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Consideration of knee pain can be crucial for identifying fall-related gait patterns. While walking, gait parameters at usual speed were examined in persons with different falls and knee pain status. A total of 439 adults aged 60–92 years participated in this study. Persons with a history of falls had a wider stride width (p =.036) and longer double support time (p =.034) than nonfallers. In the absence of knee pain, fallers had longer double support time than nonfallers (p =.012), but no differences in double support time by history of falls were observed in participants with knee pain. With slower gait speed, fallers with knee pain have narrower stride width and larger hip range of motion (p =.027 and p =.001, respectively). Results suggest the importance of considering knee pain in fall studies for better understanding the fall-related differential gait mechanisms and for designing fall prevention intervention strategies. [ABSTRACT FROM AUTHOR]

Background: Gradual disengagement from daily physical activity (PA) could signal present or emerging mild cognitive impairment (MCI) or Alzheimer's disease (AD).Objective: This study examined whether accelerometry-derived patterns of everyday movement differ by cognitive diagnosis in participants of the Baltimore Longitudinal Study of Aging (BLSA).Methods: Activity patterns, overall and by time-of-day, were cross-sectionally compared between participants with adjudicated normal cognition (n = 549) and MCI/AD diagnoses (n = 36; 5 participants [14%] living with AD) using covariate-adjusted regression models.Results: Compared to those with normal cognition, those with MCI/AD had 2.1% higher activity fragmentation (SE = 1.0%, p = 0.036) but similar mean total activity counts/day (p = 0.075) and minutes/day spent active (p = 0.174). Time-of-day analyses show MCI/AD participants had lower activity counts and minutes spent active during waking hours (6:00 am-5:59 pm; p < 0.01 for all). Also, they had lower activity fragmentation from 12:00-5:59 am (p < 0.001), but higher fragmentation from 12:00-5:59 pm (p = 0.026).Conclusion: Differences in the timing and patterns of physical activity throughout the day linked to MCI/AD diagnoses warrant further investigation into potential clinical utility. [ABSTRACT FROM AUTHOR]

Stress, social isolation, and changes in health behaviors during the COVID-19 pandemic period may have a lasting influence on health. Here, the correlation between current or prior demographic, social and health related characteristics, including psychosocial factors with perceived impact of the COVID-19 pandemic assessed by questionnaire during the early pandemic period is evaluated among 770 participants of the Baltimore Longitudinal Study of Aging. In multinomial logistic regression models participants with higher pre-pandemic personal mastery, a construct related to self-efficacy, were more likely to report "both positive and negative" impact of the pandemic than a solely "negative" impact (OR: 2.17, 95% CI: 1.29–3.65). Higher perceived stress and frequent contact with family prior to the pandemic were also associated with pandemic impact. These observations highlight the relevance of psychosocial factors in the COVID-19 pandemic experience and identify characteristics that may inform interventions in future public health crises. [ABSTRACT FROM AUTHOR]

Background: Although elevated thyrotropin (TSH) is common in older adults, controversy exists over what degree of elevation should be treated with thyroid hormone supplements. Isolated, elevated TSH in this population can be consistent with aging‐related adaptations rather than indicative of primary thyroid disease, raising the possibility that thyroid hormone replacement may be harmful. Objectives: Determine the association between all‐cause mortality and levothyroxine use among older adults. Design: Longitudinal observational study. Setting: Baltimore Longitudinal Study of Aging. Participants: One thousand two hundred and fifty eight community dwelling adult participants aged 65+ with an average of 9 years of follow up. Measurements: Thyroid and pituitary hormone levels and thyroid hormone supplementation were determined at each visit. Incident rate ratios (IRR) for all‐cause mortality were calculated using time‐dependent Poisson regression models to accommodate the varying start times. To isolate the effects of hormone replacement from its effects on TSH, the association between treatment and all‐cause mortality was analyzed in participants with stable thyroid function status throughout follow‐up (N = 638). Results: Thyroid hormone supplementation was not associated with a significant increase all‐cause mortality in the subsequent year in the fully adjusted model (IRR = 1.40, 95% confidence interval (CI) = 0.93–2.12). In a stratified analysis of euthyroid participants, thyroid hormone use was associated with significantly greater mortality, with an adjusted IRR = 1.81 (95% CI = 1.10–2.98). Conclusion: The increased mortality associated with thyroid hormone use among the subclass of euthyroid community dwelling older adults is consistent with a model in which TSH elevation can result from a variety of underlying pathophysiologic processes, not all of which should be treated with thyroid hormone supplementation. Clinicians should consider overall clinical status when interpreting an isolated elevated TSH in older adults. [ABSTRACT FROM AUTHOR]

Background: Although mitochondrial dysfunction appears to be a contributing factor in the pathogenesis of cardiovascular and metabolic diseases, empirical data on this association are still lacking. This study evaluated whether mitochondrial oxidative capacity, as assessed by phosphorus magnetic resonance spectroscopy, was associated with cardiovascular risk, as estimated by the Framingham Risk Score (FRS), and with a clinical history of cardiovascular disease (CVD), in community-dwelling adults.Method: A total of 616 subjects from the Baltimore Longitudinal Study of Aging (mean age 66 years) underwent a comprehensive clinical evaluation. Mitochondrial oxidative capacity in skeletal muscle was assessed as post-exercise phosphocreatine recovery time constant by phosphorus magnetic resonance spectroscopy. Multivariate regression models were employed to determine the cross-sectional association of mitochondrial oxidative capacity with FRS and history of CVD.Results: Decreased mitochondrial oxidative capacity was strongly associated with higher FRS independent of age, body composition, and physical activity. Lower oxidative capacity was also associated with a history of positive of CVD and higher number of CVD events.Conclusions: We speculate that the observed association could reflect the effect of an excessive production of oxidative species by dysfunctional mitochondria. Furthermore, decreased energy production could hamper the functionality of heart and vessels. In turn, a malfunctioning cardiovascular apparatus could fail to deliver the oxygen necessary for optimal mitochondrial energy production, therefore creating a vicious cycle. Longitudinal studies are necessary to ascertain the directionality of the association and the eventual presence of common pathogenetic roots. In conclusion, mitochondria could represent an important target for intervention in cardiovascular health. [ABSTRACT FROM AUTHOR]

