Seasonal and Monthly Variation in Stroke and its Subtypes-10 Year Hospital-Based Study

Abstract

Background and Objectives:There is no evidence of long-term studies of seasonal variations in stroke in Iran. Hence, the aim of this study was to determine the seasonal and monthly variation of 28-day mortality in Isfahan, Iran.Methods:From 2003 to 2013, In a Hospital-based retrospective study which was conducted by Isfahan Cardiovascular Research Center(ICRC), 24186 cases with first-ever stroke were recruited. Multinomial logistic regression was used to calculate odds ratios (OR) with 95% confidence intervals (CI) for seasonal and monthly 28-day mortality for stroke in general and three subtypes of stroke including intracranial hemorrhage (ICH), ischemic (IS) and subarachnoid hemorrhage (SAH).Results:In this study, unadjusted and adjusted odds ratios of seasonal 28-day mortality of stroke was highest in the winter and lowest in the summer. Although, differences were not statistically significant. For total and IS stroke, the unadjusted 28-day mortality ratio (UMR) was significant in February (1.19, 95% CI 1.00 -1.42, P= 0.04) as compared to March. Whereas after adjusted, for total stroke, 28-day mortality was significantly lowest in May (0.746, 95% CI 0.575-0.97, p=0.029), June (0.777, 95% CI 0.60-0.99, p=0.49) and July (0.771, 95% CI 0.59-0.99 p=0.049) as compared to March. The AMR between months were not significant in SAH and IS.Conclusion:Our findings demonstrate clear obvious monthly variation of 28-day mortality of stroke and its subtypes in Isfahan but no seasonal variations were observed.

An analysis of recent stroke cases in South Africa: Trend, seasonality and predictors

“…These findings are consistent with a study by Raj et al [15] Few studies have demonstrated no significant seasonal variations in stroke cases or identified summer as the season with most cases of stroke. [1,4,17] Similar results to ours, showing high rates of stroke in winter and spring, were obtained in Poland and Hungary. [18] The above finding also corresponds with our results and those of Moinuddin et al [19] Stroke, like any other non-communicable disease, has a complex, multifactorial aetiology.…”

“…These findings were similar to those of a recent study in Iran. [1] While we found the prevalence of diabetes to be high in white female stroke patients, hypertension was found to be the most common risk factor in black females. Table 5 indicates considerable monthly variation in risk factors, with high proportions of cases in patients with hypertension, diabetes and heart problems in the winter months, in accordance with the findings of Bahonar et al [1] and Wang et al [11] In contrast, there were few stroke patients with these risk factors in the month of November.…”

“…Globally, stroke is the second leading cause of mortality and the third leading cause of disability. [1,2] African countries are experiencing an epidemiological transition as a result of sociodemographic and lifestyle changes. [3] This process is leading to an increase in non-communicable diseases.…”

“…In the case of South Africa (SA), this transition, which significantly increased at the advent of democracy in 1994, continues unabated. In sub-Saharan Africa, which includes SA, the burden of stroke is on the rise [1,2,4] owing to increasing cases. Stroke is among the top 10 leading causes of disability in SA, [5,6] accounting for 25 000 deaths a year and 95 000 years lived with disability (YLD).…”

Chronic lifestyle diseases display seasonal sensitive comorbid trend in human population evidence from Google Trends

“…Even though seasonal variations affect the entire human physiological systems, the cardio-vascular systems, cardio-respiratory systems, and circadian rhythms are most sensitive to these seasonal changes. In recent days, there is an impressive pattern of seasonal rhythm in hospitalizations of patients with cardio-vascular and cardio-respiratory diseases or disorders, with a notable increase in winter [8–11].…”