Long-term trajectories of lower extremity function in older adults: estimating gender differences while accounting for potential mortality bias

Racial/ethnic/gender-Based Differences in Health Trajectories Among American Older Adults: 10-Year Longitudinal Evidence from the Health and Retirement Study

Health disparity by race/ethnicity or gender has been well-documented. However, few researchers have examined health outcomes based on the intersection of individuals' race, ethnicity, and gender or investigated various health dimensions. Guided by an intersectionality framework, this study explores racial/ethnic/gender-based differences in trajectories of multiple health outcomes over a ten-year period among American older adults. Longitudinal data from the Health and Retirement Study (2004-2014) were used (N = 16,654). Older adults (65+) were stratified into six mutually-exclusive groups based on their race, ethnicity, and gender: Non-Hispanic (NH) White Men, NH White Women, NH Black Men, NH Black Women, Hispanic Men, and Hispanic Women. Growth curve models examined the trajectories of three health measures, including cognitive function, physical function limitations (i.e. activities of daily living and instrumental activities of daily living), and depressive symptoms. NH White men and women reported significantly better outcomes in cognition and physical function trajectories than racial/ethnic minority groups. Women in all racial/ethnic groups had more depressive symptoms but better cognition than men. Hispanic women reported the most depressive symptoms. Hispanic women and NH Black women had the worst physical function limitations. NH Black men/women were the most disadvantaged in cognition. Racial/ethnic/gender-based differences were stable over time in all health trajectories. Study findings highlight the utility of an intersectional framework in understanding how multiple social identities intersect to generate protective and/or risk effects on cognitive, mental, and physical health. Multilevel intervention strategies are warranted to reduce the persistent health inequity gap.

Associations between diabetes status and grip strength trajectory sub-groups in adulthood: findings from over 16 years of follow-up in the MRC National Survey of Health and Development

BACKGROUND

Cross-sectional studies suggest a relationship between diabetes status and weaker grip strength (GS) in adulthood and limited evidence from longitudinal studies has focussed on the association with average change in GS. We aimed to investigate whether diabetes status was related to membership of distinct GS trajectories in mid-to-late adulthood in 2,263 participants in the Medical Research Council National Survey of Health and Development.

METHODS

Grip strength (kg) was measured at 53, 60-64 and 69 years. Pre-/diabetes was defined at 53 years based on HbA1c > 5.6% and/or doctor-diagnosis of diabetes. Sex-specific latent class trajectory models were developed and multinomial logistic regression was used to investigate the association between pre-/diabetes status and membership into GS trajectory classes.

RESULTS

For both males and females, a 3-class solution ('High', 'Intermediate', 'Low') provided the best representation of the GS data and the most plausible solution. There was no evidence that pre-/diabetes status was associated with class membership in either sex: e.g., adjusted odds ratios of being in the 'Low' class (vs. 'High') for males with pre-/diabetes (vs. no-diabetes) was 1.07 (95% CI:0.45,2.55).

CONCLUSION

Using a flexible data-driven approach to identify GS trajectories between 53 and 69 years, we observed three distinct GS trajectories, all declining, in both sexes. There was no association between pre-/diabetes status at 53 years and membership into these GS trajectories. Understanding the diabetes status-GS trajectories association is vital to ascertain the consequences that projected increases in pre-/diabetes prevalence's are likely to have.

Patterns of Muscle-Related Risk Factors for Sarcopenia in Older Mexican Women

Early detriment in the muscle mass quantity, quality, and functionality, determined by calf circumference (CC), phase angle (PA), gait time (GT), and grip strength (GSt), may be considered a risk factor for sarcopenia. Patterns derived from these parameters could timely identify an early stage of this disease. Thus, the present work aims to identify those patterns of muscle-related parameters and their association with sarcopenia in a cohort of older Mexican women with neural network analysis. Methods: Information from the functional decline patterns at the end of life, related factors, and associated costs study was used. A self-organizing map was used to analyze the information. A SOM is an unsupervised machine learning technique that projects input variables on a low-dimensional hexagonal grid that can be effectively utilized to visualize and explore properties of the data allowing to cluster individuals with similar age, GT, GSt, CC, and PA. An unadjusted logistic regression model assessed the probability of having sarcopenia given a particular cluster. Results: 250 women were evaluated. Mean age was 68.54 ± 5.99, sarcopenia was present in 31 (12.4%). Clusters 1 and 2 had similar GT, GSt, and CC values. Moreover, in cluster 1, women were older with higher PA values (p < 0.001). From cluster 3 upward, there is a trend of worse scores for every variable. Moreover, 100% of the participants in cluster 6 have sarcopenia (p < 0.001). Women in clusters 4 and 5 were 19.29 and 90 respectively, times more likely to develop sarcopenia than those from cluster 2 (p < 0.01). Conclusions: The joint use of age, GSt, GT, CC, and PA is strongly associated with the probability women have of presenting sarcopenia.

