[Influence of circadian and temperature variations on the ischemic stroke].
BACKGROUND
Ischemic stroke (IS) ranks third as cause of death and annual costs. Literature shows a greater number of cases in the first hours of the morning and on colder days, allowing for better prevention at these times. The objectives were to identify risk factors, evaluate the influence of circadian and temperature variations on prevalence of IS.


METHODS
Onset time was analyzed during four periods and obtained from the patient or family. Weather temperature was obtained from the INMET. The IS were classified according to subtypes established by the TOAST project.


RESULTS
Hypertension was the main risk factor in 66% of the patients. There was a predominance of cases between 06:00 AM and 11:59 AM (p < 0. 0001) and after a negative variation of temperature (p < 0. 0001).


CONCLUSIONS
A strong relationship was found between prevalence of IS and negative variation of temperature. Events were more frequent between 6:00 AM and 11:59 AM. It was not possible to evaluate the variations for each subtype of IS because the number of cases did not allow for significant statistic evaluation.
FAMERP, São José do Rio Preto, SP, Brasil. gvfr@uol.com.br
Gibran Franzoni
GF
Rufca
Eduardo
E
Zaffani
Rachel
R
Zerbini
Felipe Franco Pinheiro
FF
Gaia
Fabio de Nazaré
Fde N
Oliveira
Waldir Antonio
WA
Tognolla
D000368:Aged; D002545:Brain Ischemia / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D001938:Brazil / Q000453:epidemiology; D016009:Chi-Square Distribution; D002940:Circadian Rhythm / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D012307:Risk Factors; D012621:Seasons; D013696:Temperature