Trends of myocardial infarction morbidity and its associations with weather conditions

Abstract

Objective: The aim of this study was to assess the trends of myocardial infarction (MI) morbidity and evaluate the associations with some meteorological factors.

Materials and methods: Data on MI morbidity were collected from Kaunas ischemic heart disease registry and information about meteorological factors from Kaunas meteorological station was collected.

Results: The overall morbidity rates of acute MI among men aged 25-64 increased by 2.0%/yr. (P=0.02), whereas among women did not change significantly (+1.2%/yr., P=0.2) during 1995-2007. Among men aged 65-84 the overall morbidity rates of MI were without significant changes (-1.0%/yr., P=0.3) and among women decreased significantly by -1.7%/yr. (P=0.03). During 1995-2000, a weak inverse significant correlation between atmospheric air temperature and morbidity of MI (r=-0.05, P=0.019) was documented (in women and the elderly r=-0.045 and -0.048, respectively, P<0.05). Weak correlation between atmospheric air wind speed and MI morbidity in women (r=-0.042, P=0.05) and in population of older age (r=-0.056, P=0.099) was determined. In men and in elderly population a direct weak correlation between atmospheric pressure and MI morbidity was found (r=0.114 and 0.166, respectively, P<0.01). In this study monthly and seasonal variation of MI rates were observed. In winter period MI rates were higher to compare with other seasons (χ(2)=18.682, df=3, P<0.0001).

Conclusions: The overall morbidity rates of MI increased among Kaunas men aged 25-64 and tended to increase among women, whereas among men aged 65-84 MI morbidity trends were without statistically significant changes and significantly decreased among women during 1995-2007. Weak inverse correlations between atmospheric air temperatures, rainfall level and direct correlation between air wind speed, atmospheric pressure and MI morbidity were established. Months/seasonal variations during analyzed period were observed.

Keywords: Morbidity; Myocardial infarction; Trend; Weather conditions.