Trajectories of physical capacity among community-dwelling older adults in the United States

OBJECTIVE

Although the prognostic value of physical capacity is well-established, less is known about longitudinal patterns of physical capacity among community-dwelling older adults. We sought to describe long-term trajectories of physical capacity in a nationally representative sample of Medicare beneficiaries.

DESIGN

Cohort study SETTING AND PARTICIPANTS: Annually collected data on 6,783 community-dwelling participants in the National Health and Aging Trends Study from 2011 to 2016 were analyzed.

METHODS

Performance-based physical capacity was measured using the Short Physical Performance Battery [(SPPB) range: 0-12, higher is better]. Self-reported physical capacity was measured using six pairs of activities with composite scores from 0 to 12 (higher is better). We then used group-based trajectory modeling to identify longitudinal patterns of each physical capacity measure over 6 years. Associations of baseline characteristics with trajectories were examined using multinomial logistic regression.

RESULTS

The cohort was 57% female, 68% white, and 58% were ≥75 years. Six distinct trajectories of SPPB scores were identified. Two "high" groups (n = 2192, 43%) maintained high average SPPB scores. Two "moderate decline" groups (n = 1459, 29%) had a mid-range SPPB score at baseline and demonstrated gradual decline. A "low decline" group (n = 811, 16%) started with a low SPPB score and experienced a greater decline. A "very low" group (n = 590, 12%) had very low SPPB scores in all years. Six trajectories for self-reported physical capacity were also identified. Older age, worse health, lower income and education, and being Black or Hispanic were associated with lower and declining physical capacity.

Associations of Word Memory, Verbal Fluency, Processing Speed, and Crystallized Cognitive Ability With One-Legged Balance Performance in Mid- and Later Life

BACKGROUND

Cognitive integration of sensory input and motor output plays an important role in balance. Despite this, it is not clear if specific cognitive processes are associated with balance and how these associations change with age. We examined longitudinal associations of word memory, verbal fluency, search speed, and reading ability with repeated measures of one-legged balance performance.

METHOD

Up to 2 934 participants in the MRC National Survey of Health and Development, a British birth cohort study, were included. At age 53, word memory, verbal fluency, search speed, and reading ability were assessed. One-legged balance times (eyes closed) were measured at ages 53, 60-64, and 69 years. Associations between each cognitive measure and balance time were assessed using random-effects models. Adjustments were made for sex, death, attrition, height, body mass index, health conditions, health behaviors, education, and occupational class.

RESULTS

In sex-adjusted models, 1 SD higher scores in word memory, search speed, and verbal fluency were associated with 14.1% (95% CI: 11.3, 16.8), 7.2% (4.4, 9.9), and 10.3% (7.5, 13.0) better balance times at age 53, respectively. Higher reading scores were associated with better balance, although this association plateaued. Associations were partially attenuated in mutually adjusted models and effect sizes were smaller at ages 60-64 and 69. In fully adjusted models, associations were largely explained by education, although remained for word memory and search speed.

CONCLUSIONS

Higher cognitive performance across all measures was independently associated with better balance performance in midlife. Identification of individual cognitive mechanisms involved in balance could lead to opportunities for targeted interventions in midlife.

Bidirectional associations between word memory and one-legged balance performance in mid and later life

BACKGROUND

Age-related changes in cognitive and balance capabilities are well-established, as is their correlation with one another. Given limited evidence regarding the directionality of associations, we aimed to explore the direction and potential explanations of associations between word memory and one-legged balance performance in mid-later life.

METHODS

A total of 3062 participants in the Medical Research Council National Survey of Health and Development, a British birth cohort study, were included. One-legged balance times (eyes closed) were measured at ages 53, 60-64 and 69 years. Word memory was assessed at ages 43, 53, 60-64 and 69 with three 15-item word-recall trials. Autoregressive cross-lagged and dual change score models assessed bidirectional associations between word memory and balance. Random-effects models quantified the extent to which these associations were explained by adjustment for anthropometric, socioeconomic, behavioural and health status indicators.

