Predicting the risk of mobility difficulty in older women with screening nomograms: the Women's Health and Aging Study II

BACKGROUND: A major obstacle to screening for early mobility disability (ie, mobility difficulty), a major public health concern, is the lack of a method that identifies those who are at high risk. The goal of this study was to develop easy-to-use clinical nomograms for estimation of the probability of incident mobility difficulty. METHODS: We conducted a population-based prospective study using data from 266 high physically and cognitively functioning older women, aged 70 to 80 years, who were free of mobility disability at the baseline evaluation of the Women's Health and Aging Study II. The outcome measure was incident mobility disability within 18 months, defined as self-reported difficulty walking 0.8 km, climbing 10 steps, or transferring from or into a car or bus. Logistic regression and receiver operating characteristic curve analyses were used for evaluation of the optimal combination of self-reported and performance-based mobility measures. Bootstrap sampling and estimation was used for validation. RESULTS: Predictive nomograms were developed based on a final model that included 3 simple-to-obtain measures of preclinical disability: self-report of modification in mobility tasks without having difficulty with them, one-leg stance balance, and time to walk 1 m at a usual pace. Final model accuracy (as estimated by the area under the receiver operating characteristic curve) was 73% (SE = 0.04). Validation analysis confirmed the high accuracy of these nomograms. CONCLUSIONS: An original tool was developed for assessment of the risk of mobility difficulty in older women that can be used to assist physicians and researchers in deciding which women to target for preventive interventions.     

Preclinical disability as a risk factor for falls in community-dwelling older adults

BACKGROUND: Falls are common and serious problems in older adults. The goal of this study was to examine whether preclinical disability predicts incident falls in a European population of community-dwelling older adults. METHODS: Secondary data analysis was performed on a population-based longitudinal study of 1644 community-dwelling older adults living in London, U.K.; Hamburg, Germany; Solothurn, Switzerland. Data were collected at baseline and 1-year follow-up using a self-administered multidimensional health risk appraisal questionnaire, including validated questions on falls, mobility disability status (high function, preclinical disability, task difficulty), and demographic and health-related characteristics. Associations were evaluated using bivariate and multivariate logistic regression analyses. RESULTS: Overall incidence of falls was 24%, and increased by worsening mobility disability status: high function (17%), preclinical disability (32%), task difficulty (40%), test-of-trend p <.003. In multivariate analysis adjusting for other fall risk factors, preclinical disability (odds ratio [OR] = 1.7, 95% confidence interval [CI], 1.1-2.5), task difficulty (OR = 1.7, 95% CI, 1.1-2.6) and history of falls (OR = 4.7, 95% CI, 3.5-6.3) were the strongest significant predictors of falls. In stratified multivariate analyses, preclinical disability equally predicted falls in participants with (OR = 1.7, 95% CI, 1.0-3.0) and without history of falls (OR = 1.8, 95% CI, 1.1-3.0). CONCLUSIONS: This study provides longitudinal evidence that self-reported preclinical disability predicts incident falls at 1-year follow-up independent of other self-reported fall risk factors. Multidimensional geriatric assessment that includes preclinical disability may provide a unique early warning system as well as potential targets for intervention.     

Exploring the hierarchy of mobility performance in high-functioning older women

BACKGROUND: Preventing mobility disability depends on matching interventions to individual needs. The purpose of this study is to improve targeting by determining whether mobility performance is associated with, and predicts, mobility disability hierarchically. The hypothesis is that poorer performance tested by more demanding tasks is more strongly associated with current and future mobility "limitation" (self-reported task modification or difficulty) than is that tested by less demanding tasks, in a graded manner. METHODS: Data come from the Women's Health and Aging Study II (n = 436) at baseline and at 36-month follow-up. Logistic and multinomial regression models examined associations between performance on mobility tests and reported limitation in walking one-half mile, adjusting for risk factors for disability. RESULTS: We found that 76.6% of prevalent and 88.4% of new-onset self-reported limitation fit within the hypothesized hierarchical pattern. The estimated strength of association between a decrement in lower extremity performance and reported limitation increased with task demand for the primary outcome, reported limitation in walking one-half mile. For example, the odds ratios for prevalent report of walking limitation, versus no limitation, for 10% lower performance walking, dressing, repeating chair stands, and climbing, respectively, were 1.05 (95% confidence interval, 0.97-1.17), 1.08 (1.00-1.16), 1.15 (1.06-1.25), and 1.22 (1.12-1.33). CONCLUSIONS: This study partially supports the hypothesis that mobility performance tends to follow a hierarchical pattern. For studying mild mobility disability, walking speed may not be as useful as more demanding tests. Identifying declines in performance through more demanding tests such as climbing should improve the ability to target preventive interventions to individuals at risk of mild mobility decline within a high-functioning population.     

