Epidemiology of Locomotive Organ Disorders and Symptoms: An Estimation Using the Population-Based Cohorts in Japan

Although locomotive organ diseases such as osteoporotic fractures and osteoarthritis are major reasons for disability and require support, little information is available regarding the epidemiology of musculoskeletal dysfunction and its symptoms including knee pain and lumbar pain in Japan. The research on osteoarthritis/osteoporosis against disability (ROAD) study is a prospective cohort study that aims at elucidating the environmental and genetic background for locomotive organ diseases, and has been ongoing since 2005. In this review, epidemiological indices such as prevalence of locomotive organ diseases including knee osteoarthritis, lumbar spondylosis, and osteoporosis were clarified using baseline survey results of the ROAD study. The number of subjects with such diseases was estimated. In addition, 3-year follow-up data from the ROAD study revealed the effect of osteoarthritis on the occurrence of osteoporosis, and vice versa. The prevalences of osteoarthritis and osteoporosis were shown to be high. Also, the large estimates of patients with these conditions suggest that urgent strategies are needed for addressing locomotive organ diseases that cause disability in the elderly. We also clarified the prevalence of knee pain, lumbar pain, and their co-existence using the survey results of the longitudinal cohorts of motor system organ study. We found that both knee pain and lumbar pain were prevalent in 12.2 % of the total population and the presence of knee pain affected lumbar pain, and vice versa.