Slow walking speed is strongly associated with older age, but mechanisms underlying this relationship are not well-understood. We hypothesize that slow gait represents a compensatory strategy to reduce the energetic cost of walking with age.
Community-dwelling volunteers from the Baltimore Longitudinal Study of Aging (BLSA).
420 community-dwelling persons aged 32 to 96 (mean 68.1 ± 12.5) who underwent a physical examination, physical function testing, and energy expenditure assessment.
Energy expenditure per minute (ml/kg/min) and per meter (ml/kg/m) during 2.5 minutes of overground walking at customary speed, and usual gait speed over six meters (m/s) were examined. General linear regression models were used to assess the relationship between customary walking energy expenditure and usual gait speed, adjusted for potential confounders including smoking, medical diagnoses, walking-related pain, and balance difficulty.
Usual gait speed was slower with increasing age after age 65. Energy expenditure per minute during customary walking averaged 13.0 ml/kg/min (± 2.8) and was independent of age (ρ < 0.01, p = .88). In contrast, energy expenditure per meter walked was progressively higher after age 65 (ρ = 0.35, p < .001) and heightened after age 80 (ρ = 0.57, p < .001), mirroring the observed pattern of usual gait speed. This relationship remained significant after adjusting for multiple impairments and comorbidities.
These observations support the hypothesis that slower gait at older ages may reflect a compensatory action to offset a greater energetic cost of walking associated with aging and chronic conditions. Future studies should evaluate the specific mechanisms that contribute to this phenomenon as novel targets for clinical intervention.
Energy Expenditure; Gait Speed; Physical Function
Heavy alcohol consumption is toxic to the brain, especially to the frontal white matter (WM), but whether lesser amounts of alcohol negatively impact the brain WM is unclear. In this study, we examined the relationship between self-reported alcohol consumption and regional WM and grey matter (GM) volume in fifty-six men and thirtyseven women (70 +- 7 years) cognitively intact participants of the Baltimore Longitudinal Study of Aging (BLSA) with no history of alcohol abuse. We used regional analysis of volumes examined in normalized space (RAVENS) maps methodology for WM and GM segmentation and normalization followed by voxel based morphometry statistical parametric mapping (in SPM8) to examine the cross-sectional association between alcohol consumption and WM (and, separately, GM) volume controlling for age, sex, smoking, blood pressure and dietary thiamine intake. WM VBM revealed that in men, but not in women, higher alcohol consumption was associated with lower volume in premotor frontal corpus callosum. This finding suggests that even moderate amounts of alcohol may be detrimental to corpus callosum and white matter integrity.
Alcohol; corpus callosum; premotor; white matter
Background & Aims
Chronic inflammation impairs recovery among the 1.6 million people who suffer from hip fracture annually. Vitamin E and the carotenoids are two classes of dietary antioxidants with profound anti-inflammatory effects, and the goal of this study was to assess whether higher post-fracture concentrations of these antioxidants were associated with lower levels of interleukin 6 (IL-6) and the soluble receptor for tumor necrosis factor-alpha (sTNF-αR1), two common markers of inflammation.
Serum concentrations of the dietary antioxidants and inflammatory markers were assessed at baseline and 2, 6, and 12 month follow-up visits among 148 hip fracture patients from The Baltimore Hip Studies. Generalized estimating equations modeled the relationship between baseline and time-varying antioxidant concentrations and inflammatory markers.
Higher post-fracture concentrations of vitamin E and the carotenoids were associated with lower levels of inflammatory markers. Associations were strongest at baseline, particularly between the α-tocopherol form of vitamin E and sTNF-αR1 (p=0.05) and total carotenoids and both sTNF-αR1(p=0.01) and IL-6 (p=0.05). Higher baseline and time-varying α-carotene and time-varying lutein concentrations were also associated with lower sTNF-αR1 at all post-fracture visits (p ≤ 0.05).
