Association of fatigue, inflammation, and physical activity on gait speed: the Long Life Family Study.

BACKGROUND: Fatigue, inflammation, and physical activity (PA) are all independently associated with gait speed, but their directionality is not fully elucidated. AIMS: Evaluate the bidirectional associations amongst fatigue, inflammation, and PA on gait speed. METHODS: This cross sectional study included probands (n = 1280, aged 49-105) and offspring (n = 2772, aged 24-88) in the Long Life Family Study. We assessed gait speed, fatigue with the question "I could not get going", inflammation using fasting interleukin-6 (IL-6) and high sensitivity C-reactive protein (CRP), and self-reported PA as walking frequency in the past two weeks. The two generations were examined separately using linear mixed modeling. RESULTS: Lower fatigue, lower IL-6, and greater PA were all associated with faster gait speed in both generations (all p < 0.05); lower CRP was only associated with faster gait speed in the offspring. PA explained the association of fatigue and gait speed via a 16.1% (95% CI 9.7%, 26.7%) attenuation of the direct associations for the probands and 9.9% (95% CI 6.3%, 18.8%) in the offspring. In addition, IL-6 explained more of the association of fatigue and gait speed than the association between PA and gait speed, via a 14.9% (95% CI 9.2%, 23.4%) attenuation of the direct association in the offspring only. DISCUSSION: Results revealed a potential directionality from fatigue to IL-6 to PA that may lead to faster gait speed. Future work should examine these relationships longitudinally to establish temporality and causality. CONCLUSIONS: Our findings support a signal that lowering fatigue and inflammation and increasing physical activity may delay functional decline.

Perceived Physical Fatigability Predicts All-Cause Mortality in Older Adults.

BACKGROUND: Perceived physical fatigability is highly prevalent in older adults and associated with mobility decline and other health consequences. We examined the prognostic value of perceived physical fatigability as an independent predictor of risk of death among older adults. METHODS: Participants (N = 2 906), mean age 73.5 [SD, 10.4] years, 54.2% women, 99.7% white enrolled in the Long Life Family Study, were assessed at Visit 2 (2014-2017) with 2.7 [SD, 1.0] years follow-up. The Pittsburgh Fatigability Scale (PFS), a 10-item, self-administered validated questionnaire (score range 0-50, higher = greater fatigability) measured perceived physical fatigability at Visit 2. Deaths post-Visit 2 through December 31, 2019 were identified by family members notifying field centers, reporting during another family member's annual phone follow-up, an obituary, or Civil Registration System (Denmark). We censored all other participants at their last contact. Cox proportional hazard models predicted mortality by fatigability severity, adjusted for family relatedness and other covariates. RESULTS: Age-adjusted PFS Physical scores were higher for those who died (19.1 [SE, 0.8]) compared with alive (12.2, [SE, 0.4]) overall, as well as across age strata (p < .001), except for those 60-69 years (p = .79). Participants with the most severe fatigability (PFS Physical scores ≥ 25) were over twice as likely to die (hazard ratio, 2.33 [95% CI, 1.65-3.28]) compared with those who had less severe fatigability (PFS Physical scores < 25) after adjustment. CONCLUSIONS: Our work underscores the utility of the PFS as a novel patient-reported prognostic indicator of phenotypic aging that captures both overt and underlying disease burden that predicts death.

Impact of Prediabetes and Type-2 Diabetes on Outcomes in Patients with COVID-19.

INTRODUCTION: The true impact of prediabetes and type-2 diabetes in patients with COVID-19 remains unknown, with studies thus far providing conflicting evidence. METHODS: This is a single-center retrospective observational study involving 843 hospitalized patients with SARS-CoV-2 infection. Primary outcomes, mortality, and mechanical ventilation use were compared among the three groups: control, prediabetes, and type-2 diabetes. Binomial regression analysis was used to determine predictors of mortality and mechanical ventilation requirement. RESULTS: Age was a significant predictor of mortality. On stratifying our patients based on their age, older patients aged 55 years and above had no difference in mortality or mechanical ventilation requirement among the three groups of control, prediabetes, and type-2 diabetes. However, among the younger population aged less than 55 years, patients with type-2 diabetes had significantly higher mortality as compared with patients in control and prediabetes groups (27% vs 12.5% vs 9%, p 0.025). Additionally, newly diagnosed type-2 diabetes patients demonstrated lower mortality rate in comparison to previously known type-2 diabetes patients (18% vs 40%, p 0.005). Outcomes in the prediabetes group were similar to that in the control group. Admission hyperglycemia was associated with higher mortality regardless of diabetes status. CONCLUSION: In older patients aged 55 years and above, status of type-2 diabetes does not influence their mortality. However, in younger patients aged less than 55 years, the presence of type-2 diabetes is an important driver of mortality. Newly diagnosed type-2 diabetes, in comparison with previously diagnosed type-2 diabetes, may have better survival. Presence of prediabetes did not affect outcomes in patients with COVID-19 infection.

