Original article
Vol. 146 No. 4950 (2016)
Excess mortality during the warm summer of 2015 in Switzerland
- Ana M Vicedo-Cabrera
- Martina S Ragettli
- Christian Schindler
- Martin Röösli
Summary
QUESTION UNDER STUDY: 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.
References
- Gasparrini A, Guo Y, Hashizume M, Lavigne E, Zanobetti A, Schwartz J, et al. Mortality risk attributable to high and low ambient temperature: a multicountry observational study. Lancet. 2015;386(9991):369–75. doi:http://dx.doi.org/10.1016/S0140-6736(14)62114-0. PubMed
- Baccini M, Kosatsky T, Biggeri A. Impact of summer heat on urban population mortality in Europe during the 1990s: an evaluation of years of life lost adjusted for harvesting. PLoS One. 2013;8(7):e69638. doi:http://dx.doi.org/10.1371/journal.pone.0069638. PubMed
- Schifano P, Leone M, De Sario M, de’Donato F, Bargagli AM, D’Ippoliti D, et al. Changes in the effects of heat on mortality among the elderly from 1998-2010: results from a multicenter time series study in Italy. Environ Health. 2012;11(1):58. doi:http://dx.doi.org/10.1186/1476-069X-11-58. PubMed
- Michelozzi P, Accetta G, De Sario M, D’Ippoliti D, Marino C, Baccini M, et al.; PHEWE Collaborative Group. High temperature and hospitalizations for cardiovascular and respiratory causes in 12 European cities. Am J Respir Crit Care Med. 2009;179(5):383–9. doi:http://dx.doi.org/10.1164/rccm.200802-217OC. PubMed
- Benmarhnia T, Deguen S, Kaufman JS, Smargiassi A. Review Article: Vulnerability to Heat-related Mortality: A Systematic Review, Meta-analysis, and Meta-regression Analysis. Epidemiology. 2015;26(6):781–93. doi:http://dx.doi.org/10.1097/EDE.0000000000000375. PubMed
- Xu Z, Etzel RA, Su H, Huang C, Guo Y, Tong S. Impact of ambient temperature on children’s health: a systematic review. Environ Res. 2012;117:120–31. doi:http://dx.doi.org/10.1016/j.envres.2012.07.002. PubMed
- Meehl S. Collins. Global Climate Projections. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. 2007.
- Fischer AM, Weigel AP, Buser CM, Knutti R, Künsch HR, Liniger MA, et al. Climate change projections for Switzerland based on a Bayesian multi-model approach. Int J Climatol. 2012;32(15):2348–71. doi:http://dx.doi.org/10.1002/joc.3396.
- Robine J-M, Cheung SLK, Le Roy S, Van Oyen H, Griffiths C, Michel J-P, et al. Death toll exceeded 70,000 in Europe during the summer of 2003. C R Biol. 2008;331(2):171–8. doi:http://dx.doi.org/10.1016/j.crvi.2007.12.001. PubMed
- Grize L, Huss A, Thommen O, Schindler C, Braun-Fahrländer C. Heat wave 2003 and mortality in Switzerland. Swiss Med Wkly. 2005;135(13-14):200–5. PubMed
- Kalkstein LS, Valimont KM. An Evaluation of Summer Discomfort in the United State Using a Relative Climatological Index. Bull Am Meteorol Soc. 1986;67(7):842–8. doi:http://dx.doi.org/10.1175/1520-0477(1986)067<0842:AEOSDI>2.0.CO;2.
- Abschluss Hitzewelle Juli 2015 [Internet]. [cited 2016 Jul 1]. Available from: http://www.meteoschweiz.admin.ch/home/aktuell/news.subpage.html/de/data/news/2015/7/abschluss-hitzewelle-juli-2015.html
- Åström DO, Tornevi A, Ebi KL, Rocklöv J, Forsberg B. Evolution of Minimum Mortality Temperature in Stockholm, Sweden, 1901-2009. Environ Health Perspect. 2016;124(6):740–4. PubMed
- Todd N, Valleron A-J. Space-Time Covariation of Mortality with Temperature: A Systematic Study of Deaths in France, 1968-2009. Environ Health Perspect. 2015;123(7):659–64. PubMed
- Fouillet A, Rey G, Wagner V, Laaidi K, Empereur-Bissonnet P, Le Tertre A, et al. Has the impact of heat waves on mortality changed in France since the European heat wave of summer 2003? A study of the 2006 heat wave. Int J Epidemiol. 2008;37(2):309–17. doi:http://dx.doi.org/10.1093/ije/dym253. PubMed
- Fouillet A, Rey G, Laurent F, Pavillon G, Bellec S, Guihenneuc-Jouyaux C, et al. Excess mortality related to the August 2003 heat wave in France. Int Arch Occup Environ Health. 2006;80(1):16–24. doi:http://dx.doi.org/10.1007/s00420-006-0089-4. PubMed
- Green HK, Andrews N, Armstrong B, Bickler G, Pebody R. Mortality during the 2013 heatwave in England--How did it compare to previous heatwaves? A retrospective observational study. Environ Res. 2016;147:343–9. doi:http://dx.doi.org/10.1016/j.envres.2016.02.028. PubMed