Resting metabolic rate (RMR) tends to decline with aging. The age-trajectory of decline in RMR is similar to changes that occur in muscle mass, muscle strength, and fitness, but while the decline in these phenotypes has been related to changes of mitochondrial function and oxidative capacity, whether lower RMR is associated with poorer mitochondrial oxidative capacity is unknown. In 619 participants of the Baltimore Longitudinal Study of Aging, we analyzed the cross-sectional association between RMR (kcal/day), assessed by indirect calorimetry, and skeletal muscle maximal oxidative phosphorylation capacity, assessed as postexercise phosphocreatine recovery time constant (τ PCr), by phosphorous magnetic resonance spectroscopy. Linear regression models were used to evaluate the relationship between τ PCr and RMR, adjusting for potential confounders. Independent of age, sex, lean body mass, muscle density, and fat mass, higher RMR was significantly associated with shorter τ PCr, indicating greater mitochondrial oxidative capacity. Higher RMR is associated with a higher mitochondrial oxidative capacity in skeletal muscle. This association may reflect a relationship between better muscle quality and greater mitochondrial health. [ABSTRACT FROM AUTHOR]

BACKGROUND: Age‐related decline in muscle oxidative capacity reduces muscle function and physical performance, leading to disability and frailty. Whether age‐related decline in oxidative capacity is modified by exercise and other lifestyle practices is unclear. Therefore, we tested the hypothesis that physical activity is associated with better oxidative capacity, independent of age. DESIGN: Cross‐sectional study performed in the Baltimore Longitudinal Study of Aging, conducted by the Intramural Research Program (IRP) of the National Institute on Aging (NIA). SETTING: NIA IRP Clinical Research Unit, Baltimore, MD. PARTICIPANTS: Participants included 384 adults (54.7% women), aged 22 to 92 years, seen between 2013 and 2017. MEASUREMENTS: Muscle oxidative capacity was measured in vivo using phosphorous magnetic resonance spectroscopy. We determined the postexercise time constant (τPCr; in seconds) for phosphocreatine (PCr) recovery, with lower values of τPCr, (ie, more rapid recovery of PCr levels after exercise) reflecting greater oxidative capacity. Time spent in moderate‐to‐vigorous physical activity (MVPA) was assessed using wearable accelerometers that participants wore 5.9 ± 0.9 consecutive days in the free‐living environment. RESULTS: In linear regression models, higher τPCr was associated with older age (standardized β =.39; P <.001) after adjusting for sex, race, height, and weight. After including MVPA as an independent variable, the standardized regression coefficient of age decreased by 40%, but remained associated with τPCr (βage =.22; P <.001) and had a smaller standardized regression coefficient than MVPA (βMVPA = −.33; P <.001). After adjusting for health status, education, and smoking history, the standardized regression coefficient for age decreased 12% (βage =.20; P =.003), while the standardized coefficient for MVPA decreased only 3% (βMVPA = −.32; P <.001). CONCLUSION: Study findings suggest that MVPA is strongly associated with muscle oxidative capacity, independent of age, providing mechanistic insights into the health benefits of exercise in older age. J Am Geriatr Soc 67:1695–1699, 2019 [ABSTRACT FROM AUTHOR]

Background: Fatigability, defined as fatigue in relation to a standardized task, predicts functional decline in older adults independent of reported tiredness or energy level. Although the sensation of fatigue, tiredness, and energy level adversely affect physical activity (PA), the association between fatigability and objectively measured PA is unknown.Methods: Participants in the Baltimore Longitudinal Study of Aging (n = 557, 50% women, aged 50-97 years) were instructed to wear an Actiheart accelerometer for 7 consecutive days in the free-living environment. Perceived fatigability was assessed using the Borg rating of perceived exertion (RPE) after 5 minutes of treadmill walking at 1.5 mph (0.67 m/s) and categorized as low (6-7 RPE), intermediate (8-9 RPE), and high (10+ RPE) fatigability. Time-of-day PA differences between fatigability groups were assessed using mixed-effects modeling.Results: Total daily PA was 1.3% lower for every unit increment in perceived fatigability after adjusting for demographic, behavioral, and medical factors (p = .01). In time-of-day analyses, the high fatigability group was less active compared to the low fatigability group throughout the day (8:00 am to 8:00 pm) and the intermediate fatigability group in the morning (8:00 am to 12:00 pm). Patterns of PA within the high fatigability group differed from both the intermediate and low groups in the morning but mirrored the intermediate group in the afternoon and evening.Discussion: These results suggest that RPE is a bio-marker of fatigability associated with progressively lower PA with aging. Whether the effects of fatigability occurring at the end of the day reflect waning energy levels or a voluntary choice that could be modified remains to be evaluated. [ABSTRACT FROM AUTHOR]

