Racial differences in gait velocity in an urban elderly cohort

Gait speed and its associated factors among older black adults in Sub-Saharan Africa: Evidence from the WHO study on Global AGEing in older adults (SAGE)

Gait speed is an essential predictor of functional and cognitive decline in older adults. The study aimed to investigate the gait speed of older adults in Ghana and South Africa and to determine its associated factors, as the Sub-Saharan representatives in the World Health Organization's Study on Global AGEing in Older Adults (SAGE). A secondary analysis of data from the SAGE study which consists of nationally representative data involving participants aged ≥50+ years with smaller samples of younger adults aged 18-49 years in Ghana and South Africa was conducted. SAGE study employed a multistage, stratified clustered sample design and involved the use of a standardised questionnaire to obtain participants' (n = 5808) demographic, anthropometric and gait speed information. The standard 4 metre-gait speed was used. Median gait speed for the study group, which comprised African/Black participants aged ≥50+ years was 0.769(Q1 = 0.571, Q3 = 0.952)m/s for males and 0.667 (Q1 = 0.500,Q3 = 0.833)m/s for females. For every unit increase in age, the odds of being in a higher-ranked gait speed category was 0.96(95%CI 0·96, 0·97, p<0.001) times that of the previous age. Females had odds of 0.55 (95%CI 0.50, 0.61, p<0.001) of recording higher gait speed, as compared to males. Rural dwellers had odds of 1.43 (95%CI 1.29, 1.58, p < 0.001) of being in a higher-ranked category of gait speed compared to urban dwellers. Underweight (OR = 0.85, 95%C1 = 0.73-1.00, p<0.05) and obesity (OR = 0.53, 95%CI = 0.46-0.61, p<0.001) were associated with slower gait speed. Amongst functional indices, the World Health Organization Disability Assessment Schedule (WHODAS) score was the biggest determinant of gait speed. Having a "Severe/Extreme" WHODAS score had the strongest association with gait speed (OR = 0.18, 95%CI = 0.14-0.23, p<0.001). These gait speed results provide an essential reference for older adults' care in Ghana and South Africa.

Correlates of Gait Speed Among Older Adults From 6 Countries: Findings From the COSMIC Collaboration

BACKGROUND

Few studies have compared gait speed and its correlates among different ethnogeographic regions. The goals of this study were to describe usual and rapid gait speed, and identify their correlates across Australian, Asian, and African countries.

METHODS

We used data from 6 population-based cohorts of adults aged 65+ from 6 countries and 3 continents (N = 6 472), with samples ranging from 231 to 1 913. All cohorts are members of the Cohort Studies of Memory in an International Consortium collaboration. We investigated whether clinical (body mass index [BMI], hypertension, stroke, apolipoprotein status), psychological (cognition, mood, general health), and behavioral factors (smoking, drinking, physical activity) correlated with usual (N = 4 cohorts) and rapid gait speed (N = 3 cohorts) similarly across cohorts. Regression models were controlled for age, sex, and education, and were sex-stratified.

RESULTS

Age- and sex-standardized usual gait speed means ranged from 0.61 to 1.06 m/s and rapid gait speed means ranged from 1.16 to 1.64 m/s. Lower BMI and better cognitive function consistently correlated with faster gait speed in all cohorts. Less consistently, not having hypertension and greater physical activity engagement were associated with faster gait speed. Associations with mood, smoking, and drinking were largely nonsignificant. These patterns were not attenuated by demographics. There was limited evidence that the associations differed by sex, except physical activity, where the greater intensity was associated with usual gait among men but not women.

CONCLUSIONS

This study is among the first to describe the usual and rapid gait speeds across older adults in Africa, Asia, and Australia.

A normative study of the gait features measured by a wearable inertia sensor in a healthy old population

BACKGROUND

Gait function impairments are associated with the risk of various medical conditions in older adults. As gait function declines with advancing age, normative data are required for proper interpretation of gait function in older adults.

RESEARCH PURPOSE

This study aimed to construct age-stratified normative data of non-dimensionally normalized temporal and spatial gait features in healthy older adults.

METHODS

We recruited 320 community-dwelling healthy adults aged 65 years or older from two prospective cohort studies. We stratified them into four age groups (65-69, 70-74, 75-79, and 80-84 years). Each age group comprised 40 men and 40 women. We obtained six gait features (cadence, step time, step time variability, step time asymmetry, gait speed, and step length) using a wearable inertia measurement unit attached on the skin overlying L3-L4 on the back. To mitigate the influence of body shape, we non-dimensionally normalized the gait features into unitless values using height and gravity.

RESULT

The effect of age group was significant in all raw gait features (p < 0.001 for step time variability, speed and step length; p < 0.05 for cadence, step time and step time asymmetry), and that of sex was significant in the five raw gait features, except for step time asymmetry(p < 0.001 for cadence, step time, speed, and step length; p < 0.05 for step time asymmetry). When gait features were normalized, the effect of age group remained (p < 0.001 for all gait features), whereas that of sex disappeared (p > 0.05 for all gait features).

SIGNIFICANCE

Our dimensionless normative data on gait features may be useful in comparative studies of gait function between sexes or ethnicities with different body shapes.

Thigh and Calf Myosteatosis are Strongly Associated with Muscle and Physical Function in African Caribbean Men

BACKGROUND

African Caribbeans have higher levels of myosteatosis than other populations; however, little is known about the impact of myosteatosis on physical function in African Caribbeans. Herein, we examined the association between regional myosteatosis of the calf, thigh, and abdomen versus physical function in 850 African-Ancestry men aged 64.2 ± 8.9 (range 50-95) living on the Caribbean Island of Tobago.

METHODS

Myosteatosis was measured using computed tomography and included intermuscular adipose tissue (IMAT) and muscle density levels of the thigh, calf, psoas, and paraspinous muscles. Outcomes included grip strength, time to complete 5 chair-rises, and 4-meter gait speed. Associations were quantified using separate linear models for each myosteatosis depot and were adjusted for age, height, demographics, physical activity, and chronic diseases. Beta coefficients were presented per standard deviation of each myosteatosis depot.

