Driving cessation in older men with incident dementia

OBJECTIVE: To determine the prevalence and cessation of driving among order men with incident dementia in the Honolulu-Asia Aging Study. DESIGN: Retrospective cohort data from a community-based study of incident dementia. SETTING: The Honolulu Heart Program and the Honolulu-Asia Aging Study. PARTICIPANTS: A total of 643 men who were evaluated for the incidence of Al zheimer's disease or other dementia between the fourth and the fifth examin ation of the Honolulu Heart Program. MEASUREMENTS: Driving history, diagnosis of dementia, grip strength, walkin g speed, standing balance test, interviewer's rating of vision status, and the neurologist's notes on mentions of driving behavior from informal inter views with a caregiver or family informant. RESULTS: The prevalence of driving declined dramatically with level of cogn itive functioning. Among 162 men evaluated and found to have normal cogniti ve functioning, 78% still drove, compared with 62% of 287 men with poor cog nitive functioning but no clinical dementia, 46% of 96 men with a new diagn osis of very mild dementia (Clinical Dementia Rating = 0.5), and 22% of 98 men with a new diagnosis of mild dementia (CDR = 1). Only one of 23 men dia gnosed with moderate or more severe staged incident dementia (CDR > 1) was driving. About 10% of the 59 demented persons still driving relied on co-pi lots, and only one driver was reported as involved in a crash according to a review of the neurologists' notes. CONCLUSIONS: Incident dementia is a major cause of driving cessation. Based on these data, we estimate that approximately 4% of male drivers aged 75 y ears and older nationwide (about 175,000 men) have dementia. This number wi ll increase with the projected growth of drivers aged 75 years and older.