Cognitive impairment, including dementia, is a major health concern with the increasing aging population. Preventive measures to delay cognitive decline are of utmost importance. Alzheimer's disease ...(AD) is the most frequent cause of dementia, increasing in prevalence from <1% below the age of 60 years to >40% above 85 years of age.
We systematically reviewed selected modifiable factors such as education, smoking, alcohol, physical activity, caffeine, antioxidants, homocysteine (Hcy), n-3 fatty acids that were studied in relation to various cognitive health outcomes, including incident AD. We searched MEDLINE for published literature (January 1990 through October 2012), including cross-sectional and cohort studies (sample sizes > 300). Analyses compared study finding consistency across factors, study designs and study-level characteristics. Selecting studies of incident AD, our meta-analysis estimated pooled risk ratios (RR), population attributable risk percent (PAR%) and assessed publication bias.
In total, 247 studies were retrieved for systematic review. Consistency analysis for each risk factor suggested positive findings ranging from ~38.9% for caffeine to ~89% for physical activity. Education also had a significantly higher propensity for "a positive finding" compared to caffeine, smoking and antioxidant-related studies. Meta-analysis of 31 studies with incident AD yielded pooled RR for low education (RR = 1.99; 95% CI: 1.30-3.04), high Hcy (RR = 1.93; 95% CI: 1.50-2.49), and current/ever smoking status (RR = 1.37; 95% CI: 1.23-1.52) while indicating protective effects of higher physical activity and n-3 fatty acids. Estimated PAR% were particularly high for physical activity (PAR% = 31.9; 95% CI: 22.7-41.2) and smoking (PAR% = 31.09%; 95% CI: 17.9-44.3). Overall, no significant publication bias was found.
Higher Hcy levels, lower educational attainment, and decreased physical activity were particularly strong predictors of incident AD. Further studies are needed to support other potential modifiable protective factors, such as caffeine.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
IMPORTANCE Older adults commonly report disturbed sleep, and recent studies in humans and animals suggest links between sleep and Alzheimer disease biomarkers. Studies are needed that evaluate ...whether sleep variables are associated with neuroimaging evidence of β-amyloid (Aβ) deposition. OBJECTIVE To determine the association between self-reported sleep variables and Aβ deposition in community-dwelling older adults. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional study of 70 adults (mean age, 76 range, 53-91 years) from the neuroimaging substudy of the Baltimore Longitudinal Study of Aging, a normative aging study. EXPOSURE Self-reported sleep variables. MAIN OUTCOMES AND MEASURES β-Amyloid burden, measured by carbon 11–labeled Pittsburgh compound B positron emission tomography distribution volume ratios (DVRs). RESULTS After adjustment for potential confounders, reports of shorter sleep duration were associated with greater Aβ burden, measured by mean cortical DVR (B = 0.08 95% CI, 0.03-0.14; P = .005) and precuneus DVR (B = 0.11 0.03-0.18; P = .007). Reports of lower sleep quality were associated with greater Aβ burden measured by precuneus DVR (B = 0.08 0.01-0.15; P = .03). CONCLUSIONS AND RELEVANCE Among community-dwelling older adults, reports of shorter sleep duration and poorer sleep quality are associated with greater Aβ burden. Additional studies with objective sleep measures are needed to determine whether sleep disturbance causes or accelerates Alzheimer disease.
The associations between nutritional biomarkers and measures of sleep quantity and quality remain unclear.
Cross-sectional data from the National Health and Nutrition Examination Surveys (NHANES) ...2005-2006 were used. We selected 2,459 adults aged 20-85, with complete data on key variables. Five sleep measures were constructed as primary outcomes: (A) Sleep duration; (B) Sleep disorder; (C) Three factors obtained from factor analysis of 15 items and labeled as "Poor sleep-related daytime dysfunction" (Factor 1), "Sleepiness" (Factor 2) and "Sleep disturbance" (Factor 3). Main exposures were serum concentrations of key nutrients, namely retinol, retinyl esters, carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein+zeaxanthin, lycopene), folate, vitamin B-12, total homocysteine (tHcy), vitamin C, 25-hydroxyvitamin D (25(OH)D) and vitamin E. Main analyses consisted of multiple linear, logistic and multinomial logit models.
