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Introduction: Although exercise is associated with a lower risk for mild cognitive impairment (MCI), it is unclear whether its protective effect depends on the presence or absence of vascular factors.Methods: In an exploratory study of data from a population-based cohort, 1254 participants aged 65+ years were followed for 10 years for incident MCI. The main effect of baseline total minutes of exercise per week (0 vs. 1 to 149 vs. 150+), and its interaction with several vascular factors, on risk for incident MCI was examined using Cox proportional hazards regression models, adjusting for demographics.Results: Compared with no exercise, 1 to 149 minutes [hazard ratio (HR)=0.90; 95% confidence interval (95% CI), 0.69-1.16] and 150 or more minutes per week (HR=0.84; 95% CI, 0.66-1.07) of exercise lowered risk for incident MCI in a dose-dependent manner. The majority of interactions were not statistically significant, but risk reduction effect sizes of <0.75 suggested that exercise may have stronger effects among those without high cholesterol, never smoking, and not currently consuming alcohol; also, those with arrhythmia, coronary artery disease, and heart failure. Overall, there was a pattern of exercise being associated with lower MCI risk among those without vascular factors.Conclusions: Spending more time engaging in exercise each week may offer protection against MCI in late life, with some variation among those with different vascular conditions and risk factors. Our findings may help target subgroups for exercise recommendations and interventions, and also generate hypotheses to test regarding underlying mechanisms. [ABSTRACT FROM AUTHOR]

Background: Incidence of dementia increases exponentially with age; little is known about its risk factors in the ninth and 10th decades of life. We identified predictors of dementia with onset after age 85 years in a longitudinal population-based cohort.Methods: On the basis of annual assessments, incident cases of dementia were defined as those newly receiving Clinical Dementia Rating (CDR) ≥1. We used a machine learning method, Markov modeling with hybrid density-based and partition-based clustering, to identify variables associated with subsequent incident dementia.Results: Of 1439 participants, 641 reached age 85 years during 10 years of follow-up and 45 of these became incident dementia cases. Using hybrid density-based and partition-based, among those aged 85+ years, probability of incident dementia was associated with worse self-rated health, more prescription drugs, subjective memory complaints, heart disease, cardiac arrhythmia, thyroid disease, arthritis, reported hypertension, higher systolic and diastolic blood pressure, and hearing impairment. In the subgroup aged 85 to 89 years, risk of dementia was also associated with depression symptoms, not currently smoking, and lacking confidantes.Conclusions: An atheoretical machine learning method revealed several factors associated with increased probability of dementia after age 85 years in a population-based cohort. If independently validated in other cohorts, these findings could help identify the oldest-old at the highest risk of dementia. [ABSTRACT FROM AUTHOR]

Background: Linear models cannot capture nonlinear associations when the relationships between cognition and risk factors vary across risk levels. We demonstrate a method of modelling nonlinear associations using the example of blood pressure (BP) and memory.Methods: We measured memory and BP (in mm Hg) annually for 10 years in a population-based cohort (N=1982) aged 65+. We evaluated the relationship between BP and memory at the same time points using both linear mixed models and generalized additive mixed models with smoothing splines, adjusting for relevant covariates.Results: Linear mixed models found no significant associations. Generalized additive mixed models detected different associations between BP and memory across baseline BP categories (normotensive, hypertensive, hypotensive). Among normotensives, systolic blood pressure (SBP)/diastolic blood pressure (DBP) around 140/80 was associated with the highest, while SBP/DBP around 110/60 was associated with the lowest, predicted memory scores. Among hypertensives, SBP/DBP around 130/85 was associated with the highest, while SBP/DBP around 150/65 was associated with the lowest, predicted memory scores. Among hypotensives, no significant association was found. Among both normotensives and hypertensives, a DBP >75 was associated with better memory.Conclusions: By modelling nonlinear associations, we showed that the relationship between BP and memory performance varied by baseline BP among normotensives and hypertensives. [ABSTRACT FROM AUTHOR]

Engagement in cognitively stimulating activities is gaining prominence as a potential strategy to maintain cognitive functioning in old age. In a population-based cohort of individuals aged 65+ years, we examined patterns of change in frequency of engagement in total cognitive activity (TCA), higher cognitive activity (HCA), and frequent cognitive activity (FCA) based on the Florida Cognitive Activities Scale over an average of 3.62 years, and whether these patterns were associated with incident mild cognitive impairment (MCI) during this same period. Among 867 cognitively normal participants, 129 (15%) progressed to MCI. Latent class trajectory modeling identified high and stable, slowly, and quickly declining patterns for TCA; high and stable, slowly declining, and slowing increasing patterns for FCA; and high and stable, and slowly declining patterns for HCA. Separate, adjusted Cox proportional hazard models, revealed that compared with the high, stable pattern, both slow decline [hazard ratio (HR), 2.5; 95% confidence interval (CI), 1.5-4.0] and quick decline (HR, 11.0; 95% CI, 6.3-19.2) in TCA, and slow decline in the FCA (HR, 8.7; 95% CI, 5.3-14.3) and HCA (HR, 3.4; 95% CI, 2.0-5.6) subscales increased risk for incident MCI. Maintaining engagement in cognitive activities may be protective against progression to MCI, alternatively, declining engagement may be a marker for impending cognitive impairment. [ABSTRACT FROM AUTHOR]

