Trends of myocardial infarction morbidity and its associations with weather conditions

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 (χ² = 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.