Seasonal and weekly patterns of occurrence of acute cardiovascular diseases: does a gender difference exist?

Abstract Background: Cardiovascular (CV) disease is the leading cause of death in women. It is known that acute CV events exhibit temporal patterns of onset, that is, seasonal and weekly. We aimed to verify whether such patterns show differences by gender. Methods: We analyzed cumulative data from our previous studies dealing with hospital admissions for CV events, such as acute myocardial infarction (AMI), stroke, transient ischemic attack (TIA), aortic diseases (AD), and pulmonary embolism (PE), in the region Emilia-Romagna (RER) of Italy (ICDM9-CM codes, years 1998?2006). Total population and subgroups by gender (percentage of monthly and daily events) were tested for uniformity with the chi-square test, and a chronobiologic method was applied to monthly percentage of data for seasonal rhythmic analysis. Results: Season: We considered 130,693 patients (45.1% women): 64,191 AMI, 43,642 TIA, 4,615 AD, 19,425 PE. The monthly and seasonal distribution showed respective peaks in January and in winter, with no differences by gender. Day-of-week: We considered 168,921 patients (45.6% women): 64,191 AMI, 56,453 stroke, 43,642 TIA, 4,615 AD. The weekly distribution showed a peak on Monday, with no differences by gender. A multivariate regression logistic analysis, including in the model either major CV risk factors (hypertension, dyslipidemia, diabetes mellitus) and subgroups by age, did not find any difference in the temporal distribution of events in women and men. Conclusions: The seasonal and day-of-week distribution of occurrence of CV events seems to be independent of gender.