The dynamic relationship between cognitive function and walking speed: the English Longitudinal Study of Ageing

Discrete Relationships between Spatiotemporal Gait Characteristics and Domain-Specific Neuropsychological Performance in Midlife

Midlife risk factors such as type 2 diabetes mellitus (T2DM) confer a significantly increased risk of cognitive impairment in later life with executive function, memory, and attention domains often affected first. Spatiotemporal gait characteristics are emerging as important integrative biomarkers of neurocognitive function and of later dementia risk. We examined 24 spatiotemporal gait parameters across five domains of gait previously linked to cognitive function on usual-pace, maximal-pace, and cognitive dual-task gait conditions in 102 middle-aged adults with (57.5 ± 8.0 years; 40% female) and without (57.0 ± 8.3 years; 62.1% female) T2DM. Neurocognitive function was measured using a neuropsychological assessment battery. T2DM was associated with significant changes in gait phases and rhythm domains at usual pace, and greater gait variability observed during maximal pace and dual tasks. In the overall cohort, both the gait pace and rhythm domains were associated with memory and executive function during usual pace. At maximal pace, gait pace parameters were associated with reaction time and delayed memory. During the cognitive dual task, associations between gait variability and both delayed memory/executive function were observed. Associations persisted following covariate adjustment and did not differ by T2DM status. Principal components analysis identified a consistent association of slower gait pace (step/stride length) and increased gait variability during maximal-pace walking with poorer memory and executive function performance. These data support the use of spatiotemporal gait as an integrative biomarker of neurocognitive function in otherwise healthy middle-aged individuals and reveal discrete associations between both differing gait tasks and gait domains with domain-specific neuropsychological performance. Employing both maximal-pace and dual-task paradigms may be important in cognitively unimpaired populations with risk factors for later cognitive decline-with the aim of identifying individuals who may benefit from potential preventative interventions.

The time course of motor and cognitive decline in older adults and their associations with brain pathologies: a multicohort study

BACKGROUND

Many studies have reported that impaired gait precedes cognitive impairment in older people. We aimed to characterise the time course of cognitive and motor decline in older individuals and the association of these declines with the pathologies of Alzheimer's disease and related dementias.

METHODS

This multicohort study used data from three community-based cohort studies (Religious Orders Study, Rush Memory and Aging Project, and Minority Aging Research Study, all in the USA). The inclusion criteria for all three cohorts were no clinical dementia at the time of enrolment and consent to annual clinical assessments. Eligible participants consented to post-mortem brain donation and had post-mortem pathological assessments and three or more repeated annual measures of cognition and motor functions. Clinical and post-mortem data were analysed using functional mixed-effects models. Global cognition was based on 19 neuropsychological tests, a hand strength score was based on grip and pinch strength, and a gait score was based on the number of steps and time to walk 8 feet and turn 360°. Brain pathologies of Alzheimer's disease and related dementias were assessed at autopsy.

FINDINGS

From 1994 to 2022, there were 1570 eligible cohort participants aged 65 years or older, 1303 of whom had cognitive and motor measurements and were included in the analysis. Mean age at death was 90·3 years (SD 6·3), 905 (69%) participants were female, and 398 (31%) were male. Median follow-up time was 9 years (IQR 5-11). On average, cognition was stable from 25 to 15 years before death, when cognition began to decline. By contrast, gait function and hand strength declined during the entire study. The combinations of pathologies of Alzheimer's disease and related dementias associated with cognitive and motor decline and their onsets of associations varied; only tau tangles, Parkinson's disease pathology, and macroinfarcts were associated with decline of all three phenotypes. Tau tangles were significantly associated with cognitive decline, gait function decline, and hand function decline (p<0·0001 for each); however, the association with cognitive decline persisted for more than 11 years before death, but the association with hand strength only began 3·57 years before death and the association with gait began 3·49 years before death. By contrast, the association of macroinfarcts with declining gait function began 9·25 years before death (p<0·0001) compared with 6·65 years before death (p=0·0005) for cognitive decline and 2·66 years before death (p=0·024) for decline in hand strength.

INTERPRETATION

Our findings suggest that average motor decline in older adults precedes cognitive decline. Macroinfarcts but not tau tangles are associated with declining gait function that precedes cognitive decline. This suggests the need for further studies to test if gait impairment is a clinical proxy for preclinical vascular cognitive impairment.

FUNDING

National Institutes of Health.

Visuospatial cognition predicts performance on an obstructed vision obstacle walking task in older adults

Walking performance and cognitive function demonstrate strong associations in older adults, with both declining with advancing age. Walking requires the use of cognitive resources, particularly in complex environments like stepping over obstacles. A commonly implemented approach for measuring the cognitive control of walking is a dual-task walking assessment, in which walking is combined with a second task. However, dual-task assessments have shortcomings, including issues with scaling the task difficulty and controlling for task prioritization. Here we present a new assessment designed to be less susceptible to these shortcomings while still challenging cognitive control of walking: the Obstructed Vision Obstacle (OBVIO) task. During the task, participants hold a lightweight tray at waist level obstructing their view of upcoming foam blocks, which are intermittently spaced along a 10 m walkway. This forces the participants to use cognitive resources (e.g., attention and working memory) to remember the exact placement of upcoming obstacles to facilitate successful crossing. The results demonstrate that adding the obstructed vision board significantly slowed walking speed by an average of 0.26 m/s and increased the number of obstacle strikes by 8-fold in healthy older adults (n = 74). Additionally, OBVIO walking performance (a score based on both speed and number of obstacle strikes) significantly correlated with computer-based assessments of visuospatial working memory, attention, and verbal working memory. These results provide initial support that the OBVIO task is a feasible walking test that demands cognitive resources. This study lays the groundwork for using the OBVIO task in future assessment and intervention studies.

A new nomogram model for the individualized prediction of mild cognitive impairment in elderly patients with type 2 diabetes mellitus

Background

A high risk of developing mild cognitive impairment (MCI) is faced by elderly patients with type 2 diabetes mellitus (T2DM). In this study, independent risk factors for MCI in elderly patients with T2DM were investigated, and an individualized nomogram model was developed.

Methods

In this study, clinical data of elderly patients with T2DM admitted to the endocrine ward of the hospital from November 2021 to March 2023 were collected to evaluate cognitive function using the Montreal Cognitive Assessment scale. To screen the independent risk factors for MCI in elderly patients with T2DM, a logistic multifactorial regression model was employed. In addition, a nomogram to detect MCI was developed based on the findings of logistic multifactorial regression analysis. Furthermore, the accuracy of the prediction model was evaluated using calibration and receiver operating characteristic curves. Finally, decision curve analysis was used to evaluate the clinical utility of the nomogram.

Results

In this study, 306 patients were included. Among them, 186 patients were identified as having MCI. The results of multivariate logistic regression analysis demonstrated that educational level, duration of diabetes, depression, glycated hemoglobin, walking speed, and sedentary duration were independently correlated with MCI, and correlation analyses showed which influencing factors were significantly correlated with cognitive function (p <0.05). The nomogram based on these factors had an area under the curve of 0.893 (95%CI:0.856-0.930)(p <0.05), and the sensitivity and specificity were 0.785 and 0.850, respectively. An adequate fit of the nomogram in the predictive value was demonstrated by the calibration plot.

Conclusions

The nomogram developed in this study exhibits high accuracy in predicting the occurrence of cognitive dysfunction in elderly patients with T2DM, thereby offering a clinical basis for detecting MCI in patients with T2DM.

Biological and Physical Performance Markers for Early Detection of Cognitive Impairment in Older Adults

Dementia is a major cause of poor quality of life, disability, and mortality in old age. According to the geroscience paradigm, the mechanisms that drive the aging process are also involved in the pathogenesis of chronic degenerative diseases, including dementia. The dissection of such mechanisms is therefore instrumental in providing biological targets for interventions and new sources for biomarkers. Within the geroscience paradigm, several biomarkers have been discovered that can be measured in blood and that allow early identification of individuals at risk of cognitive impairment. Examples of such markers include inflammatory biomolecules, markers of neuroaxonal damage, extracellular vesicles, and DNA methylation. Furthermore, gait speed, measured at a usual and fast pace and as part of a dual task, has been shown to detect individuals at risk of future dementia. Here, we provide an overview of available biomarkers that may be used to gauge the risk of cognitive impairment in apparently healthy older adults. Further research should establish which combination of biomarkers possesses the highest predictive accuracy toward incident dementia. The implementation of currently available markers may allow the identification of a large share of at-risk individuals in whom preventive interventions should be implemented to maintain or increase cognitive reserves, thereby reducing the risk of progression to dementia.

