Cognitive Function In Old Age Research Articles

Evaluation of a multidisciplinary concept of mental demands at work on cognitive functioning in old age

Objectives Previous work has shown that high mental demands are associated with better cognitive functioning in old age. As there is a lack of a general conceptual framework for this association, the aim of the study was to investigate how mental demands and other work-related factors relate to cognitive functioning as a foundation for developing such a framework. Methods An expert panel discussion was conducted with the aim of determining relevant work-related factors, which were then tested in a survey with 346 employees aged 50+ years, who were actively working. Assessment of cognitive functioning comprised complex attention, executive function, learning/memory, language, perceptual-motor, and social cognition. Confirmatory factor analysis was conducted to confirm factor belonging. Associations with cognitive functioning were analyzed using structure equation modelling to confirm associations and to identify additional direct and indirect paths. Results Only 42.3% (22/52) of the work-related factors and 19.0% (4/21) of the mediating paths suggested by the experts were significant with respect to cognitive functioning. Factor analysis and structural equation modeling indicated that high mental demands are only associated with better cognitive functioning in old age to the extent that they are intellectually stimulating and this effect is embedded in individual capacities and the social context. Conclusion Based on the panel discussion and the empirical testing, we propose the Conceptual Framework of Social Dependency of Intellectual Stimulation on Cognitive Health. We recommend researchers and workplace health experts to pay attention to the component of this theory when assessing workplace risk.

Effects of daily L-dopa administration on learning and brain structure in older adults undergoing cognitive training: a randomised clinical trial

Cognitive aging creates major individual and societal burden, motivating search for treatment and preventive care strategies. Behavioural interventions can improve cognitive performance in older age, but effects are small. Basic research has implicated dopaminergic signalling in plasticity. We investigated whether supplementation with the dopamine-precursor L-dopa improves effects of cognitive training on performance. Sixty-three participants for this randomised, parallel-group, double-blind, placebo-controlled trial were recruited via newspaper advertisements. Inclusion criteria were: age of 65–75 years, Mini-Mental State Examination score >25, absence of serious medical conditions. Eligible subjects were randomly allocated to either receive 100/25 mg L-dopa/benserazide (n = 32) or placebo (n = 31) prior to each of twenty cognitive training sessions administered during a four-week period. Participants and staff were blinded to group assignment. Primary outcomes were latent variables of spatial and verbal fluid intelligence. Compared to the placebo group, subjects receiving L-dopa improved less in spatial intelligence (−0.267 SDs; 95%CI [−0.498, −0.036]; p = 0.024). Change in verbal intelligence did not significantly differ between the groups (−0.081 SDs, 95%CI [−0.242, 0.080]; p = 0.323). Subjects receiving L-dopa also progressed slower through the training and the groups displayed differential volumetric changes in the midbrain. No statistically significant differences were found for the secondary cognitive outcomes. Adverse events occurred for 10 (31%) and 7 (23%) participants in the active and control groups, correspondingly. The results speak against early pharmacological interventions in older healthy adults to improve broader cognitive functions by targeting the dopaminergic system and provide no support for learning-enhancing properties of L-dopa supplements in the healthy elderly. The findings warrant closer investigation about the cognitive effects of early dopamine-replacement therapy in neurological disorders. This trial was preregistered at the European Clinical Trial Registry, EudraCT#2016-000891-54 (2016-10-05).

Prediction of cognitive performance in old age from spatial probability maps of white matter lesions.

