American Indians Disproportionately Affected by Sjögren’s Syndrome

Sjögren’s Syndrome affects American Indians at a higher rather rate than other ethnic groups, but the lack of classically-associated disease symptoms makes diagnosis difficult, new research shows.

In a study published in Arthritis Care & Research, investigators found that American Indians have a higher incidence of Sjögren’s than other ethnicities. They also experienced higher levels of disease activity.

“American Indians are affected at high rates with Sjögren’s Syndrome, but present with few classical features, potentially preventing timely diagnosis,” said study author Astrid Rasmussen, M.D., Ph.D., an arthritis and clinical immunology researcher at Oklahoma Medical Research Foundation.

To determine how Sjögren’s behaves clinically and in the blood, researchers analyzed manifestations in 648 individuals with the condition, including 20 African-Americans, 164 American Indians, and 426 Caucasians. Although the majority of Sjögren’s patients are Caucasian, this study found that American Indians were over-represented in this patient group at twice their population rate. This group also constitutes between 13 percent and 16 percent oflupus cases.

Additionally, investigators discovered that while more American Indians had Sjögren’s and were diagnosed at younger ages that other ethnic groups, their symptoms were less severe. Fewer individuals had decreased salivary flow and tear production. They also experienced a lower presence of autoantibodies associated with the condition, as well as lymph node inflammation.

Because they experience a lower level of symptoms most commonly associated with Sjögren’s, researchers said, providing an accurate diagnosis could be more difficult.

Meanwhile, African-Americans were nine times more likely to have lupus than Sjögren’s. Based on findings, these patients also have a higher risk of lymphoma, including elevated immunoglobulins in the blood, elevated inflammation levels, and salivary gland swelling.

Ultimately, researchers said, these findings should alert clinicians to the unconventional presentation of Sjögren’s in the American Indian population, as well as prompt them to monitor African-American patients for malignancies.

REFERENCE

Scofield RH, Sharma R, Pezant N, et al. “American Indians Have a Higher Risk of Sjögren’s Syndrome and More Disease Activity Than Caucasians and African-Americans."Arthritis Care & Research (2019), doi: 10.1002/acr.24003