Stroke rates were decreasing in urban Uusimaa and rural North Savo of Finland in 2018–2022

Background

There are claims that stroke incidence among younger adults in high-income countries is increasing. To contribute to the understanding of the current situation in Finland, we examined changes in annual stroke rates among adults aged 18 years and older in urban Uusimaa and rural North Savo of Finland in 2018–2022.

Methods

This hospital-based registry study includes all adult patients with acute stroke in Uusimaa and North Savo regions of Finland in 2018–2022. Uusimaa locates in Southern Finland and includes the metropolitan area of the capital city of Helsinki, whereas North Savo locates in sparsely populated Eastern Finland. Uusimaa residents represent about 31%, and North Savo residents about 5% of Finnish population (∼5,5 million in total). Annual stroke rates were estimated using Poisson log-linear regression (incidence rate ratio, IRR) adjusted for sex, region, stroke type, and age group, with the logarithm of the population at risk as an offset term.

Results

Of 19 057 adult patients with stroke, 83.5 % were living in Uusimaa and 16.5 % in North Savo. The stroke rate showed an average annual decrease of -2.6% from 2018 to 2022 (IRR 0.974, 95% CI 0.965–0.984), and -3.0% among the youngest group of patients aged 18-54 years (IRR 0.970, 95% CI 0.945–0.996). This decrease was consistent with the decrease observed in ischaemic stroke, while subarachnoid and intracerebral haemorrhage rates remained stable. The decrease was statistically significant in both sexes and regions, in ischaemic and not specified strokes, and in every age group except in patients aged 55–64 and 85 years and older.

Conclusions

This study suggests decrease in stroke rates from 2018 to 2022 among the study population representing approximately one third of the Finnish population. The decrease was also seen among younger patients aged 18–54 years, and especially in ischaemic strokes. The change was similar in both regions and may reflect improvements in primary stroke prevention.

Key messages

• Ischaemic stroke rate showed a gradual decrease from 2018 to 2022 among the urban Uusimaa and rural North Savo residents of Finland, also among the younger adults aged 18–54 years.

• Despite the known differences in health and wellbeing among the residents of Uusimaa compared to those of North Savo, we did not find significant differences in decreasing stroke rates between them.