The dynamic nature of mobility disability in older persons

OBJECTIVES: To determine the rates of clinically meaningful transitions in mobility disability; evaluate how these transitions differ according to age, sex, and physical frailty; and depict the duration of the resulting episodes of mobility disability. DESIGN: Prospective cohort study. SETTING: General community in greater New Haven, Connecticut, from March 1998 to October 2004. PARTICIPANTS: Seven hundred fifty-four community-living older persons, aged 70 and older, who were nondisabled (i.e., required no personal assistance) in four activities of daily living. MEASUREMENTS: Mobility disability, defined as the inability to walk one quarter of a mile and to climb a flight of stairs, respectively without personal assistance, was assessed every month for up to 5 years. RESULTS: For both mobility tasks, rates per 1,000 person-months were higher for transitions from no disability to intermittent disability (34.7 for walking one quarter of a mile and 17.4 for climbing a flight of stairs), intermittent to continuous disability (52.0 and 42.5), continuous to intermittent disability (35.4 and 31.5), and intermittent to no disability (68.6 and 85.4) than for other transitions. Older age, female sex, and physical frailty were associated with greater likelihood of transition to states of greater disability and lower likelihood of regaining independent mobility. CONCLUSION: Mobility disability in older persons is a highly dynamic process, characterized by frequent transitions between states of independence and disability. Programs designed to enhance independent mobility should focus not only on the prevention of mobility disability but also on the restoration and maintenance of independent mobility in older persons who become disabled.     

Type and intensity of activity and risk of mobility limitation: the mediating role of muscle parameters

OBJECTIVES: To investigate the association between different types of physical activity behavior and incident mobility limitation in older men and women and to examine whether muscle parameters mediate these associations. DESIGN: Cohort study with 4.5-year follow-up. SETTING: Metropolitan areas surrounding Pittsburgh, Pennsylvania, and Memphis, Tennessee. A random sample of white Medicare beneficiaries and all age-eligible blacks. PARTICIPANTS: Three thousand seventy-five black and white men and women aged 70 to 79 with no self-reported difficulty walking one-quarter of a mile or climbing 10 steps, enrolled in the Health, Aging and Body Composition (Health ABC) Study. MEASUREMENTS: Participants were classified as exercisers (reporting > or = 1,000 kcal/wk of exercise activity), lifestyle active (reporting < 1,000 kcal/wk of exercise activity and > or = 2,719 kcal/wk of total physical activity), or inactive (reporting < 1,000 kcal/wk of exercise activity and < 2,719 kcal/wk of total physical activity). The study outcome, incident mobility limitation, was defined as two consecutive, semiannual self-reports of any difficulty walking one quarter of a mile or climbing 10 steps. Thigh muscle area, thigh muscle attenuation (a marker of fat infiltration in muscle), appendicular lean soft tissue mass, and isokinetic knee extensor strength were examined as potential mediators. RESULTS: Over 4.5 years, 34.3% of men and 47.4% of women developed mobility limitation. Inactive persons had twice the risk of incident mobility limitation as exercisers (hazard ratio (HR)=2.08, 95% confidence interval (CI)=1.60-2.70, for men, HR=1.98, 95% CI=1.51-2.60, for women). Lifestyle-active men and women had an intermediate risk (HR=1.47 and 1.44, respectively). For the lifestyle active and inactive, absence of walking activity conferred an additional risk of mobility limitation. Muscle parameters did not mediate the relationship between physical activity and mobility limitation, except for knee extensor strength in men. CONCLUSION: Exercise and an active lifestyle that includes walking protect against mobility loss in older men and women. Activity effects on muscle parameters do not explain this association.     

