Table 2

 Baseline characteristics

Disability retirees (n = 839)Percentages or mean (SD)Non-illness based retirees (n = 329)Percentages or mean (SD)Working men and old age retirees (n = 560)Percentages or mean (SD)p Value for difference between groups
*Includes back problems and osteoarthritis. †Includes coronary heart disease, cardiac insufficiency, hypertension, claudication, and stroke. ‡Includes mental problems and mental illnesses diagnosed by a physician.
Age52.5 (4.1)53.9 (2.9)49.4 (6.3)0.000
Body mass index (kg/m2)26.9 (3.6)26.6 (3.5)26.4 (3.1)0.047
Alcohol (g/week)76.0 (119.4)72.0 (155.9)75.6 (116.0)0.881
Smoking (cigarettes/day)5.7 (9.9)5.1 (9.6)5.1 (9.9)0.493
Maximal oxygen uptake (ml/kg/min)30.3 (7.3)31.8 (7.2)34.4 (7.4)0.000
Education
    High school or above (n = 147)5.85.514.40.000
    Middle school (n = 661)36.733.442.5
    Elementary school or less (n = 946)57.461.143.1
Illness (n = 1611)
    Musculoskeletal* (n = 757)49.043.534.20.000
    Cardiovascular† (n = 883)58.651.437.50.000
    Mental‡ (n = 68)4.44.03.00.433