Prognostic relevance of gait-related cognitive functions for dementia conversion in amnestic mild cognitive impairment

BACKGROUND

Increasing research suggests that gait abnormalities can be a risk factor for Alzheimer's Disease (AD). Notably, there is growing evidence highlighting this risk factor in individuals with amnestic Mild Cognitive Impairment (aMCI), however further studies are needed. The aim of this study is to analyze cognitive tests results and brain-related measures over time in aMCI and examine how the presence of gait abnormalities (neurological or orthopedic) or normal gait affects these trends. Additionally, we sought to assess the significance of gait and gait-related measures as prognostic indicators for the progression from aMCI to AD dementia, comparing those who converted to AD with those who remained with a stable aMCI diagnosis during the follow-up.

METHODS

Four hundred two individuals with aMCI from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database were included. Robust linear mixed-effects models were used to study the impact of gait abnormalities on a comprehensive neuropsychological battery over 36 months while controlling for relevant medical variables at baseline. The impact of gait on brain measures was also investigated. Lastly, the Cox proportional-hazards model was used to explore the prognostic relevance of abnormal gait and neuropsychological associated tests.

RESULTS

While controlling for relevant covariates, we found that gait abnormalities led to a greater decline over time in attention (DSST) and global cognition (MMSE). Intriguingly, psychomotor speed (TMT-A) and divided attention (TMT-B) declined uniquely in the abnormal gait group. Conversely, specific AD global cognition tests (ADAS-13) and auditory-verbal memory (RAVLT immediate recall) declined over time independently of gait profile. All the other cognitive tests were not significantly affected by time or by gait profile. In addition, we found that ventricles size increased faster in the abnormal gait group compared to the normal gait group. In terms of prognosis, abnormal gait (HR = 1.7), MMSE (HR = 1.09), and DSST (HR = 1.03) covariates showed a higher impact on AD dementia conversion.

CONCLUSIONS

The importance of the link between gait and related cognitive functions in terms of diagnosis, prognosis, and rehabilitation in aMCI is critical. We showed that in aMCI gait abnormalities lead to executive functions/attention deterioration and conversion to AD dementia.

Comorbid pain and falls among Chinese older adults: the association, healthcare utilization and the role of subjective and objective physical functioning

BACKGROUND

Pain and falls are significant disabling health conditions which cause substantial economic burdens on older adults and their families. Physical functioning (both subjective and objective) might play a significant role in older adults' pain and falls. In this study we aimed to examine: (1) the relationship between pain and falls among Chinese older adults; (2) pain-fall status (i.e., comorbid pain-fall, pain-only, fall-only, and neither-pain-nor-fall) in relation to healthcare utilization; and (3) whether physical functioning measured either subjectively or objectively would contribute differently to the pain intensity and to the occurrence of falls.

METHODS

We used a nationally-representative sample of older adults from the 2011-2012 baseline survey of the China Health and Retirement Longitudinal Study (N = 4,461, aged 60-95 years). Logistic, linear, and negative binomial models adjusted for demographic variables were used in the analysis.

RESULTS

Overall, 36% of older adults reported pain, 20% had fall occurrences, and 11% had comorbid pain and falls. Pain intensity was significantly associated with falls. Individuals in groups of pain-only, fall-only, and comorbid pain-fall reported significantly higher healthcare utilization, that is, more frequent inpatient care and doctor visits than those in the neither-pain-nor-fall group. Subjective, not objective, physical functioning was associated with pain and falls.

CONCLUSION

Pain and falls are significantly associated with each other, and both can lead to increased healthcare utilization. Compared to objective physical functioning, subjective physical functioning is more likely to correlate with pain and falls, suggesting that self-reported physical status should be considered when designing pain-fall preventive strategies.

The Bidirectional Association Between Cognitive Function and Gait Speed in Chinese Older Adults: Longitudinal Observational Study

BACKGROUND

Cognitive and gait speed decline are common conditions in older adults and are often associated with future adverse consequences. Although an association between cognitive function and gait speed has been demonstrated, its temporal sequence remains unclear, especially in older Chinese adults. Clarifying this could help identify interventions to improve public health in older adults.

OBJECTIVE

This study aims to examine the longitudinal reciprocal association between gait speed and cognitive function and the possible temporal sequence of changes in both factors in a national longitudinal cohort.

METHODS

Data were derived from 2 waves (2011 baseline and 2015 follow-up) of the China Health and Retirement Longitudinal Study (CHARLS). Participants 60 years or older, without dementia or Parkinson disease at baseline, and with completed data on gait speed and cognition at both baseline and follow-up were included. Usual gait speed was measured over two 2.5-m walks. Mental intactness and episodic memory were used to assess global cognitive function. Cross-lagged panel models and linear mixed-effects models were used to examine the association between cognition and gait speed over time. Standardized coefficients were reported.

RESULTS

A total of 3009 participants (mean age 66.4 years, SD 5.4 years; 1422/3009, 47.26%, female participants) were eligible for inclusion in our analyses. Cross-lagged panel analyses revealed that after accounting for baseline gait speed, cognition, and potential confounders, baseline global cognition (β=.117, 95% CI 0.082-0.152; P<.001), mental intactness (β=.082, 95% CI 0.047-0.118; P<.001), and episodic memory (β=.102, 95% CI 0.067-0.137; P<.001) were associated with subsequent gait speed. Simultaneously, baseline gait speed was also associated with subsequent global cognition (β=.056, 95% CI 0.024-0.087; P=.001), mental intactness (β=.039, 95% CI 0.008-0.069; P=.01), and episodic memory (β=.057, 95% CI 0.023-0.092; P=.001). The comparison of standardized cross-lagged coefficients suggested that the effect size of baseline global cognition on subsequent gait speed was significantly larger than the reverse effect (χ₁²=6.50, P for difference=.01). However, the effects of both mental intactness and episodic memory on subsequent gait speed were not significantly stronger than those of the reverse pathway (χ₁²=3.33, P for difference=.07 and χ₁²=3.21, P for difference=.07). Linear mixed-effects analyses further supported these bidirectional relationships, revealing that lower baseline cognitive scores predicted steeper declines in gait speed trajectory, and slower baseline gait speed predicted more declines in cognitive trajectory over time.

CONCLUSIONS

There is a longitudinal bidirectional association between usual gait speed and both global cognitive function and specific domains of mental intactness and episodic memory among Chinese older adults. Baseline global cognition is likely to have a stronger association with subsequent gait speed than the reverse pathway. This interlinkage is noteworthy and may have implications for public health. Maintaining normal cognitive function may be an important interventional strategy for mitigating age-related gait speed reduction.

Gait in cerebral small vessel disease, pre-dementia, and dementia: A systematic review

BACKGROUND

The interrelationships between gait, cerebral small vessel disease (CSVD), and cognitive impairments in aging are not well-understood-despite their common co-occurrence.

OBJECTIVE

To systematically review studies of gait impairment in CSVD, pre-dementia, and dementia, and to identify key gaps for future research and novel pathways toward intervention.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided search strategy was implemented in PubMed to identify relevant studies. Potential articles (n = 263) published prior to 1 December 2021 were screened by two reviewers. Studies with sample sizes >20 and including some adults over > 65 years (n = 202) were included.

RESULTS

The key findings were that (1) adverse gait and cognitive outcomes were associated with several (rather than select) CSVD pathologies distributed across the brain, and (2) poor gait and CSVD pathologies were more strongly associated with dementia with a vascular, rather than an Alzheimer's disease-related, cause.

DISCUSSION

A better understanding of the interrelationships between gait performance in CSVD, pre-dementia, and dementia requires studies examining (1) comprehensive patterns in the clinical manifestations of CSVD, (2) racially/ethnically diverse samples, (3) samples followed for extended periods of time or across the adult life span, (4) non-traditional CSVD neuroimaging markers (e.g. resting-state functional magnetic resonance imaging (fMRI)), and (5) continuous (e.g. wearable sensors) and complex (e.g. dual-task) walking performance.

Grip Strength Trajectories and Cognition in English and Chilean Older Adults: A Cross-Cohort Study

Growing evidence about the link between cognitive and physical decline suggests the early changes in physical functioning as a potential biomarker for cognitive impairment. Thus, we compared grip-strength trajectories over 12-16 years in three groups classified according to their cognitive status (two stable patterns, normal and impaired cognitive performance, and a declining pattern) in two representative UK and Chilean older adult samples. The samples consisted of 7069 UK (ELSA) and 1363 Chilean participants (ALEXANDROS). Linear Mixed models were performed. Adjustments included socio-demographics and health variables. The Declined and Impaired group had significantly lower grip-strength at baseline when compared to the Non-Impaired. In ELSA, the Declined and Impaired showed a faster decline in their grip strength compared to the Non-Impaired group but differences disappeared in the fully adjusted models. In ALEXANDROS, the differences were only found between the Declined and Non-Impaired and they were partially attenuated by covariates. Our study provides robust evidence of the association between grip strength and cognitive performance and how socio-economic factors might be key to understanding this association and their variability across countries. This has implications for future epidemiological research, as hand-grip strength measurements have the potential to be used as an indicator of cognitive performance.