The purposes of this study were to explore the association between cognitive performance and white matter lesions (WMLs), and to investigate whether it is possible to predict cognitive impairment using spatial maps of WMLs. These WML maps were produced for 263 elders from the OASIS-3 dataset, and a relevance vector regression (RVR) model was applied to predict neuropsychological performance based on the maps. The association between the spatial distribution of WMLs and cognitive function was examined using diffusion tensor imaging data. WML burden significantly associated with increasing age (r=0.318, p<0.001) and cognitive decline. Eight of 15 neuropsychological measures could be accurately predicted, and the mini-mental state examination (MMSE) test achieved the highest predictive accuracy (CORR=0.28, p<0.003). WMLs located in bilateral tapetum, posterior corona radiata, and thalamic radiation contributed the most prediction power. Diffusion indexes in these regions associated significantly with cognitive performance (axial diffusivity>radial diffusivity>mean diffusivity>fractional anisotropy). These results show that the combination of the extent and location of WMLs exhibit great potential to serve as a generalizable marker of multidomain neurocognitive decline in the aging population. The results may also shed light on the mechanism underlying white matter changes during the progression of cognitive decline and aging.

Relation between cadmium body burden and cognitive function in older men: A cross-sectional study in China

Cadmium (Cd) is a known neurotoxicant and its relation with cognition has been well studied in children. However, evidence linking Cd and cognitive function among older individuals is limited. To evaluate the association between Cd exposure and cognitive function in older age, we conducted a cross-sectional study involving 375 older men aged 60–74 years (mean age: 66.0 years) in Guangxi, China. Urinary Cd concentrations were measured. Cognitive function was assessed by the Chinese version of Mini-Mental State Examination (MMSE) and cognitive impairment was identified using education-specific cutoff points of MMSE scores. General linear regression and logistic regression models were applied to evaluate the associations of urinary Cd concentrations with MMSE scores and the risk of cognitive impairment, respectively. The median urinary Cd concentration of all participants was 1.58 μg/g creatinine. Urinary Cd levels were inversely associated with MMSE scores [β = −0.76; 95% confidence interval (CI): -1.28 to −0.23 for a 2-fold increase in urinary Cd]. A 2-fold increase in urinary Cd was associated with increased risk of cognitive impairment [adjusted odds ratio (OR) = 1.46; 95% CI: 1.14 to 1.86]. When urinary Cd levels were analyzed as quartiles, higher urinary Cd levels were also significantly associated with increased risk of cognitive impairment in a dose-response manner (adjusted OR = 2.68; 95% CI: 1.33 to 5.38 for the highest vs. lowest quartile; p for trend = 0.002). Our findings suggest that long-term exposure to Cd may have adverse consequences for older men’s cognitive function, but these results need further confirmation.

Nutritivni aspekti poremećaja kognitivnih funkcija

Many scientific arguments in this area, implicate low level of important nutrients in cognitive decline, simultaneously suggesting better nutritional status as an important goal in the management of cognitive aging. Key nutrients for the protection of cognitive function are B-group vitamins, polyphenols, vitamin D, and omega-3 polyunsaturated fatty acids (PUFAs). The body of scientific evidence widely supports the roles of folic acid and metabolically related B6 and B12 vitamins in protecting cognitive function in old age. High concentrations of polyphenols in dementia therapy showed a significant increase in cerebral blood volume. Although low vitamin D blood levels were associated with a higher risk of developing dementia, vitamin D supplementation alone was not sufficient to improve cognitive outcomes. In relation to the role of omega-3 PUFAs, research findings indicate protective effects in individuals with cognitive decline. The importance of diets and a healthy lifestyle in the prevention of cognitive impairment are extensively accepted. The Mediterranean diet is the most investigated dietary pattern in observational studies. MIND diet (Mediterranean-DASH Intervention for Neurodegenerative Delay) is updated dietary approach of the Mediterranean-DASH diets. Its components are linked to dementia prevention and overall neuroprotection. It is also reported that regular physical activity maintains the brain function improving blood flow and oxygen supply.

Association of midlife stroke risk with structural brain integrity and memory performance at older ages: a longitudinal cohort study.

