Toro, K., Bartholy, J., Pongracz, R., Kis, Z., Keller, E. and Dunay, G. 2010. Evaluation of meteorological factors on sudden cardiovascular death. Journal of Forensic and Legal Medicine 17: 236-242.
The authors write that "several studies have demonstrated that cardiovascular mortality has a seasonal distribution (Arntz et al., 2000; Weerasinghe et al. 2002; Nakaji et al., 2004; Kloner, 2006)," and that "the relationship between cold weather and ischemic heart disease mortality is well established (Vuori, 1987; Gyllerup et al., 1993; Gyllerup, 2000)," after which they state that "cold temperature may be an important factor in bringing on the onset of life-threatening cardiac events, even in regions with relatively mild winters," citing the study of Cagle and Hubbard (2005).
What was done
Working with data pertaining to 7450 cardiovascular-related deaths that occurred within Budapest, Hungary, between 1995 and 2004 -- where the deceased were "medico-legally autopsied" -- Toro et al. looked for potential relationships between daily maximum, minimum and mean temperature, air humidity, air pressure, wind speed, global radiation and daily numbers of the heart-related deaths.
What was learned
The six Hungarian scientists report and restate their primary finding numerous times throughout their paper, writing that (1) "both the maximum and the minimum daily temperatures tend to be lower when more death cases occur in a day," (2) "on the days with four or more death cases, the daily maximum and minimum temperatures tend to be lower than on days without any cardiovascular death events," (3) "the largest frequency of cardiovascular death cases was detected in cold and cooling weather conditions," (4) "we found a significant negative relationship between temperature and cardiovascular mortality," (5) "the analysis of 6-hour change of air pressure suggests that more acute or chronic vascular death cases occur during increasing air pressure conditions (implying cold weather fronts)," (6) "we found a high frequency of cardiovascular death in cold weather," (7) "a significant negative relationship was detected between daily maximum [and] minimum temperature[s] and the number of sudden cardiovascular death cases," and (8) "a significant negative correlation was detected between daily mean temperature and cardiovascular mortality."
What it means
In a summary statement pertaining to their work, Toro et al. write that "with these analyses, we confirmed the results of other studies (Donaldson et al., 1998; Gyllerup, 2000; Mercer, 2003) that mortality was in inverse relation to air temperature."
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