These findings suggest that a clinical trial increasing post-fracture intake of vitamin E and the carotenoids may be warranted.
antioxidants; inflammation; vitamin E; carotenoids; micronutrients; hip fracture
Reciprocal relations between weight and psychological factors suggest deep connections between mind and body. Personality traits are linked to weight gain; weight gain may likewise be associated with personality change. Using data from two diverse longitudinal samples (total N=1,919; 10 years average follow-up), we show that significant weight gain is associated with increases in both impulsiveness and deliberation: In both samples, middle-aged adults who gained ≥10% of their baseline body weight by follow-up increased in their tendency to give in to temptation, yet were more thoughtful about the consequences of their actions. The present research moves beyond life events to implicate health status in adult personality development. The findings also suggest that interventions that focus on the emotional component of impulse control may be more effective because even those who become more thoughtful about the consequences of their actions may have limited success at inhibiting their behavior.
Physical inactivity plays a central role in the age-related decline in muscle strength, an important component in the process leading to disability. Personality, a significant determinant of health behaviors including physical activity, could therefore impact muscle strength throughout adulthood and affect the rate of muscle strength decline with aging. Personality typologies combining “high neuroticism” (N≥55), “low extraversion” (E<45), and “low conscientiousness” (C<45) have been associated with multiple risky health behaviors but have not been investigated with regards to muscle strength.
The purpose of this study is to investigate associations between individual and combined typologies consisting of high N, low E, and low C and muscle strength, and whether physical activity and body mass index act as mediators.
This cross-sectional study includes 1,220 participants from the Baltimore Longitudinal Study of Aging.
High N was found among 18%, low E among 31%, and low C among 26% of the sample. High levels of N, particularly when combined with either low E or low C, were associated with lower muscle strength compared with having only one or none of these personality types. Facet analyses suggest an important role for the N components of depression and hostility. Physical activity level appears to partly explain some of these associations.
Findings provide support for the notion that the typological approach to personality may be useful in identifying specific personality types at risk of low muscle strength and offer the possibility for more targeted prevention and intervention programs.
Personality; Muscle strength; Physical activity; Cross-sectional studies
The aim of the present study was to examine differences in gait characteristics across the adult lifespan and to test the hypothesis that such differences are attributable at least in part to the decline in muscle strength. The data presented here are from 190 participants of the Baltimore Longitudinal Study of Aging (BLSA) aged from 32 to 93 years. Based on two age thresholds that best capture the effect of age on walking speed, participants were divided into three age groups: middle-age (32–57 years; N=27), old-age (58–78 years; N=125), and oldest-age (79–93 years; N=38). Participants were asked to walk at their preferred and maximum speeds while recorded with 3D gait analysis system. In addition, maximum isokinetic knee extensor strength was assessed. While walking at preferred speed, range of motion (ROM) and mechanical work expenditure (MWE) of the ankle were lower within middle-age (p < 0.001, p = 0.047, respectively), while hip ROM and MWE were lower (p = 0.006) and higher (p < 0.001), respectively within oldest-age with older age. Deterioration in ankle function during customary walking initiates already at middle-age. Differences in the maximum walking speed and ankle ROM between middle-age and old-age were explained by knee strength.
Aging in gait; Adult lifespan; Knee strength; Ankle function; Stride width
Anemia has been associated with elevated cerebral blood flow (CBF) in animal models and
certain clinical conditions (eg, renal disease), but whether hemoglobin level variations
across a relatively normal range are associated with local or diffuse CBF changes is
unclear. We investigated whether lower hemoglobin is associated with regional increases
in relative CBF in older individuals, and if these increases occur in watershed
Seventy-four older nondemented adults underwent serial 15O water positron
emission tomography scans. Voxel-based analysis was used to investigate regional
relative CBF patterns in association with hemoglobin level and in individuals with and
without anemia. Analyses of cross-sectional relations between regional CBF and anemia
were performed separately at two time points, 2 years apart, to identify replicable
patterns of associations.