RESULTS

Higher thigh IMAT was the only IMAT depot significantly associated with weaker grip strength (β = -1.3 ± 0.43 kg, p = .003). However, lower muscle density of all 4 muscle groups was associated with weaker grip strength (all p < .05). Calf and thigh myosteatosis (IMAT and muscle density) were significantly associated with both worse chair rise time and gait speed (all p < .05), whereas psoas IMAT and paraspinous muscle density were associated with gait speed.

CONCLUSION

Myosteatosis of the calf and thigh-but not the abdomen-were strongly associated with grip strength and performance measures of physical function in African Caribbean men. However, posterior abdominal myosteatosis may have some utility when abdominal images are all that are available.

Racial Differences in the Effect of HIV Status on Motor and Pulmonary Function and Mobility Disability in Older Adults

BACKGROUND

Older Black adults face a disproportionate burden of HIV prevalence, but less is known about racial disparities in age-related outcomes in HIV. We assessed the effect of HIV status and race on motor and pulmonary function, as well as how they contribute to mobility disability.

SETTING

Community-based study; Chicago, IL METHODS: Participants were 363 community-dwelling adults age ≥ 50 years, 48% living with HIV, and 68% Black. Participants with HIV were recruited from a specialty HIV clinic, and participants without HIV (comparable on key demographic, lifestyle, and behavioral characteristics) were recruited from the community. Measures included motor function summarized by 10 motor performance measures, pulmonary function summarized by 3 measures assessed using handheld spirometry, and self-reported mobility disability.

RESULTS

In fully adjusted linear models, HIV was associated with better motor (β = 9.35, p < 0.001) and pulmonary function (β = 16.34, p < 0.001). For pulmonary function, the effect of HIV status was moderated by race (interaction between Black race and HIV status: β =  - 11.66, p = 0.02), indicating that better pulmonary function among participants with HIV was less evident among Black participants. In fully adjusted models, odds of mobility disability did not differ by race, HIV status, or pulmonary function; better motor function was associated with lower odds of mobility disability (OR = 0.91 per 1-point higher, 95% CI 0.88-0.93).

CONCLUSION

Better motor and pulmonary function exhibited by participants with HIV could reflect access to medical care. Racial differences in lung function among participants with HIV indicate potential disparities in prevention or treatment of pulmonary disease or underlying risk factors.

The 5-Cog paradigm to improve detection of cognitive impairment and dementia: clinical trial protocol

Cognitive impairment related to dementia is under-diagnosed in primary care despite availability of numerous cognitive assessment tools; under-diagnosis is more prevalent for members of racial and ethnic minority groups. Clinical decision-support systems may improve rates of primary care providers responding to positive cognitive assessments with appropriate follow-up. The 5-Cog study is a randomized controlled trial in 1200 predominantly Black and Hispanic older adults from an urban underserved community who are presenting to primary care with cognitive concerns. The study will validate a novel 5-minute cognitive assessment coupled with an electronic medical record-embedded decision tree to overcome the barriers of current cognitive assessment paradigms in primary care and facilitate improved dementia care.

Feasibility of Markerless Motion Capture for Three-Dimensional Gait Assessment in Community Settings

Three-dimensional (3D) kinematic analysis of gait holds potential as a digital biomarker to identify neuropathologies, monitor disease progression, and provide a high-resolution outcome measure to monitor neurorehabilitation efficacy by characterizing the mechanisms underlying gait impairments. There is a need for 3D motion capture technologies accessible to community, clinical, and rehabilitation settings. Image-based markerless motion capture (MLMC) using neural network-based deep learning algorithms shows promise as an accessible technology in these settings. In this study, we assessed the feasibility of implementing 3D MLMC technology outside the traditional laboratory environment to evaluate its potential as a tool for outcomes assessment in neurorehabilitation. A sample population of 166 individuals aged 9-87 years (mean 43.7, S.D. 20.4) of varied health history were evaluated at six different locations in the community over a 3-month period. Participants walked overground at self-selected (SS) and fastest comfortable (FC) speeds. Feasibility measures considered the expansion, implementation, and practicality of this MLMC system. A subset of the sample population (46 individuals) walked over a pressure-sensitive walkway (PSW) concurrently with MLMC to assess agreement of the spatiotemporal gait parameters measured between the two systems. Twelve spatiotemporal parameters were compared using mean differences, Bland-Altman analysis, and intraclass correlation coefficients for agreement (ICC2,1) and consistency (ICC3,1). All measures showed good to excellent agreement between MLMC and the PSW system with cadence, speed, step length, step time, stride length, and stride time showing strong similarity. Furthermore, this information can inform the development of rehabilitation strategies targeting gait dysfunction. These first experiments provide evidence for feasibility of using MLMC in community and clinical practice environments to acquire robust 3D kinematic data from a diverse population. This foundational work enables future investigation with MLMC especially its use as a digital biomarker of disease progression and rehabilitation outcome.

Factors contributing to racial differences in gait mechanics differ by sex

BACKGROUND

Racial differences in gait mechanics have been recently reported, but we don't know what factors may drive differences in gait and whether these factors are innate or modifiable. The answers to those questions will inform both basic research and clinical interventions and outcomes.

RESEARCH QUESTION

Do anthropometric, strength, and health status measures explain racial differences in gait between African Americans (AA) and white Americans (WA)?

METHODS

Venous blood samples, anthropometric measures, lower extremity strength, and an assessment of health status were collected from 92 participants (18-30 years old) as part of an Institutional Review Board-approved study. 3D motion capture and force plate data were recorded during 7 walking trials at set regular (1.35 m/s) and fast (1.6 m/s) speeds. Racial differences in gait were identified at both speeds. Correlations between anthropometric, strength, and health status independent variables and outcome measures were computed after stratifying data by sex. Stepwise linear regression models evaluated whether the inclusion of anthropometric, strength, and health status independent variables explained racial effects.

