The epidemiology of Alzheimer disease in intellectual disability: results and recommendations from an international conference.

Among adults with intellectual disability, virtually everyone with Down's syndrome (DS) over the age of 40 years has neuropathology currently viewed to be consistent with a diagnosis of Alzheimer disease (AD), while other adults with intellectual disability without DS display an increased prevalence of Alzheimer-type neuropathology after they reach the age of 65. This paper presents the results of discussions by an epidemiology workgroup, formed at an international conference convened to discuss AD among people with intellectual disability, concerning: (1) the incidence and prevalence of clinical dementia in adults with intellectual disability; (2) risk factors for the development of AD in adults with intellectual disability; and (3) a minimum data set that would be of great utility for future research on AD in adults with intellectual disability.