Restricting results to associations replicated across two cross-sectional analyses,
lower hemoglobin was associated with higher relative CBF within the middle/inferior
frontal, occipital, precuneus, and cerebellar regions. In addition, individuals with
anemia (n = 15) showed higher relative CBF in superior frontal,
middle temporal, hippocampal, and gyrus rectus regions than those without anemia. In
some regions (right superior temporal gyrus, left inferior frontal gyrus, midline
cuneus, and right precuneus); however, lower hemoglobin was associated with lower
In nondemented individuals, lower hemoglobin is associated with elevated relative CBF
in specific cortical areas but reduced CBF in other areas. Whether this association
between anemia and CBF in the absence of chronic diseases and in a normal physiologic
range is related to clinical endpoints warrants further study.
Cerebral blood flow; Anemia; PET; Aging
The present research examines the effect of age, cohort, and time of measurement on well-being across adulthood. Cross-sectional and longitudinal analyses of two independent samples – one with >10,000 repeated assessments across 30 years (Assessments per participant: M =4.44, SD=3.47) and one with nationally representative data – suggested that well-being declines with age. This decline, however, reversed when we controlled for birth cohort. That is, once we accounted for the fact that older cohorts had lower levels of well-being, all cohorts increased in well-being with age relative to their own baseline. Participants tested more recently had higher well-being, but this time of measurement effect did not change the shape of the trajectory as did cohort. Although well-being increased with age for everyone, cohorts that lived through the economic challenges of the early 20th century had lower well-being than those born during more prosperous times.
Chronic kidney disease (CKD), the result of permanent loss of kidney function, is a major global problem. We identify common genetic variants at chr2p12-p13, chr6q26, chr17q23 and chr19q13 associated with serum creatinine, a marker of kidney function (P=10−10 to 10−15). SNPs rs10206899 (near NAT8, chr2p12-p13) and rs4805834 (near SLC7A9, chr19q13) were also associated with CKD. Our findings provide new insight into metabolic, solute and drug-transport pathways underlying susceptibility to CKD.
Associations among personality as measured by the Five Factor Model, physical activity, and muscle strength were assessed using data from the Baltimore Longitudinal Study of Aging (N = 1220, age: mean = 58, SD = 16). General linear modeling with adjustment for age, sex, race, and body mass index, and bootstrapping for mediation were used. We found neuroticism and most of its facets to negatively correlate with strength. The extraversion domain and its facets of warmth, activity, and positive-emotions were positively correlated with strength, independent of covariates. Mediation analysis results suggest that these associations are partly explained by physical activity level. Findings extend the evidence of an association between personality and physical function to its strength component and indicate health behavior as an important pathway.
Personality; Neuroticism; Extraversion; Agreeableness; Physical activity; Muscle strength
Peak energy expenditure is highly correlated with usual gait speed, however it is unknown whether the energetic cost of walking is also an important contributor to usual gait speed when considered as a component of peak walking capacity.
The energetic cost of five minutes of slow treadmill walking (0.67 m/s), peak overground walking energy expenditure, and usual gait speed over 6 meters were assessed cross-sectionally in 405 adults aged 33 to 94 in the Baltimore Longitudinal Study of Aging.
Average energy expenditure during slow and peak sustained walking were 8.9 (± 1.4) and 18.38 (± 4.8) ml/kg/min, respectively. Overall, the energetic cost of slow walking as a percentage of peak walking energy expenditure was strongly associated with usual gait speed (p < 0.001), however in stratified analyses, this association was maintained only in those with peak walking capacity below 18.3 ml/kg/min (p = 0.04), the threshold associated with independent living.
In older persons with substantially reduced peak walking capacity, the energetic cost of walking is associated with gait speed, particularly when peak walking capacity nears the minimum level considered necessary for independent living. Thus, optimal habilitation in older frail persons may benefit from both improving fitness and reducing the energetic cost of walking.
