Table 1 Sample baseline characteristics

 London, UK

14 (19)

14 (19)

 Lyon, France

20 (27)

20 (27)

 Cologne, Germany

19 (27)

20 (27)

 Barcelona, Spain

20 (27)

20 (27)

Sex (female; n (%))

47 (64)

48 (65)

Ethnicity (white; n (%))

69 (95)

72 (99)

Age (years; x̅ ± SD)

72.1 ± 7.5

73.2 ± 6.2

Education (years; x̅ ± SD)

13.9 ± 3.8

13.4 ± 3.4

MMSE (x̅ ± SD)

28.7 ± 1.2

28.9 ± 1.0

PACC5_Abridged (x̅ ± SD)^a

0.05 ± 1.05

− 0.05 ± 0.96

Attention composite (x̅ ± SD)^b

0.04 ± 1.10

− 0.01 ± 1.03

Executive composite (x̅ ± SD)^c

− 0.01 ± 1.01

0.01 ± 1.00

STAI-A (x̅ ± SD)^d

33.6 ± 9.8

31.6 ± 8.4

GDS-15 (x̅ ± SD)^d

3.1 ± 2.5

2.0 ± 2.0