Seasonal patterns of incidence and case fatality of stroke in Malmo, Sweden: the STROMA study.

BACKGROUND: Studies on the temporal variation in stroke incidence have reported inconsistent results. Few have studied the temporal variations in case fatality. No study on incidence and case fatality of stroke by season in Sweden has been found. This study explores the weekly, monthly and seasonal variations in incidence and 28-day case fatality of stroke. METHODS: A total of 7,129 patients with first-ever stroke during the period 1989-1999 were retrieved from the Stroke Register of Malmo, Sweden. chi(2) test was performed to test the seasonal differences and Poisson regression analysis was used to calculate the case fatality ratios adjusted for sex and age. RESULTS: The stroke cases were on the whole randomly distributed over the study period of 4,017 days. Incidence of all types of stroke, intracerebral hemorrhage and subarachnoid hemorrhage showed no variation by season, month or weekday, but incidence of cerebral infarction for the total population was higher in autumn and winter. Twenty-eight-day case fatality (930 fatal events, 13%) clustered significantly over the study period. Winter emerged as the peak season among men (12.5%), women (17.2%) and total population (15.1%). No consistent variation of incidence and case fatality of stroke by month or weekday was found. CONCLUSION: Case fatality after stroke demonstrates a seasonal variation with a peak in winter. Incidence of stroke showed no consistent association with season, month or weekday.

Marital dissolution is followed by an increased incidence of stroke.

BACKGROUND: Many studies have reported lower mortality in married people. The relation between marital status and incidence of haemorrhagic and ischaemic stroke is unclear. It is largely unknown whether the risk of stroke is increased the first years after divorce or death of spouse. METHODS: Incidence of first-ever stroke (n = 6,184) was followed over 10 years in a cohort consisting of all 40- to 89-year-old inhabitants (n = 118,134) in the city of Malmö, Sweden. Marital dissolution (i.e. divorce or death of spouse) prior to the date of stroke was compared in a nested case-control design (3,134 initially married stroke cases, 9,402 initially married controls). RESULTS: As compared to the married groups, the incidence of stroke was increased in divorced men and women (RR = 1.23, CI: 1.10-1.39 and RR = 1.26, CI: 1.12-1.41, respectively) and widowed men and women (RR = 1.13, CI: 0.99-1.28 and RR = 1.13, CI: 1.02-1.24, respectively) after adjustments for age, country of birth and socioeconomic indicators. The risk of stroke was not increased in never married men. Marital dissolution was followed by increased risk of stroke, which was significant for men (adjusted odds ratio: 1.23, CI: 1.03-1.5) and borderline significant for women below 65 years of age (odds ratio: 1.45, CI: 0.99-2.14). CONCLUSION: The incidence of stroke is increased in divorced and widowed individuals. Never married men do not have an increased incidence. The risk of stroke is elevated during the first years after divorce or death of spouse.

Increasing stroke incidence and decreasing case fatality, 1989-1998: a study from the stroke register in Malmö, Sweden.

BACKGROUND AND PURPOSE: Although the incidence of and mortality from myocardial infarction (MI) have declined in most industrialized countries, incidence studies of stroke have shown less consistent trends. This study examines time trends in the incidence of stroke and case fatality rates in relation to socioeconomic circumstances and history of MI. METHODS: Stroke incidence in the city of Malmö, Sweden (250,000 citizens), has been continuously monitored since 1989. All patients 50 to 79 years of age who experienced a first-ever stroke between 1989 and 1998 were included. RESULTS: We included 3621 patients (1969 men, 1652 women). The age-standardized incidence was 647 per 100,000 persons-years for men and 400 per 100,000 persons-years for women. The annual increase-3.1% in men (P<0.05) and 2.9% in women (P<0.05)-was more pronounced in the younger age groups and was lowest in areas with poor socioeconomic circumstances. We found that 13% of the men and 6% of the women had a history of MI; this proportion was stable over the study period. The average case fatality rates in 1989 to 1998 were 10% for men and 9.3% for women. Rates remained stable for men but declined significantly in women (odds ratio per year, 0.895; 95% confidence interval, 0.84 to 0.95). CONCLUSIONS: In this urban population, stroke incidence increased between 1989 and 1998. The rate of increase tended to be lower in residential areas with least favorable socioeconomic circumstances. The proportion with a history of MI remained unchanged during the study period. There has been significant improvement in the case fatality rate in women but not in men.