RESULTS

In males, no racial differences in gait were explained by independent variables. Q-angle and ankle dorsiflexion strength accounted for racial differences in self-selected walking speed in females. Racial differences in ankle plantarflexion angle were explained by ankle plantarflexion strength differences.

SIGNIFICANCE

Factors that explain racial differences in gait in females were both innate and modifiable. These data make clear that it is important to include racially diverse normative gait databases in research studies. These results also identify potential intervention targets aimed at reducing racial health disparities.

Gradient and Acceleration of Decline in Physical and Cognitive Functions in Older Adults: A Disparity Analysis

BACKGROUND

Substantive previous work has shown that both gait speed and global cognition decline as people age. Rates of their decline, as opposed to cross-sectional measurements, could be more informative of future functional status and other clinical outcomes because they more accurately represent deteriorating systems. Additionally, understanding the sex and racial disparity in the speed of deterioration, if any, is also important as ethnic minorities are at an increased risk of mobility disability and dementia.

METHOD

Data from 2 large longitudinal intervention studies were integrated. Rates of decline were derived from individual-level measures of gait speed of 400-m walk and scores on the Modified Mini Mental State Examination (3MSE). We also assessed age-associated declines and accelerations in changes across the ages represented in the studies (age range 53-90).

RESULTS

The mean rate of decline in 400-m gait speed across individuals was 0.03 m/s per year, and multivariable analysis showed a significant acceleration in decline of -0.0013 m/s/y2 (p < .001). Both race and sex moderated the rate of decline. For global cognition, the mean rate of decline was 0.05 of a point per year on the 3MSE scale, and acceleration in the rate of decline was significant (-0.017 point/y2, p < .001), but neither sex nor race moderated the decline.

CONCLUSION

Rate of decline in physical but not cognitive function appears moderated by sex and race. This finding, as well as rates and accelerations of decline estimated herein, could inform future intervention studies.

CLINICAL TRIALS REGISTRATION NUMBER

NCT00017953 (Look AHEAD); NCT01410097 (Look AHEAD ancillary); NCT00116194 (LIFE).

Motor and Physical Function Impairments as Contributors to Slow Gait Speed and Mobility Difficulty in Middle-Aged and Older Adults

BACKGROUND

Motor function affects ability to perform daily activities and maintain independence. Yet, the interrelatedness of upper and lower extremity motor impairments and the magnitude of their contribution to slow gait and mobility difficulty are not well investigated.

METHODS

Participants in the Baltimore Longitudinal Study of Aging (N = 728, aged 50-99) completed motor and physical function tests including grip and knee extension strength, pegboard, finger tapping, standing balance, chair stands, fast-paced 400-m walk, and usual gait speed. Slow gait was defined as usual gait speed <1.0 m/s. Mobility difficulty was defined as self-reported difficulty walking ¼ mile or climbing stairs. Structural equation modeling examined the interrelationships of motor measures and their contributions to slow gait and mobility difficulty, adjusting for demographics and comorbidities.

RESULTS

Poorer manual dexterity (-0.571 standard deviation [SD] units, p < .001) and lower muscle strength (upper and lower extremity; -0.447 SD units, p = .014) were most strongly associated with slow gait speed, followed by slower chair stand pace (-0.195 SD units, p = .002) and greater lap time variation (0.102 SD units, p = .028). Lower muscle strength (-0.582 SD units, p = .001) was most strongly associated with mobility difficulty, followed by slower chair stand pace (-0.322 SD units, p < .001), slower gait speed (-0.247 SD units, p < .001), and poorer standing balance (-0.190 SD units, p = .043).

CONCLUSIONS

Components of manual dexterity and strength were the strongest correlates of slow gait and mobility difficulty in mid-to-late life. Longitudinal studies examining relationships between changes in these motor parameters and mobility are needed to elucidate possible causal effects.

What cut-point in gait speed best discriminates community dwelling older adults with mobility complaints from those without? A pooled analysis from the Sarcopenia Definitions and Outcomes Consortium

BACKGROUND

Cut-points to define slow walking speed have largely been derived from expert opinion.

METHODS

Study participants (13,589 men and 5,043 women aged ≥65years) had walking speed (m/s) measured over 4-6 meters (mean ± SD: 1.20 ± 0.27 m/s in men and 0.94 ± 0.24 m/s in women.) Mobility limitation was defined as self-reported any difficulty with walking ~1/4 mile (prevalence: 12.6% men, 26.4% women). Sex-stratified classification and regression tree (CART) models with 10-fold cross-validation identified walking speed cut-points that optimally discriminated those who reported mobility limitation from those who did not.

RESULTS

Among 5,043 women, CART analysis identified two cut-points, classifying 4,144 (82.2%) with walking speed ≥0.75 m/s, which we labeled as "fast"; 478 (9.5%) as "intermediate" (walking speed ≥0.62 m/s but <0.75 m/s); and 421 (8.3%) as "slow" (walking speed <0.62 m/s). Among 13,589 men, CART analysis identified three cut-points, classifying 10,001 (73.6%) with walking speed ≥1.00 m/s ("very fast"); 2,901 (21.3%) as "fast" (walking speed ≥0.74 m/s but <1.00 m/s); 497 (3.7%) as "intermediate" (walking speed ≥0.57 m/s but <0.74 m/s); and 190 (1.4%) as "slow" (walking speed <0.57 m/s). Prevalence of self-reported mobility limitation was lowest in the "fast" or "very fast" (11% for men and 19% for women) and highest in the "slow" (60.5% in men and 71.0% in women). Rounding the two slower cut-points to 0.60 m/s and 0.75 m/s reclassified very few participants.

CONCLUSIONS

Cut-points in walking speed of ~0.60 m/s and 0.75 m/s discriminate those with self-reported mobility limitation from those without.

The Roles of Body Composition and Specific Strength in the Relationship Between Race and Physical Performance in Older Adults

BACKGROUND

Socioeconomics may explain black-white differences in physical performance; few studies examine racial differences among socioeconomically similar groups. Performance is also affected by body composition and specific strength, which differ by race. We assessed whether racial differences in physical performance exist among older adults with high education and similar income and whether body composition and specific strength attenuate observed differences.

