Concurrent change in dehydroepiandrosterone sulfate and functional performance in the oldest old: results from the Cardiovascular Health Study All Stars study.

INTRODUCTION: The correlation between dehydroepiandrosterone sulfate (DHEAS) decline and age led to the hypothesis that DHEAS might be a marker of primary aging, though conflicting data from observational studies of mortality do not support this. We evaluated concurrent DHEAS and functional decline in a very old cohort to test if DHEAS change tracks with functional change during aging. METHODS: DHEAS and functional performance (gait speed, grip strength, Modified Mini-Mental State Examination [3MSE] score, and digit symbol substitution test [DSST] score) were measured in 1996-1997 and 2005-2006 in 989 participants in the Cardiovascular Health Study All Stars study (mean age 85.2 years in 2005-2006, 63.5% women and 16.5% African American). We used multivariable linear regression to test the association of DHEAS decline with functional decline. RESULTS: After adjustment, each standard deviation decrease in DHEAS was associated with greater declines in gait speed (0.12 m/s, p = .01), grip strength (0.09 kg, p = .03), 3MSE score (0.13 points, p < .001), and DSST score (0.14 points, p = .001) in women only. Additional adjustment for baseline DHEAS attenuated the association with grip strength but did not alter other estimates appreciably, and baseline DHEAS was unassociated with functional decline. CONCLUSIONS: In this cohort of very old individuals, DHEAS decline tracked with declines in gait speed, 3MSE score, and DSST score, but not grip strength, in women independent of baseline DHEAS level. DHEAS decline might be a marker for age-associated performance decline, but its relevance is specific to women.

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 mobility disability predicts incident mobility disability in older women.

BACKGROUND: Physical disability and dependency are serious, and frequent, adverse health outcomes associated with aging and resulting from chronic disease. Reasoning has suggested that there might be a preclinical, intermediate phase of disablement which might develop in parallel with progression of underlying disease and precede and predict disability. Definition of this stage could provide a basis for screening and early intervention to prevent disability. The objective of this study was to determine preclinical functional predictors of incident mobility difficulty and provide evidence for a preclinical stage of disability. METHODS: A prospective, population-based cohort study was carried out in Baltimore, Maryland, with two evaluations 18 months apart. The participants were 436 community-dwelling women, 70-80 years of age at baseline, not cognitively impaired, and reporting difficulty in no areas, or only one area, of physical function (primarily mobility), who were participating in the Women's Health and Aging Study II. Participants were recruited from a population-based, age-stratified random sample. Incident mobility disability was studied in the subset without such disability at baseline. The main outcome measure was self-reported incident difficulty walking 1/2 mile or climbing up 10 steps. RESULTS: At baseline, 69.3% of the cohort reported no difficulty with mobility. After 18 months, 16.0 and 11.7% of this group reported incident difficulty walking 1/2 mile or climbing up 10 steps, respectively. Those reporting baseline task modification due to underlying health problems, our measure of preclinical disability, were at three- to fourfold higher odds of progressing to difficulty than were those without such modification. In multivariate logistic regression analyses, this self-report measure, task modification without difficulty, and objective measures of performance were independently and jointly predictive of incident mobility difficulty. Specifically, for incident difficulty walking 1/2 mile, self-reported task modification odds ratio (OR) = 3.67, walking speed (.5 m/s difference) OR = 2.16; for incident difficulty climbing up 10 stairs, OR for task modification = 3.84, for stair climb speed (1/3 step/s difference) = 2.08 (95% CI did not include 1 for any). Covariates, age, living alone, number of chronic diseases, depression score, knee strength, and balance by functional reach, were not significant predictors in either model. CONCLUSIONS: Two indicators of functional changes in older women without mobility difficulty, self-report of modification of method of doing a task in the absence of difficulty and performance measures, are independent and strong predictors of risk of incident mobility disability. The self-report measure provides substantial strength in predicting risk of incident disability across the full range of performance, and may identify a vulnerable point at which other risk factors act to cause transitions to disability. Together, the preclinical indicators identify a subset of high-functioning older women who are at high risk of mobility disability, and provide a potential basis for screening for disability risk and targeting interventions to prevent mobility disability.