Native American patients tend to be diagnosed earlier in life with lupus than do Americans of European descent, and they also tend to have worse rheumatic disease symptoms and higher autoantibodies rates. That’s according to new research published in Lupus: Science & Medicine.

The autoimmune disease, in which the immune system attacks healthy tissue, is generally diagnosed in patients between the ages of 15 and 45, and it is more common in African Americans, Hispanics, and Asian Americans, according to the Mayo Clinic. It also afflicts women at a rate nine times that of men.

Judith James, of the Oklahoma Medical Research Foundation, and colleagues studied 3,148 lupus patients in the Lupus Family Registry and Repository, 268 of whom were Native American. Two hundred and thirty-nine patients were Hispanic, 1,567 were of European ancestry, and 1,074 were African American.

On average, the researchers found, Native Americans were diagnosed with lupus just shy of their 30th birthdays — at age 29.9 — compared to European Americans, whose average diagnosis came at just over 32 years of age. African Americans and Hispanics had rates similar to those of Native Americans: 30.8 and 27.8 respectively.

The researchers also found that significantly higher percentages of Native Americans (26 percent) were classified as having lupus by age 20 than were African Americans (19 percent) and European Americans (21 percent), and at similar rates as Hispanic patients (28 percent).

“Native American patients can face persistent disparities in healthcare in part due to high numbers of patients being under-insured and having poor health status, along with other significant barriers to care,” they write. “Even if patients have access to insurance, patients who live in remote, impoverished areas are less likely to receive regular care from specialists. These obstacles translate into less effective disease management and worse outcomes.”

The researchers also found disparities in the ways the different groups were treated, as well as in concurrent (or coexisting) autoimmune diseases. “The team added that research will be needed to identify potential molecular and genetic markers of [lupus] that might enable earlier and more specific diagnosis among Native Americans,” notes Medpage.