switzerland.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Vicedo-Cabrera
authors.affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Switzerland.
authors.forename: Martina S
authors.initials: MS
authors.lastname: Ragettli
authors.affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Schindler
authors.affiliation: Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Röösli
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D018882:Heat Stress Disorders / Q000401:mortality*; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012111:Residence Characteristics; D012621:Seasons; D017678:Sex Distribution; D013557:Switzerland / Q000453:epidemiology; D055815:Young Adult