To define the prevalence of Sjögren's syndrome (SS) through an epidemiological survey in a closed rural community. The classification of SS is based on the validated criteria reported by a multicentre study performed in Europe and supported by the Epidemiology Committee of the European Community (EEC-COMAC Epidemiology).
The population under study consisted of 837 women aged 18 years or older, residing in the Astakos community of Aitoloakarnania, Greece. The study protocol was subdivided in two parts. In part I, an exhaustive epidemiological survey of these women was conducted in July and August of 1992. The validated questionnaire used in the survey assesses both ocular and oral involvement. In part II, 45 of the women reporting symptoms of both dry eye and dry mouth were approached for a full examination based on the validated set of classification criteria of SS. The full complement of the diagnostic tests was performed on 35 of these women. A subject is classified as a definite primary SS case if at least four of six items of the subject's test items are positive. If three of six items are positive the subject is classified as a probable primary SS case.
The classification criteria for definite primary SS were satisfied by five women. This number corresponds to an estimated prevalence of 0.60% (exact 95% CI 0.19%, 1.39%). Probable primary SS was diagnosed for 25 women (prevalence = 2.99%).
Because of the loss of follow up (10 of 45) and the use of slightly stricter criteria for inclusion of possible SS cases in part II of the study, we consider our estimate of the prevalence of SS to be conservative. This study concurring with other recent reports, suggests that SS is more prevalent than previously thought.