Prevalence and involvement patterns of radiographic hand osteoarthritis in Japanese women: the Hizen-Oshima Study.

The prevalence and pattern of joint involvement in radiographic hand osteoarthritis (OA) have been reported in Western populations, but similar data are lacking for Japanese. We examined this issue in 551 Japanese women aged > or = 40 years. Radiographs were obtained of both hands and graded according to the Kellgren-Lawrence (K-L) criteria. OA was defined as K-L grade 2 or higher. The prevalence of radiographic OA in the IP, MCP, and CMC joints was distributed similarly in both hands. The most frequent locations of radiographic OA were the distal IP joints of the index finger, the IP joint of the thumb, and the distal IP joints of the middle finger, in this order. The prevalence of radiographic OA in each joint group increased significantly with age, and that in Japanese women was lower in the thumb CMC joint and higher in the thumb IP joint compared to those in Caucasian women reported previously. The strongest predictor for the presence of radiographic OA in a particular joint was the disease status in the same joint of the opposite hand (OR = 18.5; 95% CI; 15.2-22.7), followed by the joints in the same row of the same hand (OR = 15.5; 95% CI, 11.9-20.1), and then by the joints in the same ray of the same hand (OR = 1.3; 95% CI, 1.0-1.6). Although the prevalence of hand OA is likely to show site-specific differences between Japanese and Caucasian women, our results indicate that both groups show similar involvement pattern symmetrically and in the same row of the same hand.