Cardiovascular health in midlife is an established risk factor for cognitive function later in life. Knowing mechanisms of this association may allow preventative steps to be taken to preserve brain health and cognitive performance in older age. In this study, we investigated the association of the Framingham stroke-risk score, a validated multifactorial predictor of 10-year risk of stroke, with brain measures and cognitive performance in stroke-free individuals. We used a large (N = 800) longitudinal cohort of community-dwelling adults of the Whitehall II imaging sub-study with no obvious structural brain abnormalities, who had Framingham stroke risk measured five times between 1991 and 2013 and MRI measures of structural integrity, and cognitive function performed between 2012 and 2016 [baseline mean age 47.9 (5.2) years, range 39.7–62.7 years; MRI mean age 69.81 (5.2) years, range 60.3–84.6 years; 80.6% men]. Unadjusted linear associations were assessed between the Framingham stroke-risk score in each wave and voxelwise grey matter density, fractional anisotropy and mean diffusivity at follow-up. These analyses were repeated including socio-demographic confounders as well as stroke risk in previous waves to examine the effect of residual risk acquired between waves. Finally, we used structural equation modelling to assess whether stroke risk negatively affects cognitive performance via specific brain measures. Higher unadjusted stroke risk measured at each of the five waves over 20 years prior to the MRI scan was associated with lower voxelwise grey and white matter measures. After adjusting for socio-demographic variables, higher stroke risk from 1991 to 2009 was associated with lower grey matter volume in the medial temporal lobe. Higher stroke risk from 1997 to 2013 was associated with lower fractional anisotropy along the corpus callosum. In addition, higher stroke risk from 2012 to 2013, sequentially adjusted for risk measured in 1991–94, 1997–98 and 2002–04 (i.e. ‘residual risks’ acquired from the time of these examinations onwards), was associated with widespread lower fractional anisotropy, and lower grey matter volume in sub-neocortical structures. Structural equation modelling suggested that such reductions in brain integrity were associated with cognitive impairment. These findings highlight the importance of considering cerebrovascular health in midlife as important for brain integrity and cognitive function later in life (ClinicalTrials.gov Identifier: NCT03335696).

THE ROLE OF WORK AND RETIREMENT IN COGNITIVE AND BRAIN AGING

According to the “use it or lose it” hypothesis of cognitive aging, cognitive enrichment and cognitively engaging activities are associated with the maintenance of high levels of cognitive functioning in old age. Similar ideas have been brought forward with respect to characteristics of individuals’ work environment, with more cognitively enriching work demands providing an optimal environment for cognitive development and maintenance. The goal of this research group is to showcase new developments in research on work, retirement and cognitive aging. Hülür et al. examine the role of perceived work environment for cohort differences in trajectories of cognitive change based on 56-year longitudinal data from the Seattle Longitudinal Study. Andel et al. use data from the Swedish Adoption/Twin Study of Aging to examine trajectories of cognitive aging before vs. after retirement with two-slope growth curve models. Zulka et al. conduct a systematic literature review on the association between retirement and cognition and examine the role of factors such as occupational experiences and the cognitive domain studied. Burzynska et al. investigate the relationship between stressful and stimulating occupational exposures and structural brain health and cognition in older age. The discussion by George Rebok will focus on how these findings contribute to our understanding of the role of occupational experiences for cognitive and brain aging and how they can be utilized to promote maintenance of cognitive functioning in old age.

