The effect of daily weather conditions on myocardial infarction incidence in a subarctic population: the Tromsø Study 1974–2004

Abstract

In this subarctic population, MI incidence was little affected by the weather, probably due to behavioural protection. However, cold weather and heavy snowfall may be associated with increased risk of MI among older people.

Seasonal variation in cardiovascular disease risk factors in a subarctic population: the Tromsø Study 1979–2008

“…The Tromsø Study, a population-based cohort study with repeated measurements of CVD risk factors during more than 3 decades, is a valuable data set for adding to the scarce literature on individual seasonal patterns of CVD risk factors. In this subarctic population, we observed a small increase in MI incidence during the darkest winter months8 and, in the older people, after cold temperatures and heavy snowfall 9. This study extends our previous work by describing seasonal variations in CVD risk factors.…”

“…A marginal effect of season8 and weather9 on MI incidence and CVD risk factor levels in the Tromsø population is probably due to the combination of high living standards and long-time climate-adaptive behavioural protection like wearing adequate clothing when being outdoors1 37 and having well-insulated buildings with throughout-the-year warm and stable indoor temperatures 38 39. Better protection against cold weather could prevent the winter excess in CVD and coronary heart disease mortality,1 all-cause mortality1 38 40 and seasonal variation in CVD risk factors,19 observed in milder climates.…”

The relationship between meteorological conditions and index acute coronary events in a global clinical trial

“…Conflicting results were seen with one study showing that a cold temperature (−8°C) reduced the ischemic threshold only in a group of "cold sensitive" patients, and in the other study that all patients, even those without prior angina, were sensitive to colder temperatures and developed angina at a earlier time in colder temperatures. Prior studies have correlated a 3-day average temperature and found that the number of coronary events was greater during cold periods in a warm climate, with a smaller effect in a cold climate, [22] and in a cold-adapted climate, no effect was seen [23]. Consistently, heat has not been shown to be a driver of the clinical events.…”

Association between quantity and duration of snowfall and risk of myocardial infarction

“…[12][13][14] Snowfall is flagged as a possible MI risk factor in northern countries, 9,10,15,16 but evidence based on aggregate patient data is conflicting. 9,10,12,[15][16][17][18][19][20] Because the analysis of aggregate data can result in a loss of statistical power 21 and carries a risk of ecologic bias, 22 conclusive evidence of an association between snowfall and MI has yet to be established. Extreme weather patterns, including blizzards, are predicted to increase with climate change; 23 thus, an increased risk of MI in connection with snowfall has clear public health implications.…”

“…6 New data suggest that cold temperatures may be associated with an even greater risk of death, 7 in addition to documented peaks in MI incidence during winter months. 6,[8][9][10][11] Associations with other weather conditions, including snowstorms, however, have received less attention.…”