Obesity and mobility disability in the older adult

Mobility disability is becoming prevalent in the obese older population (≥60 years of age). We included a total of 13 cross‐sectional and 15 longitudinal studies based on actual physical assessments of mobility in the obese older population in this review. We systematically examined existing evidence of which adiposity estimate best predicted mobility disability. Cross‐sectional studies (82–4000 participants) showed poorer lower extremity mobility with increasing obesity severity in both men and women. All longitudinal studies (1–22 years) except for one, reported relationships between adiposity and declining mobility. While different physical tests made interpretation challenging, a consistent finding was that walking, stair climbing and chair rise ability were compromised with obesity, especially if the body mass index (BMI) exceeded 35 kg m^?2. More studies found that obese women were at an increased risk for mobility impairment than men. Existing evidence suggests that BMI and waist circumference are emerging as the more consistent predictors of the onset or worsening of mobility disability. Limited interventional evidence shows that weight loss is related with increased mobility and lower extremity function. Additional longitudinal studies are warranted that address overall body composition fat and muscle mass or change on future disability.     

Lipoprotein peroxidation and mobility limitation: results from the Health, Aging, and Body Composition Study

BACKGROUND: Oxidative damage plays an important role in leading to major health-related events. The aim of this study was to assess the predictive value of a lipoprotein peroxidation marker, oxidized low-density lipoprotein (oxLDL) for incident mobility limitation (ML). METHODS: Data are from 2985 well-functioning elders enrolled in the Health ABC study (median follow-up, 4.1 years). All oxLDL levels were measured at the baseline assessment. The oxLDL/LDL cholesterol (LDL-C) ratio (log value) was used as a measure of lipoprotein peroxidation. Mobility limitation was defined by 2 consecutive semiannual reports of any difficulty either walking 1/4 mile or climbing up 10 steps without resting. Severe ML was defined by 2 consecutive reports of great difficulty or inability to do the same tasks. Cox proportional hazards models were performed to assess hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: The mean (SD) age of the sample was 74.2 (2.9) years. After adjustment for potential confounders (sociodemographic factors, smoking, physical activity, body mass index, clinical conditions, biological markers, and medications), the relationship between the oxLDL/LDL-C ratio and disability events was statistically significant (per log-unit difference in the oxLDL/LDL-C ratio) (for ML: HR, 1.22; 95% CI, 1.06-1.41; for severe ML: HR, 1.43; 95% CI, 1.15-1.79). Consistent results were found when interleukin 6 level was included as a covariate in the adjusted models (ML: HR, 1.13; 95% CI, 0.98-1.31; severe ML: HR, 1.31; 95% CI, 1.05-1.64). No significant sex, race, interleukin 6 level, or clinical conditions interaction was found with the oxLDL/LDL-C ratio and mobility disability. CONCLUSIONS: Lipoprotein peroxidation predicts the onset of ML in older persons. The oxLDL predictive value for ML is partly explained by interleukin 6 levels.     

Report of having slowed down: evidence for the validity of a new way to inquire about mild disability in elders

BACKGROUND: Mild disability in elderly persons may be detected by eliciting reports of modified task performance, even in the absence of reported difficulty. This study provides evidence for the validity of one type of task modification. namely, slowing, as a measure of mild walking disability. METHODS: Community-dwelling elders (N = 287) were questioned about whether they were walking indoors as quickly as they had 1 year before and 10 years before. Construct validity was assessed by the degree to which responses to these two questions were logically consistent with a general decline in walking speed, and by determining whether reported slowing was associated with concurrent reports of difficulty walking and with measured gait speed. Predictive validity in subjects without reported difficulty walking was gauged by the association of reported slowing with adverse walking outcomes at 1-year follow-up. RESULTS: Reports of slowing over 10- and 1-year periods were almost uniformly consistent with a general decline in speed. Reported slowing was significantly associated with reported difficulty walking and with slower gait speed. In the subgroup of elders initially reporting no difficulty walking, reported slowing significantly predicted incident difficulty walking at follow-up, as well as other adverse walking outcomes. For example, among elders who reported slowing, 7%, 10%, and 19% developed new difficulty walking indoors, new difficulty walking outdoors, or stopped walking for pleasure, compared with 0%, 0%, and 3% for those who had not reported slowing (p < .05). CONCLUSIONS: This study provides evidence for the construct and predictive validity of one type of task modification, namely, slowing in indoor walking. This work contributes to the development of new methods for measuring mild disability, which may in turn form the basis for clinical interventions based on the early identification of functional problems.     

