Guralnik et al8 | United States before 1989 | General population (survey) | 60–69 y: 35 | |
| | | 70–79 y: 47 | — |
| | | 80+ y: 53 | |
Metsemakers et al5 | Netherlands, 1990 | Family medicine registry | | 25–44 y: 2.4, 2.9† |
| | | | 45–64 y: 3.8, 4.3† |
| | | -— | 65–74 y: 5.0, 5.2† |
| | | | 75+ y: 5.7, 6.2† |
Hoffman et al9 | United States, 1987 | General population (survey) | 18–44 y: 28.4‡ | |
| | | 45–64 y: 51.0‡ | — |
| | | 65+ y: 69.2‡ | |
Van den Akker et al4 | Netherlands, 1994 | Family medicine registry | 0–19 y: 10.0 | |
| | | 20–39 y: 17.4 | |
| | | 40–59 y: 34.7 | 40–59 y: 1.3 |
| | | 60–79 y: 63.1 | 60–79 y: 2.5 |
| | | 80+ y: 78.2 | 80+ y: 3.5 |
Daveluy10 | Canada (Quebec), 1998 | General population (survey) | 25–44 y: 27.7 | |
| | | 45–64 y: 40.2 | — |
| | | 65+ y: 63.4 | |
Fuchs6 | Israel, 1989–1992 | General population (survey) | 75+ y: 64.0 | 2.2 |
Wolff7 | United States, 1999 | Medicare | 65–69 y: 53.9 | 2.3 |
| | | 70–74 y: 63.1 | |
| | | 75–79 y: 68.8 | |
| | | 80–84 y: 72.5 | |
| | | 85+ y: 72.8 | |
This study | Canada, 2003 | Family medicine | 18–44 y: 69.3 | 18–14 y: 2.8 |
| | | 45–64 y: 92.8 | 45–64 y: 4.6 |
| | | 65+ y: 98.7 | 65+ y: 6.5 |