Depression score and background factors
| Depression score | Whole study population | ||||
|---|---|---|---|---|---|
| Low (n = 567) | Medium (n = 559) | High (n = 600) | p Value | Mean (SD) | |
| Mean (SD) | Mean (SD) | Mean (SD) | |||
| *Includes back problems and osteoarthritis. †Includes coronary heart disease, cardiac insufficiency, hypertension, claudication, and stroke. ‡Includes mental disorders. §Includes chronic bronchitis, bronchial asthma, farmer’s lung or other pneumoconiosis, lung tuberculosis, diabetes, epilepsy, liver or pancreatic diseases, cancer, and rheumatoid arthritis. | |||||
| Age (y) | 51.3 (5.2) | 51.7 (5.1) | 52.4 (4.7) | 0.001 | 51.8 (5.0) |
| Body mass index (kg/m2) | 26.4 (3.2) | 26.7 (3.3) | 26.9 (3.7) | 0.03 | 26.7 (3.4) |
| Alcohol (g/week) | 58.2 (78.4) | 73.2 (118.5) | 92.9 (162.1) | 0.000 | 75.1 (126.1) |
| Smoking (cigarettes/day) | 3.8 (8.3) | 5.2 (9.5) | 7.0 (11.2) | 0.000 | 5.4 (9.8) |
| Maximal oxygen uptake (ml/kg/min) | 2.67 (0.61) | 2.54 (0.59) | 2.38 (0.58) | 0.000 | 2.53 (0.60) |
| Education | Proportion (%) | Proportion (%) | Proportion (%) | Proportion (%) | |
| High school or above (n = 147) | 9.2 | 9.5 | 7.0 | 0.000 | 8.5 |
| Middle school (n = 655) | 44.7 | 37.0 | 32.5 | 38.0 | |
| Elementary school or less (n = 923) | 46.1 | 53.5 | 60.5 | 53.5 | |
| Occupation | |||||
| Farmer (n = 331) | 18.2 | 19.4 | 20.7 | 0.019 | 19.5 |
| Blue collar worker (n = 627) | 32.4 | 36.6 | 41.4 | 36.9 | |
| White collar worker (n = 743) | 49.4 | 44.0 | 38.0 | 43.7 | |
| Illness (at baseline) | |||||
| Musculoskeletal* (n = 745) | 27.8 | 31.1 | 41.1 | 0.000 | 43.2 |
| Cardiovascular† (n = 870) | 26.4 | 30.5 | 43.1 | 0.000 | 50.4 |
| Mental‡ (n = 67) | 11.9 | 20.9 | 67.2 | 0.000 | 3.9 |
| Other chronic disease§ (n = 581) | 27.9 | 30.5 | 41.7 | 0.000 | 33.7 |