METHODS

Cross-sectional analysis of 536 men (18% black) and 576 women (28% black) aged more than 60 years from the Baltimore Longitudinal Study of Aging. Body composition was evaluated using dual-energy x-ray absorptiometry. Specific strength was assessed by quadricep peak torque divided by height-normalized thigh cross-sectional area and grip strength divided by body mass index-normalized appendicular lean mass. Physical performance was assessed using usual gait speed and fast 400 m walk time. Sex-stratified linear regression models, adjusted for age, height, education, and recent income, determined whether body composition or specific strength attenuated associations between race and physical performance.

RESULTS

Blacks were younger, with higher weight and appendicular lean mass. Black women had higher percent fat and specific strength. In both sexes, blacks had poorer physical performance after adjustment for socioeconomic factors. In women, neither body composition nor specific strength altered the association with gait speed. In men, neither body composition nor specific strength attenuated racial differences in either performance measure.

CONCLUSIONS

Poorer physical performance among black compared to white older adults persists among persons with high education and similar income and cannot generally be attributed to differences in body composition or specific strength.

Physical Performance and Cognition in a Diverse Cohort: Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study

BACKGROUND

The authors assessed the cross-sectional association of physical function measures with cognition in the Kaiser Healthy Aging and Diverse Life Experiences Cohort.

METHODS

Analyses included 1369 participants (24% Asian, 26% Black, 18% Latino, 32% White). Grip strength was measured using a hand-held dynamometer (kilograms) and gait speed was measured over a 4-m walk (seconds/meter). The Spanish and English Neuropsychological Assessment Scales was used to evaluate cognitive domains of executive function, semantic memory, and verbal episodic memory. Physical function measures (per SD) were associated with cognitive test z-scores in linear regression models adjusted for demographic, behavioral, and clinical factors. Racial/ethnic differences were tested using interaction terms and stratification.

RESULTS

Stronger grip was associated with better executive function [β=0.10 (95% confidence interval, 0.05-0.15)], semantic memory [β=0.13 (0.09-0.18)] and verbal episodic memory [β=0.07 (0.02-0.13)] with no racial/ethnic differences. Faster gait was associated with better executive function [β=0.29 (0.22-0.36)], semantic memory [β=0.23 (0.16-0.30)], and verbal episodic memory [β=0.20 (0.13-0.27)]; however, the association between gait speed and executive function varied by race/ethnicity with the strongest associations in Asians and Whites.

CONCLUSION

Across race/ethnicity, grip strength and gait speed were associated with cognition with racial/ethnic differences in the association of gait speed and executive function.

Subjective Motoric Complaints and New Onset Slow Gait

BACKGROUND

While reports of mobility problems are common with aging, their relationship to new onset of slow gait is unknown. Our objective was to examine the validity of subjective motoric complaints for predicting the incidence of slow gait.

METHODS

Ambulatory community-residing participants (mean age 76.6, 55% women) with gait speeds in the normal range enrolled in an aging cohort. Five subjective motoric complaints were assessed. Incident slow gait (walking speed 1 SD below age and sex means) was the primary outcome.

RESULTS

Of the 548 participants at baseline, 90 had prevalent slow gait and 253 participants (73.7%) reported one or more subjective motoric complaints. Subjective motoric complaints were more common in women than men (1.78 vs 1.23). Over a median follow-up of 3.34 years, 68 participants developed new onset slow gait. All 5 questions predicted incident slow gait (adjusted hazard ratios varying from 2.26 to 4.44). More subjective motoric complaints were associated with increased risk of developing incident slow gait (hazard ratio per complaint 1.81). Predictive validity of subjective motoric complaints for incident slow gait was unchanged when using alternate outcome definitions, accounting for diagnostic misclassification, recall bias, or adjusting for multiple confounders.

CONCLUSIONS

Subjective motoric complaints are a harbinger of mobility disability, and can help improve clinical risk assessments and identify high-risk individuals for interventions to prevent onset of slow gait.

Racial differences in gait mechanics

The effect of race has rarely been investigated in biomechanics studies despite racial health disparities in the incidence of musculoskeletal injuries and disease, hindering both treatment and assessment of rehabilitation. The purpose of this study was to test the hypothesis that racial differences in gait mechanics exist between African Americans (AA) and white Americans (WA). Ninety-two participants (18-30 years old) were recruited with equal numbers in each racial group and sex. Self-selected walking speed was measured for each participant. 3D motion capture and force plate data were recorded during 7 walking trials at regular and fast set speeds. Step length, step width, peak vertical ground reaction force, peak hip extension, peak knee flexion, and peak ankle plantarflexion were computed for all trials at both set speeds. Multivariate and post-hoc univariate ANOVA models were fit to determine main and interaction effects of sex and race (SPSS V26, α = 0.05). Self-selected walking speed was slower in AA (p = 0.004, ƞ_p² = 0.088). No significant interactions between race and sex were identified. Males took longer steps (regular: p < 0.001, ƞ_p² = 0.288, fast: p < 0.001, ƞ_p² = 0.193) and had larger peak knee flexion (regular: p = 0.007, ƞ_p² = 0.081, fast: p < 0.001, ƞ_p² = 0.188) and ankle plantarflexion angles (regular: p = 0.050, ƞ_p² = 0.044, fast: p = 0.049, ƞ_p² = 0.044). Peak ankle plantarflexion angle (regular: p = 0.012, ƞ_p² = 0.071, fast: p < 0.001, ƞ_p² = 0.137) and peak hip extension angle during fast walking (p = 0.007, ƞ_p² = 0.083) were smaller in AA. Equivalency in gait measures between racial groups should not be assumed. Racially diverse study samples should be prioritized in the development of future research and individualized treatment protocols.