Energy Expenditure; Walking Efficiency; Usual Gait Speed; Physical Function
Older people with type 2 diabetes are at high risk of mobility disability. We investigated the association of diabetes with lower-limb muscle mass and muscle quality to verify whether diabetes-related muscle impairments mediate the association between diabetes and low walking speed.
RESEARCH DESIGN AND METHODS
We performed a cross-sectional analysis of 835 participants (65 years old and older) enrolled in the InCHIANTI (Invecchiare in Chianti, aging in the Chianti area) population-based study. Total, muscular, and fat cross-sectional areas of the calf and relative muscle density were measured using peripheral quantitative computerized tomography. Indicators of muscle performance included knee-extension torque, ankle plantar flexion and dorsiflexion strength, lower-extremity muscle power, and ankle muscle quality (ratio of ankle strength to the muscle area [kilograms per centimeters squared]). Gait performance was assessed by 4- and 400-m walking speed. Diabetes was ascertained by standard American Diabetes Association criteria.
Prevalence of diabetes was 11.4%. After adjustment for age and sex, participants with diabetes had lower muscle density, knee and ankle strength, and muscle power and worse muscle quality (all P < 0.05). Diabetic participants were also slower on both 4-m (β: −0.115 ± 0.024 m/s, P < 0.001) and 400-m (β:−0.053 ± 0.023 m/s, P < 0.05) walking tests. In multivariable linear regression models, lower-limb muscle characteristics accounted for 24.3 and 15.1% of walking speed difference comparing diabetic and nondiabetic subjects in the 4- and 400-m walks, respectively.
In older persons, diabetes is associated with reduced muscle strength and worse muscle quality. These impairments are important contributors of walking limitations related to diabetes.
Circulating inflammatory markers may play an important role in cognitive impairment at older ages. Mice deficient for the chemokine (C-C motif) receptor 2 (CCR2) develop an accelerated Alzheimer-like pathology. CCR2 is also important in neurogenesis. To identify human gene transcripts most closely associated with Mini-Mental State Examination (MMSE) scores, we undertook a genome-wide and inflammation specific transcriptome screen in circulating leukocytes from a population-based sample.
We measured in vivo transcript levels by microarray analysis in 691 subjects (mean age 72.6 years) in the InCHIANTI study (Invecchiare in Chianti, aging in the Chianti area). We assessed expression associations with MMSE performance at RNA collection and prior 9-year change in MMSE score in linear regression models.
In genome-wide analysis, raised CCR2 expression was cross-sectionally the most strongly associated transcript with lower MMSE score (beta=−0.16, p=5.1×10−6, false discovery rate (FDR; q=0.077). Amongst inflammatory transcripts, only CCR2 expression was associated with both MMSE score and accelerated decline in score over the preceding 9 years (beta=−0.16, p=5.1×10−6, q=0.003; and beta=−0.13, p=5.5×10−5, q=0.03, respectively). CCR2 expression was also positively associated with apolipoprotein E (ApoE) e4 Alzheimer disease risk haplotype.
We show for the first time that CCR2 expression is associated with lower MMSE scores in an older human population. Laboratory models of Ccr2-mediated β-amyloid removal and regulation of neurogenesis affecting cognitive function may be applicable in humans. CCR2-mediated pathways may provide a possible focus for intervention to potentiate protective reactions to Alzheimer pathology in older people, including for people with an adverse ApoE haplotype.
To assess whether selenium and carboxymethyl-lysine (CML), two biomarkers of oxidative stress, are independent predictors of anemia in older, community-dwelling adults.
Plasma selenium, CML, folate, vitamin B12, testosterone, and markers of iron status and inflammation were measured at baseline in 1,036 adults, ≥65 years, in the InCHIANTI Study, a population-based cohort study of aging in Tuscany, Italy, and examined in relationship to prevalent anemia and incident anemia over 6 years of follow-up.
