Baseline characteristics of participants in Australia (2008), China (2011) and the USA (2008–2010)
| Australia n=3412 | China n=7347 | US n=12 346 | |||||
| n | % | n | % | n | % | ||
| Gender (women) | 1828 | 53.6 | 4314 | 58.7 | 7359 | 59.6 | |
| Age (mean, SD) | 63.8 | 9.3 | 62.0 | 7.8 | 67.9 | 9.9 | |
| Education | Below high school | 1439 | 42.2 | 6608 | 89.9 | 2041 | 16.5 |
| High school | 286 | 8.4 | 451 | 6.1 | 4425 | 35.8 | |
| Tertiary no university | 1018 | 29.8 | 253 | 3.4 | 2992 | 24.2 | |
| College/university | 669 | 19.6 | 35 | 0.5 | 2888 | 23.4 | |
| Marital status | Married/partnered | 2418 | 70.9 | 6076 | 82.7 | 7935 | 64.3 |
| Not married | 601 | 17.6 | 407 | 5.5 | 2183 | 17.7 | |
| Widowed | 393 | 11.5 | 864 | 11.8 | 2228 | 18.0 | |
| Location of residence | Urban | 1985 | 58.2 | 1548 | 21.1 | 5958 | 48.3 |
| Regional | 1377 | 40.4 | – | – | – | – | |
| Rural | 50 | 1.5 | 5799 | 78.9 | 6388 | 51.7 | |
| Retirement (yes) | 1726 | 50.6 | 1087 | 14.8 | 6130 | 49.7 | |
| Loneliness (yes) | 589 | 17.3 | 1317 | 17.9 | 1810 | 14.7 | |
| Social engagement (active) | 2923 | 85.7 | 2560 | 34.8 | 11 617 | 94.1 | |
| Health status | Very good-excellent | 1202 | 35.2 | 1573 | 21.4 | 5279 | 42.7 |
| Good | 1366 | 40.0 | 3843 | 52.3 | 4008 | 32.5 | |
| Fair-poor | 844 | 24.7 | 1931 | 26.3 | 3059 | 24.8 | |
| Mental health status mean (range), SD | 10.8 (4–30) | 4.1 | 17.2 (1–36) | 5.9 | −0.8 | 1.7 (−2–5) | |