PHYSICAL AND SOCIAL ACTIVITIES AND COGNITIVE CHANGES AMONG OLD-OLD ADULTS: RESULTS FROM 3-YEAR FOLLOW-UP PERIOD

The association between activity engagement and late-life cognitive function is considered to depend on the characteristics of the activity, the cognitive processes it involves, and the life stage of participants. A better understanding of this association is required to comprehend cognitive function in old age. The present study examined the association between baseline activity engagement and cognitive changes across a 3-year period among old-old adults. We extracted data for 873 Japanese community-dwelling participants from data of the Keio-Kawasaki Aging Study. We assessed cognitive performance thrice (at baseline, 1.5-year follow-up, and 3-year follow-up) using a short version of the Mini-Mental Status Examination. For the subsequent analyses, we used three measures of cognitive function: total score, orientation, and concentration, which showed diverse individual differences. We measured the frequency of physical activity and social group participation at baseline. Using conditional latent growth curve models, we examined which baseline activity was associated with the three measures of cognitive function over 3 years. Greater physical activity was significantly related to higher rate of orientation, after adjusting for age and education (β = −.261, p < .001). Social activity was significantly related to rates of higher total cognitive score (β = −.276, p < .001) and higher orientation (β = −.207, p < .001). These findings suggest that the association between activity engagement and late-life cognitive function among old-old adults varies by activity type and cognitive domain.

ADULT-LIFE OCCUPATIONAL EXPOSURES: ENRICHED ENVIRONMENT OR A STRESSOR FOR THE AGING BRAIN?

The positive association between midlife occupational complexity and cognitive functioning in older age is well documented. Much less is known about the underlying neural mechanisms and whether occupational stress may accelerate neurocognitive aging. According to the BOSS model (Brain aging: Occupational Stimulation and Stress), occupational exposures may serve as long-term protective and risk factors that influence the rate and extent of neurocognitive decline in aging (Burzynska, Jiao & Ganster 2018). We present findings from three independent samples linking different occupational exposures (e.g. work physical demands, innovation, autonomy, employer control) with brain volume in cognitively healthy older adults. We discuss the findings in the context of cognitive reserve and brain maintenance. Our findings suggest that occupational activities need to be acknowledged as an important factor in lifespan cognitive and brain development and warrant further research, with a possible outcome of workplace interventions aimed at optimizing neurocognitive aging.

Does community social capital buffer the relationship between educational disadvantage and cognitive impairment? A multilevel analysis in Japan

BackgroundThis study explored the relationship between community social capital and cognitive impairment, with a focus on the buffering role of community social capital in the association between educational disadvantage and cognitive impairment in community-dwelling older adults in Japan.MethodsWe used data from two population-based, cross-sectional surveys targeting people aged ≥65 years in a suburban city of the Tokyo metropolitan area (n = 897; 49.8% men; average age = 74.4 years). Social capital included social support (emotional and instrumental support) and the strength of social networks (neighborly ties). To create district-level social capital indicators, we aggregated individual responses on social capital within each district. The Mini-Mental State Examination, Japanese version was used for the assessment of cognitive function.ResultsUsing multilevel logistic regression analysis, we found that lower amounts of district-level emotional and instrumental support were associated with a greater likelihood of cognitive impairment among men. For women, district-level emotional support was associated with a greater likelihood of cognitive impairment. Additionally, a strong district-level social network buffered the relationship between low education and cognitive impairment in both sexes.ConclusionsCommunity social capital appears to have a protective role in determining cognitive function in old age. Our findings may facilitate the development of new community-based strategies to combat dementia.

An investigation into early-life stress and cognitive function in older age.

Early-life stress (ELS) has previously been identified as a risk factor for cognitive decline, but this work has predominantly focused on clinical groups and indexed traditional cognitive domains. It, therefore, remains unclear whether ELS is related to cognitive function in healthy community-dwelling older adults, as well as whether any effects of ELS also extend to social cognition. To test each of these questions, the Childhood Trauma Questionnaire (CTQ) was administered to 484 older adults along with a comprehensive neuropsychological test battery and a well-validated test of social cognitive function. The results revealed no differences in global cognition according to overall experiences of ELS. However, a closer examination into the different ELS subscales showed that global cognition was poorer in those who had experienced physical neglect (relative to those who had not). Social cognitive function did not differ according to experiences to ELS. These results indicate that the relationship between ELS and cognition in older age may be dependent on the nature of the trauma experienced.

Cognitive reserve and working memory in cognitive performance of adults with subjective cognitive complaints: longitudinal structural equation modeling.

