Mild cognitive impairment: searching for the prodrome of Alzheimer's disease

Mild cognitive impairment is a transitional state between the cognitive changes of normal aging and early Alzheimer's disease. In a double-blind study, we evaluated subjects with the amnestic subtype of mild cognitive impairment. Subjects were randomly assigned to receive 2000 IU of vitamin E daily, 10 mg of donepezil daily, or placebo for three years. The primary outcome was clinically possible or probable Alzheimer's disease; secondary outcomes were cognition and function. A total of 769 subjects were enrolled, and possible or probable Alzheimer's disease developed in 212. The overall rate of progression from mild cognitive impairment to Alzheimer's disease was 16 percent per year. As compared with the placebo group, there were no significant differences in the probability of progression to Alzheimer's disease in the vitamin E group (hazard ratio, 1.02; 95 percent confidence interval, 0.74 to 1.41; P=0.91) or the donepezil group (hazard ratio, 0.80; 95 percent confidence interval, 0.57 to 1.13; P=0.42) during the three years of treatment. Prespecified analyses of the treatment effects at 6-month intervals showed that as compared with the placebo group, the donepezil group had a reduced likelihood of progression to Alzheimer's disease during the first 12 months of the study (P=0.04), a finding supported by the secondary outcome measures. Among carriers of one or more apolipoprotein E epsilon4 alleles, the benefit of donepezil was evident throughout the three-year follow-up. There were no significant differences in the rate of progression to Alzheimer's disease between the vitamin E and placebo groups at any point, either among all patients or among apolipoprotein E epsilon4 carriers. Vitamin E had no benefit in patients with mild cognitive impairment. Although donepezil therapy was associated with a lower rate of progression to Alzheimer's disease during the first 12 months of treatment, the rate of progression to Alzheimer's disease after three years was not lower among patients treated with donepezil than among those given placebo. Copyright 2005 Massachusetts Medical Society.

To determine whether leisure activities modify the risk for incident dementia. Although high educational and occupational attainments have been associated with reduced risk of incident dementia, the relation between leisure activities and dementia risk has not been adequately investigated. A total of 1,772 nondemented individuals aged 65 years or older, living in northern Manhattan, New York, were identified and followed longitudinally in a community-based cohort incidence study. Subjects' leisure activities at baseline were assessed, annual examinations with the same standardized neurologic and neuropsychological measures were performed for up to 7 years (mean 2.9 years), and incident dementia was assessed as the main outcome measure. Cox proportional hazards models, adjusting for age, ethnic group, education, and occupation, were used to estimate the relative risk (RR) of incident dementia associated with high leisure activities. Of the 1,772 subjects, 207 became demented. The risk of dementia was decreased in subjects with high leisure activities (RR, 0.62; 95% CI 0.46 to 0.83). The association of high leisure with decreased RR of incident dementia was present even when baseline cognitive performance, health limitations interfering with desired leisure activities, cerebrovascular disease, and depression were considered. The data suggest that engagement in leisure activities may reduce the risk of incident dementia, possibly by providing a reserve that delays the onset of clinical manifestations of the disease.