Dataset Information

Propositional density and cognitive function in later life: findings from the Precursors Study.

ABSTRACT:

Objectives

We used longitudinal data from the Johns Hopkins Precursors Study to test the hypothesis that written propositional density measured early in life is lower for people who develop dementia categorized as Alzheimer's disease (AD). This association was reported in 1996 for the Nun Study, and the Precursors Study offered an unprecedented chance to reexamine it among respondents with different gender, education, and occupation profiles.

Methods

Eighteen individuals classified as AD patients (average age at diagnosis: 74) were assigned 2 sex-and-age matched controls, and propositional density in medical school admission essays (average age at writing: 22) was assessed via Computerized Propositional Idea Density Rater 3 linguistic analysis software. Adjusted odds ratios (ORs) for the matched case-control study were calculated using conditional (fixed-effects) logistic regression.

Results

Mean propositional density is lower for cases than for controls (4.70 vs. 4.99 propositions per 10 words, 1-sided p = .01). Higher propositional density substantially lowers the odds of AD (OR = 0.16, 95% confidence interval = 0.03-0.90, 1-sided p = .02).

Discussion

Propositional density scores in writing samples from early adulthood appear to predict AD in later life for men as well as women. Studies of cognition across the life course might beneficially incorporate propositional density as a potential marker of cognitive reserve.

SUBMITTER: Engelman M

PROVIDER: S-EPMC2954330 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature

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Publications

Propositional density and cognitive function in later life: findings from the Precursors Study.

Engelman Michal M Agree Emily M EM Meoni Lucy A LA Klag Michael J MJ

The journals of gerontology. Series B, Psychological sciences and social sciences 20100913 6

<h4>Objectives</h4>We used longitudinal data from the Johns Hopkins Precursors Study to test the hypothesis that written propositional density measured early in life is lower for people who develop dementia categorized as Alzheimer's disease (AD). This association was reported in 1996 for the Nun Study, and the Precursors Study offered an unprecedented chance to reexamine it among respondents with different gender, education, and occupation profiles.<h4>Methods</h4>Eighteen individuals classifie ...[more]

PMID: 20837676

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Project description:BackgroundPotentially modifiable lifestyle factors may influence cognitive health in later life and offer potential to reduce the risk of cognitive decline and dementia. The concept of cognitive reserve has been proposed as a mechanism to explain individual differences in rates of cognitive decline, but its potential role as a mediating pathway has seldom been explored using data from large epidemiological studies. We explored the mediating effect of cognitive reserve on the cross-sectional association between lifestyle factors and cognitive function in later life using data from a population-based cohort of healthy older people.Methods and findingsWe analysed data from 2,315 cognitively healthy participants aged 65 y and over in the Cognitive Function and Ageing Study Wales (CFAS-Wales) cohort collected in 2011-2013. Linear regression modelling was used to investigate the overall associations between five lifestyle factors-cognitive and social activity, physical activity, diet, alcohol consumption, and smoking-and cognition, adjusting for demographic factors and chronic conditions. Mediation analysis tested for indirect effects of the lifestyle factors on cognition via cognitive reserve. After controlling for age, gender, and the presence of chronic conditions, cognitive and social activity, physical activity, healthy diet, and light-to-moderate alcohol consumption were positively associated with cognitive function, together accounting for 20% (95% CI 17%-23%) of variance in cognitive test scores. Cognitive reserve was an important mediator of this association, with indirect effects via cognitive reserve contributing 21% (95% CI 15%-27%) of the overall effect on cognition. The main limitations of the study derive from the cross-sectional nature of the data and the challenges of accurately measuring the latent construct of cognitive reserve.ConclusionsCross-sectional associations support the view that enhancing cognitive reserve may benefit cognition, and maintenance of cognitive health may be supported by a healthy and active lifestyle, in later life.

Project description:RATIONALE:Little research has evaluated the life course drivers of cognitive aging in South Africa. OBJECTIVES:We investigated the relationships of self-rated childhood health and father's occupation during childhood with later-life cognitive function score and whether educational attainment mediated these relationships among older South Africans living in a former region of Apartheid-era racial segregation. METHODS:Data were from baseline assessments of "Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community" (HAALSI), a population-based study of 5059 men and women aged ?40 years in 2015 in rural Agincourt sub-district, South Africa. Childhood health, father's occupation during childhood, and years of education were self-reported in study interviews. Cognitive measures assessed time orientation, numeracy, and word recall, which were included in a z-standardized latent cognitive function score variable. Linear regression models adjusted for age, sex, and country of birth were used to estimate the total and direct effects of each childhood risk factor, and the indirect effects mediated by years of education. RESULTS:Poor childhood health predicted lower cognitive scores (total effect = -0.28; 95% CI = -0.35, -0.21, versus good); this effect was not mediated by educational attainment. Having a father in a professional job during childhood, while rare (3% of sample), predicted better cognitive scores (total effect = 0.25; 95% CI = 0.10, 0.40, versus unskilled manual labor, 29% of sample). Half of this effect was mediated by educational attainment. Education was linearly associated with later-life cognitive function score (0.09; 95% CI = 0.09, 0.10 per year achieved). CONCLUSION:In this post-Apartheid, rural South African context, older adults with poor self-reported childhood health or whose father worked in unskilled manual labor had relatively poor cognitive outcomes. Educational attainment strongly predicted cognitive outcomes, and appeared to be, in part, a mechanism of social stratification in later-life cognitive health in this context.

Project description:ObjectivesThis research investigates the associations between body mass index (BMI) at 21, 40-59, 60-79 years of age on cardiometabolic risk markers at 60-79 years.MethodsA prospective study of 3464 British men with BMI measured at 40-59 and 60-79 years, when cardiometabolic risk was assessed. BMI at 21 years was ascertained from military records, or recalled from middle-age (adjusted for reporting bias); associations between BMI at different ages and later cardiometabolic risk markers were examined using linear regression. Sensitive period, accumulation and mobility life course models were devised for high BMI (defined as BMI?75th centile) and compared with a saturated BMI trajectory model.ResultsAt ages 21, 40-59 and 60-79 years, prevalences of overweight (BMI?25 kg/m2) were 12%, 53%, 70%, and obesity (?30 kg/m2) 1.6%, 6.6%, and 17.6%, respectively. BMI at 21 years was positively associated with serum insulin, blood glucose, and HbA1c at 60-79 years, with increases of 1.5% (95%CI 0.8,2.3%), 0.4% (0.1,0.6%), 0.3% (0.1,0.4%) per 1 kg/m2, respectively, but showed no associations with blood pressure or blood cholesterol. However, these associations were modest compared to those between BMI at 60-79 years and serum insulin, blood glucose and HbA1c at 60-79 years, with increases of 8.6% (8.0,9.2%), 0.7% (0.5,0.9%), and 0.5% (0.4,0.7%) per 1 kg/m2, respectively. BMI at 60-79 years was also associated with total cholesterol and blood pressure. Associations for BMI at 40-59 years were mainly consistent with those of BMI at 60-79 years. None of the life course models fitted the data as well as the saturated model for serum insulin. A sensitive period at 50 years for glucose and HbA1c and sensitive period at 70 years for blood pressure were identified.ConclusionsIn this cohort of men who were thin compared to more contemporary cohorts, BMI in later life was the dominant influence on cardiovascular and diabetes risk. BMI in early adult life may have a small long-term effect on diabetes risk.

Dataset Information

Propositional density and cognitive function in later life: findings from the Precursors Study.

Objectives

Methods

Results

Discussion

Publications

Propositional density and cognitive function in later life: findings from the Precursors Study.

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