Motoric cognitive risk syndrome: Integration of two early harbingers of dementia in older adults

Dementia is characterized by a long preclinical phase that may last years to decades before the onset of mild cognitive impairment. Slow gait speed and subjective memory complaint commonly co-occur during this preclinical phase, and each is a strong independent predictor of cognitive decline and dementia. Motoric cognitive risk (MCR) syndrome is a pre-dementia syndrome that combines these two early harbingers of dementia. The risk of cognitive decline or dementia is stronger for MCR than for either slow gait speed or subjective memory complaint alone. Slow gait speed and subjective memory complaint have several common risk factors: cardiovascular disease, diabetes mellitus, abnormal cortisol profiles, low vitamin D levels, brain atrophy with decreased hippocampal volume, and increased deposition of beta-amyloid in the brain. The underlying pathogenesis of MCR remains poorly understood. Metabolomics and proteomics have great potential to provide new insights into biological pathways involved in MCR during the long preclinical phase preceding dementia.

Home-Based Gait Speed Assessment: Normative Data and Racial/Ethnic Correlates Among Older Adults

OBJECTIVES

To determine home-based gait speed performance and its associations with sociodemographic and health-related factors among older adults.

DESIGN

Cross-sectional analysis of a nationally representative US population sample.

SETTING AND PARTICIPANTS

Homes of Health and Retirement Study (HRS) participants.

METHODS

Walk test data measured at home over 2.5 m were aggregated for 6983 individuals, aged ≥65 years (mean age 74.8 ± 6.9 years, 54.2% women), from the 2006 and 2008 HRS waves. Means for gait speed at normal pace were determined for demographic and clinical groupings; association of gait speed with demographic, socioeconomic status, and health factors were examined. Four-year mortality was predicted from baseline slow gait status defined using demographic-based cutoff scores as well as commonly recommended cutoff scores (100 or 60 cm/s).

RESULTS

Home-based gait speed (cm/s) means were lower for female than male (9.6% difference), older than younger (18.0% difference), African American than white (20.5% difference), and Hispanic than Non-Hispanic (10.3% difference) participants. Differences by age group, race, and ethnicity remained significant within sexes (P < .001). Lower speed was associated with African American race and all health problems; higher speed was associated with higher socioeconomic status and alcohol consumption. Four-year mortality was predicted by slow gait status. Predictive validity was, in general, higher for slow gait cutoff scores defined by demographic characteristics.

CONCLUSIONS AND IMPLICATIONS

Mean gait speed measured at home differs among older (aged ≥65 years) US resident population groups defined by sex, age, race, ethnicity, health status, and combinations of these factors, and predicts 4-year mortality when substantially slower than group-based norms. These findings may assist researchers and clinicians in determining normal and abnormal gait performance in older adults in community settings.

Racial-Ethnic Differences in Osteoarthritis Pain and Disability: A Meta-Analysis

Osteoarthritis (OA), a leading cause of disability and pain, affects 32.5 million Americans, producing tremendous economic burden. Although some findings suggest that racial/ethnic minorities experience increased OA pain severity, other studies have shown conflicting results. This meta-analysis examined differences in clinical pain severity between African Americans (AAs) and non-Hispanic whites with OA. Articles were initially identified between October 1 and 5, 2016, and updated May 30, 2018, using PubMed, Web of Science, PsycINFO, and the Cochrane Library Database. Eligibility included English-language peer-reviewed articles comparing clinical pain severity in adult black/AA and non-Hispanic white/Caucasian patients with OA. Nonduplicate article abstracts (N = 1,194) were screened by 4 reviewers, 224 articles underwent full-text review, and 61 articles reported effect sizes of pain severity stratified by race. Forest plots of the standard mean difference showed higher pain severity in AAs for studies using the Western Ontario and McMasters Universities Osteoarthritis Index (0.57; 95% confidence interval [CI], 0.54-0.61) and non-Western Ontario and McMasters Universities Osteoarthritis Index studies (0.35, 95% CI, 0.23-0.47). AAs also showed higher self-reported disability (0.38, 95% CI, 0.22-0.54) and poorer performance testing (-0.58, 95% CI, -0.72 to -0.44). Clinical pain severity and disability in OA is higher among AAs and future studies should explore the reasons for these differences to improve pain management. PERSPECTIVE: This meta-analysis shows that differences exist in clinical pain severity, functional limitations, and poor performance between AAs and non-Hispanic whites with OA. This research may lead to a better understanding of racial/ethnic differences in OA-related pain.

Big data vs accurate data in health research: Large-scale physical activity monitoring, smartphones, wearable devices and risk of unconscious bias

Fundamental to the advancement of scientific knowledge is unbiased, accurate and validated measurement techniques. Recent United Nations and landmark Nature publications highlight the global uptake of mobile technology and the staggering potential for big data to encourage people to be physically active and to influence health policy. However, concerns exist about inconsistencies in smartphone health apps. Big data has many benefits, but noisy data may lead to wrong conclusions. In reaction to the increasing availability of low quality data; we call for a rigorous debate into the validity of substituting big data for accurate data in health research. We evaluated the step counting accuracy of a smartphone app previously used by 717,527 people from 111 countries. Our new data (from 48 participants; aged 21-59 years; body mass index 17.7-33.5 kg/m²) revealed significant (15-66%) undercounting by Apple phones. In contrast to the generally positive performances of wearable devices for stereotypical treadmill like walking, we observed extraordinarily large (0-200% of steps taken) error ranges for both Android and Apple phones. Unconscious bias (developers' perceptions of usual behaviour) may be embedded into many unvalidated smartphone apps. Consumer-grade wearable devices appear unsuitable to detect steps in people with slow, short or non-stereotypical gait patterns. Specifically, there is a risk of systematically undercounting the steps by obese people, females or people from different ethnic groups resulting in biases when reporting associations between physical inactivity and obesity. More research is required to develop smartphone apps suitable for all people of the heterogeneous global population.

