Table 3.
Preclinical CVD markers as mediators in the association of BMI with structural knee OA
| Independent variable | Dependent variable |
|||
|---|---|---|---|---|
| Total effect C | Indirect effect A | Direct effect C’ Indirect effect B | Mediation % (95% CI) | |
| Structural knee OA OR (95% CI) | Mediator β (95% CI) | Structural knee OA OR (95% CI) | ||
| BMI | 1.58 (1.24, 2.03) | 0.29 (0.21, 0.38) | 1.67 (1.33, 2.12) | NA |
| Systolic BP | 0.81 (0.64, 1.02) | |||
| BMI | 1.58 (1.24, 2.03) | 0.35 (0.27, 0.43) | 1.65 (1.30, 2.09) | NA |
| Diastolic BP | 0.87 (0.70, 1.09) | |||
| BMI | 1.58 (1.23, 2.03) | 0.33 (0.25, 0.40) | 1.56 (1.19, 2.06) | 3.1 (1.9, 7.3) |
| Carotid IMT | 1.03 (0.80, 1.34) | |||
| BMI | 1.50 (1.13, 1.99) | 0.00 (−0.07, 0.08) | 1.50 (1.13, 1.99) | NA |
| Popliteal VWT | 1.09 (0.85, 1.38) | |||
| Effusion OR (95% CI) | Mediator β (95% CI) | Effusion OR (95% CI) | ||
| BMI | 1.46 (1.14, 1.88) | 0.30 (0.22, 0.37) | 1.48 (1.13, 1.94) | NA |
| Systolic BP | 0.96 (0.74, 1.26) | |||
| BMI | 1.46 (1.14, 1.88) | 0.34 (0.27, 0.41) | 1.54 (1.19, 2.01) | NA |
| Diastolic BP | 0.84 (0.63, 1.11) | |||
| BMI | 1.44 (1.12, 1.86) | 0.33 (0.26, 0.40) | 1.40 (1.06, 1.84) | 10.8 (6.0, 37.6) |
| Carotid IMT | 1.12 (0.82, 1.52) | |||
| BMI | 1.40 (1.06, 1.84) | 0.03 (−0.03, 0.09) | 1.38 (1.04, 1.82) | NA |
| Popliteal VWT | 1.29 (1.00, 1.67) | |||
| BML OR (95% CI) | Mediator β (95% CI) | BML OR (95% CI) | ||
| BMI | 1.05 (0.87, 1.27) | NA | NA | NA |
| Systolic BP | ||||
| BMI | 1.05 (0.87, 1.27) | NA | NA | NA |
| Diastolic BP | ||||
| BMI | 1.06 (0.88, 1.28) | NA | NA | NA |
| Carotid IMT | ||||
| BMI | 0.97 (0.79, 1.20) | NA | NA | NA |
| Popliteal VWT | ||||
Results are based on analyses weighted towards the BMI distribution of the general population. Due to analyses in subpopulation and control definitions numbers included in the analyses vary; numbers included are provided Supplementary Fig. 1, available at Rheumatology online. Continuous variables were standardized (mean 0, s.d. 1), s.d. BMI=5, s.d. systolic BP=20, s.d. diastolic BP=12, s.d. carotid IMT=0.09, s.d. popliteal VWT=0.05. Analyses were adjusted for age, sex and education. BML: bone marrow lesion; BP: blood pressure; IMT: intima media thickness; NA: not applicable; OR: odds ratio; VWT: vessel wall thickness.