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

Objective: To estimate the point prevalence of primary Sjögren's syndrome (pSS) in two populations, aged 40-44 and 71-74 years, using two sets of classification criteria. Methods: The participating individuals were recruited from the Hordaland Health Study (HUSK) conducted during 1997-99. A total of 18 592 individuals born 1953-57 and 3346 individuals born 1925-27 were sent a questionnaire covering various health-related questions, including four questions about sicca symptoms. Among those answering positive to at least one of the four questions, 99 and 90 individuals born 1953-57 and 1925-27, respectively, were examined further. For diagnosis of pSS two classifications were used, the preliminary European criteria from 1993, and the revised European criteria from 1996. Results: By using the two classification criteria from 1993 and 1996, the point prevalences were 0.44% [95% confidence interval (CI) 0.34-0.57] and 0.22% (95% CI 0.15-0.32), respectively, for the population group born 1953-57. The corresponding estimates were 3.39% (95% CI 2.77-4.14) and 1.40% (95% CI 1.02-1.92) for the population born 1925-27. Conclusion: The point prevalence of pSS was approximately seven times higher in the elderly population aged 71-74 years compared to individuals aged 40-44 years, regardless of the classification criteria used.