Background: Physical activity (PA) prevents disease and promotes longevity; yet, few older adults meet the recommended daily guidelines. Wearable PA and heart rate monitors provide the opportunity to define age-related differences in the absolute and relative intensity of daily activities, and provide insight into the underlying factors influencing PA in older adults.Methods: Participants in the Baltimore Longitudinal Study of Aging (n = 440, 52% male, aged 31 to 88 years) completed a clinical assessment and wore an Actiheart monitor in the free-living environment. The association between age and minutes per day in sedentary, light, moderate, and vigorous PA was assessed using relative intensity, as defined by heart rate reserve, and absolute intensity using activity count thresholds.Results: In cross-sectional analyses, time spent in sedentary and light activities as defined by relative intensity did not differ across age (p > 0.05), whereas time spent in moderate and vigorous relative PA was higher for each 1 year increase in age (p < .01). Using absolute intensity PA thresholds, older adults registered fewer activity counts per day with more sedentary time and lesser amounts of light, moderate, and vigorous PA (p < .05). Persons with higher relative and lower absolute PA intensity had poorer functional performance and higher subclinical disease indicators.Conclusions: These findings suggest that time spent in moderate or higher intensity activities may not be lower with age after considering changes in physiology, functional ability, and subclinical disease burden and highlight the need for more age- and ability-specific PA research to inform future interventions and public health guidelines. [ABSTRACT FROM AUTHOR]

Background: Decreased muscle strength is strongly associated with future mobility limitations in older adults. Homocysteine is a risk factor for vascular disease and may exacerbate muscle strength decline. The present study aimed to examine the association between homocysteine levels and muscle strength in adults aged 50 years or older.Methods: Data were from 1,101 participants of The Baltimore Longitudinal Study of Aging between December 2004 and March 2015. Muscle strength was measured using grip strength. Mixed effects linear regression was used to estimate the association between homocysteine and muscle strength in men and women, separately.Results: Total mean follow-up time was 4.7 ± 3.1 years, range from 0 to 10.1 years. Baseline mean grip strength was 39.9 kg for men and 25.5 kg for women. Grip strength declined over the follow-up time for both men and women. Among women, there was a significant inverse relationship between homocysteine and grip strength, where grip strength declined as a function of increasing homocysteine over time (β = -0.05, p = .031). Among men, an increase of 1 μmol/L in homocysteine was associated with -0.10 kg decrease in grip strength, though not significantly.Conclusions: In this study of healthy older adults aged 50 years or older, higher homocysteine was related to lower muscle strength in women. This is the first study to characterize the relationship over a long follow-up period. Future research should focus on assessing homocysteine as a marker of physical function decline and translating the relationship into clinical and public health practice. [ABSTRACT FROM AUTHOR]

Background: Anemia is associated with poorer sleep in children, and clinically, anemia is linked to insomnia. However, the association between anemia and insomnia in older adults is understudied.Methods: We examined the cross-sectional association between anemia and insomnia in 1,053 adults (71.4 ± 10.6 years) in the Baltimore Longitudinal Study of Aging. Participants were classified as nonanemic, non-iron-deficient anemic, or iron-deficient anemic based on hemoglobin, ferritin, transferrin saturation, and mean cell volume. Insomnia symptoms were evaluated by the Women's Health Initiative Insomnia Rating Scale (WHIIRS). A total score (range 0-20) was generated, and participants were also classified as having 0, 1, or 2+ symptoms.Results: Overall, 10.5% of participants had non-iron-deficient anemia, 0.9% had iron-deficient anemia, and 88.5% had no anemia. Due to its low prevalence, the iron-deficient anemic group was dropped from analyses. In models adjusted for demographics, number of medical conditions, and Center for Epidemiologic Studies Depression Scale score, non-iron-deficient anemic individuals had significantly higher WHIIRS total scores, indicating greater insomnia severity, compared to those without anemia (predicted adjusted mean WHIIRS of 7.24 [95% confidence interval (CI): 6.40-8.08] vs 5.92 [95% CI: 5.65-6.19]). They also had twice the risk of reporting ≥2 insomnia symptoms (vs 0 symptoms; relative risk ratio = 2.20, 95% CI: 1.25-3.89).Conclusions: Results suggest that individuals with non-iron-deficient anemia are more likely to experience insomnia symptoms than those who are nonanemic. These results may have implications for insomnia treatment or the identification of underlying frailty in individuals with sleep problems. [ABSTRACT FROM AUTHOR]

Background: The impact of excess weight on current and future walking endurance in nondisabled persons is unclear. This study examines the association between obesity and walking endurance among nondisabled persons both in late mid-life and early old age.Methods: Participants in the Baltimore Longitudinal Study of Aging aged 60-79 years (n = 406) who reported no walking limitations, and completed a 400-meter walk "as quickly as possible" without lower-extremity pain, and had a follow-up assessment within 1.7-4.2 years. Adiposity was assessed by weight, body mass index (BMI), BMI category, and percent fat mass by DXA.Results: Adjusting for age, sex, race, height, and physical activity, all adiposity measures were cross-sectionally associated with slower 400 meter time in both 60-69 and 70 to 79-year-olds (weight: β = 1.0 and 1.2; BMI: β = 2.8 and 3.6; and percent fat mass: β = 2.0 and 2.0, respectively, all p < .001). With additional adjustment for initial 400-meter performance and follow-up time, in 60- to 69-year-olds, change in 400-meter time (positive β indicates decline) was associated with all adiposity measures (weight: β = 0.4; BMI: β = 1.0; and percent fat mass: β = 0.5; all p ≤ .05) but not in the older group (weight: β = -0.4; BMI: β = -1.2; and percent fat mass: β = -0.2; all p ≥ .17).Conclusion: Excess weight and adiposity were associated with worse walking endurance in nondisabled persons aged 60-79 years and predicted accelerated decline in endurance in late mid-life adults. Weight management for mobility independence may be best targeted in obese persons approaching traditional retirement age. [ABSTRACT FROM AUTHOR]

