Epidemiology of chronic disc degeneration and osteoarthritis of the lumbarspine in Britain and Japan: A comparative study

Objective. To compare the prevalence of spinal osteoarthritis (OA) in Brita in and Japan. Methods. A total of 206 men and 188 women living in Hertfordshire, UK, and a total of 100 men and 100 women living in Miyama, Japan, aged 60-79 years were studied. Participants completed a lifestyle questionnaire, and anterop osterior and lateral radiographs of the thoracic and lumbar spine were obta ined under standardized conditions. Each lumbar radiograph was graded for o steoarthritic changes according to the overall Kellgren-Lawrence (K-L) scor e. Gradings were also recorded separately for disc narrowing and osteophyte formation. Results. British subjects were much more likely to have lumbar spine radiog raphs graded as K-L grade 4 severity (p = 0.05 in men, p < 0.001 in women). British men displayed a greater prevalence of disc narrowing (p = 0.08), b ut less severe osteophytosis (p = 0.06) than their Japanese counterparts. B ritish women displayed more severe disc narrowing (p < 0.001) and osteophyt e formation (p < 0.001). On multiple regression analysis, a higher body mas s index (BMI) was associated with excess risk in the British population (OR 1.84, 95% CI 1.12-3.02), but not in the Japanese population. Differences b etween countries in K-L severity persisted after allowing for age and BMI, suggesting that differences in body build could not fully explain differenc es in lumbar spine OA in the 2 countries. Conclusion. We found that. severe lumbar degenerative disease is more commo n in the UK than in a mount;lin village in Japan, and that differences exis t in the prevalence of both osteophytosis and disc degeneration between the 2 countries.