Table 1.

Characteristics of the included study cohorts according to their publication year

Author, year	Country	Midyear	Study period	SAH cases, n	Mean age, y, overall, (w/m)	Diagnosis confirmed*, %	Current smoking, %		Hypertension, %
							women	men	women	men
Sacco et al., 1982	USA	1962	1949–1975	39	62.4	. . .	. . .	. . .	. . .	. . .
Jakovljević et al., 1996	Finland	1987	1983–1992	1,105	. . .	80–97a	. . .	. . .	. . .	. . .
Truelsen et al., 1998	New Zealand	1987	1981–1993	342	(54.1/48.8)	92	. . .	. . .	. . .	. . .
Kimura et al., 1998	Japan	1989	1989	339	(60.7/55.0)	99b	. . .	. . .	. . .	. . .
Ingall et al., 2000	Multinationalc
	Denmark	1986	1982–1991	198	. . .	95–99a,d	. . .	. . .	. . .	. . .
	Germany	1986	1984–1989	125	. . .	16–68a,d	. . .	. . .	. . .	. . .
	China	1988	1984–1993	85	51.4	86–100a,d	. . .	. . .	. . .	. . .
	Italy	1988	1984–1993	423	. . .	95–99a,d	. . .	. . .	. . .	. . .
	Sweden	1989	1984–1994	244	. . .	91–98a,d	. . .	. . .	. . .	. . .
	Poland	1989	1984–1994	306	48.6	25–43a,d	. . .	. . .	. . .	. . .
	Russia	1989	1985–1993	276	. . .	2–30a,d	. . .	. . .	. . .	. . .
	Serbia	1989	1983–1995	128	. . .	58–80a,d	. . .	. . .	. . .	. . .
	Lithuania	1990	1986–1995	215	. . .	33–83a,d	. . .	. . .	. . .	. . .
Pobereskin et al., 2001	UK	1994	1992–1996	800	(63/57)	99	. . .	. . .	. . .	. . .
Zhang et al., 2003	China	1998	1996–2000	147	. . .	92b	. . .	. . .	. . .	. . .
Stegmayr et al., 2004	Sweden	1992	1985–2000	984	. . .	98a	. . .	. . .	. . .	. . .
Khan et al., 2005	Sweden	1993	1989–1998	197	. . .	99a	. . .	. . .	. . .	. . .
Labovitz et al., 2006	USA	1995	1993–1997	54	51	85a	. . .	. . .	. . .	. . .
Kozák et al., 2007	Japan	1993	1989–1998	3,257	(64.4/58.2)	≥85	11.8	70.7	51.1	44.5
Koffijberg et al., 2008	Sweden	1994	1987–2002	18,443	58.9	96PPV,b	. . .	. . .	. . .	. . .
Vadikolias et al., 2009	Greece	2003	2001–2005	51	59	100a	. . .	. . .	. . .	. . .
Alvarez et al., 2010	Chile	2001	2000–2003	33	50.7	97	. . .	. . .	. . .	. . .
Macpherson et al., 2011	Scotland	1995	1986–2005	12,056	(56.7/52.0)	95PPV,a	. . .	. . .	9.1d	8.1d
Sandvei et al., 2011	Norway	1995	1984–2007	214	58.6	100	. . .	. . .	. . .	. . .
González-Pérez et al., 2013	UK	2004	2000–2008	1,303	57.7	91a	. . .	. . .	. . .	. . .
Olindo et al., 2014	France (Caribbean)	2005	1999, 2012	37	. . .	97b	. . .	. . .	. . .	. . .
Madsen et al., 2017 and 2020	USA	2004	1993–2015	443	. . .	95#	. . .	. . .	. . .	. . .
Guéniat et al., 2018	France	1999	1987–2012	161	. . .	90–98b	. . .	. . .	. . .	. . .
Takashima et al., 2018	Japan	2011	2011	201	65.6	97a	16.9	49.0	57.9	50.9
Chen et al., 2020	China	2010	2004–2017	702	. . .	92b	5.3	60.4	. . .	. . .
Lavados et al., 2021	Chile	2015	2015–2016	47	57.4	≥64b	. . .	. . .	. . .	. . .
Rehman et al., 2022	Multinational	2005	1994–2017	643	(60.2/51.8)	100a	26.2	31.3	52.3	50.0
Asikainen et al., 2023	Finland	2007	1998–2017	9,443	(60.4/55.4)	97–100PPV,**	. . .	. . .	. . .	. . .

^aOf all SAHs (i.e., not specifically aneurysmal SAHs confirmed).

^bOf all strokes.

^cFinland and Northern Sweden removed due to completely overlapping study populations with studies by Jakovljević et al. [9] and Stegmayr et al. [37], respectively.

^dOnly for hospitalized SAH patients.

^#During the years 1993–2010.

*Aneurysmal SAH diagnosis confirmed by imaging (CT or MRI), autopsy, or positive lumbar puncture finding combined with angiography, surgery, or autopsy. Positive predictive value (PPV) (%) for register-based studies.

**Hospitalized aneurysmal SAHs and fatal SAHs validated separately with 99.8% and 97% PPVs, respectively.