Oldest-old survivor stories notwithstanding, mild cognitive problems, as wlel as full-blown dementia, are common among women 85 years and older, and their prevalence keeps going up as these women get older, according to a new study. "There was some question in the research community as to whether the incidence of dementia might plateau after a certain age," said Kristine Yaffes, University of California at San Francisco (UCSF). The question stems partly from the notion that people who have made it past age 85 tend to be healthier and less prone to disease than younger individuals. But a handful of studies challenging that view (Corrada et al., 2010; von Strauss et al., 1999; Lobo et al., 2000) - the latest one appearing in the May issue of Archives of Neurology. "We did not find that there is a plateau. This means that someone who lives to age 95 will probably have some type of cognitive impairment," said Yaffe, the paper's first author.
People aged 85 and over, often referred to as the oldest old (Savva et al., 2009), represent the fastest growing segment of the U.S. population, according to the U.S. Census, and are expected to grow in number from 5.8 million in 2010 to 8.7 million in 2030. Although it is known that dementia and cognitive problems increase with more advanced age (Rodriguez et al., 2008), few studies have so far focused on the oldest old. "We don't have a lot of studies in this group, so it is very important to try to define the nature of cognitive impairment," said Francine Grodstein at Harvard Medical School, who was not involved in the current study.