Table 1.
Eligible longitudinal aging studies for creating questionnaire answer pattern indices.
| Study | First wavea | Sampling interval (years) | Waves, n | Minimum age (years) | Approximate sample size, n |
Survey items (noteb), n | Dementia status ascertained |
| Health and Retirement Study | 2006 | 2 | >6 | 50 | 12,000 | >100 | Tc |
| English Longitudinal Study of Ageing | 2002 | 2 | >8 | 50 | 8000 | >100 | Md, T |
| Longitudinal Aging Study Amsterdam | 1992 | 3 | >7 | 55 | 3100 | >100 | M |
| Irish Longitudinal Study on Ageing | 2010 | 2 | >4 | 50 | 5000 | >100 | M, T |
| Memory and Aging Project | 2004 | 1 | >15 | 65 | 1700 | 60 | Ce, M |
| Australian Longitudinal Study of Ageing | 1992 | 3-4 | >7 | 65 | 1100 | 80 | M |
| Canberra Longitudinal Study | 1990 | 4 | 4 | 70 | 1000 | 50 | C, M |
| Sydney Memory and Aging Study | 2005 | 2 | >7 | 70 | 1000 | 80 | C, M |
| Minority Aging Research Study | 2005 | 1 | >14 | 65 | 950 | 60 | C, M |
| Einstein Aging Study | 2004 | 1 | >7 | 70 | 800 | 80 | C, M |
| Swedish Adoption or Twin Study of Aging | 1986 | 3 | >7 | 50 | 600 | >100 | C, M |
| Octogenarian Twins Study | 1991 | 2 | 5 | 79 | 300 | 80 | C, M |
| Longbeach Longitudinal Study | 1994 | 3 | 5 | 50 | 150 | 40 | C |
| Mexican Health and Aging Study | 2012 | 3 | >3 | 50 | 15,000 | 40 | T |
| Survey of Health, Aging, and Retirement in Europe | 2004 | 2 | >7 | 50 | 20,000 | 40 | M, T |
aYears indicate the first assessment wave to be used in the analyses.
bMinimum number of available individual questions from multi-item rating scales at each assessment occasion.
cT indicates that dementia status is ascertained by validated cutoffs from Telephone Interview for Cognitive Status [13,14].
eC indicates that dementia status is ascertained by formal clinical assessment.