Underlying factors in the association between depressed mood and mobility limitation in older people

BACKGROUND: Depressed mood may either precede mobility limitation or follow from mobility limitation. OBJECTIVE: To compare mood status among people with manifest mobility limitation, those with preclinical mobility limitation and those without mobility limitation and investigate factors explaining the association between depressed mood and mobility limitation. DESIGN: Cross-sectional. Subjects: 645 community-living 75- to 81-year-old people. METHODS: Depressed mood was assessed using the Centre for Epidemiologic Studies Depression Scale (CES-D, cut-off score 16); difficulty walking 500 m was assessed by self-report. Those reporting difficulty were categorised as having manifest mobility limitation. Those with no difficulty but reporting task modifications, such as reduced frequency of walking, were categorised as having preclinical mobility limitation. The association between depressed mood and mobility limitation was analysed using logistic regression analysis with gender, age, economic situation, the availability of a confidant, chronic conditions, and widespread pain as covariates. RESULTS: Depressed mood was found in 34% of subjects with manifest mobility limitation, in 26% of those with preclinical mobility limitation, and in 13% of those without mobility limitation. The unadjusted odds ratio for depressed mood was 3.43 (95% CI 2.04-5.76) among subjects with manifest mobility limitation and 2.38 (95% CI 1.52-3.73) among those with preclinical mobility limitation, compared to those without mobility limitation.Adjustment for covariates reduced the risks to 2.10 (95% CI 1.15-3.82) and 1.99 (95% CI 1.24-3.20), respectively. Widespread pain explained 28% of the increased risk of depressed mood among those with manifest mobility limitation. CONCLUSION: The dose-response relationship between depressed mood and mobility limitation suggests that both conditions may progress simultaneously and may share aetiology, at least in part. Pain may be an underlying factor in both depressed mood and mobility limitation.     

Incident physical disability in people with lower extremity peripheral arterial disease: the role of cardiovascular disease

OBJECTIVES: To evaluate the risk of incident physical disability and the decline in gait speed over a 6-year follow-up associated with a low ankle-arm index (AAI) in older adults.
DESIGN: Observational cohort study.
SETTING: Forsyth County, North Carolina; Sacramento County, California; Washington County, Maryland; and Allegheny County, Pennsylvania.
PARTICIPANTS: Four thousand seven hundred five older adults, 58% women and 17.6% black, participating in the Cardiovascular Health Study.
MEASUREMENTS: AAI was measured in 1992/93 (baseline). Self-reported mobility, activity of daily living (ADL), and instrumental activity of daily living (IADL) disability and gait speed were recorded at baseline and at 1-year intervals over 6 years of follow-up. Mobility disability was defined as any difficulty walking half a mile and ADL and IADL disability was defined as any difficulty with 11 specific ADL and IADL tasks. Individuals with mobility, ADL, or IADL disability at baseline were excluded from the respective incident disability analyses.
RESULTS: Lower baseline AAI values were associated with increased risk of mobility disability and ADL/IADL disability. Clinical cardiovascular disease (CVD), diabetes mellitus, and interim CVD events partially explained these associations for mobility disability and clinical CVD and diabetes mellitus partially explained these associations for ADL and IADL disability. Individuals with an AAI less than 0.9 had on average a mean decrease in gait speed of 0.02 m/s per year, or a decline of 0.12 m/s over the 6-year follow-up. Prevalent CVD partly explained this decrease but interim CVD events did not further attenuate it.
CONCLUSION: Low AAI serves as marker of future disability risk. Reduction of disability risk in patients with a low AAI should consider cardiovascular comorbidity and the prevention of additional disabling CVD events.     