Background: The International Working Group (IWG) criteria for mild cognitive impairment have variable utility in predicting progression to dementia, partly depending on the setting. We explored an empiric approach to optimize the criteria and cutoff points in a population study. Methods: In a cohort of adults aged 65 years or older, we identified 1129 individuals with normal or only mildly impaired cognition by cognitive classification, and 1146 individuals without dementia (Clinical Dementia Rating < 1). Operationally defining the IWG criterion set, we examined its sensitivity and specificity for the development of severe cognitive impairment and dementia (Clinical Dementia Rating ≥ 1) over 4 years. We then disaggregated the criteria and used Classification and Regression Tree analyses to identify the optimal predictive model. Results: The operational IWG criteria had 49% sensitivity and 86% specificity for the outcome of severe cognitive impairment, and 40% sensitivity and 84% specificity for the outcome of dementia. Classification and Regression Tree modeling improved sensitivity to 82% for the cognitive outcome and 76% for the dementia outcome; specificity remained high. Memory scores were the most important predictors for both outcomes. The optimal cutoff points were around 1.0 SD below the age-education mean. The best fit was observed when prediction was modeled separately for each age-education group. Conclusions: Objective cognitive measurements contributed more to the prediction of dementia than subjective and functional measures. Those with less education only required memory testing, whereas those with more education required assessment of several cognitive domains. In cases in which only overall norms are available, the appropriate threshold will vary according to the individual's age and education. [ABSTRACT FROM AUTHOR]

We examined several vascular factors in relation to the rates of decline in 5 cognitive domains in a population-based cohort. In an age-stratified random sample (N=1982) aged 65+ years, we assessed at baseline the cognitive domains of attention, executive function, memory, language, and visuospatial function, and also vascular, inflammatory, and metabolic indices. Random effects models generated slopes of cognitive decline over the next 4 years; linear models identified vascular factors associated with these slopes, adjusting for demographics, baseline cognition, and potential interactions. Several vascular risk factors (history of stroke, diabetes, central obesity, C-reactive protein), although associated with lower baseline cognitive performance, did not predict rate of subsequent decline. APOE*4 genotype was associated with accelerated decline in language, memory, and executive functions. Homocysteine elevation was associated with faster decline in executive function. Hypertension (history or systolic blood pressure >140 mm Hg) was associated with slower decline in memory. Baseline alcohol consumption was associated with slower decline in attention, language, and memory. Different indices of vascular risk are associated with low performance and with rates of decline in different cognitive domains. Cardiovascular mechanisms explain at least some of the variance in cognitive decline. Selective survival may also play a role. [ABSTRACT FROM AUTHOR]

Subjective cognitive complaints (SCCs) are increasingly a focus in studies on prodromal Alzheimer disease (AD) and risk for dementia. Little is known about the optimal approach to measure SCCs. We used item response theory (IRT) to examine the characteristics of 24 SCC items in a sample of 3495 older adults pooled from 4 community-based studies. We investigated the potential advantages of IRT scoring over conventional scoring on the basis of participants' item response patterns. Items most likely endorsed by individuals low in SCC severity relate to word retrieval and general subjective memory decline. Items likely endorsed only by individuals high in SCC severity relate to nonepisodic memory changes, such as decline in comprehension, judgment and executive functions, praxis and procedural memory, and social behavior changes. Above and beyond conventional total score, IRT scoring of SCCs was associated with performance on objective cognitive tests, and was associated with cognitive test performance among participants endorsing only 1 SCC item. Thus, IRT scoring captures additional information beyond a simple sum of SCC symptoms. Modern psychometric approaches including IRT may be useful in developing: (1) brief community screening questionnaires; and (2) more sensitive measures of very subtle subjective decline for use in prodromal Alzheimer disease research. [ABSTRACT FROM AUTHOR]

Two cases of carcinoma in Crohn's disease of the colon are reported. One patient was a 30-year-old man who had asymptomatic Crohn's ileocolitis resulting in an acute presentation due to toxic dilatation of the colon. This was preceded by a short prodromal period of four weeks, characterized by intermittent diarrhea on the basis of a coloileal tumor fistula. A mucus-secreting adenocarcinoma was present in the sigmoid colon associated with both adjacent and one nearby focus of high-grade mucosal dysplasia. Pelvic wall and abdominal metastases were present, and the patient died two months later. The other patient was a 60-year-old woman who had a nine-year history of biopsy-proven Crohn's proctocolitis. A stricture of the sigmoid colon due to Crohn's disease also harbored an invasive adenocarcinoma. The carconima was not evident preoperatively or on initial gross pathologic examination. The presentation and pathology of large intestinal carcinoma in Crohn's colitis are discussed and illustrated. [ABSTRACT FROM AUTHOR]