Alzheimer's disease risk rose when individuals had first-, second-, or third-degree relatives with the disease, an analysis of genealogy and death certificates in Utah found.

The risk doubled if a person had both a first-degree relative (parent or sibling) and a second-degree relative (grandparent, aunt, uncle, or a sibling who shared one parent) who had the disease, according to Lisa Cannon-Albright, PhD, of the University of Utah in Salt Lake City, and colleagues.

Alzheimer's disease in only third-degree relatives (great-grandparents, great uncles, great aunts, and first cousins) also raised risks, the researchers reported in Neurology.