RA isn't caused by one thing — it's genes loaded, then an environmental trigger pulls. The most important part for you: the biggest modifiable trigger is smoking, and the disease often begins silently, years before your joints ever hurt.
RA is roughly half heritable, with the HLA-DRB1 'shared epitope' genes the biggest genetic risk. But genes aren't destiny — they load the gun; the environment pulls the trigger. The single biggest modifiable trigger is smoking, which interacts with those genes to drive the autoantibodies behind RA — and later blunts how well the drugs work. It's ~2–3× more common in women, usually starting between the 30s and 50s. Evidence ●●●●○
A leading hypothesis is that RA autoimmunity begins not in the joints but at mucosal surfaces — the gums (gum disease and the bacterium P. gingivalis can 'citrullinate' proteins, creating the very targets RA attacks), the lungs (smoke), and the gut microbiome. A loss of immune tolerance there may seed the antibodies years before arthritis appears. Promising and mechanistically appealing, but not yet settled. Evidence ●●●○○
RA-specific antibodies (anti-CCP, rheumatoid factor) frequently show up in the blood years before any joint symptoms — a 'pre-clinical' phase. That's both sobering and hopeful: it means the disease has a runway, and a whole new frontier of research is treating high-risk people during it to delay or even prevent RA entirely (covered later). Evidence ●●●●○
If you smoke and have a family history, quit
Quitting smoking is the single highest-impact modifiable step in RA: it lowers your risk of developing the disease and, if you already have it, makes every treatment work better. No supplement or protocol in this guide comes close to that one change.
The RA Guide