Epidemiology of the locomotive syndrome: The research on osteoarthritis/osteoporosis against disability study 2005-2015

Although locomotive organ disorders are major causes of disability and require support, little information is available regarding their epidemiology. Prevalence and co-existence of locomotive organ disorders including knee osteoarthritis (KOA), lumbar spondylosis (LS), hip osteoarthritis, and osteoporosis have been determined from baseline results of the Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) study. KOA, LS, and hip osteoarthritis overlap in the population, while KOA and LS co-exist in 42.0% of people. Mutual associations between locomotive organ disorders, metabolic syndrome components, and mild cognitive impairment were found using baseline and 3-year follow-up data from the ROAD study. Logistic regression analysis showed that hypertension, impaired glucose tolerance, and mild cognitive impairment increase the risk of KOA. Osteoporosis at L2-4 was significantly influenced by the presence of femoral neck osteoporosis, and vice versa. In turn, excess weight was inversely associated with the occurrence of femoral neck osteoporosis. Finally, data from the 3rd survey (7-year follow-up) were used to calculate the prevalence of the locomotive syndrome using tests proposed by the Japanese Orthopaedic Association for assessing the risk of developing locomotive syndrome. Subsequently, the age-sex prevalence of stage 1 and stage 2 locomotive syndrome was estimated at 69.8% and 25.1%, respectively.