To study the influence of cognitive reserve (CR) on cognitive performance of individuals with subjective cognitive complaints (SCCs) within a period of 36 months. We used a general linear model repeated measures procedure to analyze the differences in performance between three assessments. We used a longitudinal structural equation modeling to analyze the relationship between CR and cognitive performance at baseline and at two follow-up assessments. Participants with SCCs were recruited and assessed in primary care health centers. A total of 212 participants older than 50 years with SCCs. Cognitive reserve data were collected with an ad hoc questionnaire administered to the subjects in an interview. General cognitive performance (GCP), episodic memory (EM), and working memory (WM) have been evaluated. The Mini-Mental State Examination and the total score of Spanish version of the Cambridge Cognitive Examination evaluated the GCP. Episodic memory was assessed with the Spanish version of the California Verbal Learning. Working memory was evaluated by the counting span task and the listening span task. The satisfactory fit of the proposed model confirmed the direct effects of CR on WM and GCP at baseline, as well as indirect effects on EM and WM at first and second follow-up. Indirect effects of CR on other cognitive constructs via WM were observed over time. The proposed model is useful for measuring the influence of CR on cognitive performance over time. Cognitive response acquired throughout life may influence cognitive performance in old age and prevent cognitive deterioration, thus increasing processing resources via WM.

Associations of accelerometer-based sleep duration and self-reported sleep difficulties with cognitive function in late mid-life: the Finnish Retirement and Aging Study

ObjectivesPrior evidence suggests that sleep duration and sleep difficulties may be associated with cognitive function in old age, but little is known about the sleep–cognition association in late mid-life. Our aim was to examine the associations of accelerometer-based sleep duration as well as subjective sleep difficulties with different domains of cognitive function among aging workers. MethodsThe study population consisted of 289 participants (mean age 62.4 years, SD 1.02; 83% women) from the Finnish Retirement and Aging Study (FIREA). Sleep difficulties were measured using Jenkins Sleep Problem Scale (difficulties falling asleep, difficulties maintaining sleep, waking up too early in the morning, and nonrestorative sleep). Sleep duration was measured with wrist-worn accelerometer and self-report, and participants were divided into short (<7 h/night), mid-range (7–9 h/night) and long (≥9 h/night) sleepers. Participants underwent extensive cognitive testing covering three domains: (1) memory, (2) executive function, and (3) attention and information processing. ResultsGreater difficulties in waking up too early in the morning were associated with poorer executive function measured with Spatial Working Memory (SWM) test (p = 0.005). Additionally, nonrestorative sleep was associated with poorer executive function measured with Trail Making Test, B–A, (p = 0.036) and borderline significantly with lower SWM (p = 0.056). Compared to mid-range sleepers, long sleepers tended to have poorer cognitive function (all memory function tests and SWM), but the associations were not statistically significant due to small number of long sleepers. ConclusionsSubjective sleep difficulties may be linked to poorer executive function in a relatively healthy population of older workers in their 60 s. Thus, promoting good sleep quality may translate into better cognitive health in late mid-life.

Longitudinal associations between hearing loss and general cognitive ability: The Lothian Birth Cohort 1936.

Hearing impairment is associated with poorer cognitive function in later life. We tested for the potential contribution of childhood cognitive ability to this relationship. Childhood cognitive ability is strongly related to cognitive function in older age, and may be related to auditory function through its association with hearing impairment risk factors. Using data from the Lothian Birth Cohort, 1936, we tested whether childhood cognitive ability predicted later-life hearing ability then whether this association was mediated by demographic or health differences. We found that childhood cognitive ability was negatively associated with hearing impairment risk at age 76 (odds ratio = .834, p = .042). However, this association was nonsignificant after subsequent adjustment for potentially mediating demographic and health factors. Next, we tested whether associations observed in older age between hearing impairment and general cognitive ability level or change were accounted for by childhood cognitive ability. At age 76, in the minimally adjusted model, hearing impairment was associated with poorer general cognitive ability level (β = −.119, p = .030) but was not related to decline in general cognitive ability. The former association became nonsignificant after additional adjustment for childhood cognitive ability (β = −.068, p = .426) suggesting that childhood cognitive ability contributes (potentially via demographic and health differences) to the association between levels of hearing and cognitive function in older age. Further work is needed to test whether early life cognitive ability also contributes to the association (documented in previous studies) between older-age hearing impairment and cognitive decline.