Background: Aerobic fitness and muscle bioenergetic capacity decline with age; whether such declines explain age-related slowing of walking speed is unclear. We hypothesized that muscle energetics and aerobic capacity are independent correlates of walking speed in simple and challenging performance tests and that they account for the observed age-related decline in walking speed in these same tests.Methods: Muscle bioenergetics was assessed as postexercise recovery rate of phosphocreatine (PCr), k PCr, using phosphorus magnetic resonance spectroscopy (31P-MRS) in 126 participants (53 men) of the Baltimore Longitudinal Study of Aging aged 26-91 years (mean = 72 years). Four walking tasks were administered-usual pace over 6 m and 150 seconds and fast pace over 6 m and 400 m. Separately, aerobic fitness was assessed as peak oxygen consumption (peak VO2) using a graded treadmill test.Results: All gait speeds, k PCr, and peak VO2 were lower with older age. Independent of age, sex, height, and weight, both k PCr and peak VO2 were positively and significantly associated with fast pace and long distance walking but only peak VO2 and not k PCr was significantly associated with usual gait speed over 6 m. Both k PCr and peak VO2 substantially attenuated the association between age and gait speed for all but the least stressful walking task of 6 m at usual pace.Conclusion: Muscle bioenergetics assessed using 31P-MRS is highly correlated with walking speed and partially explains age-related poorer performance in fast and long walking tasks. [ABSTRACT FROM AUTHOR]

Objectives. To investigate whether sensory function declines independently or in parallel with age within a single individual. Methods. Cross-sectional analysis of Baltimore Longitudinal Study of Aging (BLSA) participants who underwent vision (visual acuity threshold), proprioception (ankle joint proprioceptive threshold), vestibular function (cervical vestibular-evoked myogenic potential), hearing (pure-tone average audiometric threshold), and Health ABC physical performance battery testing. Results. A total of 276 participants (mean age 70 years, range 26–93) underwent all four sensory tests. The function of all four systems declined with age. After age adjustment, there were no significant associations between sensory systems. Among 70–79-year-olds, dual or triple sensory impairment was associated with poorer physical performance. Discussion. Our findings suggest that beyond the common mechanism of aging, other distinct (nonshared) etiologic mechanisms may contribute to decline in each sensory system. Multiple sensory impairments influence physical performance among individuals in middle old-age (age 70–79). [ABSTRACT FROM AUTHOR]

Macrostructural white matter damage (WMD) is associated with less uniform and slower walking in older adults. The effect of age and subclinical microstructural WM degeneration (a potentially earlier phase of WM ischemic damage) on walking patterns and speed is less clear. This study examines the effect of age on the associations of regional microstructural WM integrity with walking variability and speed, independent of macrostructural WMD. This study involved 493 participants (n = 51 young; n = 209 young-old; n = 233 old-old) from the Baltimore Longitudinal Study of Aging. All completed a 400-meter walk test and underwent a concurrent brain MRI with diffusion tensor imaging. Microstructural WM integrity was measured as fractional anisotropy (FA). Walking variability was measured as trend-adjusted variation in time over ten 40-meter laps (lap time variation, LTV). Fast-paced walking speed was assessed as mean lap time (MLT). Multiple linear regression models of FA predicting LTV and MLT were adjusted for age, sex, height, weight, and WM hyperintensities. Independent of WM hyperintensities, lower FA in the body of the corpus callosum was associated with higher LTV and longer MLT only in the young-old. Lower FA in superior longitudinal, inferior fronto-occipital, and uncinate fasciculi, the anterior limb of the internal capsule, and the anterior corona radiate was associated with longer MLT only in the young-old. While macrostructural WMD is known to predict more variable and slower walking in older adults, microstructural WM disruption is independently associated with more variable and slower fast-paced walking only in the young-old. Disrupted regional WM integrity may be a subclinical contributor to abnormal walking at an earlier phase of aging. [ABSTRACT FROM AUTHOR]

Background: Emerging evidence suggests that mildly down-regulated thyroid function in older persons may protect and/or reflect maintained health.Methods: Using observational data collected between January 2006 and March 2014 on a volunteer sample of 602 men and women aged 68-97 years with normal thyroid function participating in the Baltimore Longitudinal Study of Aging, this study examines the concurrent relationship between reported walking ability, usual and rapid gait speed, endurance walk performance, fatigability, and reported energy level with respect to free thyroxine (FT4) within the normal range (0.76-1.50ng/dL) as a continuous variable and categorized as low (lower quartile), medium (interquartile), or high (upper quartile).Results: Adjusting for sex, age, race, height, weight, exercise and smoking, reported walking ability, usual and rapid gait speed, 400-m time, fatigability, and reported energy level were less favorable with increasing FT4 (p = .013 to <.001). In sex-strata, similar associations were observed except for walking ability in men and energy level in women. Categorical analyses revealed that persons with low FT4 exhibited better functional mobility, fitness, and reported energy than persons with intermediate or high levels (p < .05 for all). Persons with high-normal versus medium FT4 had slower usual and rapid gait speed (p < .05) only.Conclusion: Older adults with low-normal FT4 exhibit better mobility, fitness, and fatigue profiles. Mildly down-regulated thyroid function appears to align with better function in old age and may serve as a biomarker of healthy longevity. [ABSTRACT FROM AUTHOR]

