Univariate and multivariate association models to assess the relationship between risk factors and incident KOA in RS-I
| Univariate | Multivariate 1 | Multivariate 2 | Multivariate 3 | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Risk factor | OR | 95% CI | p Value | OR | 95% CI | p Value | OR | 95% CI | p Value | OR | 95% CI | p Value |
| Gender (% F) | 2.13 | 1.72 to 2.64 | 4.3×10−12 | 1.90 | 1.47 to 2.44 | 6.8×10−7 | 1.85 | 1.42 to 2.40 | 4.7×10−6 | 1.66 | 1.25 to 2.19 | 3.9×10−4 |
| Age (years) | 0.99 | 0.89 to 1.10 | 0.84 | 0.99 | 0.89 to 1.10 | 0.85 | 0.99 | 0.89 to 1.10 | 0.83 | 0.89 | 0.79 to 1.00 | 0.06 |
| BMI (kg/m2) | 1.41 | 1.28 to 1.55 | 5.0×10−12 | 1.36 | 1.23 to 1.50 | 8.8×10−10 | 1.36 | 1.23 to 1.50 | 9.6×10−10 | 1.28 | 1.15 to 1.42 | 7.3×10−6 |
| Knee pain* | 1.81 | 1.42 to 2.32 | 2.4×10−6 | 1.65 | 1.27 to 2.14 | 1.7×10−4 | 1.64 | 1.26 to 2.13 | 2.0×10−4 | 1.62 | 1.22 to 2.16 | 0.001 |
| Disability index* | 1.08 | 0.98 to 1.19 | 0.11 | 0.97 | 0.87 to 1.08 | 0.61 | 0.97 | 0.88 to 1.09 | 0.64 | 0.95 | 0.84 to 1.07 | 0.41 |
| General health* | 0.95 | 0.63 to 1.42 | 0.79 | 0.86 | 0.55 to 1.34 | 0.50 | 0.86 | 0.55 to 1.33 | 0.49 | 0.99 | 0.62 to 1.58 | 0.96 |
| Smoking* | 0.66 | 0.53 to 0.81 | 7.8×10−5 | 0.92 | 0.73 to 1.17 | 0.51 | 0.92 | 0.73 to 1.17 | 0.49 | 0.98 | 0.76 to 1.26 | 0.85 |
| Educational level* | 0.95 | 0.90 to 1.00 | 0.07 | 1.01 | 0.95 to 1.08 | 0.69 | 1.01 | 0.95 to 1.08 | 0.69 | 1.01 | 0.95 to 1.08 | 0.71 |
| Heavy work* | 0.75 | 0.55 to 1.03 | 0.08 | 0.86 | 0.62 to 1.19 | 0.35 | 0.86 | 0.62 to 1.19 | 0.35 | 0.87 | 0.61 to 1.24 | 0.44 |
| Genetic score | 1.17 | 1.06 to 1.29 | 0.002 | – | – | – | 1.04 | 0.94 to 1.16 | 0.44 | 1.12 | 0.99 to 1.25 | 0.07 |
| Hand OA† | 1.82 | 1.47 to 2.25 | 4.7×10−8 | – | – | – | – | – | – | 1.44 | 1.13 to 1.84 | 0.003 |
| Hip OA† | 1.08 | 0.75 to 1.53 | 0.69 | – | – | – | – | – | – | 1.01 | 0.68 to 1.52 | 0.95 |
| Baseline knee KL score 1† | 7.29 | 5.77 to 9.21 | 3.1×10−62 | – | – | – | – | – | – | 6.97 | 5.48 to 8.87 | 1.8×10−56 |
Standardised scores ((x-mean)/SD) were made for continuous variables, such that the OR in the multivariate models was expressed as percentage of increased or decreased risk per SD.
For continuous variables, the OR per increase in SD is shown (age, BMI, disability index and genetic score).
*‘Questionnaire’ variables.
†X-ray variables.
BMI, body mass index; KL, Kellgren & Lawrence; KOA, knee osteoarthritis; OA, osteoarthritis; RS-I, Rotterdam Study I.