By Dr Ananya Mandal, MD
Rheumatoid arthritis (RA) affects nearly 1% of the population worldwide. Due to its severely debilitating nature, especially in advanced stages, the disease burden is considerable in economic and health expenditure terms.
How many people does rheumatoid arthritis affect?
Estimates and studies show that rheumatoid arthritis plagues 0·5–1·0% of adults in developed countries. Incidence of new cases ranges from 5 to 50 per 100 000 adults in developed countries. The incidence of new cases rises with age.
Who does rheumatoid arthritis affect?
In terms of gender, rheumatoid arthritis seems to affect females three times more commonly than men. The rates of rheumatoid arthritis are more common among persons aged between 40 and 65 years. However, this debilitating disease may affect persons at any age. People in their twenties or thirties may still be affected with the condition. In USA the average age of persons with rheumatoid arthritis is 66.8 years.
Worldwide there is a wide distribution of this condition affecting people of different regions differently. While those living in northern Europe and North America are more prone to suffer from rheumatoid arthritis, those living in poorer and developing regions like rural West Africa are much less likely to develop rheumatoid arthritis.
While prevalence is 5-6% in some Native American groups, those hailing from the Caribbean region have lower prevalence rates. This suggests that there may be a genetic basis and inheritance pattern of this disease. Racial and ethnic differences may also play a role.
Those who have a parent, sibling or offspring with the condition have a prevalence rate of 2 to 3%. The rates of the condition if one of the monozygotic (identical) twins has the condition are as high as 15 to 20%. Those who inherit tissue type Major histocompatibility complex (MHC) antigen HLA-DR4 (most specifically DR0401 and 0404) are more at risk of developing rheumatoid arthritis.
Rheumatoid arthritis and lifestyle
Several lifestyle features are seen among rheumatoid arthritis patients. One of the most important one of these is smoking status. RA is 4 times more common in smokers than non-smokers.
Economic cost of rheumatoid arthritis
In England and Wales, nearly 580,000 people are affected with this debilitating condition. In the United States of America, rheumatoid arthritis affects 1.3 million people. Joint damage occurs early in the disease within the first two years of the condition. In the USA nearly $128 billion is spent each year in medical care and indirect expenses, including lost wages and productivity due to rheumatoid arthritis.
Those with rheumatoid arthritis have a higher risk of disability and early death. Those with rheumatoid arthritis are two times more likely to die than persons of the same age without the condition. Rheumatoid arthritis in addition accounts for 22% of all deaths from arthritis and other rheumatic conditions.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)