Global Trends and Statistics

RA may or may not produce noticeable clinical manifestations, is unpredictable in duration and is incurable. It is estimated around 1.3 million US adults have RA with it occurring in three to one times as many women than men,⁵⁸ and the prevalence and incidence rises with advancing age. Age onset is after 40 and peaks around age 70, then declines.⁵⁸ The prevalence of RA varies throughout the world, with an overall higher prevalence in industrialized countries.⁵⁹ This may be due to exposures to environmental risk factors, as well as by genetic factors, differing demographics and under-reporting in other parts of the world.⁶⁰ However, among Native American groups, the prevalence rates are 5-6%; with lower rates documented in the regions of the Caribbean.⁶² A prevalence study among white Europeans was equal to South African urban blacks, while lower rates were noted among South African rural blacks.⁶² It has been challenging for most countries to conduct incidence and prevalence studies on RA due to limited health data systems and sampling size.⁶⁰

In some countries, such as Sweden and Finland, registrars collect data based on medication and diagnostic criteria representative from community-based surveys. In the United Kingdom, a network of physicians document reason for medical consultations; however, some diagnoses could be viewed as biased.⁶⁰ The World Health Organization (WHO) in joint efforts with the International League of Associations for Rheumatology (ILAR) have developed community studies to determine prevalence and risk factors and to educate health care providers in the area of prevention and treatment based on RA symptoms and complaints.⁶⁰ Over two decades of results are available from Thailand, Pakistan, China, India, Kuwait, Brazil, Vietnam, Mexico, Chile, Australian Aboriginals and Australian Caucasians with additional studies ongoing.⁶⁰ The prevalence varied among the industrialized countries between 0.3 and 1%; with an overall 0.8% for adults over age 15. In developing countries, some studies reported lower prevalence rates while others were similar to levels in developed countries. With worldwide demographic trends demonstrating an aging population, an increase in RA is expected over the next 10 years in North America and Europe, yet prospective studies are suggested to continue.⁶⁰