Relative Trajectories of Gait and Cognitive Decline in Aging

BACKGROUND

Gait and cognition decline with advancing age, and presage the onset of dementia. Yet, the relative trajectories of gait and cognitive decline in aging are poorly understood-particularly among those with the motoric cognitive risk (MCR) syndrome. This study compared changes in simple and complex gait performance and cognition, as a function of age and MCR.

METHODS

We examined gait and cognitive functions of 1 095 LonGenity study participants (mean age = 75.4 ± 6.7 years) with up to 12 years of annual follow-up. Participants were of Ashkenazi Jewish descent, free of dementia, ambulatory, and had a 12.2% MCR prevalence at baseline. Gait speed was measured at usual pace walking (single-task walking, STW-speed) and walking while talking (WWT-speed). Eleven neuropsychological test scores were examined separately, and as a global cognition composite. Linear mixed-effects models adjusted for baseline sex, education, parental longevity, cognitive impairment, and global health were used to estimate changes in gait and cognition, as a function of age and MCR.

RESULTS

STW-speed, WWT-speed, and cognitive tests performance declined in a nonlinear (accelerating) fashion with age. STW-speed declined faster than WWT-speed and cognitive test scores. People with MCR showed faster rates of decline on figure copy and phonemic fluency.

CONCLUSIONS

Gait declines at a faster rate than cognition in aging. People with MCR are susceptible to faster decline in visuospatial, executive, and language functions. This study adds important knowledge of trajectories of gait and cognitive decline in aging, and identifies MCR as a risk factor for accelerated cognitive decline.

Effects of Intermittent Hypoxia-Hyperoxia Exposure Prior to Aerobic Cycling Exercise on Physical and Cognitive Performance in Geriatric Patients—A Randomized Controlled Trial

Background: It was recently shown that intermittent hypoxic-hyperoxic exposure (IHHE) applied prior to a multimodal training program promoted additional improvements in cognitive and physical performance in geriatric patients compared to physical training only. However, there is a gap in the literature to which extent the addition of IHHE can enhance the effects of an aerobic training. Therefore, the aim of this study was to investigate the efficacy of IHHE applied prior to aerobic cycling exercise on cognitive and physical performance in geriatric patients.

Methods: In a randomized, two-armed, controlled, and single-blinded trial, 25 geriatric patients (77–94 years) were assigned to two groups: intervention group (IG) and sham control group (CG). Both groups completed 6 weeks of aerobic training using a motorized cycle ergometer, three times a week for 20 min per day. The IG was additionally exposed to intermittent hypoxic and hyperoxic periods for 30 min prior to exercise. The CG followed the similar procedure breathing sham hypoxia and hyperoxia (i.e., normoxia). Within 1 week before and after the interventions, cognitive performance was assessed with the Dementia-Detection Test (DemTect) and the Clock Drawing Test (CDT), while physical performance was measured using the Timed “Up and Go” Test (TUG) and the Short-Physical-Performance-Battery (SPPB).

Results: No interaction effect was found with respect to the DemTect (η_p² = 0.02). An interaction effect with medium effect size (η_p² = 0.08) was found for CDT performance with a higher change over time for IG (d = 0.57) compared to CG (d = 0.05). The ANCOVA with baseline-adjustment indicated between-group differences with a large and medium effect size at post-test for the TUG (η_p² = 0.29) and SPPB (η_p² = 0.06) performance, respectively, in favour of the IG. Within-group post-hoc analysis showed that the TUG performance was worsened in the CG (d = 0.65) and remained unchanged in the IG (d = 0.19). Furthermore, SPPB performance was increased (d = 0.58) in IG, but no relevant change over time was found for CG (d = 0.00).

Conclusion: The current study suggests that an additional IHHE prior to aerobic cycling exercise seems to be more effective to increase global cognitive functions as well as physical performance and to preserve functional mobility in geriatric patients in comparison to aerobic exercise alone after a 6-week intervention period.

Correlation between changes in Timed Up and Go performance and cognition in older people with mild cognitive impairment: A longitudinal study

BACKGROUND

Compare changes in performance on subtasks of the Timed Up and Go test over 32 months in older adults with and without mild cognitive impairment; analyze the correlation between frontal cognitive functions at baseline and changes in Timed Up and Go subtasks over time.

METHODS

A longitudinal study was conducted involving 31 older adults (15 with and 16 without cognitive impairment). Functional mobility was assessed at both evaluations using an adapted version of the Timed Up and Go test and the Qualisys motion system. The test was divided into five subtasks: sit-to-stand, walking forward, turn-to-walk, walking back and turn-to-sit. Cognition was assessed at baseline using the Frontal Assessment Battery and the Clock Drawing Test.

FINDINGS

Significant differences in changes in the sit-to-stand subtask over time were found between groups. The difference in the time required to conclude this subtask was greater in the older adults with cognitive impairment. However, the difference in kinematic variables (peak trunk speed and range of motion) was greater in the group without cognitive impairment. Strong and moderate correlations were found between frontal cognitive functions and changes in Timed Up and Go subtasks, especially those involving transitions (sit-to-stand, turn-to-walk and turn-to-sit) in both groups.

INTERPRETATION

Motor intervention protocols should incorporate the sit-to-stand subtask in older adults with mild cognitive impairment. Moreover, changes in more complex subtasks seem to be related to frontal cognitive performance at baseline. Therefore, treatments that combine motor and cognitive functions should be administered to older adults regardless of cognitive impairment.

Components of gait in people with and without mild cognitive impairment

BACKGROUND

Several objective gait parameters are associated with cognitive impairment, but there is limited knowledge of gait models in people with mild cognitive impairment (MCI).

RESEARCH QUESTION

How can 18 objective gait characteristics be used to define different components of gait in people with MCI (with suspected incipient neurocognitive disorder) and cognitively unimpaired people (CU), respectively?

METHODS

Spatiotemporal gait data were collected by using an electronic walkway (GAITRite®), i.e. assessments in comfortable gait speed. Using cross-sectional gait data, two principal component analyses (PCA) were performed (varimax rotation) to define different components of gait in people with MCI (n = 114) and CU (n = 219), respectively, from the BioFINDER-2 study.

RESULTS

Both PCAs produced four components, here called Variability, Pace/Stability, Rhythm and Asymmetry. Total variance explained was 81.0% (MCI) versus 80.3% (CU). The Variability component explained the largest amount of variance (about 25%) in both groups. The highest loading gait parameter was the same for both groups in three out of four components, i.e. step velocity variability (Variability), mean step length (Pace/Stability) and mean step time (Rhythm). In the asymmetry component, stance time asymmetry (MCI) and swing time asymmetry (CU) loaded the highest.

SIGNIFICANCE

The gait components seem similar in people with and without MCI, although there were some differences. This study may aid the identification of gait variables that represent different components of gait. Gait parameters such as step velocity variability, mean step length, mean step time as well as swing and stance time asymmetry could serve as interesting core variables of different gait components in future research in people with MCI (with suspected incipient neurocognitive disorder) and CU. However, the selection of gait variables depends on the purpose. It needs to be noted that assessment of variability measures requires more advanced technology than is usually used in the clinic.

Association among cognitive function, physical fitness, and health status in older women

This study examined the association among cognitive function, physical fitness, and health status in healthy older women. Ninety-four females aged from 62 to 86 years (72.66±5.38 years) from community healthcare centers and an exercise club in Seoul, South Korea. Cognitive function was assessed using the Seoul Neuropsychological Screening Battery. Physical performance comprised cardiorespiratory endurance, lower extremity strength, active balance ability, and walking speed. Health status included blood pressure and waist circumference. Multiple linear regression analyses were performed to determine the relationship among cognitive function, fitness components, and health status, with age and educational attainment as covariates. In the unadjusted model, attention was significantly associated with cardiovascular endurance (B=0.19, P<0.05). Memory was significantly associated with lower limb strength (B=0.77, P<0.05) and active balance ability (B=2.35, P<0.05). In the adjusted model, attention was significantly associated with cardiovascular endurance (B=0.15, P<0.05). Memory was significantly associated with lower limb strength (B=0.87, P<0.05). In both models, cognitive function was not significantly associated with any health status variable. Though limited by a relatively small sample of female participants, who were healthy registrants of a community exercise program with normal cognitive function, the current study demonstrates that cognitive function is significantly associated with physical fitness, but not with health status, in healthy older women.

