People are living longer these days, with the average life expectancy for people in the U.S. reaching 80.7 years for women and 74.1 for men, according to a scientific study published in JAMA . Unfortunately, for many people, their later years are not spent in good health. According to the same study, the U.S. has the largest gap between healthspan (the number of years one spends in good health) and lifespan (the number of years one lives). Dementia is one of the biggest threats to healthspan.