Editing Sjögren's disease (section)

== Epidemiology ==
Sjögren's disease (SjD) is the third-most common rheumatic autoimmune disorder, behind rheumatoid arthritis and [[systemic lupus erythematosus]].<ref name=foxetal>{{cite journal | vauthors = Fox RI, Stern M, Michelson P | title = Update in Sjögren syndrome | journal = Curr Opin Rheumatol | volume = 12 | issue = 5 | pages = 391–8 | date = September 2000 | pmid = 10990175 | doi = 10.1097/00002281-200009000-00007 }}</ref>

There are no geographical differences in the rates of SS.<ref name=mavragani>{{cite journal | author = Mavragani C. P., Moutsopoulos H. M. | year = 2010 | title = The geoepidemiology of Sjogren's syndrome | journal = Autoimmunity Reviews | volume = 9 | issue = 5| pages = A305–A310 | doi=10.1016/j.autrev.2009.11.004 | pmid=19903539}}</ref> Sjögren's syndrome has been reported in all areas of the world, although regional rates have not been well studied.<ref name=mavragani /><ref name=jonssonetal />

Depending on the criteria for determining prevalence, studies estimate the prevalence of SS at between 500,000 and two million people in the United States. Broader studies of SS prevalence range widely, with some reports of up to a prevalence of 3% of the population.<ref name=foxetal /> A few studies have reported that the incidence of the syndrome varies between three and six per 100,000 per year.<ref name=foxetal /><ref name="pmid16332955">{{cite journal | vauthors = Alamanos Y, Tsifetaki N, Voulgari PV, Venetsanopoulou AI, Siozos C, Drosos AA | title = Epidemiology of primary Sjögren's syndrome in north-west Greece, 1982–2003 | journal = Rheumatology (Oxford) | volume = 45 | issue = 2 | pages = 187–91 | date = February 2006 | pmid = 16332955 | doi = 10.1093/rheumatology/kei107 | doi-access = free }}</ref>
Between 0.2 and 1.2% of the population is affected, with half having the primary form and half the secondary form.<ref name="John2008" /> It is around 10 times more common in women than in men.<ref name=Ng2016/> Though the disease commonly begins in [[middle age]], people of any age can be affected.<ref name=Bri2016/><ref name=Ng2016/>

Nine out of 10 SjD patients are women.<ref name=borchers /><ref name=jonssonetal>{{cite journal | vauthors = Jonsson R, Vogelsang P, Volchenkov R, Espinosa A, Wahren-Herlenius M, Appel S | title = The complexity of Sjögren's syndrome: novel aspects on pathogenesis | journal = Immunol. Lett. | volume = 141 | issue = 1 | pages = 1–9 | date = December 2011 | pmid = 21777618 | doi = 10.1016/j.imlet.2011.06.007 }}</ref> In addition to prevalence in women, having a [[Consanguinity|first-degree relative]] with an autoimmune disease and previous pregnancies have been identified as epidemiological risk factors.<ref name="pmid17631733">{{cite journal | vauthors = Priori R, Medda E, Conti F, Cassarà EA, Sabbadini MG, Antonioli CM, Gerli R, Danieli MG, Giacomelli R, Pietrogrande M, Valesini G, Stazi MA | title = Risk factors for Sjögren's syndrome: a case-control study | journal = Clin. Exp. Rheumatol. | volume = 25 | issue = 3 | pages = 378–84 | date = 2007 | pmid = 17631733 }}</ref> Despite the lower risk for men, primary SS in men tends to represent a more severe form of the disease.<ref>{{cite journal |last1=Ramírez Sepúlveda |first1=Jorge I. |last2=Kvarnström |first2=Marika |last3=Brauner |first3=Susanna |last4=Baldini |first4=Chiara |last5=Wahren-Herlenius |first5=Marie |title=Difference in clinical presentation between women and men in incident primary Sjögren's syndrome |journal=Biology of Sex Differences |date=December 2017 |volume=8 |issue=1 |pages=16 |doi=10.1186/s13293-017-0137-7 |pmid=28507729 |pmc=5427625 |s2cid=2500540 |doi-access=free }}</ref> The role of race and ethnicity in the prevalence of the disease is unknown.{{citation needed|date=October 2020}}

Although Sjögren's disease occurs in all age groups, the average age of onset is between ages 40 and 60, although as many as half of all cases may be left undiagnosed or unreported.<ref name=borchers /><ref name=foxetal /><ref name="pmid18189192">{{cite journal | vauthors = Haugen AJ, Peen E, Hultén B, Johannessen AC, Brun JG, Halse AK, Haga HJ | title = Estimation of the prevalence of primary Sjögren's syndrome in two age-different community-based populations using two sets of classification criteria: the Hordaland Health Study | journal = Scand. J. Rheumatol. | volume = 37 | issue = 1 | pages = 30–4 | date = 2008 | pmid = 18189192 | doi = 10.1080/03009740701678712 | s2cid = 42392790 }}</ref><ref name="pmid12169882">{{cite journal | vauthors = García-Carrasco M, Ramos-Casals M, Rosas J, Pallarés L, Calvo-Alen J, Cervera R, Font J, Ingelmo M | title = Primary Sjögren syndrome: clinical and immunologic disease patterns in a cohort of 400 patients | journal = Medicine (Baltimore) | volume = 81 | issue = 4 | pages = 270–80 | date = July 2002 | pmid = 12169882 | doi = 10.1097/00005792-200207000-00003 | s2cid = 8279532 | doi-access = free }}</ref> The prevalence of SS generally increases with age.<ref name=foxetal />

Sjögren's disease is reported in 30-50% of people with rheumatoid arthritis and in 10-25% with systemic lupus erythematosus.<ref name=borchers />