Background: Slow gait is a robust biomarker of health and a predictor of functional decline and death in older adults, yet factors contributing to the decline in gait speed with aging are not well understood. Previous research suggests that the energetic cost of walking at preferred speed is inversely associated with gait speed, but whether individuals with a rising energetic cost of walking experience a steeper rate of gait speed decline has not been investigated.Methods: In participants of the Baltimore Longitudinal Study of Aging, the energetic cost of overground walking at preferred speed (mL/kg/m) was assessed between 2007 and 2014 using a portable indirect calorimeter. The longitudinal association between the energetic cost of walking and usual gait speed over 6 meters (m/s) was assessed with multivariate linear regression models, and the risk of slow gait (<1.0 m/s) was analyzed using Cox proportional hazards models.Results: The study population consisted of 457 participants aged 40 and older who contributed 1,121 person-visits to the analysis. In fully adjusted models, increases in the energetic cost of walking predicted the rate of gait speed decline in those older than 65 years (β = -0.008 m/s, p < .001). Moreover, those with a higher energetic cost of walking (>0.17mL/kg/m) had a 57% greater risk of developing slow gait compared with a normal energetic cost of walking (≤0.17mL/kg/m; adjusted hazard ratio = 1.57, 95% confidence interval: 1.01-2.46).Conclusions: These findings suggest that strategies to maintain walking efficiency hold significant implications for maintaining mobility in late life. Efforts to curb threats to walking efficiency should focus on therapies to treat gait and balance impairments, and reduce clinical disease burden. [ABSTRACT FROM AUTHOR]

Objectives To evaluate perceived fatigability as a predictor of meaningful functional decline in non-mobility-limited older adults. Design Longitudinal analysis of data from the Baltimore Longitudinal Study of Aging ( BLSA). Setting National Institute on Aging, Clinical Research Unit, Baltimore, Maryland. Participants Men and women aged 60 to 89 participating in the BLSA with concurrent perceived fatigability and functional assessments and follow-up functional assessment within 1 to 3 years (N = 540). Measurements Perceived fatigability was ascertained using the Borg rating of perceived exertion ( RPE) after 5 minutes of treadmill walking at 1.5 miles per hour. Functional assessments included usual and fast gait speed, the Health, Aging and Body Composition physical performance battery ( HABC PPB) and reported walking ability. Reported tiredness and energy level were examined as complementary predictors. Covariates included age, age squared, race, follow-up time, and baseline function. Meaningful decline was defined as 0.05 m/s per year for usual gait speed, 0.07 m/s per year for fast gait speed, 0.12 points/year for HABC PPB, and 1 point for walking ability index. Results Over a mean 2.1 years, 20-31% of participants declined across functional assessments. Fatigability was associated with a 13-19% greater likelihood of meaningful decline in all measures ( P = .002- .02) per 1-unit RPE increase. After considering tiredness and energy level separately, findings were essentially unchanged, and neither was associated with gait speed or physical performance decline. In contrast, each separately predicted decline in reported walking ability independent of fatigability ( P = .03 and P < .001, respectively). Conclusion Routine assessment of fatigability may help identify older persons vulnerable to greater-than-expected functional decline. [ABSTRACT FROM AUTHOR]

Excessively elevated resting metabolic rate (RMR) for persons of a certain age, sex, and body composition is a mortality risk factor. Whether elevated RMR constitutes an early marker of health deterioration in older adult has not been fully investigated. Using data from the Baltimore Longitudinal Study of Aging, we hypothesized that higher RMR (i) was cross-sectionally associated with higher multimorbidity and (ii) predicted higher multimorbidity in subsequent follow-ups. The analysis included 695 Baltimore Longitudinal Study of Aging participants, aged 60 or older at baseline, of whom 248 had follow-up data available 2 years later and 109 four years later. Multimorbidity was assessed as number of chronic diseases. RMR was measured by indirect calorimetry and was tested in regression analyses adjusted for covariates age, sex, and dual-energy x-ray absorptiometry-measured total body fat mass and lean mass. Baseline RMR and multimorbidity were positively associated, independent of covariates (p = .002). Moreover, in a three-wave bivariate autoregressive cross-lagged model adjusted for covariates, higher prior RMR predicted greater future multimorbidity above and beyond the cross-sectional and autoregressive associations (p = .034). RMR higher than expected, given age, sex, and body composition, predicts future higher multimorbidity in older adults and may be used as early biomarker of impending health deterioration. Replication and the development of normative data are required for clinical translation. [ABSTRACT FROM AUTHOR]

Objectives To assess the associations among age, health status, and resting metabolic rate ( RMR) in a large population of older adults. Design Cross-sectional analysis. Setting Community-dwelling volunteers from the Baltimore Longitudinal Study of Aging ( BLSA). Participants Persons aged 40 to 96 (mean 68.2 ± 11.0) who underwent a comprehensive physical examination, cognitive assessment, RMR testing, body composition assessment, and physical function testing during a 3-day clinic visit (N = 420). Measurements Participants were assigned to Insight into the Determination of Exceptional Aging and Longevity ( IDEAL) or non- IDEAL categories based on health status. IDEAL participants were defined according to the absence of physical and cognitive impairments, chronic conditions and comorbidities, and blood profile abnormalities. A three-stage linear regression model was used to assess the relationship between RMR and age, using IDEAL classification as a predictor and adjusting for sex and body composition. Results Resting metabolic rate averaged 1,512.4 ± 442.9 kcal/d and was lower with older age ( β = −8.55, P < .001). After adjusting for age, sex, and body composition, RMR was 109.6 kcal/d lower in IDEAL than non- IDEAL participants ( P < .005). Conclusion Individuals who are fully functional and free of major medical conditions have lower RMR than those with disease and functional impairments. These findings suggest that health status plays a role in energy use and regulation independent of age and body composition and that elevated RMR may be a global biomarker of poor health in older persons. [ABSTRACT FROM AUTHOR]

