Table 1 Characteristics of interview participants and volunteers values are numbers (percentages) unless stated otherwise

Age mean ± SD (range)

85.8 ± 6.8 (74–95)

56 ± 18.2 (18–84)

64 ± 9.1 (39–73)

Women

9 (81.8)

30 (75.0)

8 (66.7)

Marital status

married

0 (0)

18 (45.0)

7 (58.3)

single

0 (0)

15 (37.5)

3 (25.0)

divorced

0 (0)

5 (12.5)

2 (16.7)

widowed

11 (100.0)

2 (5.0)

0 (0)

missing

0 (0)

0 (0)

0 (0)

Education level*

low

4 (36.4)

9 (22.5)

2 (16.3)

medium

6 (54.5)

10 (25.0)

1 (8.3)

high

1 (9.1)

21 (52.5)

9 (75.0)

Born in

Germany

11 (100.0)

34 (85.0)

10 (83.3)

other

0 (0)

1 (2.5)

0 (0)

missing

0 (0)

5 (12.5)

2 (16.7)

Further voluntary engagement

n/a

21 (52.5)

5 (41.7)

BMI mean ± SD (range)

27.1 ± 5.2

(20.3–36.4)

n/a

n/a

Care degree

1

0 (0)

n/a

n/a

2

8 (72.7)

n/a

n/a

3

2 (18.2)

n/a

n/a

4

1 (9.1)

n/a

n/a

5

0 (0)

n/a

n/a

Use of walking aid

none

3 (27.3)

n/a

n/a

cane

0 (0)

n/a

n/a

walker

8 (72.7 )

n/a

n/a

MMSE (Mini mental status examination) – baseline only

mean ± SD (range)

26.1 ± 3.1

(21–30)

n/a

n/a

SPPB (Short physical performance battery)

mean ± SD (range)

4.4 ± 1.3

(2–6)

n/a

n/a

EQ-5D-5 L (Quality of life)

mean ± SD (range)

0.7 ± 0.2

(0.4 − 1)

n/a

n/a

Clinical frailty scale^†

Very fit

0 (0)

n/a

n/a

Well

0 (0)

n/a

n/a

Managing well

1 (9.1)

n/a

n/a

Vulnerable

2 (18.2)

n/a

n/a

Mildly frail

3 (27.3)

n/a

n/a

Moderately frail

3 (27.3)

n/a

n/a

Severely frail

2 (18.2)

n/a

n/a

Very severely frail

0 (0)

n/a

n/a

Terminally ill

0 (0)

n/a

n/a