Use of a cane for ambulation: marker and mitigator of impairment in older people who report no difficulty walking

OBJECTIVES: To measure disability, patients are often asked whether they have difficulty performing daily tasks. However, recent work suggests that functional problems may be detected earlier by inquiring about modifications in the way tasks are performed. We sought to describe the characteristics of older people who deny difficulty walking but nevertheless have modified the manner in which they walk, by use of a cane. We also tested the hypothesis that, among older people who deny difficulty walking, those using a cane have more mobility problems and are at greater risk for future mobility problems than those not using a cane. DESIGN: Longitudinal survey study, with measures at baseline and 2-year follow-up. SETTING: Population-based survey of urban older people. PARTICIPANTS: One thousand two hundred fifty-one community-dwelling older persons without severe cognitive impairment who reported no difficulty walking at baseline. MEASUREMENTS: Self-reported health, activities of daily living (ADL), and mobility status. RESULTS: Among older people who denied difficulty walking, those who used a cane at baseline (7 of subjects) were older and more likely to have taken medication for a heart condition or arthritis, to have an ADL deficit, and to have been hospitalized in the past year. They were less likely to have walked for pleasure in the past month and more likely to report difficulty crossing roads or intersections. Moreover, those using a cane at baseline were more likely to develop new mobility problems at follow-up. For example, 15 of those who used a cane at baseline reported new difficulty walking at follow-up, compared with 2 of those who did not use a cane. CONCLUSION: Older people who deny difficulty walking but who use a cane are at greater risk than those who do not use a cane for the development of difficulty walking and other new mobility problems. Asking patients about task modification rather than difficulty alone may be a more sensitive way to detect early or mild functional problems.     

Benzodiazepine use and physical disability in community-dwelling older adults

OBJECTIVES: To determine whether benzodiazepine use is associated with incident disability in mobility and activities of daily living (ADLs) in older individuals. DESIGN: A prospective cohort study. SETTING: Four sites of the Established Populations for Epidemiologic Studies of the Elderly. PARTICIPANTS: This study included 9,093 subjects (aged > or =65) who were not disabled in mobility or ADLs at baseline. MEASUREMENTS: Mobility disability was defined as inability to walk half a mile or climb one flight of stairs. ADL disability was defined as inability to perform one or more basic ADLs (bathing, eating, dressing, transferring from a bed to a chair, using the toilet, or walking across a small room). Trained interviewers assessed outcomes annually. RESULTS: At baseline, 5.5% of subjects reported benzodiazepine use. In multivariable models, benzodiazepine users were 1.23 times as likely as nonusers (95% confidence interval (CI) = 1.09-1.39) to develop mobility disability and 1.28 times as likely (95% CI = 1.09-1.52) to develop ADL disability. Risk for incident mobility was increased with short- (hazard ratio (HR) = 1.27, 95% CI = 1.08-1.50) and long-acting benzodiazepines (HR = 1.20, 95% CI = 1.03-1.39) and no use. Risk for ADL disability was greater with short- (HR = 1.58, 95% CI = 1.25-2.01) but not long-acting (HR = 1.11, 95% CI = 0.89-1.39) agents than for no use. CONCLUSION: Older adults taking benzodiazepines have a greater risk for incident mobility and ADL disability. Use of short-acting agents does not appear to confer any safety benefits over long-acting agents.     

Self-reported walking ability predicts functional mobility performance in frail older adults

