Diabetes: vascular or neurodegenerative: an epidemiologic perspective.

Type 2 diabetes and cognitive impairment are 2 of the most common chronic conditions found in persons 60 years and older. After that age, approximately 18% to 20% of older persons have diabetes,1 approximately 19% suffer from mild cognitive impairment in multiple domains,2 and approximately 6% of community-dwelling individuals have some dementia.3 The prevalence of mild cognitive impairment and dementia increases with age as does the prevalence of diabetes; there is also an alarming trend toward a younger age of diabetes onset.4 Several lines of investigation suggest a link among diabetes, cognitive impairment, and dementia, described briefly subsequently. Thus, the age-related trends in diabetes and cognitive disorders indicate a further increase in the number of persons with mild cognitive impairment and dementia, beyond the increase that is expected as the population ages.