Table 3.

Characteristics of the included studies, n (%)

Characteristics	Value
Study population
U.S.	10 (53)
United Kingdom	3 (16)
Australia	2 (11)
Netherlands	1 (5)
Portugal	1 (5)
Canada	1 (5)
France	1 (5)
Type of sample
Population-based	14 (74)
Employee cohort	4 (21)
HMO insurance policy holders	1 (5)
Gender of sample
Male	4 (21)
Female	2 (11)
Both genders	13 (68)
Exposure measurement (retirement)
Self-reported retirement status	8 (42)
Self-reported employment status	9 (47)
Employer's records	1 (5)
As major life event	1 (5)
Outcome measure (physical activity)
Self-reported, validated questionnaire	3 (16)
Self-reported, nonvalidated questionnaire	6 (32)
Based on single-item question	9 (47)
Objectively measured	1 (5)

Note: 19 studies were included.