Among key findings, independent inverse associations were found between serum vitamin B-12 and sleep duration, 25(OH)D and sleepiness (as well as insomnia), and between folate and sleep disturbance. Serum total carotenoids concentration was linked to higher odds of short sleep duration (i.e. 5-6 h per night) compared to normal sleep duration (7-8 h per night).
A few of the selected serum nutritional biomarkers were associated with sleep quantity and quality. Longitudinal studies are needed to ascertain temporality and assess putative causal relationships.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background
There is growing evidence that five-factor model personality traits are associated with self-reported sleep. We test whether these associations extend to objective sleep measures in older ...adulthood and whether measures of objective sleep mediate the relation between personality and subjective sleep.
Methods
A random subsample of participants in the National Social Life and Aging Project (NSHAP) wore an accelerometer for up to three nights and had information on FFM personality traits (
N
= 620). Participants also reported on their feelings of being rested.
Results
Higher neuroticism and lower extraversion and conscientiousness were associated with more frequent wake after sleep onset, greater fragmentation, and feeling less rested. Concurrent body mass index, disease burden, perceived stress, and depressive symptoms accounted for these associations. Personality was unrelated to total time spent asleep but conscientiousness was associated with earlier and more consistent bedtimes. None of the objective sleep metrics mediated the relation between personality and subjective sleep.
Conclusions
The present research indicates that the associations typically found for personality and subjective sleep extend to objective sleep fragmentation. These objective measures, however, do not account for the relation between personality and feeling rested.
Heterogeneity among Black adults' experiences of discrimination and education quality independently influence cognitive function and sleep, and may also influence the extent to which sleep is related ...to cognitive function. We investigated the effect of discrimination on the relationship between objective sleep characteristics and cognitive function in older Black adults with varying education quality.
Cross-sectional analyses include Black participants in the Einstein Aging Study (N = 104, mean age = 77.2 years, 21% males). Sleep measures were calculated from wrist actigraphy (15.4 ± 1.3 days). Mean ambulatory cognitive function (i.e., spatial working memory, processing speed/visual attention, and short-term memory binding) was assessed with validated smartphone-based cognitive tests (6 daily). A modified Williams Everyday Discrimination Scale measured discriminatory experiences. Linear regression, stratified by reading literacy (an indicator of education quality), was conducted to investigate whether discrimination moderated associations between sleep and ambulatory cognitive function for individuals with varying reading literacy levels. Models controlled for age, income, sleep-disordered breathing, and sex assigned at birth.
Higher reading literacy was associated with better cognitive performance. For participants with both lower reading literacy and more discriminatory experiences, longer mean sleep time was associated with slower processing speed, and lower sleep quality was associated with worse working memory. Later sleep midpoint and longer nighttime sleep were associated with worse spatial working memory for participants with low reading literacy, independent of their discriminatory experiences.
Sociocultural factors (i.e., discrimination and education quality) can further explain the association between sleep and cognitive functioning and cognitive impairment risk among older Black adults.
•We demonstrate the use of multilevel modeling to examine variability in driving behaviors.•Distracted driving varied within and between drivers in a naturalistic driving study.•Cell phone use and ...reaching behaviors varied more across trips than across people.•Simulated daily sleep demonstrates how predictors of driving can vary within a person.
