Objective: To determine the prevalence of "cognitive impairment no dementia" (CIND) and "amnestic mild cognitive impairment" (aMCI) in a population sample of 70-79-year-olds and the risk factors for CIND.
Method: Cross sectional population survey.
Setting: Sutherland Shire, Sydney, Australia.
Subjects: 150 community-dwelling 70-79-year-olds were screened by telephone, 42 of whom were assessed at home.
Measures: Demographics, subjective ratings of physical and emotional health and memory, cardiovascular risk factors, medications, the Mini-Mental State Examination, Boston Naming Test, Trail Making Tests A and B, Block Design, Rey Auditory Verbal Learning Test (RAVLT), Visual Reproduction, Logical Memory, letter and category fluency, the National Adult Reading Test (NART), the Geriatric Depression Scale (GDS) and the "state" section of the State-Trait Anxiety Inventory (STAI-S).
Results: From the 400 subjects contacted initially, 150 consented to be interviewed and 131 eligible subjects were recruited. Of a 1-in-3 random sample of 42 subjects assessed at home, 14 (33.3%) subjects met criteria for CIND, 1 (2.4%) had possible dementia and the 27 remaining (64.3%) were cognitively normal. Four (9.5%) met criteria for aMCI. Subjects with CIND were older, had lower ranking occupations and were less likely to be currently working than those classified as cognitively normal. Ten subjects with CIND did not meet criteria for aMCI because they lacked subjective memory impairment (n = 3) or had cognitive deficits other than memory (n = 7). All subjects with aMCI met criteria for CIND.
Conclusions: One-third of individuals in this population sample met criteria for CIND. CIND is a broader definition than aMCI. Further research is needed to determine the longitudinal course and clinical utility of these definitions of cognitive impairment.