Ischemic stroke associated with decrease in temperature.
BACKGROUND
Some studies suggest low temperatures can affect mortality, especially deaths associated with circulatory and respiratory conditions.


METHODS
We investigated the association between ischemic stroke onset and decrease in temperature in 545 patients over a 3-year period (January 1998 to December 2000) in Incheon, Korea. We used a case-crossover study design to assess changes in the risk of ischemic stroke during a brief hazard period after exposure to decrease in temperature. For each subject, the case period was matched to 2 control periods exactly 1 week before and after onset of the ischemic stroke.


RESULTS
Decreased ambient temperature was associated with risk of acute ischemic stroke. The strongest effect was seen on day after exposure to cold weather. The odds ratio (OR) for an interquartile range decrease in temperature was 2.9 (95% confidence interval [CI] = 1.5-5.3). The risk period was 24-48 hours after cold exposure. Risk estimates associated with decreased temperature were greater in the winter than in the summer. Women, persons greater than 65 years of age, nonobese persons, and those with previous hypertension or hypercholesterolemia were more susceptible to cold-induced ischemic stroke.


CONCLUSIONS
These results suggest that stroke occurrence rises with decreasing temperature, and that even a moderate decrease in temperature can increase the risk of ischemic stroke. Susceptible people should take steps to protect themselves from cold, especially in the winter.
Hong
Yun-Chul
YC
Department of Occupational and Environmental Medicine, Inha University College of Medicine, Incheon, Korea.
Rha
Joung-Ho
JH
Lee
Jong-Tae
JT
Ha
Eun-Hee
EH
Kwon
Ho-Jang
HJ
Kim
Ho
H
D000367:Age Factors; D000368:Aged; D002545:Brain Ischemia / Q000209:etiology*; D016022:Case-Control Studies; D003080:Cold Temperature / Q000009:adverse effects*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007723:Korea / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D018570:Risk Assessment; D012621:Seasons; D012737:Sex Factors; D020521:Stroke / Q000209:etiology*