Nearly 4,000 people between the ages of 60 to 102 years, initially seen from 1991 to 1993 by primary care physicians at Wishard Health Services, a large public hospital with community health centers in Indianapolis, participated in the study. The patients were followed for 13 years. . . . The study followed 3,957 patients. At screening, 3,157 had no cognitive impairment, 533 had mild impairment, and 267 had moderate to severe impairment. During follow-up, 57 percent of patients with no impairment died, compared with 68 percent of those with mild impairment and 79 percent of those with moderate to severe impairment. Median survival time was 138 months for patients with no impairment, 106 months for those with mild impairment, and 63 months for those with moderate to severe impairment.
Study participants were screened for cognitive impairment using an easy-to-administer 10-question mental status questionnaire. On the basis of the number of errors patients made on this test, they were categorized as having no, mild, or moderate to severe cognitive impairment. . . . Cognitive impairment affects memory and thinking. Approximately 4 million to 5 million people in the United States have dementia, and the number of individuals affected is significantly higher if individuals with milder forms of cognitive impairment are included.
Cause and effect aren't necessarily easy to separate here because dementia is a well documented consequence of the aging process and the aging process also tends to bring a parade of horribles. It might be partially accurate to see the onset of dementia as a general indicator of the extent to which a person is suffering from geriatric disorders, although there are certainly many ways that cognitive impairment can causally lead to bodily harm.