The Locomotor Experience Applied Post Stroke rehabilitation trial found equivalent walking outcomes for body weight-supported treadmill plus overground walking practice versus home-based exercise that did not emphasize walking. From this large database, we examined several clinically important questions that provide insights into recovery of walking that may affect future trial designs. Using logistic regression analyses, we examined predictors of response based on a variety of walking speed-related outcomes and measures that captured disability, physical impairment, and quality of life. The most robust predictor was being closer at baseline to the primary outcome measure, which was the functional walking speed thresholds of 0.4 m/s (household walking) and 0.8 m/s (community walking). Regardless of baseline walking speed, a younger age and higher Berg Balance Scale score were relative predictors of responding, whether operationally defined by transitioning beyond each speed boundary or by a continuous change or a greater than median increase in walking speed. Of note, the cutoff values of 0.4 and 0.8 m/s had no particular significance compared with other walking speed changes despite their general use as descriptors of functional levels of walking. No evidence was found for any difference in predictors based on treatment group.

Background

Few cohort studies have examined longitudinal associations between age-related changes in cognition and physical performance. Further, whether these associations differ for men versus women or can be attributed to differences in physical activity (PA) is unknown.

Methods

Participants were 2,876 initially well-functioning community-dwelling older adults (aged 70-79 years at baseline; 52% female; 39% black) studied over a 9-year period. Usual gait speed, self-reported PA, and two cognitive measures-Digit Symbol Substitution Test (DSST) and Mini-Modified Mental State examination (3MS)-were assessed years 0 (ie, baseline), 4, and 9.

Results

Early decline between years 0 and 4 in gait speed predicted later decline between years 4 and 9 in performance on the 3MS (β = 0.10, p = .004) and on the DSST (β = 0.16, p < .001). In contrast, the associations between early decline in cognition and later decline in gait speed were weaker and were non-significant after correcting for multiple comparisons (β = 0.08, p = .019 for 3MS and β = .06, p = .051 for DSST). All associations were similar for women and men and were unaltered when accounting for PA levels.

Conclusions

The results indicate declining gait speed as a precursor to declining cognitive functioning, and suggest a weaker reciprocal process among older women and men.

The Locomotor Experience Applied Post Stroke rehabilitation trial found equivalent walking outcomes for body weight-supported treadmill plus overground walking practice versus home-based exercise that did not emphasize walking. From this large database, we examined several clinically important questions that provide insights into recovery of walking that may affect future trial designs. Using logistic regression analyses, we examined predictors of response based on a variety of walking speed-related outcomes and measures that captured disability, physical impairment, and quality of life. The most robust predictor was being closer at baseline to the primary outcome measure, which was the functional walking speed thresholds of 0.4 m/s (household walking) and 0.8 m/s (community walking). Regardless of baseline walking speed, a younger age and higher Berg Balance Scale score were relative predictors of responding, whether operationally defined by transitioning beyond each speed boundary or by a continuous change or a greater than median increase in walking speed. Of note, the cutoff values of 0.4 and 0.8 m/s had no particular significance compared with other walking speed changes despite their general use as descriptors of functional levels of walking. No evidence was found for any difference in predictors based on treatment group.

Objective

To identify the shared neuroimaging signature of gait slowing and cognitive impairment.

Methods

We assessed a cohort of older adults (n = 175, mean age 73 years, 57% female, 65% white) with repeated measures of gait speed over 14 years, MRI for gray matter volume (GMV) at year 10 or 11, and adjudicated cognitive status at year 14. Gait slowing was calculated by bayesian slopes corrected for intercepts, with higher values indicating faster decline. GMV was normalized to intracranial volume, with lower values indicating greater atrophy for 10 regions of interest (hippocampus, anterior and posterior cingulate, primary and supplementary motor cortices, posterior parietal lobe, middle frontal lobe, caudate, putamen, pallidum). Nonparametric correlations adjusted for demographics, comorbidities, muscle strength, and knee pain assessed associations of time to walk with GMV. Logistic regression models calculated odds ratios (ORs) of gait slowing with dementia or mild cognitive impairment with and without adjustment for GMV.

Results

Gait slowing was associated with cognitive impairment at year 14 (OR per 0.1 s/y slowing 1.47; 95% confidence interval 1.04-2.07). The right hippocampus was the only region that was related to both gait slowing (ρ = -0.16, p = 0.03) and cognitive impairment (OR 0.17, p = 0.009). Adjustment for right hippocampal volume attenuated the association of gait slowing with cognitive impairment by 23%.