Technology, Physical Activity, Loneliness, and Cognitive Functioning in Old Age

Abstract. Information and communication technology (ICT) has the potential to benefit aging processes. This study examined portable ICT usage and associated changes in physical activity, loneliness, and cognitive functioning. Ninety-two mostly-novice tablet-users aged 51–85 years participated in technology workshops and then reported on their portable ICT use biweekly for 6+ months. Physical activity, loneliness, and executive functioning were assessed before and after this period. More frequent use of exercise functions was associated with more moderate-intensity physical activity and less sitting, controlling for pretracking levels. More frequent use of social functions was associated with more social loneliness and a tendency toward less emotional loneliness, controlling for pretracking levels of loneliness. The use of exercise and social functions showed no associations with executive functioning. Portable ICT thus may bring both risks and benefits for physical and social functioning in older adulthood.

Repeat variations in polyglutamine disease–associated genes and cognitive function in old age

Although the heritability of cognitive function in old age is substantial, genome-wide association studies have had limited success in elucidating its genetic basis, leaving a considerable amount of “missing heritability.” Aside from single nucleotide polymorphisms, genome-wide association studies are unable to assess other large sources of genetic variation, such as tandem repeat polymorphisms. Therefore, here, we studied the association of cytosine-adenine-guanine (CAG) repeat variations in polyglutamine disease–associated genes (PDAGs) with cognitive function in older adults. In a large cohort consisting of 5786 participants, we found that the CAG repeat number in 3 PDAGs (TBP, HTT, and AR) were significantly associated with the decline in cognitive function, which together accounted for 0.49% of the variation. Furthermore, in an magnetic resonance imaging substudy, we found that CAG repeat polymorphisms in 4 PDAGs (ATXN2, CACNA1A, ATXN7, and AR) were associated with different imaging characteristics, including brain stem, putamen, globus pallidus, thalamus, and amygdala volumes. Our findings indicate that tandem repeat polymorphisms are associated with cognitive function in older adults and highlight the importance of PDAGs in elucidating its missing heritability.

Essential Amino Acids, Vitamins, and Minerals Moderate the Relationship between the Right Frontal Pole and Measures of Memory.

Nutrition has increasingly been recognized for its ability to help prevent and protect against disease, inspiring new programs of research that translate findings from nutritional science into innovative assessment tools, technologies, and therapies to advance the practice of modern medicine. A central aim in this effort is to discover specific dietary patterns that promote healthy brain aging and moderate the engagement of neural systems known to facilitate cognitive performance in later life. The present study therefore investigates estimates of nutrient intake derived from food frequency questionnaires, structural measures of brain volume via high-resolution magnetic resonance imaging, and standardized neuropsychological measures of memory performance in nondemented elders (n = 111) using a moderation analysis. The results reveal that the essential amino acids, vitamins, and minerals nutrient pattern moderates the positive relationship between the volume of the right frontal pole and measures of both delayed and auditory memory. Our findings demonstrate that a nutrient pattern including macro- and micronutrients moderate the effect of brain structure on cognitive function in old age and support the efficacy of interdisciplinary methods in nutritional cognitive neuroscience for the study of healthy brain aging.