The influence of South Asian ethnicity on the incremental shuttle walk test in UK adults

The objective of this study was to compare incremental shuttle walking test (ISWT) performance between South Asian and Caucasian British adults, identify predictors of ISWT distance and produce ethnicity-specific reference equations. Data from a mixed gender sample aged 40–75 years from Leicestershire, United Kingdom, were selected for analyses. Analysis of covariance determined differences in ISWT performance between South Asian and Caucasian British ethnic groups. Linear regressions identified predictors of ISWT distance, which determined the reference equations. In total, 144 participants took part in the study (79 South Asian (54 ± 8 years, 71% female) and 65 Caucasian British (58 ± 9 years, 74% female)). Distance walked for the ISWT was shorter for South Asian individuals compared with Caucasian British (451 ± 143 vs. 575 ± 180 m, p < 0.001). The ethnicity-specific reference equations for ISWT distance explained 33–50% of the variance (standard error of the estimate (SEE): 107–119 m) for South Asians and explained 14–58% of the variance (SEE: 121–169 m) for Caucasian British. Ethnicity univariately explained 12.9% of the variance in ISWT distance and was significantly associated with ISWT distance after controlling for age, gender, height, weight, dyspnoea and lung function (B = −70.37; 1 = Caucasian British, 2 = South Asian), uniquely explaining 3.7% of the variance. Predicted values for ISWT performance were lower in South Asian people than in Caucasian British. Ethnicity-specific reference equations should account for this.

Dizziness Handicap Inventory Score Is Highly Correlated With Markers of Gait Disturbance

OBJECTIVE

To evaluate the association between Dizziness Handicap Inventory-Screening version (DHI-S) score and spatiotemporal gait parameters using SoleSound, a newly developed, inexpensive, portable footwear-based gait analysis system.

STUDY DESIGN

Cross-sectional.

PATIENTS

One hundred eighteen patients recruited from otology clinic.

INTERVENTION(S)

Subjects completed the DHI-S survey and four uninterrupted walking laps wearing SoleSound instrumented footwear on a hard, flat surface for 100 m.

MAIN OUTCOME MEASURE(S)

For each subject, mean and coefficient of variation (CV) of stride length, cadence, walking speed, foot-ground clearance, double-support time, swing period, and stance-to-swing were computed by considering 40 strides of steady-state walking within each lap. Linear regression models were employed to study correlations between these variables and DHI-S scores after adjusting for age, sex, and race/ethnicity.

RESULTS

Patients with higher DHI-S score took shorter steps and less steps per minute (-0.017 m and -1.1 steps/min per every four-point increase in DHI-S score, p < 0.05) than patients with a lower DHI-S score, with slower walking speed (-0.025 m/s per every four-point increase in DHI-S score, p < 0.01). Additionally, patients with higher DHI-S scores showed larger variability in all analyzed temporal parameters (+0.1% for CV of cadence, +0.5% for CV of double support period, +0.2% for CV of swing period, and +0.4% for CV of stance-to-swing, per every four-point increase in DHI-S score, p < 0.01).

CONCLUSION

SoleSound was effective in measuring a wide range of gait parameters. Patients' self-perception of vestibular handicap, as assessed with DHI-S, is associated with deterioration in measurable gait parameters independent of age.

The correlates of slow gait and its relation with social network among older adults in Singapore

OBJECTIVES

This study aimed to identify socio-demographic correlates of slow gait speed among Singapore older adult residents and to examine the relationship between slow gait speed and the older adult residents' social network, physical health status, disability and mental health status.

METHODS

Trained interviewers administered the adapted 10/66 research protocol through face-to-face interviews to 2565 respondents aged 60 and over. Information on gait test, socio-demographic characteristics, obesity, social network, physical status and activity, overall health, disability and mental health status were collected. The gait test was completed by 2192 participants. Slow gait was defined as walking speed of 1 standard deviation (SD) below age and gender specific mean gait of the sample.

RESULTS

The prevalence of slow gait speed after adjusting for age and gender was 13.7%. Slow gait speed was more prevalent among Indians, respondents with low education, and those who were retired. Those with slow gait speed were significantly associated with lower probability of being unemployed and attending religious activities. They were significantly associated with not being physically active and reported a higher disability score.

CONCLUSION

Older adult residents' socio-demographic factors were found to be associated with gait speed. Those with slow gait speed were not physically active and had less frequent contact with people through religious activities and this might place them at risk of being socially isolated, which can have consequences. Gait speed can be included as a routine assessment tool to identify at-risk groups for interventions which aim to keep the older adults socially engaged and healthy.

Associations Between Inflammation and Physical Function in African Americans and European Americans with Prevalent Cardiovascular Risk Factors

OBJECTIVES

To examine associations between inflammation and physical function and potential mediation by white matter hyperintensities (WMHs) in African Americans (AAs) and European Americans (EAs).

DESIGN

Cross-sectional analysis using linear and logistic models with generalized estimating equations to account for family clustering, reporting results as regression coefficients (β) and odds ratios (ORs) adjusted for education, alcohol, exercise, body mass index, hypertension, diabetes mellitus, heart disease, cognition, ankle-brachial index, race (site), and supported interactions.

SETTING

Genetic Epidemiology Network of Arteriopathy-Genetics of Microangiopathic Brain Injury Study cohort.

PARTICIPANTS

AA and EA sibships with two or more siblings with hypertension before age 60 (N = 1,960; 65% female, 51% AA, aged 26-91, 50% obese, 72% hypertensive).

MEASUREMENTS

Inflammation (C-reactive protein (CRP), interleukin-6 (IL6), soluble tumor necrosis factor receptors (sTNFRs) 1 and 2, WMH volume (cm(3) ) according to magnetic resonance imaging), walking speed (cm/s) over 25 feet, and mobility difficulty (any self-reported difficulty walking half a mile).