At enrollment, 11.6% of participants were anemic. Of 472 participants who were non-anemic at enrollment 72 (15.3%) developed anemia within 6 years of follow-up. At enrollment, plasma CML in the highest quartile (>425 ng/mL) and plasma selenium in the lowest quartile (<66.6 μg/L) predicted incident anemia (Hazards Ratio [H.R.] 1.67, 95% Confidence Interval [C.I.] 1.07–2.59, P = 0.02; H.R. 1.55, 95% C.I.1.01–2.38, P = 0.05, respectively) in a multivariate Cox proportional hazards model that adjusted for age, education, body mass index, cognition, inflammation, red cell distribution width, ferritin, vitamin B12, testosterone, and chronic diseases.
Elevated plasma carboxymethyl-lysine and low plasma selenium are long-term independent predictors of anemia among older community-dwelling adults. These findings support the idea that oxidative stress contributes to the development of anemia.
advanced glycation end products; aging; anemia; carboxymethyl-lysine; oxidative stress; selenium
To determine if visual field (VF) loss from glaucoma is associated with greater fear of falling.
Prospective observational study.
Fear of falling was compared between 83 glaucoma subjects with bilateral VF loss, and 60 control subjects with good visual acuity and without significant VF loss recruited from patients followed for suspicion of glaucoma.
Participants completed the University of Illinois at Chicago Fear of Falling Questionnaire. The extent of fear of falling was assessed using Rasch analysis.
Main Outcome Measures
Subject ability to perform tasks without fear of falling was expressed in logits, with lower scores implying less ability and greater fear of falling.
Glaucoma subjects had greater VF loss than control subjects (median better-eye mean deviation (MD) of −8.0 decibels [dB] vs. +0.2 dB, p<0.001), but did not differ with regards to age, race, gender, employment status, the presence of other adults in the home, body mass index (BMI), grip strength, cognitive ability, mood, or comorbid illness (p≥0.1 for all).
In multivariable models, glaucoma subjects reported greater fear of falling as compared to controls (β= −1.20 logits; 95% Confidence Interval [CI] = −1.87 to −0.53; p=0.001), and fear of falling increased with greater VF loss severity (β= −0.52 logits per 5 dB decrement in the better eye VF MD; 95% CI = −0.72 to −0.33; p<0.001). Other variables predicting greater fear of falling included female gender (β= −0.55 logits; 95% CI = −1.03 to −0.06; p=0.03), higher BMI (β= −0.07 logits per 1 unit increase in BMI; 95% CI = −0.13 to −0.01; p=0.02), living with another adult (β= −1.16 logits; 95% CI = −0.34 to −1.99 logits; p=0.006), and greater comorbid illness (β= −0.53 logits/1 additional illness; 95% CI = −0.74 to −0.32; p<0.001).
Bilateral VF loss from glaucoma is associated with greater fear of falling, with an impact that exceeds numerous other risk factors. Given the physical and psychological repercussions associated with fear of falling, significant quality of life improvements may be achievable in patients with VF loss by screening for, and developing interventions to minimize, fear of falling.
Previous studies showed that negative self-stereotypes detrimentally affect the
cognitive performance of marginalized group members; however, these findings were
confined to short-term experiments. In the present study, we considered whether
stereotypes predicted memory over time, which had not been previously examined. We also
considered whether self-relevance increased the influence of stereotypes on memory over
Multiple waves of memory performance were analyzed using individual growth models. The
sample consisted of 395 participants in the Baltimore Longitudinal Study of Aging.
Those with more negative age stereotypes demonstrated significantly worse memory
performance over 38 years than those with less negative age stereotypes, after adjusting
for relevant covariates. The decline in memory performance for those aged 60 and above
was 30.2% greater for the more negative age stereotype group than for the less negative
age stereotype group. Also, the impact of age stereotypes on memory was significantly
greater among those for whom the age stereotypes were self-relevant.
This study shows that the adverse influence of negative self-stereotypes on cognitive
performance is not limited to a short-term laboratory effect. Rather, the findings
demonstrate, for the first time, that stereotypes also predict memory performance over
an extended period in the community.
