Benzodiazepine use and cognitive function among community-dwelling elderly

Objective: To evaluate the relation between benzodiazepine use and cognitiv e function among community-dwelling elderly. Methods This prospective cohort study included 2765 self-reporting subjects from the Duke Established Populations for Epidemiologic Studies of the Eld erly. The subjects were cognitively intact at baseline (1986-1987) and aliv e at follow-up data collection 3 years later. Cognitive function was assess ed with the Short Portable Mental Status Questionnaire (unimpaired versus i mpaired and change in score) and on the basis of the number of errors on th e individual domains of the Orientation-Memory-Concentration Test. Benzodia zepine use was determined during in-home interviews and classified by dose, half-life, and duration. Covariates included demographic characteristics, health status, and health behaviors. Results: After control for covariates, current users of benzodiazepine made more errors on the memory test (beta coefficient, 0.35; 95% confidence int erval [CI], 0.10 to 0.61) than nonusers. Further assessment of the negative effects on memory among current users suggested a dose response in which u sers taking the recommended or higher dose made more errors (beta coefficie nt, 0.57; 95% CT, 0.26 to 0.88) and a duration response in which long-term users made more errors (bt-ta coefficient, 0.39; 95% CI, 0.05 to 0.73) than nonusers. Users of agents with long half-lives and users of agents with sh ort half-lives both had increased memory impairment (beta coefficient, 0.32 ; 95% CI, 0.01 to 0.64 and beta coefficient, 0.38; 95% CI, 0.02 to 0.75, re spectively) relative to nonusers. Previous benzodiazepine use was unrelated to memory problems, and current and previous benzodiazepine use was unrela ted to level of cognitive functioning as measured with the other 4 tests. Conclusions: The results suggested that current benzodiazepine use, especia lly in recommended or higher doses, is associated with worse memory among c ommunity-dwelling elderly.