Associations Between Midlife Functional Limitations and Self-Reported Health and Cognitive Status: Results from the 1998-2016 Health and Retirement Study

BACKGROUND

Life-course approaches to identify and help improve modifiable risk factors, particularly in midlife, may mitigate cognitive aging.

OBJECTIVE

We examined how midlife self-rated physical functioning and health may predict cognitive health in older age.

METHODS

We used data from the Health and Retirement Study (1998-2016; unweighted-N = 4,685). We used survey multinomial logistic regression and latent growth curve models to examine how midlife (age 50-64 years) activities of daily living (ADL), physical function, and self-reported health affect cognitive trajectories and cognitive impairment not dementia (CIND) and dementia status 18 years later. Then, we tested for sex and racial/ethnic modifications.

RESULTS

After covariates-adjustment, worse instrumental ADL (IADL) functioning, mobility, and self-reported health were associated with both CIND and dementia. Hispanics were more likely to meet criteria for dementia than non-Hispanic Whites given increasing IADL impairment.

CONCLUSION

Midlife health, activities limitations, and difficulties with mobility are predictive of dementia in later life. Hispanics may be more susceptible to dementia in the presence of midlife IADLs. Assessing midlife physical function and general health with brief questionnaires may be useful for predicting cognitive impairment and dementia in later life.

Exploring bi-directional temporal associations between timed-up-and-go and cognitive domains in the Irish longitudinal study on ageing (TILDA)

INTRODUCTION

The bi-directional longitudinal associations between mobility and cognition in older adults are poorly understood. Our objective was to study the temporal associations between timed-up-and-go (TUG) and five cognitive function domains: global cognition, processing speed, verbal fluency, executive function, and sustained attention.

METHODS

We designed two longitudinal samples: A (for cognition as predictor of mobility), and B (for mobility as predictor of cognition). To examine the associations between the five cognitive domains at wave 1 and change in TUG times up to wave 5 (eight years), five linear mixed-effect models were fitted. To examine the associations between TUG times at wave 1 and change in the five cognitive domains between waves 1 and 3 (four years), five linear-regression models were fitted.

RESULTS

After removing participants with missing data, sample A numbered 4913 participants (mean age 62), and sample B 3675 (mean age 61). Baseline cognitive domains were all significant predictors of future change in TUG times. Baseline TUG time was also a significant predictor of future change in all five cognitive domains. In both cases, poorer performance at baseline predicted greater future loss of function.

CONCLUSION

There was evidence of bi-directional temporal relationships between cognition and mobility. In both directions, the effect of the explanatory variable was small, though cognition as predictor of future mobility may have greater clinical relevance than vice versa. Our findings underscore the importance for clinicians of considering the bi-directional associations between cognition and mobility when observing subtle changes in either, especially as impairments emerge.

Subjective age and multiple cognitive domains in two longitudinal samples

OBJECTIVE

Subjective age is consistently related to memory performance and global cognitive function among older adults. The present study examines whether subjective age is prospectively related to specific domains of cognitive function.

METHOD

Participants were drawn from the Health and Retirement Study (HRS, N = 2549, Mean Age = 69.66, SD = 7.36) and the Midlife in the United States Survey (MIDUS, N = 2499, Mean Age = 46.24, SD = 11.25). In both samples, subjective age, depressive symptoms, chronic conditions, and demographic factors were assessed at baseline. Four domains of cognition were assessed 8 years later in the HRS and almost 20 years later in the MIDUS: episodic memory, speed-attention-executive, verbal fluency, and numeric reasoning. HRS also assessed visuospatial ability.

RESULTS

Regression analysis revealed that an older subjective age was related to worse performance in the domains of episodic memory and speed-attention-executive in both samples. The effect size for the difference between a younger and an older subjective age was d = 0.14 (MIDUS) and d = 0.24 (HRS) for episodic memory and d = 0.25 (MIDUS) and d = 0.33 (HRS) for speed-attention-executive. Feeling older was related to lower verbal fluency in HRS (d = 0.30) but not in MIDUS, whereas no association was found with numeric reasoning in either sample. An older subjective age was related to lower visuospatial ability in HRS (d = 0.25).

CONCLUSION

Subjective age is prospectively related to performance in different cognitive domains. The associations between subjective age and both episodic memory and speed-attention-executive functions were replicable and robust over up to 20 years of follow-up.

Trajectories of Cognitive and Motor Function Between Ages 45 and 90 Years: A Population-Based Study

Background

To establish trajectories of cognitive and motor function, and to determine the sequence of change across individual tests in community-dwelling individuals aged 45–90 years.

Method

Between 1997 and 2016, we repeatedly assessed cognitive function with 5 tests in 9514 participants aged 45–90 years from the population-based Rotterdam Study. Between 1999 and 2016, we measured motor function with 3 tests in 8297 participants. All participants were free from dementia, stroke, and parkinsonism. We assessed overall and education-specific cognitive and motor trajectories using linear mixed models with age as time scale. Next, we determined the sequence of change across individual tests.

Results

The number of assessments per participant ranged between 1 and 6 (mean interval, years [SD]: 5.1 [1.4]) for cognitive function, and 1 and 4 (5.4 [1.4]) for motor function. Cognitive and motor trajectories declined linearly between ages 45 and 65 years, followed by steeper declines after ages 65–70 years. Lower educated participants had lower cognitive function at age 45 years (baseline), and declined faster on most cognitive, but not on motor tests than higher educated participants. Up to a 25-year age difference between the fastest and slowest declining test scores was observed.

Conclusions

On a population-level, cognitive and motor function decline similarly. Compared to higher educated individuals, lower educated individuals had lower cognitive function at baseline, and a faster rate of decline thereafter. These educational-effects were not seen for motor function. These findings benefit the understanding of the natural course of cognitive and motor function during aging, and highlight the role of education in the preservation of cognitive but not motor function.

Determinants of Processing Speed Trajectories among Middle Aged or Older Adults, and Their Association with Chronic Illnesses: The English Longitudinal Study of Aging

The aim of this study was to identify latent groups of similar trajectories in processing speed through aging, as well as factors that are associated with these trajectories. In the context of the Ageing Trajectories of Health: Longitudinal Opportunities and Synergies (ATHLOS) project, data from the English Longitudinal Study of Aging (ELSA) (n = 12099) were analyzed. Latent groups of similar trajectories in the processing scores as well as their predictors and covariates were investigated, using group-based trajectory models (GBTM). The coefficient estimates for potential group predictors correspond to parameters of multinomial logit functions that are integrated in the model. Potential predictors included sex, level of education, marital status, level of household wealth, level of physical activity, and history of smoking, while time-varying covariates included incidence of cardiovascular disease (CVD), diabetes mellitus, depressive symptoms, and sleep disturbances. Four trajectories were identified and named after their baseline scores and shapes: High (4.4%), Middle/Stable (31.5%), Low/Stable (44.5%), and Low Decline (19.6%). Female sex, higher levels of education, mild level of physical activity, having been married, and higher level of wealth were associated with a higher probability of belonging to any of the higher groups compared to the Low/Decline that was set as reference, while presence of CVD, diabetes mellitus, and depressive symptoms were associated with lower processing speed scores within most trajectories. All the aforementioned factors might be valid targets for interventions to reduce the burden of age-related cognitive impairment.

Joint trajectories of cognition and gait speed in Mexican American and European American older adults: The San Antonio longitudinal study of aging

OBJECTIVES

Cognitive decline and gait speed slowing are independent predictors of disability and mortality. While both factors increase in prevalence with advancing age, little is known about their combined patterns of change. The study goal was to identify joint trajectories of cognition and gait speed within an aging bi-ethnic cohort of Mexican Americans and European Americans.

METHODS/DESIGN

Participants included 182 Mexican Americans and 188 European Americans, ages 65 to 74, who were followed over a mean of 9.5 years. Cognition was assessed with the mini-mental state examination and gait speed was examined with a timed 10-ft walk. Joint trajectory classes of cognition and gait speed were identified with latent growth mixture modeling. Odd-ratios assessed predictors for trajectory classes.