Ageism; Aging; Memory; Self-perception; Stereotypes
To examine the association of fast-adapting receptor-mediated vibrotactile sensitivity and slow-adapting receptor-mediated pressure sensitivity with self-selected usual gait speed and gait speed over a challenging narrow (20 cm wide) course.
Participants from the population-based older cohort of the Health ABC study were included (n = 1721; age: 76.4 ± 2.8 yrs). Usual gait speed over 6 m and gait speed over a 6-m narrow course were measured. Vibration perception threshold (100 Hz) was measured on the plantar surface, and monofilament testing (1.4 and 10 g) was performed on the dorsum of the great toe. Covariates including knee extensor torque, standing balance, visual acuity and contrast sensitivity, knee pain, depressive symptoms, high fasting glucose levels, and peripheral arterial disease were evaluated.
Vibrotactile and monofilament sensitivity were significantly worse in slower gait speed groups in both walking conditions (P < 0.001 to P = 0.015). Adjusting for covariates, vibrotactile (P < 0.001) but not monofilament sensitivity (P = 0.655) was independently associated with self-selected normal gait speed. Neither sensory function was associated with narrow-base gait speed.
In the elderly, poor lower limb vibrotactile sensitivity measured on the plantar surface of the great toe, but not the pressure sensitivity as measured by monofilament testing on the dorsum of the great toe, is independently associated with slower self-selected normal gait speed. Narrow-based walking seems to depend on other neuromuscular mechanisms.
Aging; Gait Speed; Cutaneous Vibration Sensitivity; Monofilament Sensitivity
A chronically elevated white blood cell (WBC) count is a risk factor for morbidity and mortality. The present research tests whether facets of impulsivity – impulsiveness, excitement-seeking, self-discipline, and deliberation – are associated with chronically elevated WBC counts. Community-dwelling participants (N=5,652) from Sardinia, Italy, completed a standard personality questionnaire and provided blood samples concurrently and again three years later. Higher scores on impulsivity, in particular impulsiveness and excitement-seeking, were related to higher total WBC counts and higher lymphocyte counts at both time points. Impulsiveness was a predictor of chronic inflammation: For every standard deviation difference in this trait, there was an almost 25% higher risk of elevated WBC counts at both time points (OR=1.23, 95% CI=1.10–1.38). These associations were mediated, in part, by smoking and body mass index. The findings demonstrate that links between psychological processes and immunity are not limited to acute stressors; stable personality dispositions are associated with a chronic inflammatory state.
Personality; Impulsivity; White blood cells; Inflammation; Neuroticism; Conscientiousness
It has been hypothesized that cellular damage caused by oxidative stress is associated with late-life depression but epidemiological evidence is limited. In the present study we evaluated the association between urinary 8-iso-prostaglandin F2α (8-iso-PGF2α), a biomarker of lipid peroxidation, and depressed mood in a large sample of community-dwelling older adults. Participants were selected from the Health, Aging and Body Composition study, a community-based longitudinal study of older persons (aged 70–79 years). The present analyses was based on a subsample of 1027 men and 948 women free of mobility disability. Urinary concentration of 8-iso-PGF2α was measured by radioimmunoassay methods and adjusted for urinary creatinine. Depressed mood was defined as a score greater than 5 on the 15-item Geriatric Depression Scale and/or use of antidepressant medications. Depressed mood was present in 3.0% of men and 5.5% of women. Depressed men presented higher urinary concentrations of 8-iso-PGF2α than non-depressed men even after adjustment for multiple sociodemographic, lifestyle and health factors (p = 0.03, Cohen’s d = 0.30). This association was not present in women (depressed status-by-sex interaction p = 0.04). Our study showed that oxidative damage may be linked to depression in older men from a large sample of the general population. Further studies are needed to explore whether the modulation of oxidative stress may break down the link between late-life depression and its deleterious health consequences.
