Background and purpose: Chronobiological analyses of stroke onset may throw some light on the mechanisms that trigger stroke. Observations may generate new hypotheses for identifying significant causal relationships.
Methods: In the present study, both the circadian and the weekend and holiday versus workday times of the onset of ischemic cerebral infarction were determined for 723 consecutive subjects, aged 16 to 60 years, who were admitted for hospital treatment in the acute phase without any selection.
Results: Among young adults (16 to 40 years) and women, more infarctions occurred during weekends and holidays than were expected. Young women in particular had an increased risk for brain infarction during weekends and holidays (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.26 to 3.63). In a multivariate analysis, age of 16 to 30 years (OR, 3.13; 95% CI, 1.57 to 6.50), female sex (OR 1.71; 95% CI, 1.12 to 2.63), and recent drinking of alcohol (P < .01) were associated with the onset of brain infarction during weekends and holidays, whereas current cigarette smoking was associated with the onset of brain infarction during workdays (P < .001). A morning increase in the onset of brain infarction was observed among middle-aged people during both weekends/holidays and workdays. Among young adults, however, an evening increase was also seen during weekends/holidays and workdays.
Conclusions: We found that young adults and women are frequently stricken by brain infarction during weekends and holidays and that the circadian distribution of the onset of brain infarction among young adults is different from that of middle-aged people. These observations suggest that there may be stroke-triggering activities that are associated with lifestyle.