@article {987, title = {Gait variability and the risk of incident mobility disability in community-dwelling older adults.}, journal = {J Gerontol A Biol Sci Med Sci}, volume = {62}, year = {2007}, month = {2007 Sep}, pages = {983-8}, abstract = {

BACKGROUND: Gait speed is a strong predictor of incident walking disability. The objective was to determine if gait variability adds to the prediction of incident mobility disability independent of gait speed.

METHODS: Participants included 379 older adults (mean age = 79 years; 78\% Caucasian, and 40\% men) in the Cardiovascular Health Study at the Pittsburgh site. All could ambulate independently and reported no difficulty walking a half mile. Gait characteristics were determined from a 4-meter computerized walkway. For each gait parameter, variability was defined as the standard deviation from the individual steps from two passes. Incident walking disability was obtained by phone interview every 6 months for 54 months and was defined as new difficulty walking a half mile or inability to walk a half mile.

RESULTS: Of the 379 participants, 222 (58.6\%) developed incident mobility disability. In unadjusted Cox proportional hazards models gait speed, mean step length, mean stance time, and stance time variability were associated with incident mobility disability. After adjusting for gait speed, demographics, chronic conditions, prescription medications, health status, and physical activity level, only stance time variability remained an important indicator of disability. In the adjusted model, an increase in stance time variability of 0.01 seconds was associated with a 13\% higher incidence of mobility disability (hazard ratio 1.13, 95\% confidence interval, 1.01-1.27).

CONCLUSIONS: Stance time variability is an independent predictor of future mobility disability. Future efforts are needed to determine whether interventions that decrease stance time variability will also delay mobility disability.

}, keywords = {Aged, Aged, 80 and over, Aging, Cohort Studies, Female, Gait, Gait Disorders, Neurologic, Humans, Male, Mobility Limitation, Prospective Studies, Risk Factors, Walking}, issn = {1079-5006}, doi = {10.1093/gerona/62.9.983}, author = {Brach, Jennifer S and Studenski, Stephanie A and Perera, Subashan and VanSwearingen, Jessie M and Newman, Anne B} } @article {1259, title = {Gait speed and survival in older adults.}, journal = {JAMA}, volume = {305}, year = {2011}, month = {2011 Jan 05}, pages = {50-8}, abstract = {

CONTEXT: Survival estimates help individualize goals of care for geriatric patients, but life tables fail to account for the great variability in survival. Physical performance measures, such as gait speed, might help account for variability, allowing clinicians to make more individualized estimates.

OBJECTIVE: To evaluate the relationship between gait speed and survival.

DESIGN, SETTING, AND PARTICIPANTS: Pooled analysis of 9 cohort studies (collected between 1986 and 2000), using individual data from 34,485 community-dwelling older adults aged 65 years or older with baseline gait speed data, followed up for 6 to 21 years. Participants were a mean (SD) age of 73.5 (5.9) years; 59.6\%, women; and 79.8\%, white; and had a mean (SD) gait speed of 0.92 (0.27) m/s.

MAIN OUTCOME MEASURES: Survival rates and life expectancy.

RESULTS: There were 17,528 deaths; the overall 5-year survival rate was 84.8\% (confidence interval [CI], 79.6\%-88.8\%) and 10-year survival rate was 59.7\% (95\% CI, 46.5\%-70.6\%). Gait speed was associated with survival in all studies (pooled hazard ratio per 0.1 m/s, 0.88; 95\% CI, 0.87-0.90; P < .001). Survival increased across the full range of gait speeds, with significant increments per 0.1 m/s. At age 75, predicted 10-year survival across the range of gait speeds ranged from 19\% to 87\% in men and from 35\% to 91\% in women. Predicted survival based on age, sex, and gait speed was as accurate as predicted based on age, sex, use of mobility aids, and self-reported function or as age, sex, chronic conditions, smoking history, blood pressure, body mass index, and hospitalization.

CONCLUSION: In this pooled analysis of individual data from 9 selected cohorts, gait speed was associated with survival in older adults.

}, keywords = {Aged, Cohort Studies, Female, Gait, Geriatric Assessment, Humans, Life Expectancy, Male, Survival Analysis, United States}, issn = {1538-3598}, doi = {10.1001/jama.2010.1923}, author = {Studenski, Stephanie and Perera, Subashan and Patel, Kushang and Rosano, Caterina and Faulkner, Kimberly and Inzitari, Marco and Brach, Jennifer and Chandler, Julie and Cawthon, Peggy and Connor, Elizabeth Barrett and Nevitt, Michael and Visser, Marjolein and Kritchevsky, Stephen and Badinelli, Stefania and Harris, Tamara and Newman, Anne B and Cauley, Jane and Ferrucci, Luigi and Guralnik, Jack} } @article {1391, title = {Cardiovascular physiology in premotor Parkinson{\textquoteright}s disease: a neuroepidemiologic study.}, journal = {Mov Disord}, volume = {27}, year = {2012}, month = {2012 Jul}, pages = {988-95}, abstract = {