Because the initial reports demonstrating that circulating growth hormone and insulin-like growth factor-1 decrease with age in laboratory animals and humans, there have been numerous studies related to the importance of these hormones for healthy aging. Nevertheless, the role of these potent anabolic hormones in the genesis of the aging phenotype remains controversial. In this chapter, we review the studies demonstrating the beneficial and deleterious effects of growth hormone and insulin-like growth factor-1 deficiency and explore their effects on specific tissues and pathology as well as their potentially unique effects early during development. Based on this review, we conclude that the perceived contradictory roles of growth hormone and insulin-like growth factor-1 in the genesis of the aging phenotype should not be interpreted as a controversy on whether growth hormone or insulin-like growth factor-1 increases or decreases life span but rather as an opportunity to explore the complex roles of these hormones during specific stages of the life span.
IGF-1; Longevity; Growth hormone
To determine the association between glaucomatous visual field (VF) loss and the amount of physical activity and walking in normal life.
Prospective observational study.
Glaucoma suspects without significant VF or acuity loss (controls) and glaucoma subjects with bilateral VF loss between age 60 and 80.
Participants wore an accelerometer over 7 days of normal activity.
Main Outcome Measures
Daily minutes of moderate or vigorous physical activity (MVPA) was the primary measure. Steps/day was a secondary measure.
Fifty-eight controls and 83 glaucoma subjects provided sufficient study days for analysis. Control and glaucoma subjects were similar in age, race, gender, employment, cognitive ability and comorbid illness (p>0.1 for all). Better-eye VF mean deviation (MD) averaged 0.0 dB in controls and −11.1 dB in glaucoma subjects.
The median control subject engaged in 16.1 minutes of MVPA daily and walked 5,891 steps/day, as compared to 12.9 minutes of MVPA/day (p=0.25) and 5,004 steps/day (p=0.05) for the median glaucoma subject. In multivariable models, glaucoma was associated with 21% less MVPA (95% CI = -53 - +32%; p=0.37) and 12% fewer steps/day (95% Confidence interval [CI] = -22 to +9%; p=0.21) than controls, though differences were not statistically significant. There was a significant dose-response relating VF loss to decreased activity with each 5 dB decrement in the better-eye VF associated with 17% less MVPA (95% CI = -30 to -2%; p=0.03) and 10% fewer steps/day (95% CI = -16 to -5%; p=0.001) . Glaucoma subjects in the most severe tertile of VF damage (better-eye VF MD worse than -13.5 dB) engaged in 66% less MVPA than controls (95% CI = -82 to -37%, p=0.001) and took 31% fewer steps/day (95% CI = -44 to -15%, p=0.001). Other significant predictors of decreased physical activity included older age, comorbid illness, depressive symptoms, and higher body-mass index.
Overall, no significant difference in physical activity was found between individuals with and without glaucoma, though substantial reductions in physical activity and walking were noted with greater levels of VF loss. Further study is needed to better characterize the relationship between glaucoma and physical activity.
To examine whether deficient B12 status or low serum B12 levels are associated with worse sensory and motor peripheral nerve function in older adults.
Health, Aging and Body Composition Study.
Two thousand two hundred eighty-seven adults aged 72–83 years [mean age: 76.5 ± 2.9 years; 51.4% female; 38.3% black].
Low serum B12 was defined based solely on serum B12 of <260 pmol/L, whereas deficient B12 status was defined as B12 <260 pmol/L, methylmalonic acid [MMA] >271 nmol/L and MMA >2-methylcitrate. Peripheral nerve function was assessed by peroneal nerve conduction amplitude and velocity [NCV] (motor); 1.4g/10g monofilament detection; average vibration threshold detection; and peripheral neuropathy symptoms [numbness; aching/burning pain] (sensory).
B12 deficient status was found in 7.0% and an additional 10.1% had low serum B12 levels. B12 deficient status was associated with greater insensitivity to light (1.4g) touch (OR: 1.50; 95% CI: [1.06, 2.13]) and worse NCV [42.3 m/s vs. 43.5 m/s] (β =−1.16; p=0.01), 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.
