Short term effects of temperature on emergency admission of myocardial infarction in Korea with the thresholds of hot and cold temperatures

摘要

Background A number of studies have examined the influence of meteorological factors on myocardial infarction(MI) incidence. And there have been few studies to assess the differences of temperature threshold for increased risk of Ml with the regional effects (central or south region of Korean Peninsula), Ml status including ST-segment elevation myocardial infarction (STEMI) and non STEMI or aging effects. Methods We used the climate variables from the Korea Meteorological Administration, air pollution data provided by Korea National Institute of Environmental Research and myocardial infarction admission data from the KAMIR (Korea Acute Myocardial Infarction Registry) team. We estimated the temperature-MI relation by using generalized additive models (GAMs) and the relations were adjusted by humidity, pressure of sea level, PM10 and NO2. Results The threshold of mean temperature in hot weather was 28.5°C, and emergency admissions increased by 23% (95% CI: 0.4%-50%) and 30% (95% CI: 3%-64%) with increase of 1°C above the threshold in STEMI group and Non-STEMI group respectively. However, the threshold of mean temperature in cold weather was -1.5°C with 1% or 2% decrease below the threshold in STEMI or non-STEMI group. Old age group (above 75 years old) showed increase of 12% (95% CI: 6%-18%) of admission with increase of 1°C above the threshold of maximum temperature (31.5°C) which is greater than 6% (95% CI: 3%-9%) in young age group (below 75 years old). There were differences of temperature threshold between central and south regions in both hot and cold weather. The thresholds of mean temperature in hot weather were 19.5°C and 21.5°C in central and south region respectively, and those of minimum temperature in cold weather were -1.5°C in central region and -2.5°C in south region. Conclusions We found the variable threshold effects of temperature to increase the risk of Ml in hot and cold weather with regional and aging effects. More researches should be done to assess the risk of Ml by temperature changes with protective or aggravating factors.