RESULTS

Autoregressive cross-lagged and dual change score models suggested a unidirectional association between word memory and subsequent balance performance. In a sex-adjusted random-effects model, 1 standard deviation increase in word memory was associated with 9% (7,12%) higher balance performance at age 53. This association decreased with age (-0.4% /year (-0.6,-0.1%). Education partially attenuated the association, although it remained in the fully-adjusted model (3% (0.1,6%)).

CONCLUSIONS

There was consistent evidence that word memory is associated with subsequent balance performance but no evidence of the reverse association. Cognitive processing plays an important role in the balance process, with educational attainment providing some contribution. These findings have important implications for understanding cognitive-motor associations and for interventions aimed at improving cognitive and physical capability in the ageing population.

Relations of Executive Function and Physical Performance in Middle Adulthood: A Prospective Investigation in African American and White Adults

OBJECTIVES

Previous studies in older adults found robust associations between executive functions (EF) and physical performance, as well as sociodemographic variation in physical performance decline. To examine these associations earlier in the adult lifespan, we investigated relations of EF, race, and sex with age-related physical performance decline during middle adulthood.

METHOD

Participants were 2,084 urban-dwelling adults (57.2% female; 57.8% African American; 37.3% living in poverty; mean baseline age = 48.1) from the Healthy Aging in Neighborhoods of Diversity across the Life Span study. Mixed-effects regression was used to examine interactive relations among EF, race, sex, and age (indexing time) with change in dominant and nondominant handgrip strength and lower extremity strength over approximately 5 years. All analyses adjusted for poverty status, and subsequently adjusted for education, body mass index, hypertension, and diabetes.

RESULTS

There were no significant prospective associations between EF and decline in physical performance measures. Significant cross-sectional associations revealed that lower EF was associated with worse performance on all physical performance measures averaged across both time points (p < .05). A significant two-way interaction of Sex × Age (p = .019) revealed that men experienced greater age-related decline in lower extremity strength than women.

DISCUSSION

Findings did not reveal prospective associations between EF and physical performance decline in middle adulthood. However, they identified robust cross-sectional associations between EF and physical performance, and unexpectedly greater decline in lower extremity strength in men than women. Ultimately, these findings may inform prevention and intervention strategies targeting groups at risk for poorer physical function status and decline.

Associations Between Factors Across Life and One-Legged Balance Performance in Mid and Later Life: Evidence From a British Birth Cohort Study

Introduction: Despite its associations with falls, disability, and mortality, balance is an under-recognized and frequently overlooked aspect of aging. Studies investigating associations between factors across life and balance are limited. Understanding the factors related to balance performance could help identify protective factors and appropriate interventions across the life course. This study aimed to: (i) identify socioeconomic, anthropometric, behavioral, health, and cognitive factors that are associated with one-legged balance performance; and (ii) explore how these associations change with age.

Methods: Data came from 3,111 members of the MRC National Survey of Health and Development, a British birth cohort study. Multilevel models examined how one-legged standing balance times (assessed at ages 53, 60–64, and 69) were associated with 15 factors across life: sex, maternal education (4 years), paternal occupation (4 years), own education (26 years), own occupation (53 years), and contemporaneous measures (53, 60–64, 69 years) of height, BMI, physical activity, smoking, diabetes, respiratory symptoms, cardiovascular events, knee pain, depression and verbal memory. Age and sex interactions with each variable were assessed.

Results: Men had 18.8% (95%CI: 13.6, 23.9) longer balance times than women at age 53, although this difference decreased with age (11.8% at age 60–64 and 7.6% at age 69). Disadvantaged socioeconomic position in childhood and adulthood, low educational attainment, less healthy behaviors, poor health status, lower cognition, higher body mass index (BMI), and shorter height were associated with poorer balance at all three ages. For example, at age 53, those from the lowest paternal occupational classes had 29.6% (22.2, 38.8) worse balance than those from the highest classes. Associations of balance with socioeconomic indicators, cognition and physical activity became smaller with age, while associations with knee pain and depression became larger. There were no sex differences in these associations. In a combined model, the majority of factors remained associated with balance.

Discussion: This study identified numerous risk factors across life that are associated with one-legged balance performance and highlighted diverse patterns of association with age, suggesting that there are opportunities to intervene in early, mid and later life. A multifactorial approach to intervention, at both societal and individual levels, may have more benefit than focusing on a single risk factor.

