Stroke in Northern Sweden.
BACKGROUND
Stroke is one of the most common causes of death and long-term disability worldwide. Although stroke mortality has decreased in most industrialized countries, there are populations, particularly in East Europe, in which the mortality has increased. The WHO initiated, 20 years ago, the MONICA Project. The aim of the study was to measure trends in coronary heart disease and stroke and to assess the extent to which these were related to changes in known risk factors.


METHODS
The Northern Sweden MONICA stroke study started in 1985 and is still ongoing. All individuals with an acute stroke in the age group 25-74 years have been included in the stroke register. Death certificates, discharge records, and GPs' records are screened and validated using strict MONICA criteria.


RESULTS
Stroke event rates (first ever and recurrent stroke) per 100000 and year in the age group 25-74 years varied little over the years. Between 1985 and 1998 the annual incidence varied between 318 and 372 in men and between 195 and 240 in women, with no secular trends at all. The 28-day case fatality decreased in both men and women, from 19% to 11%. Logistic regression analyses showed a risk reduction in dying from stroke to 0.55 (p<0.0001) the last year compared with the first, with an absolute annual reduction in case fatality of 3%, in both men and women. In international comparison Northern Sweden shows an intermediately high incidence and one of the lowest case fatality rates of all participating populations. The incidence in subarachnoid haemorrhage was among the highest.


CONCLUSIONS
The ongoing decline in stroke mortality in Sweden is driven exclusively by declining case fatality, whereas event rates (first ever and recurrent stroke) have remained the same since 1985. This, together with more people entering advanced, stroke-prone age groups, implies that the burden of stroke will continue to increase in Sweden.
Stegmayr
Birgitta
B
Medicine, Department of Public Health and Clinical Medicine Umeå University, Umeå, Sweden. birgitta.stegmayr@medicine.umu.se
Asplund
Kjell
K
D000328:Adult; D000368:Aged; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D020521:Stroke / Q000453:epidemiology*; D015996:Survival Rate; D013548:Sweden / Q000453:epidemiology