An in-depth study of the associations between osteoarthritis- and osteoporosis-related phenotypes at different skeletal locations.

The relationship between OA and osteoporosis characteristics remains controversial. This study revealed that age-adjusted hand OA is associated with lower hand/arm BMD levels. Wrist fracture occurrence is associated with increased OA hand scores and low arm BMD. Conversely, age-adjusted knee and spine OA is associated with high spine, hip, and total BMDs. INTRODUCTION Osteoarthritis (OA) and osteoporosis are two common musculoskeletal diseases which contribute a high burden of disability, yet assessments of their relationship remains controversial. The aim of this study was to clarify the association between bone mineral densities (BMD) of the hand, arm, spine, hip, and total body, and OA of the hand and knee and lumbar disc degeneration in two different ethnic groups. METHODS Radiographic assessments of the hand, knee, and spine were collected and coded for joint space narrowing, osteophytes, and the Kellgren-Lawrence score from Chuvashian (n = 1504) and British (n = 2280) individuals. BMD measurements of standard skeletal sites were estimated by dual X-ray absorptiometry. Age- and familial-adjusted regression analyses were conducted to determine associations. RESULTS Knee OA affection was positively associated with elevated hip, spine, and total body BMD levels (p < 0.001). Additionally, disc degeneration phenotypes showed significant positive associations with the hip, spine, and total BMD (p < 0.001). However, increased hand OA scores was significantly negatively correlated with arm and hand BMD measurements in males and females in both samples (p < 0.001). Additionally, higher hand OA scores were significantly associated with wrist fracture. CONCLUSIONS We discovered a clear pattern of association between hand OA and low hand and arm BMD, with increased risk of wrist fracture, as well as reproducing previous associations between knee and spine OA and elevated spine, hip, and total body BMD. It appears that hand OA manifests differently in comparison to hip and knee OA.