American Indians More Commonly Develop Sjögren’s, Study Suggests

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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American Indians are more commonly affected by Sjögren’s syndrome and show more active disease compared to Americans of other ethnicities, a study shows.

The study, “American Indians Have A Higher Risk Of Sjögren’s Syndrome And More Disease Activity Than Caucasians And African-Americans,” was published in the journal Arthritis Care & Research.

The prevalence of autoimmune diseases that affect the connective tissues, such as Sjögren’s syndrome, systemic sclerosis, or rheumatoid arthritis, varies within different populations. Likewise, it is also described that race and ethnicity can influence the severity of inflammatory diseases and their specific clinical presentation.

In Sjögren’s syndrome, the immune system produces self-antibodies that mainly affect the function of salivary and lacrimal glands, causing dryness in the eyes and mouth, a symptom known as sicca. But other symptoms not related to gland function can also be found in one-third of patients.

Despite being the second-most common inflammatory rheumatic disease after rheumatoid arthritis, only recently have researchers started to explore the association between race and ethnicity with Sjögren’s syndrome’s prevalence and severity.

Thus, in this study, researchers explored the disease’s manifestations in three American populations with different descents: African-Americans, American Indians, and European-Americans.

The study included 648 patients with primary Sjogren’s syndrome from the Oklahoma Sjögren’s Syndrome Center of Research Translation cohort. Of those, 426 (65.7%) were European-Americans, 164 (25.3%) were Americans Indians, 20 (3.1%) were African-Americans, and 38 had other ethnicities.

In the general U.S. population, the proportion of Americans Indians is 1.4%; African-Americans represent 12.6% of the population. Thus, the proportions of Sjogren’s syndrome patients suggests that the condition is highly prevalent among American Indians but rarely affects African-Americans.

American Indian patients were younger than European-Americans. Also, both American Indians and African-Americans lived in low-income areas and had higher body mass indexes (a measure of body fat).

American Indians also showed increased disease activity despite presenting few classical manifestations of Sjogren’s, including more manifestations outside the glands. The EULAR Sjögren’s syndrome disease activity index (ESSDAI) scores — a measure of disease activity — were on average 3.77 for American Indians, but only 2.9 for European-Americans.

“American Indians are affected at high rates with [Sjogren’s syndrome] but present with few classical features, potentially preventing timely diagnosis,” researchers stated.

“Recognizing the [different manifestations] across population subsets should lead to improved diagnostic timeliness and accuracy, and to enhanced personalized follow-up and therapeutic strategies,” the study concluded.