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.
low B12; deficient B12; sensory peripheral nerve function; motor nerve conduction; older adults
The aging suppressor gene klotho encodes a single-pass transmembrane protein klotho that in mice is known to extend life span when overexpressed and to resemble accelerated aging, with skeletal muscle atrophy and decreased bone mineral density, when expression is disrupted. We sought to examine the relationship between plasma klotho and disability in activities of daily living (ADL) in older community-dwelling adults. In a cross-sectional study, plasma klotho was measured in a population-based sample of 802 adults, ≥65 years, who participated in the “Invecchiare in Chianti” (Aging in the Chianti Area) (InCHIANTI) study in Tuscany, Italy. The overall proportion of adults with ADL disability was 11.9%. Mean (standard deviation) klotho concentrations were 689 (238) pg/mL. From the lowest to the highest tertile of plasma klotho, 16.1%, 9.7%, and 5.6% of participants, respectively, had ADL disability (p=0.0004). Plasma klotho, per 1 standard deviation increase, was associated with ADL disability (odds ratio=0.57, 95% confidence interval 0.35–0.93, p=0.02) in a multivariate logistic regression model adjusting for age, education, cognition, physical activity, physical performance, total cholesterol, alcohol and tobacco use, and chronic diseases. Low plasma klotho concentrations were independently associated with ADL disability among older community-dwelling men and women.
Measurement error and biological variability generate distortions in quantitative phenotypic data. In longitudinal studies with repeated measurements, the multiple measurements provide a route to reduce noise and correspondingly increase the strength of signals in genome-wide association studies (GWAS).To optimize noise correction, we have developed Shrunken Average (SHAVE), an approach using a Bayesian Shrinkage estimator. This estimator uses regression toward the mean for every individual as a function of (1) their average across visits; (2) their number of visits; and (3) the correlation between visits. Computer simulations support an increase in power, with results very similar to those expected by the assumptions of the model. The method was applied to a real data set for 14 anthropomorphic traits in ∼6000 individuals enrolled in the SardiNIA project, with up to three visits (measurements) for each participant. Results show that additional measurements have a large impact on the strength of GWAS signals, especially when participants have different number of visits, with SHAVE showing a clear increase in power relative to single visits. In addition, we have derived a relation to assess the improvement in power as a function of number of visits and correlation between visits. It can also be applied in the optimization of experimental designs or usage of measuring devices. SHAVE is fast and easy to run, written in R and freely available online.
genome-wide association study; bayesian; multiple measurements; biological variability; measurement error; random-intercept
Recent studies have expanded the functions of vitamin D to a possible role in pulmonary function. Our objective was to examine the relationship between serum 25-hydroxyvitamin D (25[OH]D), serum parathyroid hormone, and pulmonary function in older women.
We examined the relationship of serum 25(OH)D and parathyroid hormone with pulmonary function (forced expiratory volume in one second [FEV1], forced vital capacity [FVC], and FEV1/FVC ratio) in a cross-sectional study of 646 moderately to severely disabled women, 65 years or more, living in the community in Baltimore, Maryland, who participated in the Women’s Health and Aging Study I.
Overall, median (25th, 75th percentile) serum 25-hydroxyvitamin D concentrations were 19.9 (14.7, 26.7) ng/mL. Serum 25(OH)D was positively associated with FEV1 (p = .03), FVC (p = .18), and FEV1/FVC (p = .04) in multivariable linear regression models adjusting for age, race, education, smoking, height, physical activity, cognition, interleukin-6, chronic diseases, and other potential confounders. In the same models, serum parathyroid hormone was not significantly associated with FEV1, FVC, or FEV1/FVC.
These findings support the idea that vitamin D deficiency is independently associated with poor pulmonary function in older disabled women.
Aging; Lung function; Parathyroid hormone; Vitamin D; Women