Epidemiology of osteoarthritis

Abstract

Osteoarthritis (OA) is the most common form of arthritis in the United States and is a leading cause of disability. It is typically defined in epidemiologic studies by radiographic findings and consideration of symptoms. Its incidence and prevalence are rising, likely related to the aging of the population and increasing obesity. Risk factors for OA include numerous person-level factors, such as age, sex, obesity, and genetics, as well as joint-specific factors that are likely reflective of abnormal loading of the joints. In studying OA, several methodologic challenges exist that can hamper our ability to identify pertinent relationships.

Figure 1

Incidence of hand, hip, and knee OA 1991-1992 by age and sex in a community health plan. Reference: Oliveria SA, et al. Arthritis Rheum. 1995;38:1134-1141.

Figure 2

Potential risk factors for susceptibility to OA incidence and progression, each with varying degrees of evidence to support their association (see text for details). LLI=leg-length inequality

Figure 3

Associations of frequent knee pain with Kellgren and Lawrence (KL) grade among people with two knees discordant for frequent knee pain status. Number of case knees (i.e., with knee pain) and control knees (i.e., without knee pain) are shown beneath the graph for each KL grade. Note the y-axis is logarithmically scaled. Reference: Neogi T, et al. BMJ 2009;339:b2844 doi:10.1136/bmj.b2844