Vascular factors predict rate of progression in Alzheimer disease.

BACKGROUND: While there is considerable epidemiologic evidence that cardiovascular risk factors increase risk of incident Alzheimer disease (AD), few studies have examined their effect on progression after an established AD diagnosis. OBJECTIVE: To examine the effect of vascular factors, and potential age modification, on rate of progression in a longitudinal study of incident dementia. METHODS: A total of 135 individuals with incident AD, identified in a population-based sample of elderly persons in Cache County, UT, were followed with in-home visits for a mean of 3.0 years (range: 0.8 to 9.5) and 2.1 follow-up visits (range: 1 to 5). The Clinical Dementia Rating (CDR) Scale and Mini-Mental State Examination (MMSE) were administered at each visit. Baseline vascular factors were determined by interview and physical examination. Generalized least-squares random-effects regression was performed with CDR Sum of Boxes (CDR-Sum) or MMSE as the outcome, and vascular index or individual vascular factors as independent variables. RESULTS: Atrial fibrillation, systolic hypertension, and angina were associated with more rapid decline on both the CDR-Sum and MMSE, while history of coronary artery bypass graft surgery, diabetes, and antihypertensive medications were associated with a slower rate of decline. There was an age interaction such that systolic hypertension, angina, and myocardial infarction were associated with greater decline with increasing baseline age. CONCLUSION: Atrial fibrillation, hypertension, and angina were associated with a greater rate of decline and may represent modifiable risk factors for secondary prevention in Alzheimer disease. The attenuated decline for diabetes and coronary artery bypass graft surgery may be due to selective survival. Some of these effects appear to vary with age.

Antioxidant intake and cognitive function of elderly men and women: the Cache County Study.

OBJECTIVE: We prospectively examined associations between intakes of antioxidants (vitamins C, vitamin E, and carotene) and cognitive function and decline among elderly men and women of the Cache County Study on Memory and Aging in Utah. PARTICIPANTS AND DESIGN: In 1995, 3831 residents 65 years of age or older completed a baseline survey that included a food frequency questionnaire and cognitive assessment. Cognitive function was assessed using an adapted version of the Modified Mini-Mental State examination (3MS) at baseline and at three subsequent follow-up interviews spanning approximately 7 years. Multivariable-mixed models were used to estimate antioxidant nutrient effects on average 3MS score over time. RESULTS: Increasing quartiles of vitamin C intake alone and combined with vitamin E were associated with higher baseline average 3MS scores (p-trend = 0.013 and 0.02 respectively); this association appeared stronger for food sources compared to supplement or food and supplement sources combined. Study participants with lower levels of intake of vitamin C, vitamin E and carotene had a greater acceleration of the rate of 3MS decline over time compared to those with higher levels of intake. CONCLUSION: High antioxidant intake from food and supplement sources of vitamin C, vitamin E, and carotene may delay cognitive decline in the elderly.

Telephone adaptation of the Modified Mini-Mental State Exam (3MS). The Cache County Study.

OBJECTIVE: To examine the concurrent validity of a newly developed telephone adaptation of the Modified Mini-Mental State Exam. BACKGROUND: Longitudinal studies of cognition may be advantaged by availability of assessment instruments that can be used over the telephone, as well as in person. METHOD: Subjects were 263 noninstitutionalized elderly residents of a rural community in southern Idaho, aged 65 to 93, who had little or no cognitive difficulty. At an average interval of four weeks, we administered the Modified Mini-Mental State Exam (3MS) and the newly adapted Telephone Modified Mini-Mental State Exam (T3MS). Order of administration was randomly assigned. RESULTS: Agreement between scores on the two instruments was good (r = 0.82, p < 0.001). When we applied various cutoff scores to the instruments, thereby generating assignments of individuals to "screen positive" and "screen negative" groups, the percent agreement in screening results ranged from 80% to 96% as we reduced the cutoff scores from 90 to 74 (100 points possible). CONCLUSIONS: At least among subjects without major cognitive syndromes, the Telephone Modified Mini-Mental State Exam provides a reasonable substitute for the more costly in-person 3MS. The telephone instrument should now be tested over a broader range of cognitive abilities in order to assess its validity in more impaired subjects, e.g., by studying an institutionalized sample.

APOE-epsilon4 count predicts age when prevalence of AD increases, then declines: the Cache County Study.

OBJECTIVE: To examine the prevalence of Alzheimer's disease (AD) and other dementias in relation to age, education, sex, and genotype at APOE. Recent studies suggest age heterogeneity in the risk of AD associated with the APOE genotype and a possible interaction between APOE-epsilon4 and female sex as risk factors. We studied these topics in the 5,677 elderly residents of Cache County, Utah, a population known for long life expectancy and high participation rates. METHODS: We screened for dementia with a brief cognitive test and structured telephone Dementia Questionnaire, then examined all individuals with apparent cognitive symptoms and a sample of others. We estimated age-specific prevalence of AD and other dementias and used multiple logistic regression models to describe relation of AD prevalence to age, sex, education, and APOE genotype. RESULTS: We found 335 demented individuals, 230 (69%) with definite, probable, or possible AD (positive predictive value versus autopsy confirmation 85%). The adjusted prevalence estimate for AD was 6.5% and for all dementias 9.6%. After age 90, the adjusted prevalence estimate for AD was 28% and for all dementias 38%. Regression models showed strong variation in AD prevalence with age, sex, education, and number of epsilon4 alleles (effect of epsilon2 not significant). Models were improved by a term for age-squared (negative coefficient) and by separate terms for interaction of age with presence of one or two epsilon4 alleles. An association of AD with female sex was ascribable entirely to individuals with epsilon4. CONCLUSIONS: In participants with no epsilon4 alleles, the age-specific prevalence of AD reached a maximum and then declined after age 95. In epsilon4 heterozygotes a similar maximum was noted earlier at age 87, in homozygotes at age 73. Female sex was a risk factor for AD only in those with epsilon4. The epsilon4 allele accounted for 70% of the population attributable risk for AD.