Objectives To examine the relationship between fruit and vegetable intake, physical activity, and all-cause mortality in older women. Design Six Cox proportional hazards models examined independent and additive relationships between physical activity, carotenoids, and all-cause mortality. Additional models tested whether physical activity and carotenoids were conjointly related to mortality. Models were adjusted for age, education, and race and ethnicity. Setting Baltimore, Maryland. Participants Seven hundred thirteen women aged 70 to 79 participating in the Women's Health and Aging Studies. Measurements Total serum carotenoids, a marker of fruit and vegetable intake, and physical activity were measured at baseline. Physical activity was measured according to kilocalorie expenditure. Results During 5 years of follow-up, 82 (11.5%) participants died. Measured continuously, physical activity improved survival ( HR = 0.52, 95% CI = 0.41-0.66, P < .001). The most active women were more likely to survive than the least physically active women ( HR = 0.28, 95% CI = 0.13-0.59, P < .001). Continuous measures of carotenoids improved survival ( HR = 0.67, 95% CI = 0.51-0.89, P = .01). Women in the highest tertile of total carotenoids were more likely to survive those in the lowest ( HR = 0.50, 95% CI = 0.27-0.91, P = .03). When examined in the same model, continuous measures of physical activity ( HR = 0.54, 95% CI = 0.42-0.68, P < .001) and carotenoids ( HR = 0.76, 95% CI = 0.59-0.98, P = .04) predicted survival during follow-up. Conclusion The combination of low total serum carotenoids and low physical activity, both modifiable risk factors, strongly predicted earlier mortality. These findings provide preliminary support that higher fruit and vegetable intake and exercise improve survival. [ABSTRACT FROM AUTHOR]

OBJECTIVES: The Health ABC Long Distance Corridor Walk (LDCW) was designed to extend the testing range of self-paced walking tests of fitness for older adults by including a warm-up and timing performance over 400 meters. This study compares performance on the LDCW and 6-minute walk to determine whether the LDCW encourages greater participant effort. DESIGN: Subjects were administered the LDCW and 6-minute walk during a single visit. Test order alternated between subjects, and a 15-minute rest was given between tests. SETTING: The Baltimore Veterans Affairs Medical Center. PARTICIPANTS: Twenty volunteers age 70 to 78. MEASUREMENTS: The LDCW, consisting of a 2-minute warm-up walk followed by a 400-meter walk and a 6-minute walk test were administered using a 20-meter long course in an unobstructed hallway. Heart rate (HR) and blood pressure (BP) were recorded at rest and before and after all walks. RESULTS: All 20 subjects walked a faster pace over 400 meters than for 6 minutes, in which the mean distance covered was 402 meters. From paired t-tests, walking speed was faster (mean difference = 0.23 m/sec; P < .001), and ending HR (mean difference = 7.6 bpm; P < .001) and systolic BP (mean difference = 8.3 mmHg; P = .024) were greater for the 400-meter walk than for the 6-minute walk. Results were independent of test order and subject fitness level. CONCLUSIONS: Providing a warm-up walk and using a target distance instead of time encouraged subjects to work closer to their maximum capacity. This low-cost alternative to treadmill testing can be used in research and clinical settings to assess fitness and help identify early functional decline in older adults. [ABSTRACT FROM AUTHOR]

• Balance related gait efficiency in older adults. • Functional leg muscle strength can be related with gait deficits in balance. • Examining the associations between leg muscle strength and gait performance under different balance conditions. • Comprehensive measurement of gait performance for early detection of gait issues in older adults. Balance-related gait patterns in older adults can be objectively discerned through the examination of gait parameters, maximum leg torques, and their interconnections. To investigate the correlation between leg muscle strength and balance during gait concerning functional performance in healthy older adults. Participants included 117 adults aged 60-95 years were recruited from the Baltimore Longitudinal Study of Aging (BLSA). They underwent evaluations of gait, balance, and maximum isometric leg torque (for both hamstrings and quadriceps). Analyses examined the association between leg torque and functional performance among those with higher and lower balances. Individuals with lower balance (n = 43) were older, more prone to experiencing a fear of falling, and exhibited lower functional performance (gait speeds and Generalized Gait Stability Scores (GGSS), ps < 0.001) compared to their counterparts with higher balance (n = 74). At a usual walking pace, the GGSS showed a positive association with concentric Quadriceps Maximum Torque (QMT) in participants with lower balance (p = 0.013). Conversely, it displayed a positive association with eccentric QMT in those with higher balance (p = 0.014). At a fast walking pace, only individuals with higher balance demonstrated a positive muscle torque association with both gait speed and GGSS, encompassing concentric and eccentric actions in both the quadriceps and hamstrings (ps < 0.050). Evaluating muscle strength capacity in both concentric and eccentric phases during dynamic high-effort events, along with investigating their associations with gait performance, can be beneficial for identifying subtle gait deficits. This comprehensive approach may assist in the early detection of gait deterioration among healthy older adults, given the intricate muscle activations involved in lower body functional performance. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Fatigue is an established prognostic indicator of mortality risk. It remains unknown whether fatigability anchored to a physical task is a more sensitive prognostic indicator and whether sensitivity differs by prevalent chronic conditions. Methods: A total of 1076 physically well-functioning participants 50 yr or older in the Baltimore Longitudinal Study of Aging self-reported fatigue (unusual tiredness or low energy) and had perceived fatigability assessed after a standardized treadmill walk. All-cause mortality was ascertained by proxy contact and National Death Index linkage. Cox proportional hazards models estimated associations of perceived fatigability and fatigue with all-cause mortality, adjusting for demographic and clinical covariates. Interactions by chronic conditions were also examined. Results: Each 1 SD higher in perceived fatigability, unusual tiredness, or low energy was associated with a higher relative hazard of all-cause mortality after covariate adjustment (fatigability: hazard ratio (HR), 1.18 (95% confidence interval (CI), 1.03–1.36); unusual tiredness: HR, 1.25 (95% CI, 1.08–1.44); low energy: HR, 1.27 (95% CI, 1.10–1.46)). Models had similar discrimination (P > 0.14 for all). Perceived fatigability was associated with mortality risk among participants free of arthritis or osteoarthritis who otherwise appeared healthy (no arthritis: HR, 1.45 (95% CI, 1.15–1.84); arthritis: HR, 1.09 (95% CI, 0.92–1.30); P -interaction = 0.031). Unusual tiredness was associated with mortality among those with a history of diabetes (no diabetes: HR, 1.16 (95% CI, 0.97–1.38); diabetes: HR, 1.65 (95% CI, 1.22–2.23); P -interaction = 0.045) or pulmonary disease (no pulmonary disease: HR, 1.22 (95% CI, 1.05–1.43); pulmonary disease: HR, 2.15 (95% CI, 1.15–4.03); P -interaction = 0.034). Conclusions: Higher perceived fatigability and fatigue symptoms were similarly associated with higher all-cause mortality, but utility differed by chronic condition. Perceived fatigability might be useful for health screening and long-term mortality risk assessment for well-functioning adults. Alternatively, self-reported fatigue seems more disease-specific with regard to mortality risk. [ABSTRACT FROM AUTHOR]

