Stephanie A. Studenski

Designing randomized, controlled trials aimed at preventing or delaying functional decline and disability in frail, older persons: a consensus report.

The discovery of effective interventions to prevent or delay disability in older persons is a public health priority. Most likely to benefit from such interventions are frail individuals who are not yet disabled and those with early disability who are at high risk of progression. In spite of this frail older persons have often been excluded from research on the assumption that they would not tolerate testing or benefit from treatment. The Interventions on Frailty Working Group developed recommendations to screen, recruit, evaluate, and retain frail older persons in clinical trials.

Clinical Global Impression of change in Physical frailty: Development of a measure based on Clinical judgment

Objectives: To expand the ability to assess physical frailty by developing a Clinical Global Impression of Change in Physical Frailty (CGIC‐PF) instrument.

Multitasking: Association Between Poorer Performance and a History of Recurrent Falls

OBJECTIVES: To examine the association between poorer performance on concurrent walking and reaction time and recurrent falls.

DNA methylation-based measures of biological age: meta-analysis predicting time to death.

Estimates of biological age based on DNA methylation patterns, often referred to as “epigenetic age”, “DNAm age”, have been shown to be robust biomarkers of age in humans. We previously demonstrated that independent of chronological age, epigenetic age assessed in blood predicted all-cause mortality in four human cohorts. Here, we expanded our original observation to 13 different cohorts for a total sample size of 13,089 individuals, including three racial/ethnic groups. In addition, we examined whether incorporating information on blood cell composition into the epigenetic age metrics improves their predictive power for mortality. All considered measures of epigenetic age acceleration were predictive of mortality (p≤8.2×10−9), independent of chronological age, even after adjusting for additional risk factors (p<5.4×10−4), and within the racial/ethnic groups that we examined (non-Hispanic whites, Hispanics, African Americans). Epigenetic age estimates that incorporated information on blood cell composition led to the smallest p-values for time to death (p=7.5×10−43). Overall, this study a) strengthens the evidence that epigenetic age predicts all-cause mortality above and beyond chronological age and traditional risk factors, and b) demonstrates that epigenetic age estimates that incorporate information on blood cell counts lead to highly significant associations with all-cause mortality.

How do physiological components of balance affect mobility in elderly men

The purpose of this study was to assess the relationship between physiological components of balance and mobility in elderly men without significant disease. Our a priori hypothesis was that physical function is influenced more by accumulated modest impairments than by a single deficit. We examined 39 ambulatory men (> 69 years). Subjects were classified functionally as high, intermediate, or low. Assessment included mobility functions (6-minute walk, mobility skills, reach, 10ft walk time) and physiological components of balance: sensory (vibration, proprioception, vision, vestibular), effector (ankle, knee, hip strength, range of motion), and central processing (response time to perturbations). All mobility functions were significantly (p < .05) different between groups. Impairments in components of postural control were rarely different between groups: the major differences were in ankle strength and visual fields. The number of impaired domains differed across the three groups. Nineteen percent of the low group had at least three domains impaired; none of the intermediate or high groups were impaired in three domains. Fifty-six percent of the low, 20% of the intermediate, and 7% of the high were impaired in two or more domains. Variability in specific mobility measures was also predicted by the number of impaired domains. The decline in physical function may be better explained by the accumulation of deficits across multiple domains than by any single specific impairment.

Does functional reach improve with rehabilitation

Functional reach (FR, maximal safe standing forward reach) is a precise, reliable, clinically accessible, age-sensitive measure of balance that approximates center of pressure excursion and validly estimates physical frailty. We now test its ability to detect improvement in balance over time. Twenty-eight inpatient male veterans (age 40 to 105, mean, 67.3) undergoing physical rehabilitation and 13 nonrehabilitation controls were evaluated at baseline and every 4 weeks using FR (yardstick method), 10-foot walking time (WT), the Duke hierarchical mobility skills protocol (HMS) and a portion of the Functional Independence Measure (FIM). Their sensitivity to change was determined using the responsiveness index (RI). FR as well as the other physical performance instruments tested were found to be sensitive to change (RI for FR = 0.97, WT = 11.26, HMS = 4.63, FIM = 4.93) and therefore, appropriate measures for use in prospective clinical trials.

