American Indians Have A Higher Risk Of Sjögren's Syndrome And More Disease Activity Than Caucasians And African-Americans.

Objective To describe the clinical and serologic manifestations of Sjogren's syndrome (SS) in ethnic groups of theUS. Methods This was a cross-sectional study of 648 patients with primarySS: 20 African American (AA), 164 American Indian (AI), 426 European American (EA), and 38 patients of other races evaluated in a multidisciplinary Sjogren's International Collaborative Clinical Alliance research clinic. Results AAsubjects comprised 3.1% of theSScohort, much lower than the percentage ofAAin the state of Oklahoma (P= 3.01 x E - 05), theUS(P= 2.24E - 13), or a systemic lupus erythematosus (SLE) cohort at the same institution (P= 4.26 x 10E - 27). In contrast, the percentage ofAIin theSScohort (25.3%) was much higher than expected (P= 3.17E - 09 versusSLEcohort,P= 6.36 - 26 versus Oklahoma, andP= 8.14E - 96 versusUSpopulation). TheSSclassification criteria were similar betweenAAandEA, but subjects ofAIancestry had lower rates of abnormal tear and salivary flow, as well as anti-Ro/SSAand anti-La/SSBantibodies. Paradoxically,AIhad higher levels of disease activity (mean +/- SDEuropean League Against Rheumatism Sjogren's Syndrome Disease Activity Index score 3.77 +/- 4.78) in comparison toEA(2.90 +/- 4.12;P= 0.011) and more extraglandular manifestations affecting mainly the articular and glandular domains. Meanwhile,AApatients were characterized by higher rates of hypergammaglobulinemia (odds ratio [OR] 1.39 [95% confidence interval (95%CI) 1.39-8.65];P= 0.01), elevated erythrocyte sedimentation rate (ESR) (OR3.95 [95%CI1.46-9.95];P= 0.009), and parotid enlargement (OR4.40 [95%CI1.49-13.07];P= 0.02). Conclusion AIare affected at high rates withSSbut present with few classical features, potentially preventing timely diagnosis. In contrast toSLE,SSis infrequent and not more severe amongAA, but the triad of hypergammaglobulinemia, increasedESR, and parotid enlargement warrants extra vigilance for lymphomagenesis.