Table 1. Characteristics of the study population.
| Knee pain | P valuea | ||||
| Never (n = 667) | Occasionally (n = 303) | Often (n = 128) | Always (n = 167) | ||
| No. (column %) | No. (column %) | No. (column %) | No. (column %) | ||
| Age group, yrs | |||||
| 65–69 | 198 (29.7) | 63 (20.8) | 14 (10.9) | 13 (7.8) | <0.001 |
| 70–79 | 315 (47.2) | 153 (50.5) | 69 (53.9) | 87 (52.1) | |
| ≥80 | 154 (23.1) | 87 (28.7) | 45 (35.2) | 67 (40.2) | |
| Sex | |||||
| Male | 337 (50.5) | 131 (43.2) | 50 (39.1) | 55 (32.9) | <0.001 |
| Female | 330 (49.5) | 172 (56.8) | 78 (60.9) | 112 (67.1) | |
| Marital status | |||||
| Married | 489 (73.6) | 193 (64.3) | 83 (65.9) | 100 (60.6) | 0.001 |
| Widowed/separated/single | 175 (26.4) | 107 (35.7) | 43 (34.1) | 65 (39.4) | |
| Education | |||||
| Junior high school | 502 (75.7) | 241 (80.6) | 99 (78.0) | 144 (86.8) | 0.014 |
| High school or higher | 161 (24.3) | 58 (19.4) | 28 (22.0) | 22 (13.3) | |
| Consultation due to knee pain | |||||
| Yes | 0 (0.0) | 85 (28.1) | 67 (52.3) | 119 (71.3) | <0.001 |
| No | 659 (100.0) | 217 (71.9) | 61 (47.7) | 48 (28.7) | |
| History of major diseaseb | |||||
| Yes | 177 (26.7) | 84 (27.9) | 41 (32.3) | 52 (31.5) | 0.448 |
| No | 485 (73.3) | 217 (72.1) | 86 (67.7) | 113 (68.5) | |
| Current smoking | |||||
| Yes | 164 (24.6) | 78 (25.8) | 25 (19.7) | 36 (21.7) | 0.482 |
| No | 503 (75.4) | 224 (74.2) | 102 (80.3) | 130 (78.3) | |
| Current alcohol drinking | |||||
| Yes | 238 (36.2) | 118 (39.3) | 41 (32.5) | 45 (27.8) | 0.079 |
| No | 419 (63.8) | 182 (60.7) | 85 (67.5) | 117 (72.2) | |
aOn χ2 test.
bStroke, myocardial infarction/angina, chronic obstructive pulmonary disease, diabetes mellitus, or cancer.
Due to missing values, the totals of stratified subgroups are not equal.