Table 2.
ORs and 95% CI of risk factors for knee pain and clinical KOA (logistic regression)
| Variables | Knee pain | Clinical KOA | ||||||
|---|---|---|---|---|---|---|---|---|
| case | control | Model 1 | Model 2 | case | control | Model 1 | Model 2 | |
| Age (years) | NA | NA | 1.03(1.02–1.03)* | NA | NA | 1.04(1.03–1.05)* | ||
| BMI (kg/m2) | NA | NA | 1.08(1.07–1.10)* | NA | NA | 1.10(1.08–1.12)* | ||
| Education | ||||||||
| Elementary or lower | 807 | 797 | 1 | 154 | 1450 | 1 | ||
| Junior high school | 1278 | 1424 | 1.06(0.93–1.21) | 229 | 2473 | 1.20(0.96–1.51) | ||
| High school | 1071 | 1379 | 1.03(0.89–1.18) | 199 | 2251 | 1.39(1.09–1.77)* | ||
| College or higher | 325 | 393 | 1.05(0.87–1.26) | 57 | 661 | 1.21(0.87–1.67) | ||
| Alcohol consumption | ||||||||
| Never | 3031 | 3513 | 1 | 557 | 2987 | 1 | ||
| Current | 410 | 433 | 1.21(1.04–1.40)* | 71 | 772 | 1.18(0.91–1.54) | ||
| Former | 47 | 58 | 0.99(0.67–1.48) | 11 | 94 | 1.42(0.75–2.70) | ||
| Physical exercise | ||||||||
| No | 400 | 408 | 1 | 63 | 745 | 1 | ||
| Yes | 3096 | 3605 | 0.89(0.77–1.03) | 577 | 6124 | 1.12(0.85–1.47) | ||
| Work posture | ||||||||
| Sitting | 1031 | 1268 | 1 | 207 | 2092 | 1 | ||
| Standing | 1765 | 1942 | 1.12(1.01–1.24)* | 320 | 3387 | 0.96(0.80–1.15) | ||
| Bending | 535 | 616 | 1.07(0.93–1.23) | 90 | 1061 | 0.86(0.66–1.11) | ||
| Squatting kneeling | 150 | 173 | 1.07(0.84–1.35) | 20 | 303 | 0.67(0.42–1.07) | ||
| Shift work | ||||||||
| No | 2001 | 2492 | 1 | 376 | 4117 | 1 | ||
| Yes | 1495 | 1522 | 1.28(1.17–1.41)* | 264 | 2753 | 1.13(0.96–1.34) | ||
| Times of pregnancy | ||||||||
| ≤1 | 387 | 553 | 1 | 1 | 67 | 873 | 1 | 1 |
| 2 | 774 | 1050 | 1.05(0.90–1.24) | 0.97(0.82–1.15) | 134 | 1690 | 0.90(0.66–1.23) | 0.97(0.70–1.34) |
| ≥3 | 2335 | 2411 | 1.38(1.20–1.60)* | 1.15(0.98–1.34) | 439 | 4307 | 0.91(0.69–1.21) | 0.98(0.73–1.32) |
| Abortion | ||||||||
| No | 1104 | 1261 | 1 | 1 | 215 | 2150 | 1 | 1 |
| Yes | 2329 | 2652 | 1.01(0.91–1.11) | 1.08(0.98–1.20) | 413 | 4568 | 1.06(0.88–1.26) | 1.01(0.85–1.22) |
| History of HT | ||||||||
| No | 3088 | 3418 | 1 | 1 | 580 | 5926 | 1 | 1 |
| Yes | 126 | 99 | 1.59(1.23–2.06)* | 1.56(1.20–2.04)* | 26 | 199 | 1.79(1.21–2.65)* | 1.65(1.11–2.47)* |
| Years of post-menopause | ||||||||
| No | 239 | 444 | 1 | 1 | 29 | 654 | 1 | 1 |
| <9 | 887 | 1208 | 1.30(1.08–1.56)* | 1.31(1.08–1.58)* | 134 | 1961 | 1.33(0.88–2.01) | 1.36(0.89–2.09) |
| 7–19 | 1065 | 1161 | 1.42(1.16–1.76)* | 1.48(1.19–1.83)* | 187 | 2039 | 1.35(0.87–2.09) | 1.38(0.89–2.16) |
| ≥17 | 1262 | 1148 | 1.46(1.12–1.91)* | 1.54(1.17–2.01)* | 285 | 2125 | 1.38(0.82–2.32) | 1.39(0.82–2.35) |
| Contraceptives use | ||||||||
| No | 2813 | 3307 | 1 | 1 | 504 | 5616 | 1 | 1 |
| Yes | 656 | 672 | 1.18(1.05–1.34)* | 1.17(1.04–1.33)* | 129 | 1199 | 1.28(1.04–1.57)* | 1.25(1.01–1.54)* |
BMI body mass index, HT post-menopausal hormone replacement therapy, NA not applicable, *p-value < 0.05
Model 1: adjusted for age (continuous) and BMI (continuous)
Model 2: adjusted for age (continuous), BMI (continuous), education, alcohol drinking, physical exercise, work posture, and shift work