Conclusions

The association between gait slowing and cognitive impairment is supported by a shared neural substrate that includes a smaller right hippocampus. This finding underscores the value of long-term gait slowing as an early indicator of dementia risk.

Objective

To examine the relationship between gait speed and prior 10 years interleukin-6 (IL-6) burden in older adults. We then assessed whether white matter characteristics influence this relationship.

Methods

In 179 community-dwelling older adults, gait speed was assessed on an automated walkway and serum IL-6 was assayed on ELISA. Concurrently, white matter characteristics were assessed on MRI by quantifying volume of white matter hyperintensities (WMH), a marker of small vessel disease, and normal-appearing white matter on fractional anisotropy (NAWM-FA), a marker of axonal integrity. IL-6 was assayed at regular intervals at gait assessment and over the prior 10 years and estimates of sustained 10-year IL-6 exposure and the rate of change in IL-6 over 10 years were obtained. Multivariate linear regressions were used to examine the relationships among sustained IL-6 exposure, rate of change in IL-6, gait speed, and white matter characteristics.

Results

In this sample (age 83 years, 58% female, 41% black, gait speed 0.9 m/s), higher sustained IL-6 levels, but not the rate of change in IL-6 or IL-6 at gait assessment, was significantly related to slower gait (β = -0.27, p < 0.001) and to higher WMH (β = 0.23, p = 0.002), but not NAWM-FA, withstanding covariate adjustments. WMH accounted for 30% attenuation in the relationship between higher sustained IL-6 levels and slower gait speed (p = 0.043) in the mediation analyses.

Conclusions

Sustained exposure to high IL-6 over 10 years rather than the rate of change in IL-6 or an isolated high IL-6 level may adversely affect gait speed by influencing cerebral WMH.

Background

White matter hyperintensities (WMH), a common marker of cerebral small vessel disease, and lower microstructural integrity of normal-appearing white matter are associated with slower gait. How these cerebral measures interact in relation to slower gait is unknown. We assessed whether microstructural integrity of normal-appearing white matter, measured by fractional anisotropy (FA), moderates the association of higher WMH with slower gait.

Methods

WMH, FA, and gait speed were acquired for 265 community-dwelling older adults (average age = 82.9 years).

Results

The inverse association between WMH and gait was robust to adjustment for age, gender, muscle strength, obesity, stroke, and hypertension (fully adjusted model: βs = -0.19, p = .001). The interaction between WMH and FA was significant; analyses stratified by FA showed that the inverse association between WMH and gait speed was significant only for those with low FA (FA < median, fully adjusted model: βs = -0.28, p = .001). Voxel-based results were similar for participants with FA less than median, there was an inverse association between gait speed and WMH which extended throughout the white matter (genu and body of corpus callosum, anterior limb of internal capsule, corona radiata, and superior longitudinal and fronto-occipital fasciculus). In contrast, for participants with FA ≥ median, the association was limited to the genu of corpus callosum, the cingulum, and the inferior longitudinal fasciculus.

Conclusions

Microstructural integrity is a moderating factor in the association between WMH and gait. Future studies should examine whether higher microstructural integrity represents a source of compensation in those with greater WMH burden to maintain function in late life.

Background

Although it is generally accepted that anticholinergic use may lead to a fall, results from studies assessing the association between anticholinergic use and falls are mixed. In addition, direct evidence of an association between use of anticholinergic medications and recurrent falls among community-dwelling elders is not available.

Objective

To assess the association between anticholinergic use across multiple anticholinergic subclasses, including over-the-counter medications, and recurrent falls.

Methods

This was a longitudinal analysis of 2948 participants, with data collected via interview at year 1 from the Health, Aging and Body Composition study and followed through year 7 (1997-2004). Self-reported use of anticholinergic medication was identified at years 1, 2, 3, 5, and 6 as defined by the list from the 2015 American Geriatrics Society Beers Criteria. Dosage and duration were also examined. The main outcome was recurrent falls (≥2) in an ensuing 12-month period from each medication data collection.

Results

Using multivariable generalized estimating equation models, controlling for demographic, health status/behaviors, and access-to-care factors, a 34% increase in likelihood of recurrent falls in anticholinergic users (adjusted odds ratio = 1.34; 95% CI = 0.93-1.93) was observed, but the results were not statistically significant; similar results were found with higher doses and longer duration of use.