MOBIlity assessment with modern TEChnology in older patients' real-life by the General Practitioner: the MOBITEC-GP study protocol

BACKGROUND

Mobility limitations in older adults are associated with poor clinical outcomes including higher mortality and disability rates. A decline in mobility (including physical function and life-space) is detectable and should be discovered as early as possible, as it can still be stabilized or even reversed in early stages by targeted interventions. General practitioners (GPs) would be in the ideal position to monitor the mobility of their older patients. However, easy-to-use and valid instruments for GPs to conduct mobility assessment in the real-life practice setting are missing. Modern technologies such as the global positioning system (GPS) and inertial measurement units (IMUs) - nowadays embedded in every smartphone - could facilitate monitoring of different aspects of mobility in the GP's practice.

METHODS

This project's aim is to provide GPs with a novel smartphone application that allows them to quantify their older patients' mobility. The project consists of three parts: development of the GPS- and IMU-based application, evaluation of its validity and reliability (Study 1), and evaluation of its applicability and acceptance (Study 2). In Study 1, participants (target N = 72, aged 65+, ≥2 chronic diseases) will perform a battery of walking tests (varying distances; varying levels of standardization). Besides videotaping and timing (gold standard), a high-end GPS device, a medium-accuracy GPS/IMU logger and three different smartphone models will be used to determine mobility parameters such as gait speed. Furthermore, participants will wear the medium-accuracy GPS/IMU logger and a smartphone for a week to determine their life-space mobility. Participants will be re-assessed after 1 week. In Study 2, participants (target N = 60, aged 65+, ≥2 chronic diseases) will be instructed on how to use the application by themselves. Participants will perform mobility assessments independently at their own homes. Aggregated test results will also be presented to GPs. Acceptance of the application will be assessed among patients and GPs. The application will then be finalized and publicly released.

DISCUSSION

If successful, the MOBITEC-GP application will offer health care providers the opportunity to follow their patients' mobility over time and to recognize impending needs (e.g. for targeted exercise) within pre-clinical stages of decline.

Physical Performance Trajectories and Mortality Among Older Mexican Americans

Background

We sought to identify distinct trajectory classes of physical performance in Mexican Americans aged 75 years and older and to examine whether these trajectories predict mortality.

Methods

We used four waves of Hispanic Established Populations for Epidemiologic Studies of the Elderly (H-EPESE) data for adults 75 years and older from 2004-2005 to 2013. Latent growth curve analysis was used to identify distinct trajectory classes. Multinomial logistic regression analysis was used to examine the association between baseline characteristics and the newly constructed trajectories. Cox proportional hazards regression models examined the hazard of mortality as a function of Short Physical Performance Battery (SPPB) trajectories.

Results

The study follow-up period was approximately 9.5 years. One thousand four hundred and eleven adults were successfully classified into three (low-declining, high-declining, and high-stable) physical performance trajectory classes. Depressive symptoms (relative risk ratio = 1.94, 95% confidence interval [CI] = 1.17-3.22), diabetes (relative risk ratio = 2.44, 95% CI = 1.63-3.65), number of other comorbid health conditions (relative risk ratio = 1.40, 95% CI = 1.16-1.68), and obesity (relative risk ratio = 2.83, 95% CI = 1.67-4.80), increased the relative risk of classification into the low, relative to high-stable trajectory class. Male gender and foreign-born status significantly reduced risk of classification in the low-declining and high-declining trajectory classes. We observed a statistically significant association between low-declining (hazard ratio = 3.01, 95% CI = 2.34-3. 87) and high-declining (hazard ratio = 1.64, 95% CI = 1.32-2.03) trajectories and increased risk of mortality.

Conclusions

Differences in mortality across physical performance trajectory classes suggest that these physical performance classes represent differences in underlying disease progression, and thus differences in mortality risk among older Mexican Americans, which warrants additional research to better understand differential physical performance trajectories and their effects on morbidity and mortality in heterogeneous aging populations.

Impact of Diabetes and Disease Duration on Work Status Among U.S. Older Adults

Objectives: To examine the effects of diabetes and disease duration on work status over a 9-year period. Method: Multinomial logistic regression models examined the probability of retirement and disability impeding work, using data from the Health and Retirement Study (n = 5,576). Results: Among participants who had retired in 2012, almost 14% had incident diabetes (4.91 mean years with diabetes, 95% confidence interval [CI] = [4.67, 5.15]). Approximately 22% of participants who reported a disability impeded labor force participation had prevalent diabetes (17.1 mean years with diabetes, 95%CI = [16.41, 17.71]). Only prevalent diabetes that indicated longer disease duration was associated with disability (relative risk ratio [RRR] = 1.83, 95% CI = [1.30, 2.57]). There was evidence of effect modification among Hispanics only (p = .02). Discussion: Diabetes increased risk of exiting the workforce due to disability, and mean disease duration was associated with changes. Disease management and workplace interventions may enable older adults to continue being productive should they choose to remain in the workforce.

