REVIEW ARTICLE An overview of OA research in two urban APLAR populations Ying Y. LEUNG 1 and Julian THUMBOO 2 1 Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong; and 2 Department of Rheumatology and Immunology, Singapore General Hospital and Duke-NUS Graduate Medical School and Yong Loo Lin School of Medicine, National University of Singapore, Singapore Abstract Osteoarthritis (OA), the most prevalent type of arthritis in the elderly, is also among the first five leading causes of disability in developed countries. With the ‘Westernized’ living environment and lifestyle among Southeast Asian urbanized cities, where obesity is on the rise and the populations are ageing, the incidence of OA is expected to rise in the next decades. There is need to summarize research work within these places. This article summarizes some of the research aspects of OA in Southeast Asian cities. These data may form a useful basis for future planning of medical resource and needs. Key words: epidemiology, health related quality of life, osteoarthritis, Southeast Asia. INTRODUCTION Osteoarthritis (OA) is the most prevalent type of arthritis among older populations worldwide. It is the fifth leading cause of disability life years (DLYs) worldwide and has significant impact on health- related quality of life (HRQoL). 1 The WHO estimates that 9.6% and 18% of men and women over age 60 have symptoms of OA, respectively, of which 80% have limitation in movement and 25% cannot per- form major activities of daily living. 2 Asian cities like Hong Kong and Singapore are highly urbanized and both cities face the same problem of an ageing population and increasing prevalence of obesity. The incidence of OA is expected to rise. We therefore reviewed and summarized results for OA research in Hong Kong and Singapore over a 20 year period, which would be valuable to guide future research and help policy makers in resource allocation. EPIDEMIOLOGY Symptoms and radiographical features of OA are poorly correlated, thus prevalence studies based on either symptoms or radiography alone may overesti- mate the true prevalence. 2–4 This is compounded by the lack of an internationally agreed and consistently used definition for OA. Classification criteria based on both features have been developed and validated 5 but were not sensitive, particularly in the primary care setting. 6 There are few if any epidemiological studies of the prevalence of OA in the Asia Pacific League of Associations for Rheumatology (APLAR) region. A stratified random survey in Hong Kong revealed that arthritis was the commonest medical condition affect- ing 30% of the elderly above 70 years and was more common in women. As a result of joint pain, 42% and 68% of men and women, respectively, had limi- tation in activities. 7 Another large study involving over 4000 community-dwelling elderly aged ‡ 65 revealed a high prevalence of back (48%), knee (31%) and hip pain (8.9%), the major underlying causes of which were osteoporosis and OA. 8 Self- reported prevalence usually overestimates the true prevalence of OA. 2,3 A Singaporean study reported a Correspondence: Dr Leung Y. Ying, Department of Medicine & Therapeutics, Chinese University of Hong Kong, Hong Kong. Email: katyccc@hotmail.com International Journal of Rheumatic Diseases 2011; 14: 130–135 ª 2011 The Authors International Journal of Rheumatic Diseases ª 2011 Asia Pacific League of Associations for Rheumatology and Blackwell Publishing Asia Pty Ltd