Validation of Perceived Mental Fatigability Using the Pittsburgh Fatigability Scale.

OBJECTIVES: Establish reliability, concurrent and convergent validity of the Pittsburgh Fatigability Scale (PFS) Mental subscale. DESIGN: Cross-sectional. SETTING: Older adults from two University of Pittsburgh registries, Baltimore Longitudinal Study of Aging (BLSA), and Long Life Family Study (LLFS). PARTICIPANTS: PFS Mental subscale validation was conducted using three cohorts: (1) Development Sample (N = 664, 59.1% women, age 74.8 ± 6.4 years, PFS Mental scores 10.3 ± 9.1), (2) Validation Sample I-BLSA (N = 430, 51.9% women, age 74.5 ± 8.2 years, PFS Mental scores 9.4 ± 7.9), and (3) Validation Sample II-LLFS (N = 1,917, 54.5% women, age 72.2 ± 9.3 years, PFS Mental scores 7.5 ± 8.2). MEASUREMENTS: Development Sample, Validation Sample I-BLSA, and Validation Sample II-LLFS participants self-administered the 10-item Pittsburgh Fatigability Scale. Validation Sample II-LLFS completed cognition measures (Trail Making Tests A and B), depressive symptomatology (Center for Epidemiologic Studies-Depression Scale, CES-D), and global fatigue from two CES-D items. RESULTS: In the Development Sample and Validation Sample I-BLSA, confirmatory factor analysis showed all 10 items loaded on two factors: social and physical activities (fit indices: SRMSR = 0.064, RMSEA = 0.095, CFI = 0.91). PFS Mental scores had strong internal consistency (Cronbach's α = 0.85) and good test-retest reliability (ICC = 0.78). Validation Sample II-LLFS PFS Mental scores demonstrated moderate concurrent and construct validity using Pearson (r) or Spearman (ρ) correlations against measures of cognition (Trail Making Tests A (r = 0.14) and B (r = 0.17) time), depressive symptoms (r = 0.31), and global fatigue (ρ = 0.21). Additionally, the PFS Mental subscale had strong convergent validity, discriminating according to established clinical or cognitive testing cut points, with differences in PFS Mental scores ranging from 3.9 to 7.6 points (all P < .001). All analyses were adjusted for family relatedness, field center, age, sex, and education. CONCLUSIONS: The validated PFS Mental subscale may be used in clinical and research settings as a sensitive, one-page self-administered tool of perceived mental fatigability in older adults.

Higher Fatigue Prospectively Increases the Risk of Falls in Older Men.

BACKGROUND AND OBJECTIVES: Fatigue is a common complaint and shares many risk factors with falls, yet the independent contribution of fatigue on fall risk is unclear. This study's primary aim was to assess the association between fatigue and prospective fall risk in 5642 men aged 64-100 enrolled in the Osteoporotic Fractures in Men Study (MrOS). The secondary aim was to examine the association between fatigue and recurrent fall risk. RESEARCH DESIGN AND METHODS: Fatigue was measured at baseline using the Medical Outcomes Study (short form) single-item question "During the past four weeks, how much of the time did you feel energetic?" Responses were then classified: higher fatigue = "none," "a little," or "some" of the time and lower fatigue = "a good bit," "most," or "all" of the time. We assessed falls using triannual questionnaires. Fall risk was examined prospectively over 3 years; recurrent falling was defined as at least 2 falls within the first year. Generalized estimating equations and multinomial logistic regression modeled prospective and recurrent fall risk as a function of baseline fatigue status, adjusted for demographics, medications, physical activity, and gait speed. RESULTS: Men with higher (26%) versus lower baseline fatigue were older (75.1 ± 6.2 vs 73.2 ± 5.7 years), 24% less active, and had worse physical function (gait speed = 1.09 ± 0.24 vs 1.24 ± 0.21 m/s), all p < .0001. Within 1 year, 25.4% (n = 1409) had fallen at least once, of which 47.4% (n = 668) were recurrent fallers. Men with higher versus lower fatigue had 25% increased fall risk (relative risk = 1.25, 95% CI: 1.14-1.36) over 3 years follow-up, but had 50% increased odds of recurrent falling (odds ratio = 1.50, 95% CI: 1.22-1.85) within the first year. DISCUSSION AND IMPLICATIONS: Fatigue is an important risk factor of falling independent of established risk factors. Reductions in fatigue (ie, increased energy) may lessen the burden of falls in older men and provide a novel avenue for fall risk intervention.

