Backgrounds: Although patients with radiographic knee osteoarthritis (OA) have a higher areal bone mineral density (BMD) compared to non-OA individuals, their fracture risk was not significantly different. This study sought to define the association between radiographic knee OA and volumetric BMD.
Methods: The study was part of the Vietnam Osteoporosis Study, in which 944 men and 1506 women aged ≥ 40 years were randomly recruited from Ho Chi Minh City (Vietnam). Radiographs of the knee were evaluated using the Kellgren and Lawrence scale, with grades ranging from 0 to 4. Knee OA was defined as the presence of radiographic grades of 2 or higher in a knee joint. Trabecular and cortical volumetric bone density (vBMD) was measured in the tibia bone by a pQCT XCT2000 (Stratec, Germany). Linear regression model was used to analyze the association between pQCT parameters and knee OA.
Results: The prevalence of radiographic knee OA was approximately 31% (n = 755), and it increased with advancing age. In comparison to non-OA individuals, those with knee OA exhibited higher femoral neck aBMD (effect size [ES] = 0.05, 95% CI: 0.01 to 0.09; P = 0.02 in men vs. ES = 0.02, 95% CI: 0.0004 to 0.04; P = 0.02 in women); however, they had lower vBMD at the cortical tibia bone (ES = -16, 95% CI: -27 to -4.3; P < 0.001 in men vs. ES = -11, 95% CI: -2.2 to -2.6; P = 0.01 in women).
Conclusion: These data indicate that approximately a third of Vietnamese people have radiographic knee OA and that the cortical vBMD was lower in knee OA patients.