Rheumatoid Arthritis: Epidemiology and Genetics

Rheumatoid Arthritis is a chronic inflammatory disorder of joints. At present, the etiology of RA is not known. It is an autoimmune disorder which is defined by the inflammation in joints tissues. Frequently, the immune cells infiltrate to the affected joints and synovial hyperplasia occurs. This leads further to destruction of bone and cartilage in long run. In more than 70% of the cases, radiographic changes can be seen after 3 years of the onset. About 1% of the total world population is currently affected with RA, leading to sever disabilities. In Pakistan, the prevalence of RA is about 0.1 to 0.2%, however its rate of prevalence changes from time to time. In general, the prevalence of RA is higher in North America and Europe in comparison to most of the developing countries. The differences in the prevalence of RA in different populations have been attributed mainly to the genetic susceptibility, degree of affluence, urbanization and/or population structure. Women are 2-3 times more consistently affected by RA as compared to men. Different genes, especially the human leukocyte antigens (HLA-DRB1) are also shown to be associated with RA.