Late-life brain perfusion after prenatal famine exposure

Early nutritional deprivation may cause irreversible damage to the brain and seems to affect cognitive function in older age. We investigated whether prenatal undernutrition was associated with brain perfusion differences in older age. We acquired Arterial spin labeling scans in 118 Dutch famine birth cohort members. Using linear regression analyses, cerebral blood flow was compared between exposed and unexposed groups in gray matter (GM) and white matter (WM), perfusion territories, the neurodegeneration-related regions anterior and posterior cingulate cortex and precuneus. Furthermore, we compared the GM/WM ratio and the spatial coefficient of variation as a proxy of overall cerebrovascular health. The WM arterial spin labeling signal and the GM/WM ratio were significantly lower and higher, respectively, among exposed participants (−2.5 mL/100 g/min [95% CI: −4.3 to −0.8; p = 0.01] and 0.48 [0.19 to 0.76; p = 0.002], respectively). Exposed men had lower cerebral blood flow in anterior and posterior cingulate cortices (−8.0 mL/100 g/min [−15.1 to −0.9; p = 0.03]; −11.4 mL/100 g/min [−19.6 to −3.2; p = 0.02]) and higher spatial coefficient of variation (0.05 [0.00 to 0.09; p = 0.05]). The latter seemed largely mediated by higher 2h-glucose levels at age 50. Our findings suggest that prenatal undernutrition affects brain perfusion parameters providing further evidence for life-long effects of undernutrition during early brain development.

Pregnancy history and cognitive aging among older women: the Rancho Bernardo Study.

The aim of the study was to examine the association of pregnancy history with trajectories of cognitive function in older women. Participants were 1,025 women (mean age = 73.1 ± 9.6 y) enrolled in the Rancho Bernardo Study who attended a clinic visit between 1988 and 1992, when pregnancy history (ever pregnant, number of pregnancies, ages at first and last pregnancy) was recorded and cognitive function was assessed with a battery of four tests repeated up to 7 times through 2016. Linear mixed-effects regression models were used to examine the association between pregnancy history and longitudinal change in cognitive function. Overall, 77% of women had at least one pregnancy; number of pregnancies ranged from 1 to 14 (mean = 2.9 ± 1.7). Ages at first and last pregnancy ranged from 16 to 44 years (mean = 24.9 ± 4.7) and 16 to 49 years (mean = 30.7 ± 5.5), respectively. Of 16 associations tested (4 pregnancy exposures by 4 cognitive tests), one was statistically significant without correction for multiple comparisons. Women who reported ever being pregnant recalled 0.12 fewer words on the Buschke Selective Reminding Test for every year increase in age than women who had never been pregnant (P = 0.05). No other significant associations of pregnancy history with cognitive decline were observed. Our results show no clinically meaningful long-term influence of pregnancy history on age-related change in cognitive function. These reassuring findings suggest childbearing decisions and timing will not affect cognitive function in older age.

Public Transportation Use and Cognitive Function in Older Age: A Quasiexperimental Evaluation of the Free Bus Pass Policy in the United Kingdom.

In this quasiexperimental study, we examined whether the introduction of an age-friendly transportation policy-free bus passes for older adults-increased public transport use and in turn affected cognitive function among older people in England. Data came from 7 waves (2002-2014) of the English Longitudinal Study of Ageing (n = 17,953), which measured total cognitive function, memory, executive function, and processing speed before and after the bus pass was introduced in 2006. The analytical strategy was an instrumental-variable approach with fixed effects, which made use of the age-eligibility criteria for free bus passes and addressed bias due to reverse causality, measurement error, and time-invariant confounding. Eligibility for the bus pass was associated with a 7% increase in public transport use. The increase in public transportation use was associated with a 0.346 (95% confidence interval: 0.017, 0.674) increase in the total cognitive function z score and with a 0.546 (95% confidence interval: 0.111, 0.982) increase in memory z score. Free bus passes were associated with an increase in public transport use and, in turn, benefits to cognitive function in older age. Public transport use might promote cognitive health through encouraging intellectually, socially, and physically active lifestyles. Transport policies could serve as public health tools to promote cognitive health in aging populations.