WSO - April 2023 - 465

Kõrv et al.
465
Table 1. (Continued)
Men and Women
15-24
25-34
35-44
45-54
Total
Total (EURa)
1991-1993
No. at risk
3/19,526
7/15,858
22/14,094
75/12,899
107/62,377
Rate (95% CI)
5.1
14.7
52.0
193.8
57.2
65.8
15-24
25-34
35-44
45-54
Total
Total (EURa)
2001-2003 vs 1991-1993
Trend
-5.1
-3.4
-0.8
-3.9
-3.8
-3.1
0.66
0.92
0.61*
0.62*
0.69*
(1.1-15.0)
(5.9-30.3)
(32.6-78.8)
(152.5-243.0)
(46.9-69.1)
(53.3-78.3)
RR (95 % CI)
0.49
2001-2003
No. at risk
1/19,926
3/15,348
12/12,523
26/11,034
42/58,831
Rate (95% CI)
2.5
9.8
47.9
117.8
35.7
45.1
(0.05-4.71)
(0.17-2.57)
(0.46-1.86)
(0.39-0.95)
(0.44-0.89)
(0.47-0.99)
2013-2017 vs 2001-2003
Trend
-0.9
9.7
-1.7
0.2
0.5
0.2
Incidence rates were calculated per 100,000 person years.
RR was calculated to compare incidence rates between study periods.
Trends were calculated as percentage change per year.
CI: confidence interval; EUR: European standard population; RR: rate ratio.
aStandardized to the 1976 European standard population (EUR).
*Significant decrease.
period, incidence in 45- to 54-year-old men decreased by
45% in 2001-2003 (RR: 0.55, 95% CI: 0.3-0.99)) from
261.3 to 143.1 per 100,000 person-years.
When looking more closely at the incidence rates of
smaller subgroups stratified by age, it can be observed from
Table 1 and Figure 1 that the overall incidence rates
decreased the most in 45- to 54-year olds. Moreover, a significant
decrease occurred in 35- to 44-year-old men from
2001 to 2017.
Further analysis of incidence rates by stroke subtype
revealed no statistically significant changes. Data can be
found from Supplementary Table 1.
Discussion
We have conducted a population-based study with prospective
design following the ideal criteria for studying stroke
incidence.14
As the incidence of stroke in young adults has previously
been shown to be higher in Tartu, Estonia, than has
been reported from other population-based studies,18 we
expected to see a decrease in incidence rates from the
previous study period in 2001-2003. This hypothesis was
not proven; the incidence of stroke in 15- to 54-year-old
residents of Tartu decreased from 1991 to 2003 and
remained stable thereafter, persisting to be higher than
reported from other countries.10,25,26 The changes were
mainly found among men aged 45-54 years between the
first two study periods and among men aged 35-44 years
between the second and third study period.
When looking at results from population-based studies
conducted in other countries for comparison, the data are
somewhat conflicting. Similar to our findings, decreases in
all stroke incidence were reported from London, United
Kingdom,27 Lund11 and Örebro28 in Sweden, and Matão,
Brazil.29
Contrasting our findings, data from the Arcadia Stroke
Registry in Greece show stable rates already from 1993 to
2016.30
Data from Auckland, New Zealand31 and Dijon, France10
imply increasing incidence rates in young adults. Notably,
authors of the Dijon Stroke Registry reported an increase in
the incidence of first-ever AIS in 18- to 55-year-old adults
from 1985 to 2007, but thereafter, the rates remained stable
International Journal of Stroke, 18(4)
2.27
0.78
1.03
1.06
1.02
(0.1-14.0)
(2.0-28.6)
(24.8-83.7)
(77.0-172.6)
(25.7-48.3)
(31.4-58.8)
RR (95 % CI)
0.89
2013-2017
No. at risk
2/14,441
18/16,257
24/12,804
66/10,923
110/54,425
Rate (95% CI)
2.2
22.1
37.5
120.9
38.0
46.1
(0.3-8.1)
(13.1-35)
(24.0-55.8)
(93.5-153.8)
(31.2-45.8)
(37.4-54.8)
(0.08-9.80)
(0.67-7.69)
(0.39-1.57)
(0.65-1.62)
(0.75-1.52)
(0.71-1.50)
2013-2017 vs 1991-1993
Trend
-2.5
2.2
-1.2
-1.6
-1.5
-1.3
1.51
0.72
0.62*
0.66*
0.70*
RR (95 % CI)
0.44
(0.07-2.60)
(0.63-3.60)
(0.40-1.29)
(0.45-0.87)
(0.51-0.87)
(0.53-0.92)
WSO - April 2023

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