Mild cognitive impairment as a predictor of falls in community-dwelling older people

摘要

OBJECTIVE: Incidence of falls in people with cognitive impairment with or without a formal diagnosis of dementia is estimated to be twice that of cognitively intact older adults. This study aimed to investigate whether mild cognitive impairment (MCI) is associated with falls in older people. DESIGN: Prospective cohort study. SETTING: Community sample, Sydney Memory and Ageing Study. PARTICIPANTS: A total of 419 nondemented community-dwelling adults, age 70-90 years. MEASUREMENTS: A comprehensive neuropsychological test battery measuring four cognitive domains provided classification being with or without MCI on the basis of objective published criteria. Assessments of medical, physiologic, and psychological measures were also performed. Fallers were defined as people who had at least one injurious fall or at least two noninjurious falls during a 12-month follow-up period. RESULTS: Of the participants, 342 (81.6%) had normal cognitive functioning, 58 (13.8%) had nonamnestic MCI, and 19 (4.5%) had amnestic MCI. People with MCI performed worse than people without MCI in measures of general health and balance. Logistic regression analyses showed that fall risk was significantly greater in people with MCI (odds ratio [OR]: 1.72, 95% confidence interval [95% CI]: 1.03-2.89). This association was mainly apparent when the analysis was restricted to those with nonamnestic MCI (OR: 1.98, 95% CI: 1.11-3.53), where the relationship was primarily explained by impaired executive functioning (OR: 1.27, 95% CI: 1.02-1.59). CONCLUSION: The findings indicate that objectively defined MCI is an independent risk factor for injurious or multiple falls in a representative sample of community-dwelling older people. The presence of nonamnestic MCI, based primarily on executive function, was found to be an important factor in increasing fall risk.