Objective: Age-related declines in physical activity are commonly observed in human and animal populations, but their physiologic bases are not fully understood. The authors hypothesize that a lack of available energy contributes to low levels of activity in older persons. Design: Cross-sectional analyses of relationships between physical activity level and energy availability were performed in 602 community-dwelling volunteers aged 45-91 yrs from the Baltimore Longitudinal Study of Aging. Energy expenditure was measured at rest and during a maximal 400-m walk for calculation of “available energy.’’ Overall and vigorous physical activity levels were assessed using standardized questionnaires. General linear regression models were used to assess the relationships between available energy and general and vigorous physical activity, and stratified analyses were used to analyze the possible differential association between available energy and physical activity across high and low (peak sustained walking oxygen consumption per unit time, <18.3 ml of oxygen per kilogram per minute) levels of aerobic fitness. Results: Low available energy was associated with low levels of total physical activity ((β = 64.678, P = 0.015) and vigorous activity ((β = 9.123, P< 0.0001). The direct relationship between available energy and physical activity was particularly strong in persons categorized as having low aerobic fitness between available energy and physical activity with both total ((β = 119.783, P = 0.022) and vigorous activity (p = 10.246, P = 0.015) and was independent of body composition and age. Conclusions: The findings from this study support the hypothesis that available energy promotes the maintenance of physical activity in older persons. The findings also run counter to the perception that age-related declines in physical activity are primarily societally or behaviorally driven. [ABSTRACT FROM AUTHOR]

Objective: Previouswork demonstrates the consequences of falling in older adults and the potential of physical activity (PA) to reduce falls, but few studies have used accelerometer-measured PA to compare overall and time-of-day activity patterns of nonfallers, fallers, or subgroups of fallers. Methods: In 840 participants (mean age, 66.7; s = 13.2; range, 26-97) of the Baltimore Longitudinal Study of Aging between 2007 and 2014, PA was measured objectively with Actiheart accelerometers and falling status (faller/nonfaller) was assessed during an in-person interview. Differences in daily PA and PA by time-of-day were assessed using multiple linear regression. Differences in PA (multiple linear regression), and functional status (χ² ) were further examined in subgroups of "risky" or "normal" fallers. Results:Overall, fallers and nonfallers exhibited similar daily (β = 22.6, P = 0.48) and time-specific PA; however, thosewho fell doing risky activities were more active overall (β = 243.8, P = 0.002), during the morning (β = 77.3, P = 0.004), afternoon (β =78.4, P = 0.001), and late afternoon/evening (β =56.3, P = 0.006) than those who fell doing normal activities. Risky fallers were significantly higher functioning than normal fallers. Conclusions: Persons who fell while engaging in normal activities exhibited lower PA overall and throughout most of the day, and were of lower functional status than persons who fell while engaging in risky or unusual activities, suggesting that engagement in risky or unusual PA is associated with higher functional ability and lower falls risk in older persons. [ABSTRACT FROM AUTHOR]

Background Understanding the mechanisms that contribute to walking speed decline can provide needed insight for developing targeted interventions to reduce the rate and likelihood of decline. Objective Examine the association between gait characteristics and walking speed decline in older adults. Methods Participants in the Baltimore Longitudinal Study of Aging aged 60 to 89 were evaluated in the gait laboratory which used a three dimensional motion capture system and force platforms to assess cadence, stride length, stride width, percent of gait cycle in double stance, anterior–posterior mechanical work expenditure (MWE), and medial–lateral MWE. Usual walking speed was assessed over 6 m at baseline and follow-up. Gait characteristics associated with meaningful decline (decline ≥0.05 m/s/y) in walking speed were evaluated by logistic regression adjusted for age, sex, race, height, weight, initial walking speed and follow-up time. Results Among 362 participants, the average age was 72.4 (SD = 8.1) years, 51% were female, 27% were black and 23% were identified has having meaningful decline in usual walking speed with an average follow-up time of 3.2 (1.1) years. In the fully adjusted model, faster cadence [OR adj = 0.65, 95% CI (0.43,0.97)] and longer strides [OR adj = 0.87, 95% CI (0.83,0.91)] were associated with lower odds of decline. However age [OR adj = 1.04, 95% CI (0.99,1.10)] was not associated with decline when controlling for gait characteristics and other demographics. Conclusion A sizable proportion of healthy older adults experienced walking speed decline over an average of 3 years. Longer stride and faster cadence were protective against meaningful decline in usual walking speed. [ABSTRACT FROM AUTHOR]