OBJECTIVE: To determine how self-reported physical function relates to performance in each of three mobility domains: walking, stance maintenance, and rising from chairs. DESIGN: Cross-sectional analysis of older adults. SETTING: University-based laboratory and community-based congregate housing facilities. PARTICIPANTS: Two hundred twenty-one older adults (mean age, 79.9 years; range, 60-102 years) without clinical evidence of dementia (mean Folstein Mini-Mental State score, 28; range, 24-30). INTERVENTION AND MAIN OUTCOME MEASURES: We compared the responses of these older adults on a questionnaire battery used by the Established Populations for the Epidemiologic Study of the Elderly (EPESE) project, to performance on mobility tasks of graded difficulty. Responses to the EPESE battery included: (1) whether assistance was required to perform seven Katz activities of daily living (ADL) items, specifically with walking and transferring; (2) three Rosow-Breslau items, including the ability to walk up stairs and walk a half mile; and (3) five Nagi items, including difficulty stooping, reaching, and lifting objects. The performance measures included the ability to perform, and time taken to perform, tasks in three summary score domains: (1) walking ("Walking," seven tasks, including walking with an assistive device, turning, stair climbing, tandem walking); (2) stance maintenance ("Stance," six tasks, including unipedal, bipedal, tandem, and maximum lean); and (3) chair rise ("Chair Rise," six tasks, including rising from a variety of seat heights with and without the use of hands for assistance). A total score combines scores in each Walking, Stance, and Chair Rise domain. We also analyzed how cognitive/ behavioral factors such as depression and self-efficacy related to the residuals from the self-report and performance-based ANOVA models. RESULTS: Rosow-Breslau items have the strongest relationship with the three performance domains, Walking, Stance, and Chair Rise (eta-squared ranging from 0.21 to 0.44). These three performance domains are as strongly related to one Katz ADL item, walking (eta-squared ranging from 0.15 to 0.33) as all of the Katz ADL items combined (eta-squared ranging from 0.21 to 0.35). Tests of problem solving and psychomotor speed, the Trails A and Trails B tests, are significantly correlated with the residuals from the self-report and performance-based ANOVA models. CONCLUSIONS: Compared with the rest of the EPESE self-report items, self-report items related to walking (such as Katz walking and Rosow-Breslau items) are better predictors of functional mobility performance on tasks involving walking, stance maintenance, and rising from chairs. Compared with other self-report items, self-reported walking ability may be the best predictor of overall functional mobility.     

Persistent mobility deficit in the absence of deficits in activities of daily living: a risk factor for mortality

OBJECTIVES: To investigate the extent to which self-reported mobility deficit in the absence of impairment in activities of daily living (ADL) is associated with elevated mortality risk. DESIGN: Prospective cohort study, with annual assessments of mobility and ADL status and ongoing monitoring of vital status. SETTING: Population-based cohort drawn from Medicare enrollees in New York City. PARTICIPANTS: One thousand two hundred ninety-eight older adults reporting functional status at baseline (1992-1994) and 2 years later. MEASUREMENTS: Subjects reported mobility (e.g., walking, climbing stairs, and rising from a chair) and ADL (e.g., bathing, toilet use, dressing, grooming, and feeding) limitations. Two-year functional status trajectories were noted. We used two additional follow-up periods, at 2 and 4 years, to examine the likelihood that older people with mobility deficit may face an increased risk of death without first passing through a state of enduring ADL disability. RESULTS: At 2 years, 12.7% had incident mobility deficit without ADL disability, and 21.3% were persistently disabled in mobility without ADL disability. Relative to subjects free of disability at baseline and follow-up, risk of mortality in the incident mobility deficit group was elevated at 2 and 4 years but did not achieve statistical significance. By contrast, for subjects with persistent mobility impairment who did not report ADL impairment, the mortality risk was significantly elevated both at 2 years (relative risk (RR) = 2.5; 95% confidence interval (CI) = 1.1-5.7)) and 4 years (RR = 2.9; 95% CI = 1.7-4.9)) of follow-up. Mortality was significantly elevated in this group in analyses restricted to respondents with no or only one comorbid condition. CONCLUSION: Continuing, self-reported mobility impairment in the absence of ADL deficit is a risk factor for mortality. Older people with self-reported mobility deficit face an increased risk of mortality without first passing through enduring states of ADL disability.     

Further evidence for the importance of subclinical functional limitation and subclinical disability assessment in gerontology and geriatrics

