Sudden weather changes have long been thought to be associated with negative impacts on human health, but relatively few studies have attempted to quantify these relationships. We use large 6-h changes in atmospheric pressure as a proxy for sudden weather changes and evaluate their association with hospital admissions for cardiovascular diseases (CVD). Winter and summer seasons and positive and negative pressure changes are analysed separately, using data for the city of Prague (population 1.2 million) over a 16-year period (1994-2009). We found that sudden pressure drops in winter are associated with significant rise in hospital admissions. Increased CVD morbidity was observed neither for pressure drops in summer nor pressure increases in any season. Analysis of synoptic weather maps shows that large pressure drops in winter are associated with strong zonal flow and rapidly moving low-pressure systems with centres over northern Europe and atmospheric fronts affecting western and central Europe. Analysis of links between passages of strong atmospheric fronts and hospital admissions, however, shows that the links disappear if weather changes are characterised by frontal passages. Sudden pressure drops in winter are associated also with significant excess CVD mortality. As climate models project strengthening of zonal circulation in winter and increased frequency of windstorms, the negative effects of such weather phenomena and their possible changes in a warmer climate of the twenty-first century need to be better understood, particularly as their importance in inducing excess morbidity and mortality in winter may increase compared to cold spells.

• MeSH
• dítě MeSH
• dospělí MeSH
• hospitalizace statistika a číselné údaje   MeSH
• kardiovaskulární nemoci epidemiologie   MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• novorozenec MeSH
• počasí MeSH
• předškolní dítě MeSH
• roční období MeSH
• senioři MeSH
• tlak vzduchu * MeSH
• velkoměsta epidemiologie   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• velkoměsta epidemiologie   MeSH

The study examines the relationship between sudden changes in weather conditions in summer, represented by (1) sudden air temperature changes, (2) sudden atmospheric pressure changes, and (3) passages of strong atmospheric fronts; and variations in daily mortality in the population of the Czech Republic. The events are selected from data covering 1986-2005 and compared with the database of daily excess all-cause mortality for the whole population and persons aged 70 years and above. Relative deviations of mortality, i.e., ratios of the excess mortality to the expected number of deaths, were averaged over the selected events for days D-2 (2 days before a change) up to D+7 (7 days after), and their statistical significance was tested by means of the Monte Carlo method. We find that the periods around weather changes are associated with pronounced patterns in mortality: a significant increase in mortality is found after large temperature increases and on days of large pressure drops; a decrease in mortality (partly due to a harvesting effect) occurs after large temperature drops, pressure increases, and passages of strong cold fronts. The relationship to variations in excess mortality is better expressed for sudden air temperature/pressure changes than for passages of atmospheric fronts. The mortality effects are usually more pronounced in the age group 70 years and above. The impacts associated with large negative changes of pressure are statistically independent of the effects of temperature; the corresponding dummy variable is found to be a significant predictor in the ARIMA model for relative deviations of mortality. This suggests that sudden weather changes should be tested also in time series models for predicting excess mortality as they may enhance their performance.

• MeSH
• časové faktory MeSH
• lidé MeSH
• metoda Monte Carlo MeSH
• míra přežití MeSH
• mortalita MeSH
• nadmořská výška MeSH
• nízká teplota MeSH
• počasí MeSH
• roční období MeSH
• tlak vzduchu MeSH
• zeměpis MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH

Pomocí navrženého algoritmu byly v období 1986-2005 identifikovány situace, během kterých došlo na území České republiky k výrazně velké změně teploty nebo tlaku vzduchu. Vybrané termíny byly porovnány s databází celkové denní úmrtnosti a úmrtnosti na kardiovaskulární nemoci, zvlášť pro celkovou populaci a osoby starší 70 let. Pro každý den byla vypočítána relativní odchylka úmrtnosti jako rozdíl skutečné úmrtnosti a normálové dělený normálovou úmrtností (samostatně pro všechny zkoumané skupiny). Použity byly 3hodinové údaje o atmosférickém tlaku na 10 meteorologických stanicích a hodinová data o teplotě vzduchu z 9 stanic reprezentujících území ČR. Změny tlaku byly posuzovány na časových škálách 3, 6 a 12 hodin zvlášť pro letní a zimní období, změny teploty na škále 24 hodin zvlášť v létě a v zimě. Vybrány byly pouze termíny, ve kterých došlo k nadkriticky velké změně teploty nebo tlaku vzduchu během 24 hodin na více než 50 % stanic. Velikost kriticky velké změny byla určena pro každou stanici zvlášť pomocí kvantilů rozdělení změn teploty a tlaku. Pro dny D-2 (2 dny před změnou) až D+7 (sedmý den po změně) byla průměrována relativní odchylka úmrtnosti přes vybrané události. Její statistická významnost byla testována pomocí metody Monte Carlo. Vzestup úmrtnosti byl detekován po výrazné kladné změně teploty a poklesu tlaku vzduchu v obou ročních obdobích. K poklesu úmrtnosti dochází po výrazných vzestupech tlaku a výrazných ochlazeních v létě. Odchylky úmrtnosti jsou většinou výraznější pro populaci starší 70 let, většina úmrtí po výrazných změnách teploty připadá na kardiovaskulární nemoci.

We have developed an algorithm for identifying sudden changes in air pressure and temperature over the Czech Republic. Such events were retrieved from the data covering in 1986-2005 and were matched with the daily numbers of all-cause deaths and deaths due to cardiovascular diseases from the national database, separately for the whole population and that aged 70 years and over. Excess daily mortality was determined by calculating deviations of the observed number of deaths from the expected number of deaths for each day in the respective groups. The relative deviation of the mortality the mean was calculated as the ratio of the excess mortality to the expected number of deaths. We used 3-hour air pressure data from 10 meteorological stations and hourly air temperature data from 9 stations representative of the Czech Republic. Pressure changes were evaluated on time scales of 3, 6 and 12 hours, separately for summer and winter time. Temperature changes were evaluated on a 24-hour time scale, separately for summer and winter season. Events characterized by pressure or temperature changes above the critical threshold and recorded within 24 hours at more than 50 % of meteorological stations were retrieved. The critical thresholds were defined separately for each station using quantiles of distributions of air pressure and temperature changes. Relative mortality deviations for days D-2 (2 days before the change) to D+7 (7 days after the change) were averaged over the retrieved events. Statistical significance of the mean relative deviation was tested using the Monte Carlo method. Increased mortality followed large temperature increases and large pressure drops both in summer and winter months. Decreased mortality was observed after large pressure increases and large temperature drops in summer. Mortality variations are usually more pronounced in the population aged 70 years and over, and cardiovascular diseases account for most deaths after sudden temperature changes.

• MeSH
• lidé MeSH
• meteorologické pojmy MeSH
• mortalita MeSH
• teplota MeSH
• tlak vzduchu MeSH
• Check Tag
• lidé MeSH
• Geografické názvy
• Česká republika MeSH