Changes in cardiovascular physiology in Parkinson{\textquoteright}s disease (PD) are common and may occur prior to diagnostic parkinsonian motor signs. We investigated associations of electrocardiographic (ECG) abnormalities, orthostasis, heart rate variability, and carotid stenosis with the risk of PD diagnosis in the Cardiovascular Health Study, a community-based cohort of older adults. ECG abnormality, orthostasis (symptomatic or asymptomatic), heart rate variability (24-hour Holter monitoring), and any carotid stenosis (>=1\%) by ultrasound were modeled as primary predictors of incident PD diagnosis using multivariable logistic regression. Incident PD cases were identified by at least 1 of the following: self-report, antiparkinsonian medication use, and ICD-9. If unadjusted models were significant, they were adjusted or stratified by age, sex, and smoking status, and those in which predictors were still significant (P <= .05) were also adjusted for race, diabetes, total cholesterol, low-density lipoprotein, blood pressure, body mass index, physical activity, education level, stroke, and C-reactive protein. Of 5888 participants, 154 incident PD cases were identified over 14 years of follow-up. After adjusting models with all covariates, those with any ECG abnormality (odds ratio [OR], 1.45; 95\% CI, 1.02-2.07; P = .04) or any carotid stenosis (OR, 2.40; 95\% CI, 1.40-4.09; P = .001) at baseline had a higher risk of incident PD diagnosis. Orthostasis and heart rate variability were not significant predictors. This exploratory study suggests that carotid stenosis and ECG abnormalities occur prior to motor signs in PD, thus serving as potential premotor features or risk factors for PD diagnosis. Replication is needed in a population with more thorough ascertainment of PD onset.

}, keywords = {Aged, Antiparkinson Agents, Cardiovascular Physiological Phenomena, Carotid Stenosis, Cohort Studies, Data Interpretation, Statistical, Dizziness, Electrocardiography, Female, Heart Rate, Hospitalization, Humans, Longitudinal Studies, Male, Movement Disorders, Neurologic Examination, Parkinson Disease, Risk, Ultrasonography}, issn = {1531-8257}, doi = {10.1002/mds.24979}, author = {Jain, Samay and Ton, Thanh G and Perera, Subashan and Zheng, Yan and Stein, Phyllis K and Thacker, Evan and Strotmeyer, Elsa S and Newman, Anne B and Longstreth, Will T} } @article {7161, title = {Gait Speed Predicts Incident Disability: A Pooled Analysis.}, journal = {J Gerontol A Biol Sci Med Sci}, volume = {71}, year = {2016}, month = {2016 Jan}, pages = {63-71}, abstract = {

BACKGROUND: Functional independence with aging is an important goal for individuals and society. Simple prognostic indicators can inform health promotion and care planning, but evidence is limited by heterogeneity in measures of function.

METHODS: We performed a pooled analysis of data from seven studies of 27,220 community-dwelling older adults aged 65 or older with baseline gait speed, followed for disability and mortality. Outcomes were incident inability or dependence on another person in bathing or dressing; and difficulty walking {\textonequarter} - {\textonehalf} mile or climbing 10 steps within 3 years.

RESULTS: Participants with faster baseline gait had lower rates of incident disability. In subgroups (defined by 0.2 m/s-wide intervals from <0.4 to >= 1.4 m/s) with increasingly greater gait speed, 3-year rates of bathing or dressing dependence trended from 10\% to 1\% in men, and from 15\% to 1\% in women, while mobility difficulty trended from 47\% to 4\% in men and 40\% to 6\% in women. The age-adjusted relative risk ratio per 0.1 m/s greater speed for bathing or dressing dependence in men was 0.68 (0.57-0.81) and in women: 0.74 (0.66-0.82); for mobility difficulty, men: 0.75 (0.68-0.82), women: 0.73 (0.67-0.80). Results were similar for combined disability and mortality. Effects were largely consistent across subgroups based on age, gender, race, body mass index, prior hospitalization, and selected chronic conditions. In the presence of multiple other risk factors for disability, gait speed significantly increased the area under the receiver operator characteristic curve.

CONCLUSION: In older adults, gait speed predicts 3 year incidence of bathing or dressing dependence, mobility difficulty, and a composite outcome of disability and mortality.

}, keywords = {Activities of Daily Living, Aged, Aged, 80 and over, Aging, Cohort Studies, Disability Evaluation, Disabled Persons, Female, Gait, Geriatric Assessment, Humans, Independent Living, Male, Mobility Limitation, Predictive Value of Tests, Prognosis, Psychomotor Performance, Risk Assessment, Risk Factors, ROC Curve, Survival Analysis, United States}, issn = {1758-535X}, doi = {10.1093/gerona/glv126}, author = {Perera, Subashan and Patel, Kushang V and Rosano, Caterina and Rubin, Susan M and Satterfield, Suzanne and Harris, Tamara and Ensrud, Kristine and Orwoll, Eric and Lee, Christine G and Chandler, Julie M and Newman, Anne B and Cauley, Jane A and Guralnik, Jack M and Ferrucci, Luigi and Studenski, Stephanie A} }