RESULTS

Three latent trajectory classes were identified: (a) relatively stable cognition and gait (termed stable cognition and gait class, 65.4%); (b) deteriorating cognition and gait (termed cognitive and physical vulnerability class, 22.2%); (c) stable cognition and deteriorating gait (termed physical vulnerability class, 12.4%). The odds of classification in the cognitive and physical vulnerability class vs stable cognition and gait class was associated with Mexican American ethnicity (OR = 3.771, P = .016), age (OR = 1.186, P = .017), income (OR = 0.828, P = .029), education (OR = 0.703, P < .001), and diabetes (OR = 4.547, P = .010). The odds of classification in the physical vulnerability class was associated with female sex (OR = 6.481, P = .004) and body mass index (OR = 1.118, P = .025).

CONCLUSIONS

The trajectories of cognition and gait speed were generally parallel, suggesting the two domains may act synergistically to shape important health outcomes. Socioeconomic disparities and Mexican American ethnicity independently conferred risk for accelerated decline.

The Bidirectional Association Between Physical and Cognitive Function Among Chinese Older Adults: A Mediation Analysis

This study investigated the bidirectional association between physical and cognitive function in later life and examined the mechanisms underlying the interrelationship. We employed cross-lagged panel models to analyze a sample of 4232 unique participants aged 65 years and older from three waves of the Chinese Longitudinal Healthy Longevity Survey. Physical activity and social participation were tested as potential mediators between physical and cognitive function. Our findings revealed a reciprocal relationship between physical and cognitive function and a reciprocal relationship between physical and cognitive decline. Moreover, physical activity was confirmed to mediate the bidirectional association between physical and cognitive function, whereas social participation did not seem to be a mediator. A vicious cycle linking physical and cognitive decline may exist in Chinese older adults. However, leading a physically active lifestyle could be an effective intervention to slow physical and cognitive aging, thereby toning down the vicious cycle.

Muscle strength and gait speed rather than lean mass are better indicators for poor cognitive function in older men

We aimed to examine muscle strength, function and mass in relation to cognition in older men. This cross-sectional data-set included 292 men aged ≥60 yr. Handgrip strength (kg) was measured by dynamometry, gait speed by 4-metre walk (m/s) and appendicular lean mass (kg) by dual-energy x-ray absorptiometry. Cognition was assessed across four domains: psychomotor function, attention, visual learning and working memory. Composite scores for overall cognition were calculated. Bivariate analyses indicated that handgrip strength and gait speed were positively associated with cognitive function. After accounting for confounders, positive associations between individual muscle (or physical) measures and cognitive performance were sustained for handgrip strength and psychomotor function, gait speed and psychomotor function, gait speed and attention, handgrip strength and overall cognition, and gait speed and overall cognition. In multivariable models, handgrip strength and gait speed independently predicted psychomotor function and overall cognition. No associations were detected between lean mass and cognition after adjusting for confounders. Thus, low muscle strength and slower gait speed, rather than low lean mass, were associated with poor cognition in older men.

Associations Between Declining Physical and Cognitive Functions in the Lothian Birth Cohort 1936

BACKGROUND

The ageing process is characterized by declines in physical and cognitive function. However, the relationship between these trajectories remains a topic of investigation.

METHODS

Using four data waves collected triennially between ages 70 and 79, we tested for associations between multiple cognitive ability domains (verbal memory, processing speed, and visuospatial ability) and physical functions (walking speed, grip strength, and lung function). We first tested for associations between linear declines in physical and cognitive functions over the entire 9-year study period, and then, for lead-lag coupling effects between 3-year changes in cognitive and physical functions.

RESULTS

Steeper linear decline in walking speed was moderately correlated with steeper linear declines in each cognitive domain. Steeper linear decline in grip strength was moderately correlated with steeper linear declines in verbal memory and processing speed. Lead-lag coupling models showed that decline in verbal memory was preceded by declines in walking speed and grip strength. By contrast, decline in grip strength was preceded by declines in processing speed and visuospatial ability, and decline in walking speed was preceded by decline in visuospatial ability. Following additional adjustment for covariates, only coupling effects from earlier decline in processing speed to later decline in grip strength remained significant (β = 0.545, p = .006).

CONCLUSION

Our findings provide further evidence of an association between cognitive and physical declines and point to the potential order in which these changes occur. Decline in processing speed in particular may serve as a unique early marker of declining upper body strength.

Age-Varying Relationships Between Physical Function and Cognition in Older Adulthood

OBJECTIVES

There are positive relationships between physical and cognitive function in older adulthood; however, the strength of these relationships are inconsistent across studies. Although novel statistical tools provide flexibility to explore age-related differences in relationship magnitude, such methods have not been implemented in gerontological research. This study applied such methods to examine variations in relationship magnitude between physical function and cognition in healthy older adults (N = 2,783).

METHOD

Time-varying effects modeling (TVEM) is an extension of regression that models changes in relationships as a function of time-varying metrics like age. TVEM was used to examine if physical function (Turn 360, grip strength) predicted cognitive performance (memory, processing speed/attention, and reasoning) similarly across adults aged 65-90.

RESULTS

All associations between Turn 360 and all cognitive domains were significant and positive; however, speed of processing had significant magnitude variation across age such that the young-old and the old-old demonstrated the strongest relationships. Associations between grip strength and all cognitive domains significantly strengthened with increased age.

DISCUSSION

Results suggest that depending on the sample age, there may be inconsistencies in the relationships between physical and cognitive performance. Future research should explore these relationships longitudinally to better elucidate discrepant findings.

Declines in grip strength may indicate early changes in cognition in healthy middle-aged adults

Declining grip strength is an indicator of cognitive loss in older individuals but it has not been explored people younger than 65 years old. The purpose of this study was to investigate the relationship between grip strength and specific cognitive tests known to decline with mild cognitive impairment in young and middle-aged adults. Declines in cognitive performance in middle-aged adults may provide evidence that these changes occur earlier than previously reported. A cross sectional design was used to compare differences between young and middle-aged healthy adults and to investigate associations between cognitive and grip strength measures within groups. Healthy young (20–30 years old) and middle-aged (45–65 years old) adults completed five cognitive tests including the Stroop, California Verbal Learning Test, Symbol Digit Modalities Test, Trail Making Tests and the Controlled Oral Word Association Test. All participants completed right and left maximum grip strength measures. Middle-aged adults performed significantly worse on right and left grip strength and the Stroop test (p<0.05) when compared to the younger group. There were no significant relationships among grip strength and cognitive performance at the whole-group level or within the younger-age group; however, weaker grip strength was significantly associated with poorer Controlled Oral Word Association Test total cluster (r = 0.458; p < .05) and Stroop interference (r = 0.471; p < .05) scores in the middle-aged group. Findings from this study suggest that cognitive changes may occur earlier than previously thought (prior to age 65). Weaker grip strength was significantly associated with poorer function in two of the cognitive measures in the middle-age group, suggesting that some domains of cognition, specifically semantic categorization and executive function, may be particularly sensitive to age-related changes.

Role of gait speed and grip strength in predicting 10-year cognitive decline among community-dwelling older people

BACKGROUND

The gait speed and handgrip strength represented the core determinants of physical frailty and sarcopenia, which were reported to be associated with cognitive impairment and decline. Different physical measures might differentially affect cognitive changes, such as higher-level cognitive change and global cognitive decline. This study examined the differential associations of gait speed and handgrip strength with 10-year cognitive changes among community-dwelling older people.

METHODS

Participants aged 60 years and over living in the community were invited for study. Gait speed and handgrip strength were classified into 5 groups based on quintiles at baseline. Cognitive functions were assessed using the Mini-Mental State Examination (MMSE) and Digit Symbol Substitution Test (DSST) every 2 years from baseline for a period of 10 years. Linear mixed effects models were used to determine the role of gait speed and handgrip strength in the prediction of 10-year cognitive changes by adjusting covariates, including age, gender, education, depressive symptoms, marital status, smoking status, instrumental activities of daily life (IADL), Charlson Comorbidity Index (CCI), and body mass index (BMI) at baseline.

RESULTS

A total of 1096 participants were enrolled in the study. The mean age was 69.4 ± 5.8 years and 50.9% were male. The slowest gait speed group showed a significantly greater decline in the DSST scores over 10 years than the highest group (estimate = 0.28 and P = 0.003), but not in the MMSE scores (estimate = 0.05 and P = 0.078). The lowest handgrip strength group showed a significantly greater decline in the MMSE scores than the highest group (estimate = 0.06 and P = 0.039) and in the DSST scores than the highest two quintiles (estimate = 0.20 and P = 0.033 for the fourth quintile; estimate = 0.20 and P = 0.040 for the highest quintile) over 10-year follow-up.

CONCLUSIONS

A slow gait speed could predict 10-year cognitive decline using DSST, and a low handgrip strength could predict 10-year cognitive decline using MMSE in addition to DSST. Thus both physical measures are lined to cognitive decline but there may be different mechanisms between brain and physical functions.