OBJECTIVE: The objectives of this work were to determine the prevalence of self-reported subclinical status for functional limitation and disability at baseline and assess their independent effects on the onset of functional limitation and disability 1-2 years later. METHODS: Nine hundred ninety-eight African American men and women 49-65 years old in St. Louis, MO, received comprehensive in-home evaluations at baseline and two annual telephone follow-ups. Outcome measures included walking a half-mile, climbing steps, stooping-crouching-kneeling, lifting or carrying 10 lbs., and doing heavy housework. RESULT: The baseline prevalence of subclinical status was 26.4% for walking a half-mile, 26.8% for climbing steps, 39.0% for stooping-crouching-kneeling, 29.1% for lifting or carrying 10 lbs., and 22.7% for doing heavy housework. The adjusted odds ratios for the task-specific subclinical status measure at baseline on developing difficulty 1-2 years later were 1.68 (p < .05) for walking a half-mile, 4.46 (p < .001) for climbing steps, 2.48 (p < .001) for stooping-crouching-kneeling, 2.51 (p < .001) for lifting or carrying 10 lbs., and 2.22 (p < .001) for doing heavy housework. Performance tests (tandem stand, chair stands, and preferred gait speed) did not have consistent independent effects on the onset of functional limitation or disability. CONCLUSION: The subclinical status measures were the main predictors of the onset of difficulty in all tasks and functions 1-2 years later. Interventions to reduce frailty should focus on self-reported subclinical status as an early warning system.     

Joint effects of adiposity and physical activity on incident mobility limitation in older adults

OBJECTIVES: To examine joint associations of physical activity and adiposity measures (body mass index (BMI), waist circumference, percentage body fat) with incident mobility limitation. DESIGN: Prospective observational cohort study. SETTING: Memphis, Tennessee and Pittsburgh, Pennsylvania. PARTICIPANTS: Two thousand nine hundred and eighty‐two black and white men and women aged 70 to 79 participating in the Health, Aging and Body Composition (Health ABC) study. MEASUREMENTS: Mobility limitation was defined as reported difficulty walking one‐quarter of a mile or climbing 10 steps during two consecutive semiannual assessments over 6.5 years. Three measures of adiposity were included in this study: BMI, total percentage body fat, and waist circumference. Physical activity was assessed using a modified leisure‐time physical activity questionnaire. RESULTS: Forty‐six percent of the cohort developed mobility limitation. White and black men with a high BMI (≥30 kg/m²), high total percentage body fat (>31.3%), or high waist circumference (≥102 cm) had an approximately 60%, 40%, and 40%, respectively, higher risk of incident mobility limitation than those with low adiposity. In women, high adiposity was also associated with a significantly higher mobility limitation risk than in those with low adiposity. Low physical activity (lowest quartile) was associated with a 70% higher risk of mobility limitation in all groups. Persons with high adiposity and low physical activity were at particularly high risk of mobility limitation. People with high adiposity who were physically active had an equally high risk of mobility limitation as inactive people with low adiposity. CONCLUSION: High adiposity and low self‐reported physical activity predicted the onset of mobility limitation in well‐functioning older persons. Preventing weight gain in old age and promoting physical activity in obese and non‐obese older persons may therefore be effective strategies to prevent mobility loss and future disability.     

Moderate Alcohol Intake and Risk of Functional Decline: The Health, Aging, and Body Composition Study

OBJECTIVES: To investigate the prospective relationship between alcohol consumption and incident mobility limitation. DESIGN: Cohort study. SETTING: The Health Aging and Body Composition study, conducted in Memphis, Tennessee, and Pittsburgh, Pennsylvania. PARTICIPANTS: Three thousand sixty‐one adults aged 70 to 79 without mobility disability at baseline. MEASUREMENTS: Incidence of mobility limitation, defined as self‐report at two consecutive semiannual interviews of any difficulty walking one‐quarter of a mile or climbing stairs, and incidence of mobility disability, defined as severe difficulty or inability to perform these tasks at two consecutive reports. Alcohol intake, lifestyle‐related variables, diseases, and health status indicators were assessed at baseline. RESULTS: During a follow‐up time of 6.5 years, participants consuming moderate levels of alcohol had the lowest incidence of mobility limitation (total: 6.4 per 100 person‐years (person‐years); men: 6.4 per 100 person‐years; women: 7.3 per 100 person‐years) and mobility disability (total: 2.7 per 100 person‐years; men: 2.5 per 100 person‐years; women: 2.9 per 100 person‐years). Adjusting for demographic characteristics, moderate alcohol intake was associated with lower risk of mobility limitation (hazard ratio (HR)=0.70, 95% confidence interval (CI)=0.55–0.89) and mobility disability (HR=0.66, 95% CI=0.45–0.95) than never or occasional consumption. Additional adjustment for lifestyle‐related variables substantially reduced the strength of the associations (HR=0.85, 95% CI=0.66–1.08 and HR=0.81, 95% CI=0.56–1.18, respectively). Adjustment for diseases and health status indicators did not affect the strength of the associations, suggesting that lifestyle is most important in confounding this relationship. CONCLUSION: Lifestyle‐related characteristics mainly accounted for the association between moderate alcohol intake and lower risk of functional decline over time. These findings do not support a direct causal effect of alcohol intake on physical function.     

