[Epidemiological studies on primary Sjogren's syndrome].

2,066 adult people of a Beijing suburb village were surveyed for primary Sjogren's syndrome, using questionnaire and serological tests in each case as the primary screening tool. 16 cases were discovered by Copenhagen criteria indicating a prevalence rate of 0.77% and 7 cases with a prevalence rate of 0.33% by Fox criteria. Similar study was done in 100 non-connective tissue diseases in-patients. 4 cases were discovered by Copenhagen criteria and one case by Fox criteria. In 126 definite cases of primary Sjogren's syndrome, the longest time interval between first onset of symptoms and firm establishment of diagnosis was 20 years with an average of 7.8 years indicating most cases were wrongly diagnosed or highly neglected.