NEW YORK (Reuters Health) — Brothers and sisters of people who have had a stroke are nearly twice as likely as the average American to experience a stroke themselves, according to observational data reported at the American Academy of Neurology’s annual meeting in Boston on Wednesday.“The risk to the sibling is especially prominent in Mexican-American men with over a doubling of the risk compared to the general population,” Dr. Lewis B. Morgenstern from University of Michigan, Ann Arbor, told a gathering of reporters at the conference. Sibling risk is also particularly high in non-Hispanic white women. The study involved 807 adult brothers and sisters of 181 patients who had a stroke or mini-stroke, known as a TIA, in Nueces County, Texas. Fifty-nine percent of the stroke patients were Mexican American; the rest were non-Hispanic whites. Overall, the risk of stroke for siblings of stroke cases was 92 percent greater than would be expected based on national prevalence estimates. The risk varied by gender of the sibling and their ethnicity.

“Sisters and brothers of non-Hispanic white women who had a stroke had a significant 2.7-fold increased risk of stroke compared to the general population. But siblings of non-Hispanic white men did not have an increased risk of stroke,” Morgenstern reported.