Current methods of analyzing data from naturalistic driving studies provide important insights into real-world safety-related driving behaviors, but are limited in the depth of information they currently offer. Driving measures are frequently collapsed to summary levels across the study period, excluding more fine-grained differences such as changes that occur from trip to trip. By retaining trip-specific data, it is possible to quantify how much a driver differs from trip to trip (within-person variability) in addition to how he or she differs from other drivers (between-person variability). To the authors’ knowledge, the current study is the first to use multilevel modeling to quantify variability in distracted driving behavior in a naturalistic dataset of older drivers. The current study demonstrates the utility of examining within-person variability in a naturalistic driving dataset of 68 older drivers across two weeks. First, multilevel models were conducted for three distracted driving behaviors to distinguish within-person variability from between-person variability in these behaviors. A high percentage of variation in distracted driving behaviors was attributable to within-person differences, indicating that drivers’ behaviors varied more across their own driving trips than from other drivers (ICCs = .93). Then, to demonstrate the utility of personal characteristics in predicting daily driving behavior, a hypothetical model is presented using simulated daily sleep duration from the previous night to predict distracted driving behavior the following day. The current study demonstrates substantial variability in driving behaviors within an older adult sample and the promise of individual characteristics to provide better prediction of driving behaviors relevant to safety, which can be applied in investigations of current naturalistic driving datasets and in designing future studies.
Abstract
Objectives
The present study examined potential sources of intra- and inter-individual differences in older adults’ control beliefs using a micro-longitudinal design.
Method
Older adults (n ...= 205) ranging in age from 60 to 94 (M = 72.70, SD = 6.72) completed 8 in-person testing sessions within 3 weeks which included assessments of control beliefs (Locus of Control and Perceived Competence), physical health (physical symptoms and sleep self-efficacy), stressors, emotional well-being (Positive Affect and Negative Affect), and cognition (basic cognition tests, everyday cognition, and memory failures).
Results
Multilevel models indicated that on days when older adults had higher sleep self-efficacy, more positive affect, and less negative affect, they also had more internal locus of control and higher perceived competence. Having stressors on the previous occasion was associated with lower internal locus of control on the subsequent occasion. Physical symptoms, everyday cognition, and memory failures could be predictive of locus of control for some older adults.
Discussion
Our findings showed the differentiated antecedents of locus of control and perceived competence, the unique role of sleep self-efficacy, positive affect, and negative affect in understanding antecedents of both, as well as the need to study well-being and cognition antecedents of control beliefs in future studies.
•Higher neuroticism was associated with more cognitive errors.•Higher conscientiousness and openness were associated with fewer cognitive errors.•The associations were generally similar across age, ...sex, race, education, and poverty status.
This study examines the association between personality and cognitive errors in the Healthy Aging in Neighborhoods of Diversity across the Life Span study, a sample diverse across race (Black, White) and SES (above, below 125% of the federal poverty line). Participants (N = 1062) completed a comprehensive personality questionnaire and were administered a brief mental status screener of cognitive errors. Higher neuroticism was associated with more cognitive errors, whereas higher openness and conscientiousness were associated with fewer errors. These associations were independent of age, sex, race, poverty status, and education and were generally not moderated by these factors. These findings support the associations between personality and cognition across race and SES.
The beneficial effect of acute physical exercise on cognitive performance has been studied in laboratory settings and in long-term longitudinal studies. Less is known about these associations in ...everyday environment and on a momentary timeframe. This study investigated momentary and daily associations between physical activity and cognitive functioning in the context of everyday life.
Middle-aged adults (n = 291, aged 40-70) were asked to wear accelerometers and complete ecological momentary assessments for eight consecutive days. Processing speed and visual memory were assessed three times per day and self-rated evaluations of daily cognition (memory, thinking, and sharpness of mind) were collected each night. The number of minutes spent above the active threshold (active time) and the maximum vector magnitude counts (the highest intensity obtained) before each cognitive test and at a daily level were used as predictors of momentary cognitive performance and nightly subjective cognition. Analyses were done with multilevel linear models. The models were adjusted for temporal and contextual factors, age, sex, education, and race/ethnicity.
When participants had a more active time or higher intensity than their average level within the 20 or 60 minutes prior to the cognitive test, they performed better on the processing speed task. On days when participants had more active time than their average day, they rated their memory in the evening better. Physical activity was not associated with visual memory or self-rated thinking and sharpness of mind.
This study provides novel evidence that outside of laboratory settings, even small increases in physical activity boost daily processing speed abilities and self-rated memory. The finding of temporary beneficial effects is consistent with long-term longitudinal research on the cognitive benefits of physical activity.
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