The Intersection of Physical Function, Cognitive Performance, Aging, and Multiple Sclerosis: A Cross-sectional Comparative Study

OBJECTIVE

To examine the associations between physical function (walking speed and endurance and functional mobility) and cognitive function (information processing speed and verbal memory) in older adults with multiple sclerosis (MS) and healthy controls.

BACKGROUND

Older adults with MS have worse physical and cognitive function than older adults without MS and young and middle-aged adults with MS. To date, little is known about the associations between, or coupling of, physical and cognitive function outcomes in older adults with MS.

METHODS

We administered physical and cognitive function measures to 40 older adults with MS and 40 demographically matched healthy controls. Pearson product moment correlations were used to examine bivariate linear relationships in the overall sample and in the subsamples of (a) older adults with MS and (b) healthy controls. Linear regression analyses were used to examine the independent associations between demographic characteristics and physical and cognitive function variables in the two subsamples.

RESULTS

In the overall sample, all physical function variables were significantly correlated with cognitive function, as measured by information processing speed, and these correlations were mainly due to the subsample of older adults with MS. The linear regression analyses further indicated that information processing speed and years of education consistently explained variance in all physical function variables, beyond the influence of demographic variables, in older adults with MS.

CONCLUSIONS

Physical function and information processing speed are strongly correlated in older adults with MS. Future research should examine underlying neurobehavioral mechanisms associated with physical and cognitive function as well as behavioral strategies for jointly improving these functions in older adults with MS.

Measuring gait speed to better identify prodromal dementia

Slow gait speed has been shown to predict incident dementia and cognitive decline in older individuals. We aimed to summarize the evidence concerning the association of slow gait speed with cognitive decline and dementia, and discuss the possible shared pathways leading to cognitive and motor impairments, under the unifying hypothesis that body and mind are intimately connected. This is a scoping review supported by a systematic search of the literature, performed on PubMed and Web of Science. Longitudinal studies providing information on the role of gait speed in the prediction of cognitive decline and dementia in cognitively intact people and in those with initial cognitive impairment were eligible. Of 39 studies selected, including overall 57,456 participants, 33 reported a significant association between gait speed and cognitive outcomes, including dementia. Neurodegenerative pathology and cerebrovascular burden may damage cerebral areas involved in both cognitive functions and motor control. At the same time, systemic conditions, characterized by higher cardiorespiratory, and metabolic and inflammatory burden, can affect a number of organs and systems involved in motor functions, including the brain, having ultimately an impact on cognition. The interplay of body and mind seems relevant during the development of cognitive decline and dementia. The measurement of gait speed may improve the detection of prodromal dementia and cognitive impairment in individuals with and without initial cognitive deficits. The potential applicability of such a measure in both clinical and research settings points at the importance of expanding our knowledge about the common underlying mechanisms of cognitive and motor decline.

Evaluation of the directional relationship between handgrip strength and cognitive function: the Korean Longitudinal Study of Ageing

BACKGROUND

recent studies suggest that handgrip strength is linked with cognitive impairment at older ages. However, it remains unclear as to whether muscular strength influences subsequent cognitive performance, or whether lower levels of cognitive function increase the likelihood of muscle strength decline.

OBJECTIVE

to investigate the directional relationship between handgrip strength and cognitive impairment using longitudinal data among older adults.

METHODS

repeated measures of handgrip strength and cognitive function were collected in a sample of 5,995 participants of the Korean Longitudinal Study of Aging (KLoSA) over a period of 8 years. Time-lagged general estimating equations, while accounting for correlation among repeated measures, was used to assess the temporal effect of handgrip strength on cognitive impairment and vice versa with adjustment for other confounding factors.

RESULTS

after adjustment, greater handgrip strength was related to subsequent reduction in the risk of cognitive impairment, such that participants in the highest quartile presented approximately 50% decrease in their risk of cognitive impairment [adjusted odds ratio (OR) = 0.499 (95% CI 0.422 to 0.589] compared to the lowest quartile after controlling for potential confounding factors. Conversely, cognitive impairment was a significant predictor of reduced muscular strength [β regression coefficient -0.804, 95% CI, -1.168 to -0.439, for participants with dementia compared with those with normal cognitive function].

CONCLUSIONS

in conclusion, a significant bi-directional relationship was found between muscular strength and cognitive function, suggesting that these may have shared common pathways that are worthy of being further elucidated in future studies.

Baseline Mobility is Not Associated with Decline in Cognitive Function in Healthy Community-Dwelling Older Adults: Findings From The Irish Longitudinal Study on Ageing (TILDA)

OBJECTIVES

Few studies examine the relationship between Timed Up-and-Go (TUG), a commonly used clinical test, and cognitive decline. This study examines whether TUG, usual gait speed (UGS), and dual-task gait speed (DTGS) predict decline in global cognition, executive function, processing speed, memory, and attention with follow-up of up to 5.9 years.

DESIGN

Longitudinal study.

SETTING

The Irish Longitudinal Study on Ageing (TILDA), a nationally representative cohort study.

PARTICIPANTS

Community-dwelling adults aged ≥65 years, with Mini-Mental State Examination (MMSE) score ≥18 and no known history of memory impairment, dementia, Alzheimer's disease or Parkinson's disease were included (N = 2,250).

MEASUREMENTS

Participants completed mobility tasks during the baseline health assessment and cognitive tasks during interviews conducted at 2 year intervals (waves 1, 2, and 3) and health assessments (waves 1 and 3). Linear and Poisson mixed effects regression models were used to examine longitudinal associations between mobility and each cognitive test, adjusting for sociodemographics and physical and mental health.

RESULTS

There was little evidence of an association between TUG, UGS, or DTGS with decline in cognitive function after adjusting for confounders.

CONCLUSIONS

These mobility tasks are not sensitive predictors of cognitive decline in this high-functioning, community-dwelling sample; nonetheless, limited decline in cognitive function was observed during follow-up. Further work with longer follow-up and/or analysis of more specific and comprehensive measures associated with gait is required.

Walking Speed, Cognitive Function, and Dementia Risk in the English Longitudinal Study of Ageing

Objectives

To determine the relationships between walking speed, cognitive function, and the interaction between changes in these measures and dementia risk.

Design

Longitudinal observational study.

Setting

English Longitudinal Study of Ageing.

Participants

Individuals aged 60 and older (N=3,932).

Measurements

Walking speed and cognition were assessed at Waves 1 (2002–03) and 2 (2004–05) of the English Longitudinal Study of Ageing. New dementia cases were assessed from Wave 3 (2006–07) to Wave 7 (2014–15). The associations were modelled using Cox proportional hazards regression.

Results

Participants with faster baseline walking speeds were at lower risk of developing dementia (hazard ratio (HR)=0.36, 95% confidence interval (CI)=0.22–0.60). Those with a greater decline in walking speed from Wave 1 to 2 were at greater risk of developing dementia (HR=1.23, 95% CI=1.03–1.47). Participants with better baseline cognition (HR=0.42, 95% CI=0.34–0.54) were at lower risk of developing dementia. Those with a greater decline in cognition from Wave 1 to 2 were at greater risk of developing dementia (HR=1.78, 95% CI=1.53–2.06). Change in walking speed and change in cognition did not have an interactive effect on dementia risk (HR=1.01, 95% CI=0.88–1.17).

Conclusion

In this community‐dwelling sample of English adults, those with slower walking speeds and a greater decline in speed over time were at greater risk of developing dementia independent of changes in cognition. Further research is required to understand the mechanisms that may drive these associations.

See related editorial by https://doi.org/https://doi.org/10.1111/jgs.15368.

Associations of pet ownership with biomarkers of ageing: population based cohort study

OBJECTIVE

To examine the prospective relation between animal companionship and biomarkers of ageing in older people.

DESIGN

Analyses of data from the English Longitudinal Study of Ageing, an ongoing, open, prospective cohort study initiated in 2002-03.

SETTING

Nationally representative study from England.

PARTICIPANTS

8785 adults (55% women) with a mean age of 67 years (SD 9) at pet ownership assessment in 2010-11 (wave 5).

MAIN OUTCOME MEASURE

Established biomarkers of ageing in the domains of physical, immunological, and psychological function, as assessed in 2012-13 (wave 6).

RESULTS

One third of study members reported pet ownership: 1619 (18%) owned a dog, 1077 (12%) a cat, and 274 (3%) another animal. After adjustment for a range of covariates, there was no evidence of a clear association of any type of pet ownership with walking speed, lung function, chair rise time, grip strength, leg raises, balance, three markers of systemic inflammation, memory, or depressive symptoms.

CONCLUSION

In this population of older adults, the companionship of creatures great and small seems to essentially confer no relation with standard ageing phenotypes.

