Stroke and heart attack admissions are linked to cold weather
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《英国医生杂志》
Cold weather can increase the number of women being admitted to hospital for stroke or heart attack. Researchers who looked at hospital admissions among women aged under 50 years in 17 countries found links between lower temperatures and a higher risk of hospitalisation.
Overall, a 5癈 drop in temperature was associated with a 7% increase in admissions for stroke (incidence rate ratio 0.93 (95% confidence interval 0.89 to 0.97)) and a 12% increase in admissions for heart attack (incidence rate ratio 0.88 (0.8 to 0.97)), say the authors of the study (Journal of Clinical Epidemiology 2004:57:749-57).
"To our knowledge, this is the first report based on an international multi-centre study to investigate and show a clear association between climate and hospital admission rates of these events among young women from a range of different climatic zones," write the authors, Choon Lan Chang, Martin Shipley, Michael Marmot, and Neil Poulter, from Imperial College and University College London.
The researchers used data from the World Health Organization collaboration study from 24 centres in Africa, Asia, Europe, and Latin America with a wide range of average monthly temperatures, from a low of - 4.6癈 in Beijing to a high of 30.1癈 in Thailand.
The study looked at the relation between variation in three climatic variables—temperature, rainfall, and humidity—and the risk of hospitalisation among women aged 15 to 49 for venous thromboembolism, arterial stroke, and acute myocardial infarction. The study included 1146 cases of venous thromboembolism, 2269 patients with stroke, and 369 cases of acute myocardial infarction.
The results show significant associations between temperature and the rates of admission for stroke and acute myocardial infarction but not venous thromboembolism.
"Although the negative association between AMI and stroke with mean air temperature was not seen in all countries, on average, a 5癈 reduction in mean air temperature was associated with a 7% and 12% increase in the expected hospitalisation rates of stroke and AMI, respectively," write the authors.
"These data show that among young women from 17 countries, the rate of hospitalised AMI, and to a lesser extent stroke, was higher with lower mean environmental air temperature. No such association was seen with VTE events nor were humidity and rainfall linked with either AMI, stroke, or VTE hospitalisation rates."
The authors say that several mechanisms may explain the association between temperature and the risk of stroke and acute myocardial infarction, including changes in clotting mechanisms, lipid levels, and blood pressure. They say that seasonal variation in lipid levels seems an unlikely explanation for the large seasonal variation in the incidence of stroke recorded in the study.
"By contrast, blood pressure, which shows marked seasonal variation—being higher in winter (colder) months—is a strong risk factor for both stroke and AMI but not for VTE," they write.(Abergavenny Roger Dobson)
Overall, a 5癈 drop in temperature was associated with a 7% increase in admissions for stroke (incidence rate ratio 0.93 (95% confidence interval 0.89 to 0.97)) and a 12% increase in admissions for heart attack (incidence rate ratio 0.88 (0.8 to 0.97)), say the authors of the study (Journal of Clinical Epidemiology 2004:57:749-57).
"To our knowledge, this is the first report based on an international multi-centre study to investigate and show a clear association between climate and hospital admission rates of these events among young women from a range of different climatic zones," write the authors, Choon Lan Chang, Martin Shipley, Michael Marmot, and Neil Poulter, from Imperial College and University College London.
The researchers used data from the World Health Organization collaboration study from 24 centres in Africa, Asia, Europe, and Latin America with a wide range of average monthly temperatures, from a low of - 4.6癈 in Beijing to a high of 30.1癈 in Thailand.
The study looked at the relation between variation in three climatic variables—temperature, rainfall, and humidity—and the risk of hospitalisation among women aged 15 to 49 for venous thromboembolism, arterial stroke, and acute myocardial infarction. The study included 1146 cases of venous thromboembolism, 2269 patients with stroke, and 369 cases of acute myocardial infarction.
The results show significant associations between temperature and the rates of admission for stroke and acute myocardial infarction but not venous thromboembolism.
"Although the negative association between AMI and stroke with mean air temperature was not seen in all countries, on average, a 5癈 reduction in mean air temperature was associated with a 7% and 12% increase in the expected hospitalisation rates of stroke and AMI, respectively," write the authors.
"These data show that among young women from 17 countries, the rate of hospitalised AMI, and to a lesser extent stroke, was higher with lower mean environmental air temperature. No such association was seen with VTE events nor were humidity and rainfall linked with either AMI, stroke, or VTE hospitalisation rates."
The authors say that several mechanisms may explain the association between temperature and the risk of stroke and acute myocardial infarction, including changes in clotting mechanisms, lipid levels, and blood pressure. They say that seasonal variation in lipid levels seems an unlikely explanation for the large seasonal variation in the incidence of stroke recorded in the study.
"By contrast, blood pressure, which shows marked seasonal variation—being higher in winter (colder) months—is a strong risk factor for both stroke and AMI but not for VTE," they write.(Abergavenny Roger Dobson)