Seniors' risk of dementia is more than double what was previously thought. The risk of developing dementia after age 55 is more than 42% among Americans, researchers reported in a study published Monday in the journal Nature Medicine.

New research suggests that the risk for developing dementia is significantly higher than previously estimated, and the burden on the United States population will grow substantially over the next few decades.

Cases of dementia in the United States are expected to rise to 1 million per year by 2060, with Black individuals, women and those older than 75 years expected to be most affected, according to new data published in Nature Medicine.