Editing Rheumatoid arthritis (section)

==Epidemiology==
[[File:Rheumatoid arthritis world map-Deaths per million persons-WHO2012.svg|thumb|upright=1.3|Deaths from rheumatoid arthritis per million persons in 2012 {{Div col|small=yes|colwidth=10em}}{{legend|#ffff20|0–0}}{{legend|#ffe820|1–1}}{{legend|#ffd820|2–3}}{{legend|#ffc020|4–5}}{{legend|#ffa020|6–6}}{{legend|#ff9a20|7–8}}{{legend|#f08015|9–9}}{{legend|#e06815|10–12}}{{legend|#d85010|13–20}}{{legend|#d02010|21–55}}{{div col end}}]]

RA affects 0.5–1% of adults in the developed world with between 5 and 50 per 100,000 people newly developing the condition each year.<ref name=Lancet2016/> In 2010 it resulted in about 49,000 deaths globally.<ref name=Loz2012>{{cite journal | vauthors = Lozano R, Naghavi M, Foreman K, Lim S, Shibuya K, Aboyans V, etal | s2cid = 1541253 | title = Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010 | journal = Lancet | volume = 380 | issue = 9859 | pages = 2095–2128 | date = December 2012 | pmid = 23245604 | doi = 10.1016/S0140-6736(12)61728-0 | pmc = 10790329 | hdl = 10536/DRO/DU:30050819 | url = https://zenodo.org/record/2557786 | hdl-access = free }}</ref>

Onset is uncommon under the age of 15 and from then on the incidence rises with age until the age of 80. Women are affected three to five times as often as men.<ref name="McGraw Hill"/>

The age at which the disease most commonly starts is in women between 40 and 50 years of age, and for men somewhat later.<ref>{{cite journal | vauthors = Alamanos Y, Voulgari PV, Drosos AA | title = Incidence and prevalence of rheumatoid arthritis, based on the 1987 American College of Rheumatology criteria: a systematic review | journal = Seminars in Arthritis and Rheumatism | volume = 36 | issue = 3 | pages = 182–188 | date = December 2006 | pmid = 17045630 | doi = 10.1016/j.semarthrit.2006.08.006 }}</ref> RA is a chronic disease,<ref name="q271">{{cite web | title=Rheumatoid Arthritis | website=National Institute of Arthritis and Musculoskeletal and Skin Diseases | date=2017-04-20 | url=https://www.niams.nih.gov/health-topics/rheumatoid-arthritis#:~:text=Rheumatoid%20arthritis%20(RA)%20is%20a,loss%20of%20function%20in%20joints. | access-date=2024-09-26}}</ref> and although rarely, a spontaneous remission may occur,<ref>{{cite journal |doi=10.1007/s11926-010-0121-2 |title=Remission in Rheumatoid Arthritis |date=2010 |last1=Shammas |first1=Rania M. |last2=Ranganath |first2=Veena K. |last3=Paulus |first3=Harold E. |journal=Current Rheumatology Reports |volume=12 |issue=5 |pages=355–362 |pmid=20697983 |pmc=2927687 }}</ref> the common course of progression consists of persistent symptoms that wax and wane in intensity, along with continued deterioration of joint structures, leading to deformation and disability.<ref name="o179">{{cite web | last=Watson | first=Stephanie | title=Progression of Rheumatoid Arthritis | website=WebMD | date=2024-08-13 | url=https://www.webmd.com/rheumatoid-arthritis/ra-progression | access-date=2024-09-26}}</ref><ref name="k591">{{cite web | title=Rheumatoid Arthritis (RA): Causes, Symptoms & Treatment FAQs | website=Cleveland Clinic | date=2023-08-31 | url=https://my.clevelandclinic.org/health/diseases/4924-rheumatoid-arthritis | access-date=2024-09-26}}</ref>

There is an association between periodontitis and rheumatoid arthritis (RA), hypothesised to lead to enhanced generation of RA-related autoantibodies. Oral bacteria that invade the blood may also contribute to chronic inflammatory responses and generation of autoantibodies.<ref>{{cite journal | vauthors = Cheng Z, Meade J, Mankia K, Emery P, Devine DA | title = Periodontal disease and periodontal bacteria as triggers for rheumatoid arthritis | journal = Best Practice & Research. Clinical Rheumatology | volume = 31 | issue = 1 | pages = 19–30 | date = February 2017 | pmid = 29221594 | doi = 10.1016/j.berh.2017.08.001 | url = http://eprints.whiterose.ac.uk/119931/1/Cheng_et_al_PDRA%20review_final.pdf }}</ref>