Arthritis remains the most common cause of disability in adults in the United States,1 and it is among the leading conditions causing work limitations.2 By 2030, the number of adults affected with doctor-diagnosed arthritis is projected to reach 67 million, or 25% of the adult population. Corresponding arthritis-attributable activity limitation is projected to reach 25 million, meaning that 9.3 % of all adults will be affected.3 Estimating the prevalence and burden of the various conditions that comprise arthritis and other rheumatic conditions is important for understanding the current and growing impact of these conditions on the health care and public health systems. It is equally important to identify the gaps in our understanding of these measures and target potential interventions.

• 1. Brault MW, Hootman J, Helmick CG, Theis KA, Armour BS: Prevalence and most common causes of disability among adults—United States, 2005. MMWR 2009;58(16):421-426.
• 2. Theis KA, Hootman JM, Helmick CG, Murphy L, Bolen J, Langmaid G: State-specific prevalence of arthritis-attributable work limitation—United States, 2003. MMWR 2007;56(40):1045-1049.
• 3. Hootman JM, Helmick CG: Projections of US prevalence of arthritis and associated activity limitations. Arthritis Rheum 2006;54(1):226-229.