PURPOSE: To describe the epidemiology of objectively measured physical activity among older adults participating in the Baltimore Longitudinal Study of Aging (BLSA), America's longest running study of human aging, which switched to wrist-worn accelerometry collected since 2015. METHODS: Data were from 658 participants (mean age 70 years, 55% women) enrolled in the BLSA who were instructed to wear a wrist-worn accelerometer for 7 consecutive days and were seen in clinic between 2015-2019. Accelerometer data were processed into activity counts (unitless quantities of movement) and summarized into three continuous metrics: 1) total activity counts/d; 2) active minutes/d using a threshold of ≥1,853 counts/min; and 3) activity fragmentation defined as the reciprocal of the mean active bout length (consecutively occurring active minutes) x 100 (%). Since the BLSA visit schedule is age-dependent (i.e., older persons have more repeated visits), longitudinal analyses were conducted in a restricted sample aged ≥65 years old (n=225). Mixed effects models were constructed to estimate longitudinal changes (baseline age x years since baseline) in each accelerometer metric. Years since baseline was treated as a random effect. Covariates included sex, race, education, employment, body mass index, chronic conditions, usual gait speed, and wear days. RESULTS: Participants, aged 22-97 years, had a mean total 2,209,488 activity counts/d, 430 active minutes/d and 24% activity fragmentation at baseline. Mean wear time was high (1440 min/d) and mean wear days was 6 days. The longitudinal sample, aged 65-97 years, descriptively engaged in less physical activity at baseline, with a mean of 2,060,886 activity counts/d, 414 active minutes/d and activity fragmentation of 25%. Mixed effects modeling estimates showed that, per year, total activity counts decreased by 4894 (SE=1379, p<0.001) counts/d, activity minutes decreased by 1 (SE=0.28, p=0.001) min/d, and activity fragmentation increased by 0.06 (SE=0.02, p=0.0001) %. CONCLUSIONS: Findings update objectively measured physical activity patterns previously measured in the BLSA. With more studies switching to wrist accelerometry collection, these results help define and characterize physical activity patterns and longitudinal change, particularly later in life. [ABSTRACT FROM AUTHOR]

Background/objectives: Anemia is a common condition in older adults for which fatigue, the primary symptom, often goes unrecognized as individuals typically equilibrate their activity to avoid fatigue. Whether assessing fatigability (i.e., susceptibility to fatigue) facilitates identification of anemia is unknown. This study examines the association between fatigability and prevalent, incident, and persistent subclinical and clinical anemia in well-functioning older adults., Design, Setting, Participants: Longitudinal analysis of 905 well-functioning men and women aged 60 to 89 years and followed for 1 to 5 years from the Baltimore Longitudinal Study of Aging conducted at the National Institute on Aging, Clinical Research Unit, Baltimore, MD., Measurements: Perceived fatigability was assessed as a rating of perceived exertion (RPE) from 6 to 20 following a 5-minute treadmill walk at 1.5 mph (.67 m/s); fatigue was assessed as reported unusual tiredness in the past month. Clinical anemia was defined using World Health Organization hemoglobin cutpoints of below 13 g/dL and below 12 g/dL for men and women, respectively, and subclinical anemia was defined as 13.0 to 13.9 g/dL and 12.0 to 12.9 g/dL, respectively., Results: Overall, 14% of participants had clinical and 30% had subclinical anemia at baseline. Each increment (1 RPE) of fatigability was associated after covariate adjustment with 14% (95% confidence interval [CI] = 5-25%, P = .005) and 8% (CI = 1-17%; P = .031), respectively, greater likelihood of prevalent clinical and subclinical anemia. An average of 2.2 years later, each 1 RPE increment in baseline fatigability predicted an 11% (CI = 2-20%; P = .016) higher likelihood of incident and/or persistent subclinical and clinical anemia. Reports of unusual tiredness were associated with prevalent subclinical anemia only., Conclusion: This study provides evidence that perceived fatigability may help identify well-functioning older adults with borderline to clinical anemia who are on a trajectory of persistently suboptimal or worsening hemoglobin status. Assessing fatigability may facilitate earlier diagnosis of health conditions that underlie persistent suboptimal hemoglobin status. J Am Geriatr Soc 68:2297-2302, 2020., (Published 2020. This article is a U.S. Government work and is in the public domain in the USA.)

Objective: Low back pain (LBP) is the most frequently reported musculoskeletal problem in older adults, but its impact on health status is not well understood. Our objective was to determine whether LBP and concurrent leg pain are associated with health-related quality of life (HRQOL) and function in a cohort of older adults, and to examine care-seeking behaviors related to LBP., Methods: This was a population-based, cross-sectional survey study of 522 community-dwelling men and women (67.4%) ages >or=62 living in 4 retirement communities in Maryland and northern Virginia. LBP status in the past year was categorized as no pain in the low back or leg, LBP only, and LBP with leg pain. HRQOL and function were measured with the Medical Outcomes Study Short Form 36 (SF-36)., Results: A total of 26.8% of the sample reported LBP only and 21.3% reported LBP plus leg pain. Participants with LBP and LBP plus leg pain had lower scores in all SF-36 domains, reflecting worse HRQOL (P < 0.0001). LBP and LBP plus leg pain were associated with 2-fold greater odds of falling and increased difficulty lifting grocery bags, walking several blocks, and bathing. LBP plus leg pain was associated with difficulty in social interactions (odds ratio 10.63, 95% confidence interval 3.57-31.60). Less than half sought care for LBP and those who did had poorer health status and greater pain burden., Conclusion: LBP is common among older adults and strongly associated with reduced HRQOL and function. These findings argue strongly for both identifying cases of LBP by health care practitioners and pursuing effective treatments for LBP given the potential consequences.