Open AccessComparison of the prevalence of knee osteoarthritis between the elderly Chinese population in Beijing and whites in the United States: The Beijing osteoarthritis study
Author(s) -
Zhang Yuqing,
Xu Ling,
Nevitt Michael C.,
Aliabadi Piran,
Yu Wei,
Qin Mingwei,
Lui LiYung,
Felson David T.
Publication year - 2001
Publication title -
arthritis & rheumatism
Language(s) - English
Resource type - Journals
eISSN - 1529-0131
pISSN - 0004-3591
DOI - 10.1002/1529-0131(200109)44:9<2065::aid-art356>3.0.co;2-z
Subject(s) - medicine , osteoarthritis , beijing , confidence interval , physical therapy , framingham heart study , knee pain , epidemiology , population , framingham risk score , china , disease , pathology , environmental health , alternative medicine , political science , law
Objective To estimate the prevalence of radiographic and symptomatic knee osteoarthritis (OA) in a population‐based sample of elderly subjects in Beijing, China and compare it with that reported in the Framingham (Massachusetts) OA Study. Methods We recruited a sample of persons age ≥60, using door‐to‐door enumeration in randomly selected neighborhoods in Beijing. Subjects completed a home interview including questions on knee symptoms and a hospital examination including knee radiographs obtained during weight bearing. The protocol was identical to that used in the Framingham OA Study. A reader read intermingled Beijing and Framingham Study films to ensure high reliability. We defined a subject as having radiographic knee OA when the Kellgren/Lawrence grade was ≥2 in at least 1 knee. Symptomatic knee OA was recorded as present when knee pain was reported and the symptomatic knee had radiographic OA. We estimated the prevalence of these entities in elderly subjects in Beijing and compared it with OA prevalence in Framingham, using an age‐standardized prevalence ratio. Results Of 2,180 age‐eligible Beijing subjects contacted, knee radiographs were obtained in 1,787 (82.0%). The prevalence of radiographic knee OA was 42.8% in women and 21.5% in men. Symptomatic knee OA occurred in 15.0% of women and 5.6% of men. Compared with women of the same age in Framingham, women in Beijing had a higher prevalence of radiographic knee OA (prevalence ratio 1.45, 95% confidence interval 1.31–1.60) and of symptomatic knee OA (prevalence ratio 1.43, 95% confidence interval 1.16–1.75). The prevalence of knee OA in Chinese men was similar to that in their white US counterparts (for radiographic OA, prevalence ratio 0.90; for symptomatic OA, prevalence ratio 1.02). Conclusion Using identical methods and definitions to evaluate the prevalence of OA across populations, we found, surprisingly, that older Chinese women have a higher prevalence of knee OA than women in Framingham, Massachusetts. The prevalence in men was comparable. Possible explanations for these differences range from genetic differences to heavy physical activity among Chinese.