Epidemiology of Chronic Disc Degeneration and Osteoarthritis of the Lumbar Spine in Britain and Japan: a Comparative Study

Objective: To compare the prevalence of spinal osteoarthritis (OA) in Britain 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 anteroposterior and lateral radiographs of the thoracic and lumbar spine were obtained under standardized conditions. Each lumbar radiograph was graded for osteoarthritic changes according to the overall Kellgren-Lawrence (K-L) score. Gradings were also recorded separately for disc narrowing and osteophyte formation.

Results: British subjects were much more likely to have lumbar spine radiographs 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), but less severe osteophytosis (p = 0.06) than their Japanese counterparts. British women displayed more severe disc narrowing (p < 0.001) and osteophyte formation (p < 0.001). On multiple regression analysis, a higher body mass 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 between countries in K-L severity persisted after allowing for age and BMI, suggesting that differences in body build could not fully explain differences in lumbar spine OA in the 2 countries.

Conclusion: We found that severe lumbar degenerative disease is more common in the UK than in a mountain village in Japan, and that differences exist in the prevalence of both osteophytosis and disc degeneration between the 2 countries.