Conclusion

Increased point estimates suggest an association of anticholinergic use with recurrent falls, but the associations did not reach statistical significance. Future studies are needed for more definitive evidence and to examine other measures of anticholinergic burden and associations with more intermediate adverse effects such as cognitive function.

OBJECTIVES: To examine whether deficient B12 status or low serum B12 levels are associated with worse sensory and motor peripheral nerve function in older adults. DESIGN: Cross-sectional. SETTING: Health, Aging and Body Composition Study. PARTICIPANTS: Two thousand two hundred and eighty-seven adults aged 72 to 83 (mean 76.5 ± 2.9; 51.4% female; 38.3% black). MEASUREMENTS: Low serum B12 was defined as serum B12 less than 260 pmol/L, and deficient B12 status was defined as B12 less than 260 pmol/L, methylmalonic acid (MMA) greater than 271 nmol/L, and MMA greater than 2-methylcitrate. Peripheral nerve function was assessed according to peroneal nerve conduction amplitude and velocity (NCV) (motor), 1.4 g/10 g monofilament detection, average vibration threshold detection, and peripheral neuropathy symptoms (numbness, aching or burning pain, or both) (sensory). RESULTS: B12-deficient status was found in 7.0% of participants, and an additional 10.1% had low serum B12 levels. B12 deficient status was associated with greater insensitivity to light (1.4 g) touch (odds ratio = 1.50, 95% confidence interval = 1.06-2.13) and worse NCV (42.3 vs 43.5 m/s) (β = -1.16, P = .01) after multivariable adjustment for demographics, lifestyle factors, and health conditions. Associations were consistent for the alternative definition using low serum B12 only. No significant associations were found for deficient B12 status or the alternative low serum B12 definition and vibration detection, nerve conduction amplitude, or peripheral neuropathy symptoms. CONCLUSION: Poor B12 (deficient B12 status and low serum B12) is associated with worse sensory and motor peripheral nerve function. Nerve function impairments may lead to physical function declines and disability in older adults, suggesting that prevention and treatment of low B12 levels may be important to evaluate.

Previous studies have shown that more active older adults have better cognition and brain health based on a variety of structural neuroimaging measures. Nevertheless, the effects of maintaining physical activity (PA) over an extended period of time on future changes in older adults' cognition and brain structure are unknown. Participants were 141 initially well-functioning community-dwelling older adults (aged 70-79 years at baseline; 60% female; 42% black) studied over a 13-year period. PA (self-reported time spent walking) was assessed annually from years 1 to 10. Magnetic resonance imaging with diffusion tensor was performed at years 10 and 13. Time spent walking decreased on average by 8.4% annually from year 1 to year 10. Independent of initial time spent walking, demographics, and APOE e4 status, better maintenance of time spent walking over the decade predicted less reduction in hippocampal volume (p = 0.03), smaller increases in global gray matter mean diffusivity and white matter axial diffusivity (p < 0.01), and maintenance of general cognitive performance (p < 0.01). Maintenance of cognitive performance was associated with smaller increases in white matter axial diffusivity (p < 0.01). PA at baseline and at year 10, as well as changes in PA over a 5-year period, was less predictive of future changes in brain structure and cognition. Thus, how PA levels change over longer periods of aging may be an important contributor to cognitive and neural protection.

Background

Despite wide-spread use of antihypertensives in older adults, the literature is unclear about their association with incident recurrent falls over time.

Methods

Health, Aging and Body Composition study participants (n = 2,948) who were well functioning at baseline (1997) were followed to Year 7 (2004). The main outcome was recurrent falls (≥2) in the ensuing 12 months. Antihypertensive use was examined as: (a) any versus none, (b) long- versus short-term (≥2 vs <2 years), and by (c) summated standardized daily dose (SDD; 1 = maximum recommended daily dose for one antihypertensive), and (d) subclass.

Results

Controlling for potential demographic, health status/behavior and access to care confounders, we found no increase in risk of recurrent falls in antihypertensive users compared to nonusers (adjusted odds ratio [AOR] = 1.13; 95% CI = 0.88-1.46), or those taking higher SDDs or for longer durations. Only those using a loop diuretic were found to have a modest increased risk of recurrent falls (AOR = 1.50; 95% CI = 1.11-2.03).

Conclusions

Antihypertensive use overall was not statistically significantly associated with recurrent falls after adjusting for important confounders. Loop diuretic use may be associated with recurrent falls and needs further study.