The protective effect of emotional vitality on adverse health outcomes in disabled older women

OBJECTIVE: Although the adverse physical health consequences of negative emotions have been studied extensively, much less is known about the potential impact of positive emotions. This study examines whether emotional vitality protects against progression of disability and mortality in disabled older women. DESIGN: A community-based study, The Women's Health and Aging Study. PARTICIPANTS: A total of 1002 moderately to severely disabled women aged 65 years and older living in the community. MEASUREMENTS: Emotional vitality was defined as having a high sense of personal mastery, being happy, and having low depressive symptomatology and anxiety. The onset of new disability was determined by semiannual assessments of disability in performing activities of daily living (ADLs), walking across a room, walking 1/4 mile, and lifting/carrying 10 pounds. Mortality status was determined by proxy interviews and linkage with death certificates. Survival analyses with time to onset of specific disabilities (among those not disabled at baseline) and time to mortality were performed and adjusted for age, baseline level of difficulty, physical performance, and chronic conditions. RESULTS: Three hundred fifty-one of the 1002 older disabled women studied were emotionally vital. Among women without the specific disability at baseline, emotional vitality was associated with a significantly decreased risk for incident disability performing ADLs (RR = 0.81, 95% CI = 0.66-0.99), for incident disability walking one-quarter mile (RR = 0.73, 95% CI = 0.59-0.92), and for incident disability lifting/carrying 10 pounds (RR = 0.77, 95% CI = 0.63-0.95). Emotional vitality was also associated with a lower risk of dying (RR = 0.56, 95% CI = 0.39-0.80). These results were not simply caused by the absence of depression since protective health effects remained when emotionally vital women were compared with 334 women who were not emotionally vital and not depressed. CONCLUSIONS: Emotional vitality in older disabled women reduces the risk for subsequent new disability and mortality. Our findings suggest that positive emotions can protect older persons against adverse health outcomes.     

At the tipping point: predicting severe mobility difficulty in vulnerable older women

OBJECTIVES: To identify clinical measures that aid detection of impending severe mobility difficulty in older women. DESIGN: Cross‐sectional and longitudinal cohort study. SETTING: Urban community in Baltimore, Maryland. PARTICIPANTS: One thousand two community‐dwelling, moderate to severely disabled women aged 65 and older in the Women's Health and Aging Study I. MEASUREMENTS: Self‐report and performance measures representing six domains necessary for mobility: central and peripheral nervous systems, muscles, bones and joints, perception, and energy. Severe mobility difficulty was defined as usual gait of 0.5 m/s or less, any reported difficulty walking across a small room, or dependence on a walking aid during a 4‐m walking test. RESULTS: Four hundred sixty‐seven out of 984 (47%) had severe mobility difficulty at baseline, and 104/474 (22%) developed it within 12 months. Baseline mobility difficulty was correlated with poor vision, knee pain, feelings of helplessness, inability to stand with feet side by side for 10 seconds, difficulty keeping balance while dressing or walking, inability to rise from a chair five times, and cognitive impairment. Of these, knee pain (odds ratio (OR)=1.74, 95% confidence interval (CI)=1.05–2.89), helplessness (OR=1.87, 95% CI=1.10–3.24), poor vision (OR=2.03, 95% CI=1.06–3.89), inability to rise from a chair five times (OR=2.50, 95% CI=1.15–5.41), and cognitive impairment (OR=4.75, 95% CI=1.67–13.48) predicted incident severe mobility difficulty within 12 months, independent of age. CONCLUSION: Five simple measures may aid identification of disabled older women at high risk of severe mobility difficulty. Further studies should determine generalizability to men and higher‐functioning individuals.