Background: Osteoarthritis (OA) is common and disabling among older patients around the world. Data exploring the prevalence and risk factors of OA are of paramount importance in establishing healthcare policies. However, few studies have evaluated these topics among Asian populations.

Questions/purposes: This study was conducted to determine the prevalence and risk factors of radiographic OA in the spine, shoulder, hand, hip, and knee in Koreans older than age 65 years.

Methods: A simple random sample (N = 1118) was drawn from a roster of elderly individuals older than age 65 years in Seongnam. Of the 1118 invited subjects, 696 (males = 298, females = 398) participated in this study (a response rate of 62%). The mean age of respondents was 72 ± 5 years (range, 65-91 years). Radiographs of the lumbar spine, shoulder, hand, hip, and knee were taken and afterward evaluated for radiographic OA. The Kellgren-Lawrence grading system was used for all mentioned joints, and radiographic OA was defined as Grade 2 changes or higher. The association of sex, aging, and obesity with OA in each of the mentioned joints was determined with the help of multivariate logistic regression.

Results: The highest prevalence of radiographic OA was seen in the spine (number of subjects with OA/number of whole population = 462 of 696 [66%]) followed by the hand (415 of 692 [60%]), knee (265 of 696 [38%]), shoulder (36 of 696 [5%]), and hip (15 of 686 [2%]). Female sex was associated with knee OA (odds ratio [OR], 5.7; 95% confidence interval [CI], 3.9-8.4; p < 0.001) and hand OA (OR, 2.3; 95% CI, 1.6-3.1; p < 0.001), and male sex was associated with spine OA (OR, 0.7; 95% CI, 0.5-1.0; p = 0.025). Aging was associated with radiographic OA in the spine, knee, and hand (OR per 5-year increments, 1.3 [95% CI, 1.1-1.6; p = 0.001], 1.6 [95% CI, 1.4-1.9; p < 0.001], and 1.4 [95% CI, 1.2-1.7; p < 0.001]), respectively) but not associated with OA in the hip and shoulder. Obesity was associated with knee OA (OR, 3.4; 95% CI, 2.4-5.0; p < 0.001) and spine OA (OR, 1.5; 95% CI, 1.1-2.2; p = 0.014) but not with OA in other joints.

Conclusions: OA of the spine, hand, and knee is likely to become a major public health problem rather than shoulder and hip OA in Korea. Associations of demographic factors with radiographic OA differed among each joint, and that would be valuable information to assess the role and influence of risk factors of OA in various joints.

Level of evidence: Level III, prognostic study.