RESULTS

In separate models, inflammatory markers were associated with walking speed (sTNFR1: β = -2.74, P < .001; sTNFR2: β = -1.23, P = .03; CRP: β = -1.95, P = .001; IL6: β = -1.24, P = .03) and mobility difficulty (sTNFR1: OR = 1.36, P = .001; sTNFR2: OR = 1.25, P = .005; CRP: OR = 1.22, P = .005; IL6: OR = 1.18, P = .02); the association between WMH volume and sTNFR1 in AA (β = 0.07, P = .06) did not reach typical statistical thresholds. WMH volume was associated with walking speed in AA (β = -3.17, P = .02) but not with mobility difficulty (OR = 1.10, P = .54). Adjusting for WMH did not change associations.

CONCLUSION

In young, middle-aged, and older adults with prevalent cardiovascular risk factors, multiple inflammatory biomarkers were associated with slower walking speed independent of microvascular disease in the brain. There was little evidence of mediation by brain WMH volume. Inflammation may contribute to physical function impairments through pathways other than brain microvascular disease, particularly in AAs.

Clinically relevant weakness in diverse populations of older adults participating in the International Mobility in Aging Study

The aims of this study were to compare cut points for weakness proposed by Foundation for the National Institutes of Health (FNIH) Sarcopenia Project with cut points estimated with our own data; to assess the prevalence of clinically relevant handgrip strength (HGS) weakness according to published criteria across distinct populations of older adults; to estimate the ability of HGS weakness to identify slowness. This is a cross-sectional analysis of International Mobility in Aging Study (IMIAS) involving 1935 community-dwelling older adults, between 65 and 74 years, who completed HGS and gait speed assessment. We used baseline data from Tirana (Albania), Natal (Brazil), Manizales (Colombia), Kingston (Ontario, Canada), and Saint-Hyacinthe (Quebec, Canada). Weakness was defined according to sex-specific HGS cut points associated with slowness proposed by FNIH Sarcopenia Project. Slowness was defined as gait speed <0.8 m/s. IMIAS cut points for clinical weakness had good agreement with those proposed by FNIH. Weakness prevalence across the research sites ranged from 1.1 % (Saint-Hyacinthe) to 19.2 % (Manizales) among men. Women from Manizales (13.5 %) and Natal (19.3 %) had higher prevalence of weakness than their counterparts. FNIH cut points had a strong association with slowness, for both sexes. The IMIAS population generated cut points which were close to those proposed by FNIH. There was large variability in prevalence of weakness across our research sites. The HGS cut points for weakness proposed by FNIH performed well in IMIAS populations, providing a useful tool for screening older adults at risk for functional problems.

Race Differences: Use of Walking Speed to Identify Community-Dwelling Women at Risk for Poor Health Outcomes--Osteoarthritis Initiative Study

BACKGROUND

Onset of disability, risk for future falls, frailty, functional decline, and mortality are strongly associated with a walking speed of less than 1.0 m/s.

OBJECTIVE

The study objective was to determine whether there were differences in slow walking speed (<1.0 m/s) between community-dwelling African American and white American adult women with osteoarthritis symptoms. An additional aim was to examine whether racial differences in walking speed can be attributed to age, obesity, socioeconomic factors, disease severity, or comorbidities.

DESIGN

A cross-sectional design was used.

METHODS

Community-dwelling adults were recruited from Baltimore, Maryland; Columbus, Ohio; Pittsburgh, Pennsylvania; and Pawtucket, Rhode Island. Participants were 2,648 women (23% African American) who were 45 to 79 years of age and had a self-selected baseline walking speed of 20 m/s in the Osteoarthritis Initiative Study. Mixed-effects logistic regression models were used to examine racial differences in walking speed (<1.0 m/s versus ≥1.0 m/s), with adjustments for demographic factors, socioeconomic factors, disease severity, and comorbidities.

RESULTS

Walking speed was significantly slower for African American women than for white American women (mean walking speed=1.19 and 1.33 m/s, respectively). The prevalence of a walking speed of less than 1.0 m/s in this cohort of middle-aged women was 9%; about 50% of the women with a walking speed of less than 1.0 m/s were younger than 65 years. Women with a walking speed of less than 1.0 m/s had lower values for socioeconomic factors, higher values for disease severity, and higher prevalences of obesity and comorbidities than those with a walking speed of ≥1.0 m/s. After controlling for these covariates, it was found that African American women were 3 times (odds ratio=2.9; 95% confidence interval=2.0, 4.1) more likely to have a walking speed of less than 1.0 m/s than white American women.

LIMITATIONS

The study design made it impossible to know whether a walking speed of less than 1.0 m/s in women who were 45 years of age or older was a predictor of future poor health outcomes.

CONCLUSIONS

In this study, race was independently associated with a walking speed of less than 1.0 m/s in community-dwelling women who had or were at risk for osteoarthritis, with African American women having 3 times the risk for slow walking as white American women. This finding suggests that middle-aged African American women have an increased risk for poor health outcomes. Further longitudinal evaluations are needed to confirm the long-term health outcomes in a middle-aged population and to establish walking speed as a useful tool for identifying middle-aged women at high risk for poor health outcomes.

Efeito agudo do alongamento na marcha de idosas em terreno inclinado

Introdução O envelhecimento causa modificações musculares que influenciam negativamente a capacidade funcional dos idosos na locomoção, em especial durante a transposição de superfícies inclinadas. Essas mudanças geram redução da performance, diminuindo a mobilidade e aumentando o risco de queda na execução de tal tarefa. Os exercícios de alongamento podem reduzir a influência de dessas degenerações, preservando a capacidade muscular e a mobilidade. Objetivo O objetivo deste estudo foi avaliar a atuação do efeito agudo de uma sessão de exercícios de alongamento sobre a marcha de idosas durante a locomoção em uma rampa. Materiais e métodos Doze mulheres idosas, saudáveis e independentes, caminharam subindo e descendo uma rampa com inclinação de 10%. A análise cinemática (2D) e eletromiográfica foi realizada durante uma única sessão experimental, imediatamente antes (PRÉ) e após (PÓS) a realização de um exercício de alongamento estático dos flexores do quadril. Resultados O exercício de alongamento gerou aumento da amplitude (PRÉ 52,3 ± 18,30; PÓS 63,6 ± 16,90) e velocidade (PRÉ 195,8 ± 31,20/s; PÓS 241,8 ± 29,80/s) do quadril, assim como redução do tempo de ativação do tibial anterior (PRÉ TAFIN1 29,7 ± 6,7%; TAFIN2 100,0 ± 0,0%; PÓS TAFIN1 23,3 ± 7,4%; TAFIN2 87,7 ± 3,4%) e do bíceps femoral (PRÉ 45,0 ± 5,4%; PÓS 36,1 ± 10,4%) na subida na rampa. Na descida ocorreu aumento na velocidade da marcha (PRÉ 0,95 ± 0,18 m.s-1; PÓS 1,01 ± 0,22 m.s-1) e tamanho do passo (PRÉ 1,02 ± 0,15 m; PÓS 1,08 ± 0,18 m). Conclusão Os exercícios utilizados foram capazes de alterar de forma significativa os parâmetros avaliados, permitindo uma marcha mais veloz e reduzindo a ativação muscular. Estudos longitudinais são necessários para que os resultados aqui encontrados de forma temporária possam ser confirmados de forma permanente.

