What Causes Rheumatoid Arthritis? A Look at RA Risk Factors
Researchers don’t know exactly what causes the immune system to invade the synovium, though it’s believed that genes and environmental factors play a role in the development of RA.
Research suggests that people with certain genetics, the human leukocyte antigen (HLA) genes, have an up to fivefold increased risk of developing RA. The HLA gene complex controls immune responses by producing proteins that help the immune system recognize proteins from foreign invaders.
Other genes connected to RA include some involved with the immune system and inflammation, such as STAT4, TRAF1, C5, and PTPN22.
But not everyone with these identified gene variants develops RA, and people without them can still develop it. So it’s likely that environmental factors often trigger the disease, particularly in people with a genetic makeup that makes them more susceptible to it. These factors include:
- Viruses and bacteria (though certain infections may reduce RA risk, at least temporarily)
- Female hormones
- Exposure to certain kinds of dust and fibers
- Severely stressful events
Equally important are smoking and a family history of RA in increasing a person’s risk of developing the condition