Evaluation of the Bidirectional Relations of Perceived Physical Fatigability and Physical Activity on Slower Gait Speed.

BACKGROUND: Lower physical activity levels and greater fatigability contribute independently to slower gait speed in older adults. To fully understand the bidirectional relations between physical activity and fatigability, and to inform potential intervention strategies, we examined whether physical activity or fatigability explains more of the other factor's association on slower gait speed. METHODS: Two generations (probands and offspring) of older adults (N = 2079, mean age 73.0 ± 10.0 years, 54.2% women, 99.7% White) enrolled in the Long Life Family Study were assessed at Visit 2 (2014-2017). Self-reported physical activity was measured with the Framingham Physical Activity Index and perceived physical fatigability using the Pittsburgh Fatigability Scale. Statistical mediation analyses were conducted separately by generation with linear mixed-effect models accounting for family relatedness and adjusted for demographics, health conditions, and field center. RESULTS: Greater perceived physical fatigability explained the association of lower physical activity on slower gait speed via a 22.5% attenuation of the direct association (95% confidence interval [CI]: 15.0%-35.2%) for the probands and 39.5% (95% CI: 22.8%-62.6%) for the offspring. Whereas lower physical activity explained the association of greater perceived fatigability on slower gait speed via a 22.5% attenuation of the direct association (95% CI: 13.4%-32.8%) for the probands and 6.7% (95% CI: 3.8%-15.4%) for the offspring. CONCLUSIONS: Our findings suggest that the impact of greater perceived physical fatigability on the association between lower physical activity and slower gait speed differs between younger-old and middle-to-oldest-old adults, indicating perceived physical fatigability as a potential mediator in the disablement pathway.

Epidemiology of Perceived Physical Fatigability in Older Adults: The Long Life Family Study.

BACKGROUND: Fatigability is a construct that measures whole-body tiredness anchored to activities of a fixed intensity and duration; little is known about its epidemiology and heritability. METHODS: Two generations of family members enriched for exceptional longevity and their spouses were enrolled (2006-2009) in the Long Life Family Study (LLFS). At Visit 2 (2014-2017, N = 2,355) perceived physical fatigability was measured using the 10-item self-administered Pittsburgh Fatigability Scale (PFS), along with demographic, medical, behavioral, physical, and cognitive risk factors. RESULTS: Residual genetic heritability of fatigability was 0.263 (p = 6.6 × 10-9) after adjustment for age, sex, and field center. PFS physical scores (mean ± SD) and higher physical fatigability prevalence (% PFS ≥ 15) were greater with each age strata: 60-69 (n = 1,009, 11.0 ± 7.6, 28%), 70-79 (n = 847, 12.5 ± 8.1, 37%), 80-89 (n = 253, 19.3 ± 9.9, 65.2%), and 90-108 (n = 266, 28.6 ± 9.8, 89.5%), p < .0001, adjusted for sex, field center, and family relatedness. Women had a higher prevalence of perceived physical fatigability compared to men, with the largest difference in the 80-89 age strata, 74.8% versus 53.5%, p < .0001. Those with greater body mass index, worse physical and cognitive function, and lower physical activity had significantly higher perceived physical fatigability. CONCLUSIONS: Perceived physical fatigability is highly prevalent in older adults and strongly associated with age. The family design of LLFS allowed us to estimate the genetic heritability of perceived physical fatigability. Identifying risk factors associated with higher perceived physical fatigability can inform the development of targeted interventions for those most at risk, including older women, older adults with depression, and those who are less physically active.