Functional Limitations Among Responders to the World Trade Center Attacks 14 Years After the Disaster: Implications of Chronic Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) is associated with self-reported difficulties navigating the social and physical world and may also be associated with risk of functional limitations. The Short Physical Performance Battery (SPPB), an objective functional assessment, was administered during monitoring exams between January and December 2015 to a consecutive sample of 1,268 rescue workers, volunteers, and other responders who had aided in response, recovery, and cleanup efforts at the World Trade Center (WTC) in New York after the September 11, 2011 attacks. Data were linked with diagnostic and longitudinal data from the WTC monitoring study. Multivariable analyses were used to examine predictors of functional limitations. Prevalence estimates weighted to the general responder population revealed a relatively high prevalence of functional limitations, SPPB ≤ 9; 16.0%, 95% CI [13.7, 18.4]. Current PTSD was associated with a twofold increased risk of functional limitations after controlling for predisposing factors, trauma severity, behavioral factors, and WTC-related medical conditions, adjusted risk ratio (aRR) = 2.11, 95% CI [1.48, 3.01]. Exposure to ergonomic risk factors at the WTC also increased the risk of functional impairments, aRR = 1.34 95% CI [1.05, 1.70]. Longitudinal results suggest that individuals with current functional limitations experienced high baseline PTSD severity, B = 2.94, SE = 1.33, and increasing PTSD symptom severity, B = 0.29, SE = 0.10, since September 11, 2001. This study identified a cross-sectional relationship between functional limitations and PTSD and a worsening of PTSD symptoms in persons who eventually demonstrated functional limitations. Results highlight the potential role of chronic PTSD in functional limitations.

The role of sports clubs in helping older people to stay active and prevent frailty: a longitudinal mediation analysis

Background

Frailty is a common syndrome in older adults characterised by increased vulnerability to adverse health outcomes as a result of decline in functional and physiological measures. Frailty predicts a range of poor health and social outcomes and is associated with increased risk of hospital admission. The health benefits of sport and physical activity and the health risks of inactivity are well known. However, less is known about the role of sports clubs and physical activity in preventing and managing frailty in older adults. The objective of this study is to examine the role of membership of sports clubs in promoting physical activity and reducing levels of frailty in older adults.

Methods

We used data from waves 1 to 7 of the English Longitudinal Study of Ageing (ELSA). Survey items on physical activity were combined to produce a measure of moderate or vigorous physical activity for each wave. Frailty was measured using an index of accumulated deficits. A total of sixty deficits, including symptoms, disabilities and diseases were recorded through self-report and tests. Direct and indirect relationships between sports club membership, levels of physical activity and frailty were examined using a cross-lagged panel model.

Results

We found evidence for an indirect relationship between sports club membership and frailty, mediated by physical activity. This finding was observed when examining time-specific indirect pathways and the total of all indirect pathways across seven waves of survey data (Est = −0.097 [95% CI = −0.124,-0.070], p = <0.001).

Conclusions

These analyses provide evidence to suggest that sports clubs may be useful in preventing and managing frailty in older adults, both directly and indirectly through increased physical activity levels. Sports clubs accessible to older people may improve health in this demographic by increasing activity levels and reducing frailty and associated comorbidities. There is a need for investment in these organisations to provide opportunities for older people to achieve the levels of physical activity necessary to prevent health problems associated with inactivity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-017-0552-5) contains supplementary material, which is available to authorized users.

Physical Activity and Cognitive Function of Long-Distance Walkers: Studying Four Days Marches Participants

Studies show physical activity to be beneficial for cognitive function. However, studies usually included individuals who were not particularly inclined to exercise. Following research among master athletes, we examined associations between physical activity and cognitive function in participants of the International Nijmegen Four Days Marches. These individuals are also inclined to exercise. On 4 consecutive days >40,000 participants walk a daily distance of 30-50 km (120-200 km or 75-125 miles in total). Four Days Marches participants and less active or inactive control participants from the Nijmegen Exercise Study were examined. Self-reported current and lifelong physical activities were quantified in Metabolic Equivalent of Task minutes/day, and training walking speed was estimated in km/h. Cognitive functioning in the domains of working memory, executive function, and visuospatial short-term memory was assessed using the validated Brain Aging Monitor. Data from 521 participants (mean age 54.7, standard deviation 12.9) showed neither positive associations between lifelong physical activity and working memory, executive function, and visuospatial short-term memory nor positive associations between current physical activity and cognitive functioning in these domains (p-values >0.05). However, a positive association between training walking speed and working memory was revealed (age adjusted β = 0.18, p-value <0.01). Walking speed as a surrogate marker of fitness, but not lifelong and current physical activity levels was associated with cognitive function. Therefore, walking speed deserves more attention in research aimed at unraveling associations between physical activity and cognitive function.

Temporal Relationship Between Cognitive and Physical Performance in Middle-Aged to Oldest Old People

Background

Cognitive and physical impairment frequently co-occur in older people. The aim of this study was to assess the temporal order of these age-related changes in cognitive and physical performance and to assess whether a relationship was different across specific cognitive and physical domains and age groups.

Methods

Cognitive domains included global, executive, and memory function; physical domains included gait speed and handgrip strength. These domains were assessed in two population-based longitudinal cohorts covering the age ranges of 55-64, 65-74, 75-85, and 85-90 years with a follow-up of 5-12 years. Cross-lagged panel models were applied to assess the temporal relationships between the different cognitive and physical domains adjusting for age, sex, education, comorbidity, depressive symptoms, and physical activity.

Results

Over all age groups, poorer executive function was associated with a steeper decline in gait speed (p < .05). From the age of 85 years, this relationship was found across all cognitive and physical domains (p < .02). From the age of 65 years, slower gait speed and/or weaker handgrip strength were associated with steeper declines in global cognitive function (p < .02), with statistically significant results across all cognitive domains in the age group of 75-85 years (p < .04).

Conclusions

The temporal relationship between cognitive and physical performance differs across domains and age, suggesting a specific rather than a general relationship. This emphasizes the importance of repeated measurements on different domains and encourages future research to the development of domain- and age-specific interventions.

The relative temporal sequence of decline in mobility and cognition among initially unimpaired older adults: Results from the Baltimore Longitudinal Study of Aging

Background

most older individuals who experience mobility decline, also show cognitive decline, but whether cognitive decline precedes or follows mobility limitation is not well understood.

Objective

examine the temporal sequence of mobility and cognition among initially unimpaired older adults.

Methods

mobility and cognition were assessed every 2 years for 6 years in 412 participants aged ≥60 with initially unimpaired cognition and gait speed. Using autoregressive models, accounting for the dependent variable from the prior assessment, baseline age, sex, body mass index and education, we examine the temporal sequence of change in mobility (6 m usual gait speed, 400 m fast walk time) and executive function (visuoperceptual speed: Digit Symbol Substitution Test (DSST); cognitive flexibility: Trail Making Test part B (TMT-B)) or memory (California Verbal Learning Test (CVLT) immediate, short-delay, long-delay).

Results

there was a bidirectional relationship over time between slower usual gait speed and both poorer DSST and TMT-B scores (Bonferroni-corrected P < 0.005). In contrast, slower 400 m fast walk time predicted subsequent poorer DSST, TMT-B, CVLT immediate recall and CVLT short-delay scores (P < 0.005), while these measures did not predict subsequent 400 m fast walk time (P > 0.005).

Conclusions

among initially unimpaired older adults, the temporal relationship between usual gait speed and executive function is bidirectional, with each predicting change in the other, while poor fast walking performance predicts future executive function and memory changes but not vice versa. Challenging tasks like the 400 m walk appear superior to usual gait speed for predicting executive function and memory change in unimpaired older adults.

Cognitive Ability in Late Life and Onset of Physical Frailty: The Lothian Birth Cohort 1936

Objectives

To investigate whether poorer cognitive ability is a risk factor for development of physical frailty and whether this risk varies according to cognitive domain.

Design

Prospective longitudinal study with 6‐year follow‐up.

Setting

Edinburgh, Scotland.

Participants

Members of the Lothian Birth Cohort 1936 (N = 594).

Measurements

Frailty was assessed at ages 70 and 76 using the Fried criteria. Cognitive function was assessed at age 70, 73, and 76. Factor score estimates were derived for baseline level of and change in four cognitive domains: visuospatial ability, memory, processing speed, and crystallized cognitive ability.