Cognitive and Physical Function in Relation to the Risk of Injurious Falls in Older Adults: A Population-Based Study

Background

We aimed to quantify the independent effect of cognitive and physical deficits on the risk of injurious falls, to verify whether this risk is modified by global cognitive impairment, and to explore whether risk varies by follow-up time.

Methods

Data on 2,495 participants (≥60 years) from the population-based Swedish National Study on Aging and Care in Kungsholmen (SNAC-K) study were analyzed using flexible parametric survival models. Two cognitive domains (processing speed and executive function) were assessed with standard tests. Physical function tests included balance (one-leg-stands), walking speed, chair stands, and grip strength. Global cognition was assessed using the Mini-Mental State Examination.

Results

A total of 167 people experienced an injurious fall over 3 years of follow-up, 310 over 5 years, and 571 over 10 years. Each standard deviation worse balance, slower walking speed, and longer chair stand time increased the risk of injurious falls over 3 years by 43%, 38%, and 23%, respectively (p < .05). Each standard deviation worse processing speed and executive function was significantly associated with 10% increased risk of injurious falls over 10 years (p < .05). In stratified analyses, deficits in physical functioning were associated with injurious falls only in people with cognitive impairment, whereas deficits in processing speed and executive function were associated with injurious falls only in people without cognitive impairment.

Conclusions

Deficits in specific cognitive domains, such as processing speed and executive function, appear to predict injurious falls in the long term. Deficits in physical function predict falls in the short term, especially in people with global cognitive impairment.

Change in physical function among women as they age: findings from the Australian Longitudinal Study on Women's Health

PURPOSE

Decline in physical function is common in older age, with important consequences for health-related quality of life, health care utilisation, and mortality. This study aimed to identify patterns of change in physical functioning (PF) for women in later life.

METHODS

PF was measured longitudinally using the ten-item subscale of the Medical Outcomes Study 36-item Short Form Health Survey, for 10 515 participants of the Australian Longitudinal Study on Women's Health, who completed at least two surveys between 1999 (aged 73-78 years) and 2011 (aged 85-90 years). Conditional and unconditional latent profile analysis was conducted separately for deceased and surviving subgroups of women to uncover latent patterns of change in PF scores over time.

RESULTS

Four patterns of change were identified for women who were still alive in 2011 (N = 5928), and four similar classes for deceased women (N = 4587): (1) 'poor PF' representing women with low PF scores, (2) 'moderate PF', (3) 'high PF', and (4) 'very high PF', where scores remained very high. All patterns exhibited a decrease in PF over time. Factors which predict low PF included sedentary levels of exercise, obese and overweight BMI, difficulty managing on income, and lower education.

CONCLUSIONS

The results provided evidence for a gradual decrease in PF for all women with age; however, there was no evidence for an increased rate of decline prior to death.

Sex Differences in Concomitant Trajectories of Self-Reported Disability and Measured Physical Capacity in Older Adults

BACKGROUND

Despite documented age-related declines in self-reported functional status and measured physical capacity, it is unclear whether these functional indicators follow similar trajectories over time or whether the patterns of change differ by sex.

METHODS

We used longitudinal data from 687 initially nondisabled adults, aged 70 or older, from the Precipitating Events Project, who were evaluated every 18 months for nearly 14 years. Self-reported disability was assessed with a 12-item disability scale. Physical capacity was measured using grip strength and a modified version of Short Physical Performance Battery. Hierarchical linear models estimated the intra-individual trajectory of each functional indicator and differences in trajectories' intercept and slope by sex.

RESULTS

Self-reported disability, grip strength, and Short Physical Performance Battery score declined over 13.5 years following nonlinear trajectories. Women experienced faster accumulation of self-reported disability, but slower declines in measured physical capacity, compared with men. Trajectory intercepts revealed that women had significantly weaker grip strength and reported higher levels of disability compared with men, with no differences in starting Short Physical Performance Battery scores. These findings were robust to adjustments for differences in sociodemographic characteristics, length-of-survival, health risk factors, and chronic-disease status.

CONCLUSIONS

Despite the female disadvantage in self-reported disability, older women preserve measured physical capacity better than men over time. Self-reported and measured indicators should be viewed as complementary rather than interchangeable assessments of functional status for both clinical and research purposes, especially for sex-specific comparisons.

