Excess cardiovascular mortality associated with cold spells in the Czech Republic

Abstract

BackgroundThe association between cardiovascular mortality and winter cold spells was evaluated in the population of the Czech Republic over 21-yr period 1986–2006. No comprehensive study on cold-related mortality in central Europe has been carried out despite the fact that cold air invasions are more frequent and severe in this region than in western and southern Europe.MethodsCold spells were defined as periods of days on which air temperature does not exceed -3.5°C. Days on which mortality was affected by epidemics of influenza/acute respiratory infections were identified and omitted from the analysis. Excess cardiovascular mortality was determined after the long-term changes and the seasonal cycle in mortality had been removed. Excess mortality during and after cold spells was examined in individual age groups and genders.ResultsCold spells were associated with positive mean excess cardiovascular mortality in all age groups (25–59, 60–69, 70–79 and 80+ years) and in both men and women. The relative mortality effects were most pronounced and most direct in middle-aged men (25–59 years), which contrasts with majority of studies on cold-related mortality in other regions. The estimated excess mortality during the severe cold spells in January 1987 (+274 cardiovascular deaths) is comparable to that attributed to the most severe heat wave in this region in 1994.ConclusionThe results show that cold stress has a considerable impact on mortality in central Europe, representing a public health threat of an importance similar to heat waves. The elevated mortality risks in men aged 25–59 years may be related to occupational exposure of large numbers of men working outdoors in winter. Early warnings and preventive measures based on weather forecast and targeted on the susceptible parts of the population may help mitigate the effects of cold spells and save lives.

Impact of heat and cold waves on circulatory-cause and respiratory-cause mortality in Spain: 1975–2008

“…The longer lagged effect seen for cold-related, all-cause and circulatory-and respiratory-cause mortality is in line with: underlying physiological mechanisms; what has been described in the scientific literature (Armstrong et al 2000;Carder et al 2005;Kyselý et al 2009); and the most widely accepted aetiological hypotheses, which link mortality occurring soonest after a cold wave to diseases of a cardiovascular aetiology, and mortality occurring at the longest lags to respiratory diseases (Ballester et al 1997;Díaz et al 2005). A description of specific-cause mortality related with thermal extremes can be found in a study undertaken by Medina-Ramón et al (2006).…”

“…Firstly, part of the aetiology of the excess mortality observed after exceptionally cold days is known to be of an infectious nature, whereas the increase seen during heat waves is caused by the direct effects of heat on the metabolism of the individual, provoking generalised decompensation. In the Czech Republic, the greatest increases in mortality have been reported where low temperatures coincided with the presence of the infectious agent (Kyselý et al 2009), and in Holland, no significant associations were observed for respiratory causes in the absence of influenza epidemics, in the period 1979-1997 (Huynen et al 2001). It would therefore seem that the effects of a cold wave are partly influenced by the presence or absence of a pathogenic agent, whose ability to spread is, in turn, favoured by this selfsame drop in temperatures (Hajat and Haines 2002).…”

Summertime, and the livin’ is easy: Winter and summer pseudoseasonal life expectancy in the United States

“…Yang et al (2012) and Zhao, Zhu, and Tu (2015) find similar results in subtropical Asia. Kysely et al (2009) find increased cardiovascular mortality in all ages above 25 during cold spells in the Czech Republic. Mortality in nursing homes appears to be sensitive to both hot and cold temperature extremes (Stafoggia et al 2006;Hajat, Kovats, and Lachowycz 2007).…”

Association between Extreme Cold Weather Temperatures and Mortality in Greece

“…For instance, a study conducted in England and Wales found an association between cold temperature and mortality [10]. Also, in central Europe, it was observed an increased mortality with temperature at low average daily temperatures [11]. Ireland also experiences increased cold-related mortality [12].…”