Results

Higher baseline levels of processing speed, memory, visuospatial ability and crystallized ability at age 70, and less decline in speed, memory, and crystallized ability were associated with less risk of becoming physically frail by age 76. When all cognitive domains were modelled together, processing speed was the only domain associated with frailty risk, for a standard deviation (SD) increment in initial level of processing speed, the risk of frailty was 47% less (0.53 95% confidence interval (CI) = 0.33–0.85) after adjustment for age, sex, baseline frailty status, social class, depressive symptoms, number of chronic physical diseases, levels of inflammatory biomarkers, and other cognitive factor score estimates; for a SD increment in processing speed change (less decline) risk of frailty was 74% less (RRR = 0.26, 95% CI = 0.16–0.42). When additional analyses were conducted using a single test of processing speed that did not require fast motor responses (inspection time), results were similar.

Conclusions

The speed with which older adults process information and the rate at which this declines over time may be an important indicator of the risk of physical frailty.

The Impact of Three Cognitive Training Interventions on Older Adults' Physical Functioning Across 5 Years

OBJECTIVE

Physical functioning is closely associated with cognition. The current study assessed the impact of three cognitive training programs on objective measures of physical functioning across 5 years.

METHOD

Older adults randomized to a processing speed ( n = 702), reasoning ( n = 694), or memory ( n = 703) training intervention were compared with those randomized to a no-contact control condition ( n = 698). Intention-to-treat (ITT) and treatment-received/dosage (time-varying number of training sessions) analyses were conducted.

RESULTS

There were no transfer effects in the ITT analyses. Treatment-received models demonstrated that training sessions (i.e., higher dosage) across all intervention arms transferred to better maintained Digit Symbol Copy and Turn 360 performance relative to the control group. More reasoning training transferred to better grip strength.

DISCUSSION

This is the first study to demonstrate differential longitudinal cognitive training transfer effects to three performance-based physical functioning measures. Future research should investigate mechanisms of far-transfer effects.

Different cognitive functions discriminate gait performance in younger and older women: A pilot study

AIM

Cognitive dysfunction is associated with slower gait speed in older women, but whether cognitive function affects gait performance earlier in life has yet to be investigated. Thus, the objective of this study was to test the hypothesis that cognitive function will discriminate gait performance in healthy younger women.

METHODS

Fast-pace and dual-task gait speed were measured in 30 young to middle-aged (30-45y) and 26 older (61-80y) women without mild cognitive impairment. Visuoperceptual ability, working memory, executive function, and learning ability were assessed using neuropsychological tests. Within each age group, women were divided by the median into lower and higher cognitive function groups to compare gait performance.

RESULTS

Younger women with higher visuoperceptual ability had faster fast-pace (2.25±0.30 vs. 1.98±0.18m/s, p≤0.01) and dual-task gait speed (2.02±0.27 vs. 1.69±0.25m/s, p≤0.01) than women with lower visuoperceptual ability. The difference in dual-task gait speed remained significant (p=0.02) after adjusting for age, years of education, and other covariates. Dividing younger women based on other cognitive domains showed no difference in gait performance. In contrast, working memory and executive function discriminated dual-task gait speed (p<0.05) in older women after adjusting for age and education.

CONCLUSION

To our knowledge, this is the first study to show that poorer cognitive function even at a relatively young age can negatively impact mobility. Different cognitive functions discriminated gait performance based on age, highlighting a possible influence of aging in the relationship between cognitive function and mobility in women.

Improved motor and cognitive performance with sodium nitrite supplementation is related to small metabolite signatures: a pilot trial in middle-aged and older adults

Advancing age is associated with reductions in nitric oxide bioavailability and changes in metabolic activity, which are implicated in declines in motor and cognitive function. In preclinical models, sodium nitrite supplementation (SN) increases plasma nitrite and improves motor function, whereas other nitric oxide-boosting agents improve cognitive function. This pilot study was designed to translate these findings to middle-aged and older (MA/O) humans to provide proof-of-concept support for larger trials. SN (10 weeks, 80 or 160 mg/day capsules, TheraVasc, Inc.) acutely and chronically increased plasma nitrite and improved performance on measures of motor and cognitive outcomes (all p<0.05 or better) in healthy MA/O adults (62 ± 7 years). Untargeted metabolomics analysis revealed that SN significantly altered 33 (160 mg/day) to 45 (80 mg/day) different metabolites, 13 of which were related to changes in functional outcomes; baseline concentrations of 99 different metabolites predicted functional improvements with SN. This pilot study provides the first evidence that SN improves aspects of motor and cognitive function in healthy MA/O adults, and that these improvements are associated with, and predicted by, the plasma metabolome. Our findings provide the necessary support for larger clinical trials on this promising pharmacological strategy for preserving physiological function with aging.

Intellectual ability in young adulthood as an antecedent of physical functioning in older age

OBJECTIVES

low cognitive ability is associated with subsequent functional disability. Whether this association extends across adult life has been little studied. The aim of this study was to examine the association between intellectual ability in young adulthood and physical functioning during a 10-year follow-up in older age.

METHODS

three hundred and sixty persons of the Helsinki Birth Cohort Study (HBCS) male members, born between 1934 and 1944 and residing in Finland in 1971, took part in The Finnish Defence Forces Basic Intellectual Ability Test during the first 2 weeks of their military service training between 1952 and 1972. Their physical functioning was assessed twice using the Short Form 36 (SF-36) questionnaire at average ages of 61 and 71 years. A longitudinal path model linking Intellectual Ability Test score to the physical functioning assessments was used to explore the effect of intellectual ability in young adulthood on physical functioning in older age.

RESULTS

after adjustments for age at measurement, childhood socioeconomic status and adult BMI (kg/m(2)), better intellectual ability total and arithmetic and verbal reasoning subtest scores in young adulthood predicted better physical functioning at age 61 years (P values <0.021). Intellectual ability total and arithmetic and verbal reasoning subtest scores in young adulthood had indirect effects on physical functioning at age 71 years (P values <0.022) through better physical functioning at age 61 years. Adjustment for main chronic diseases did not change the results materially.

CONCLUSION

better early-life intellectual ability helps in maintaining better physical functioning in older age.

Sarcopenia and Health Care Utilization in Older Women

BACKGROUND

Although there are several consensus definitions of sarcopenia, their association with health care utilization has not been studied.

METHODS

We included women from the prospective Study of Osteoporotic Fractures with complete assessment of sarcopenia by several definitions at the Study of Osteoporotic Fractures Year 10 (Y10) exam (1997-1998) who also had available data from Medicare Fee- For-Service Claims (N = 566) or Kaiser Encounter data (N = 194). Sarcopenia definitions evaluated were: International Working Group, European Working Group for Sarcopenia in Older Persons, Foundation for the NIH Sarcopenia Project, Baumgartner, and Newman. Hurdle models and logistic regression were used to assess the relation between sarcopenia status (the summary definition and the components of slowness, weakness and/or lean mass) and outcomes that included hospitalizations, cumulative inpatient days/year, short-term (part A paid) skilled nursing facility stay in the 3 years following the Y10 visit.

RESULTS

None of the consensus definitions, nor the definition components of weakness or low lean mass, was associated with increased risk of hospitalization or greater likelihood of short-term skilled nursing facility stay. Women with slowness by any criterion definition were about 50% more likely to be hospitalized; had a greater rate of hospitalization days amongst those hospitalized; and had 1.8 to 2.1 times greater likelihood of a short-term skilled nursing facility stay than women without slowness. There was the suggestion of a protective association of low lean mass by the various criterion definitions on short-term skilled nursing facility stay.

CONCLUSION

Estimated effects of sarcopenia on health care utilization were negligible. However, slowness was associated with greater health care utilization.

Walking ability to predict future cognitive decline in old adults: A scoping review

Early identification of individuals at risk for cognitive decline may facilitate the selection of those who benefit most from interventions. Current models predicting cognitive decline include neuropsychological and/or biological markers. Additional markers based on walking ability might improve accuracy and specificity of these models because motor and cognitive functions share neuroanatomical structures and psychological processes. We reviewed the relationship between walking ability at one point of (mid) life and cognitive decline at follow-up. A systematic literature search identified 20 longitudinal studies. The average follow-up time was 4.5 years. Gait speed quantified walking ability in most studies (n=18). Additional gait measures (n=4) were step frequency, variability and step-length. Despite methodological weaknesses, results revealed that gait slowing (0.68-1.1 m/sec) preceded cognitive decline and the presence of dementia syndromes (maximal odds and hazard ratios of 10.4 and 11.1, respectively). The results indicate that measures of walking ability could serve as additional markers to predict cognitive decline. However, gait speed alone might lack specificity. We recommend gait analysis, including dynamic gait parameters, in clinical evaluations of patients with suspected cognitive decline. Future studies should focus on examining the specificity and accuracy of various gait characteristics to predict future cognitive decline.