Associations of behavioural risk factors and health status with changes in physical capability over 10 years of follow-up: the MRC National Survey of Health and Development

OBJECTIVES

(1) To describe changes in objective measures of physical capability between ages 53 and 60-64 years; (2) to investigate the associations of behavioural risk factors (obesity, physical inactivity, smoking) and number of health conditions (range 0-4: hand osteoarthritis (OA); knee OA; severe respiratory symptoms; other disabling or life-threatening conditions (ie, cancer, cardiovascular disease, diabetes)) at age 53 years with these changes.

DESIGN

Nationally representative prospective birth cohort study.

SETTING

England, Scotland and Wales.

PARTICIPANTS

Up to 2093 men and women from the Medical Research Council National Survey of Health and Development, who have been followed-up since birth in 1946, and underwent physical capability assessments performed by nurses following standard protocols in 1999 and 2006-2010.

MAIN OUTCOME MEASURES

Grip strength and chair rise speed were assessed at ages 53 and 60-64 years. Four categories of change in grip strength and chair rise speed were identified: decline, stable high, stable low, a reference group who maintained physical capability within a 'normal' range.

RESULTS

Less healthy behavioural risk scores and an increase in the number of health conditions experienced were associated in a stepwise fashion with increased risk of decline in physical capability, and also of having low levels at baseline and remaining low. For example, the sex and mutually adjusted relative-risk ratios (95% CI) of being in the stable low versus reference category of chair rise speed were 1.58 (1.35-1.86) and 1.97 (1.57-2.47) per 1 unit change in behavioural risk score and health indicator count, respectively.

CONCLUSIONS

These findings provide evidence of the associations of a range of modifiable factors with age-related changes in physical capability. They suggest the need to target multiple risk factors at least as early as mid-life when aiming to promote maintenance and prevent decline in physical capability in later life.

Lower extremity function trajectories in the African American Health Cohort

BACKGROUND

We addressed two understudied issues in estimating lower extremity functional trajectories in older adults-incorporating the effect of mortality and evaluating heterogeneity among African Americans.

METHODS

Data were taken from the 998 participants in the African American Health cohort. A highly reliable and valid 8-item lower extremity function scale was used at baseline and at the 1-, 2-, 3-, 4-, 7-, and 9-year follow-up interviews. Semiparametric (ie, discrete) group-based mixture modeling identified the trajectories, and multinomial logistic regression identified risk factors for differential trajectory groups.

RESULTS

When treating mortality as informative censoring, six discrete trajectories were observed with 45% of the participants belonging to three stable trajectories (good, fair, or poor function), and the remainder belonging to three declining trajectories (very high function with minimal improvement then minimal decline, very good function with a slow and modest decline, and very good function with a large and quick decline).

CONCLUSION

Substantial heterogeneity in lower extremity function trajectories exists in the African American Health cohort, after appropriately treating mortality as informative censoring.

Change in fast walking speed preceding death: results from a prospective longitudinal cohort study

BACKGROUND

Walking speed (WS) predicts mortality. However, it is unclear if decline in WS increases prior to death. We examined whether (a) WS declined faster in persons who died during the follow-up compared with those who remained alive and (b) adding change in WS to a model including age, sex, and baseline WS improved prediction of mortality.

METHODS

Data are from 4,016 participants of the Dijon center of the Three-City study (France), aged 65-85 years. Fast WS (FWS) was measured up to five times over a 12-year period. Mortality was ascertained until 2012.

RESULTS

Linear mixed models using a backward time scale showed that FWS declined faster in 908 participants who died during the follow-up (annual change = -0.031 m/s) than in those who survived (-0.021 m/s), corresponding to a difference of -0.009 (95% confidence interval = -0.013 to -0.005) m/s. Compared with "normal" change in FWS (annual change ≥-0.04 m/s), "substantial" decline (<-0.08 m/s) was associated with a 1.4-fold greater risk of mortality (hazards ratio = 1.40, confidence interval = 1.02-1.92) and small decline (-0.08 to -0.04 m/s) with a 1.2-fold greater risk (hazards ratio = 1.18, confidence interval = 0.89-1.57). The net reclassification index when adding these categories of change in FWS to the model adjusted for age, sex, and baseline FWS was 19.0% (0.6, 36.8%).

CONCLUSION

Participants who died during the follow-up had a steeper decline in FWS than the others. Both baseline FWS and FWS decline predict mortality.