The neuromuscular junction: Aging at the crossroad between nerves and muscle

Aging is associated with a progressive loss of muscle mass and strength and a decline in neurophysiological functions. Age-related neuromuscular junction (NMJ) plays a key role in musculoskeletal impairment that occurs with aging. However, whether changes in the NMJ precede or follow the decline of muscle mass and strength remains unresolved. Many factors such as mitochondrial dysfunction, oxidative stress, inflammation, changes in the innervation of muscle fibers, and mechanical properties of the motor units probably perform an important role in NMJ degeneration and muscle mass and strength decline in late life. This review addresses the primary events that might lead to NMJ dysfunction with aging, including studies on biomarkers, signaling pathways, and animal models. Interventions such as caloric restriction and exercise may positively affect the NMJ through this mechanism and attenuate the age-related progressive impairment in motor function.

Associations between body composition and gait-speed decline: results from the Health, Aging, and Body Composition study

BACKGROUNDnIn older adults, every 0.1-m/s slower gait speed is associated with a 12% higher mortality. However, little research has identified risk factors for gait-speed decline.nnnOBJECTIVEnWe assessed the association between several measures of body composition and age-related decline in gait speed.nnnDESIGNnData were from 2306 older adults who were participating in the Health, Aging, and Body Composition cohort and were followed for 4 y (50% women; 38% black). Usual walking speed (m/s) over 20 m was measured in years 2 through 6, and the baseline and changes in several measures of body composition were included in mixed-effects models.nnnRESULTSnGait speed declined by 0.06 ± 0.00 m/s over the 4-y period. Baseline thigh intermuscular fat predicted the annual gait-speed decline (±SE) in both men and women (-0.01 ± 0.00 and -0.02 ± 0.00 m/s per 0.57 cm(2), respectively; P < 0.01). In men, but not in women, this relation was independent of total body adiposity. In longitudinal analyses, changes in thigh intermuscular fat and total thigh muscle were the only body-composition measures that predicted gait-speed decline in men and women combined. When modeled together, every 5.75-cm(2) increase in thigh intermuscular fat was associated with a 0.01 ± 0.00-m/s decrease in gait speed, whereas every 16.92-cm(2) decrease in thigh muscle was associated with a 0.01 ± 0.00-m/s decrease in gait speed.nnnCONCLUSIONSnHigh and increasing thigh intermuscular fat are important predictors of gait-speed decline, implying that fat infiltration into muscle contributes to a loss of mobility with age. Conversely, a decreasing thigh muscle area is also predictive of a decline in gait speed.

A Diagnosis of Dismobility—Giving Mobility Clinical Visibility: A Mobility Working Group Recommendation

Slow gait limits independence, decreases quality of life, and is associated with an increased risk of disability, hospitalization, placement in long-term care,1,2 and accelerated clinical progression of many chronic diseases, including chronic obstructive pulmonary disease, diabetes, congestive heart failure, and dementia. Slow gait speed is also a predictor of all-cause mortality.3 Measuring gait speed is simple, quick, reproducible, inexpensive, and feasible in clinical settings. These characteristics have led to the recommendation that gait speed be considered a vital sign for the care of older patients.

Gait Speed Predicts Incident Disability: A Pooled Analysis

BACKGROUNDnFunctional 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.nnnMETHODSnWe 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 ¼ - ½ mile or climbing 10 steps within 3 years.nnnRESULTSnParticipants 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.nnnCONCLUSIONnIn older adults, gait speed predicts 3 year incidence of bathing or dressing dependence, mobility difficulty, and a composite outcome of disability and mortality.