Fall Risk is Not Black and White

OBJECTIVE

To determine whether previously reported racial differences in fall rates between White and Black/African American is explained by differences in health status and neighborhood characteristics.

DESIGN

Prospective cohort.

SETTING

Community.

PARTICIPANTS

The study included 550 White and 116 Black older adults in the Greater Boston area (mean age: 78 years; 36% men) who were English-speaking, able to walk across a room, and without severe cognitive impairment.

MEASUREMENTS

Falls were prospectively reported using monthly fall calendars. The location of each fall and fall-related injuries were asked during telephone interviews. At baseline, we assessed risk factors for falls, including sociodemographic characteristics, physiologic risk factors, physical activity, and community-level characteristics.

RESULTS

Over the mean follow-up of 1,048 days, 1,539 falls occurred (incidence: 806/1,000 person-years). Whites were more likely than Blacks to experience any falls (867 versus 504 falls per 1,000 person-years; RR [95% CI]: 1.77 [1.33, 2.36]), outdoor falls (418 versus 178 falls per 1,000 person-years; 1.78 [1.08, 2.92]), indoor falls (434 versus 320 falls per 1,000 person-years; 1.44 [1.02, 2.05]), and injurious falls (367 versus 205 falls per 1,000 person-years; 1.79 [1.30, 2.46]). With exception of injurious falls, higher fall rates in Whites than Blacks were substantially attenuated with adjustment for risk factors and community-level characteristics: any fall (1.24 [0.81, 1.89]), outdoor fall (1.57 [0.86, 2.88]), indoor fall (1.08 [0.64, 1.81]), and injurious fall (1.77 [1.14, 2.74]).

CONCLUSION

Our findings suggest that the racial differences in fall rates may be largely due to confounding by individual-level and community-level characteristics.

Role of APOE genotype in gait decline and disability in aging

OBJECTIVES

Although apolipoprotein E (APOE) genetic variation may influence risk of gait decline and disability in aging through multiple mechanisms, a systematic examination of this relationship has been lacking. Our objective was to quantify the risk of gait decline and disability associated with the APOE ε4 allele in aging.

METHODS

We evaluated 627 community-dwelling adults aged 70 and older (white 67.8%) with APOE genotype and quantitative gait measurements participating in the Einstein Aging Study over a median follow-up of 3.0 years. Main outcomes were gait speed decline (cm/s/year) and incident disability.

RESULTS

APOE ε4 allele frequency was 24.1%. Presence of APOE ε4 was not significantly associated with gait speed decline overall (p = .37) but was associated with faster gait speed decline in older men (estimate: -1.16, 95% CI: -2.31 to -0.01, p = .04). The interaction between the ε4 allele and male sex predicted gait speed decline (estimate: -1.70, 95% CI: -3.33 to -0.07, p = .04). Presence of the APOE ε4 allele was associated with increased risk of disability in older men (HR 3.72, 95% CI: 1.44-9.59, p = .007). Associations of the ε4 allele with study outcomes remained significant even after accounting for several potential confounders including vascular and cognitive status. The strength of the associations was stronger in the white subgroup.

CONCLUSION

This preliminary report suggests that the APOE ε4 allele is associated with increased risk of gait speed decline and disability in older men.

Gait speed correlates in a multiracial population of community-dwelling older adults living in Brazil: a cross-sectional population-based study

Background

Gait speed is a strong predictor of a wide range of adverse health outcomes in older adults. Mean values for gait speed in community-dwelling older adults vary substantially depending on population characteristics, suggesting that social, biological, or health factors might explain why certain groups tend to self-select their gait speed in different patterns. The vast majority of studies reported in the literature present data from North American and European populations. There are few population-based studies from other regions with a different ethnicity and/or social and health conditions. To address this, the present study identified the mean usual and fast gait speeds in a representative multiracial population of community-dwelling older adults living in a developing country, and explored their association with sociodemographic, mental and physical health characteristics.

Methods

This was a cross-sectional population-based study of a sample of 137 men and 248 women, aged 65 years and over. Usual gait speed and fast gait speed were measured on a 4.6 m path. Participants were classified into slow, intermediate, and faster groups by cluster analysis. Logistic regression analysis was used to estimate the independent effect of each factor on the odds of presenting with a slower usual and slower fast gait speeds.

Results

Participants had a mean (SD) usual gait speed of 1.11 (0.27) m/s and a mean fast gait speed of 1.39 (0.34) m/s. We did not observe an independent association between gait speed and race/ethnicity, educational level, or income. The main contributors to present a slower usual gait speed were low physical activity level, stroke, diabetes, urinary incontinence, high concern about falling, and old age. A slower fast gait speed was associated with old age, low physical activity, urinary incontinence and high concern about falling.

Conclusion

A multiracial population of older adults living in a developing country showed a similar mean gait speed to that observed in previously studied populations. The results suggest that low physical activity, urinary incontinence and high concern about falling should not be neglected and may help identify those who might benefit from early intervention.