- de’ Donato FK, Leone M, Scortichini M, De Sario M, Katsouyanni K, Lanki T, et al. Changes in the Effect of Heat on Mortality in the Last 20 Years in Nine European Cities. Results from the PHASE Project. Int J Environ Res Public Health. 2015;12(12):15567–83. doi:http://dx.doi.org/10.3390/ijerph121215006. PubMed
- Anderson GB, Bell ML. Heat waves in the United States: mortality risk during heat waves and effect modification by heat wave characteristics in 43 U.S. communities. Environ Health Perspect. 2011;119(2):210–8. doi:http://dx.doi.org/10.1289/ehp.1002313. PubMed
- Gasparrini A, Guo Y, Hashizume M, Lavigne E, Tobias A, Zanobetti A, et al. Changes in Susceptibility to Heat During the Summer: A Multicountry Analysis. Am J Epidemiol. 2016;183(11):1027–36. doi:http://dx.doi.org/10.1093/aje/kwv260. PubMed
- Basu R. High ambient temperature and mortality: a review of epidemiologic studies from 2001 to 2008. Environ Health. 2009;8(1):40. doi:http://dx.doi.org/10.1186/1476-069X-8-40. PubMed
- Stafoggia M, Forastiere F, Agostini D, Biggeri A, Bisanti L, Cadum E, et al. Vulnerability to heat-related mortality: a multicity, population-based, case-crossover analysis. Epidemiology. 2006;17(3):315–23. doi:http://dx.doi.org/10.1097/01.ede.0000208477.36665.34. PubMed
- Basagaña X, Escalera-Antezana JP, Dadvand P, Llatje Ò, Barrera-Gómez J, Cunillera J, et al. High Ambient Temperatures and Risk of Motor Vehicle Crashes in Catalonia, Spain (2000–2011): A Time-Series Analysis. Environ Health Perspect. 2015;123(12):1309–16. doi:http://dx.doi.org/10.1289/ehp.1409223. PubMed
- Joe L, Hoshiko S, Dobraca D, Jackson R, Smorodinsky S, Smith D, et al. Mortality during a Large-Scale Heat Wave by Place, Demographic Group, Internal and External Causes of Death, and Building Climate Zone. Int J Environ Res Public Health. 2016;13(3):299. doi:http://dx.doi.org/10.3390/ijerph13030299. PubMed
- Dixon PG, Sinyor M, Schaffer A, Levitt A, Haney CR, Ellis KN, et al. Association of weekly suicide rates with temperature anomalies in two different climate types. Int J Environ Res Public Health. 2014;11(11):11627–44. doi:http://dx.doi.org/10.3390/ijerph111111627. PubMed
- Auger N, Fraser WD, Smargiassi A, Bilodeau-Bertrand M, Kosatsky T. Elevated outdoor temperatures and risk of stillbirth. Int J Epidemiol. 2016;dyw077. doi:http://dx.doi.org/10.1093/ije/dyw077. PubMed
- Basu R, Sarovar V, Malig BJ. Association Between High Ambient Temperature and Risk of Stillbirth in California. Am J Epidemiol. 2016;183(10):894–901. doi:http://dx.doi.org/10.1093/aje/kwv295. PubMed
- Personnes âgées [Internet]. 2016 [cited 2016 Jul 1]. Available from: http://www.bfs.admin.ch/bfs/portal/fr/index/themen/14/04/02/key/01.html
- Holstein J, Canouï-Poitrine F, Neumann A, Lepage E, Spira A. Were less disabled patients the most affected by 2003 heat wave in nursing homes in Paris, France? J Public Health (Oxf). 2005;27(4):359–65. doi:http://dx.doi.org/10.1093/pubmed/fdi059. PubMed
- Benmarhnia T, Bailey Z, Kaiser D, Auger N, King N, Kaufman J. A Difference-in-Differences Approach to Assess the Effect of a Heat Action Plan on Heat-Related Mortality, and Differences in Effectiveness According to Gender, Age, and Socioeconomic Status (Montreal, Quebec). Environ Health Perspect. 2016. Published online May 20, 2016. doi:http://dx.doi.org/10.1289/EHP203. PubMed
- Medienmitteilungen [Internet]. 2012 [cited 2016 Jul 1]. Available from: http://www.bfs.admin.ch/bfs/portal/de/index/news/medienmitteilungen.html?pressID=10146
- Tobias A, Armstrong B, Zuza I, Gasparrini A, Linares C, Diaz J. Mortality on extreme heat days using official thresholds in Spain: a multi-city time series analysis. BMC Public Health. 2012;12(1):133. doi:http://dx.doi.org/10.1186/1471-2458-12-133. PubMed
- Winkler MS, Röösli M, Ragettli MS, Cissé G, Müller P, Utzinger J, et al. Mitigating and adapting to climate change: a call to public health professionals. Int J Public Health. 2015;60(6):631–2. doi:http://dx.doi.org/10.1007/s00038-015-0722-7. PubMed