Dysmobility syndrome is associated with prevalent morphometric vertebral fracture in older adults: the Korean Urban-Rural Elderly (KURE) study

Association Between Dysmobility Syndrome with Serum Vitamin D in Community-Dwelling Older Adults

PURPOSE: To investigate the association between serum vitamin D levels and dysmobility syndrome (DMS) in community-dwelling older adults.METHODS: This cross-sectional study included 390 older adults (80.7% female) with a mean (±SD) age of 74.8±5.5 years. Based on high body fat level, osteoporosis, low muscle mass, slow gait speed, low grip strength, and fall(s), participants were classified as robust, pre-DMS, or DMS. Based on serum vitamin D levels, subjects were classified as high 33%, middle 33%, and lower 33%, and/or ≥20 ng/mL and <20 ng/mL, respectively. Logistic regression analyses were performed to determine odds ratios (OR) for serum vitamin D levels in DMS.RESULTS: There were linear increases in DMS variables such as high body fat (<i>p</i> = .040), slow gait speed (<i>p</i> = .048), fall(s) (<i>p</i> = .005), and prevalence of DMS (<i>p</i> = .001) across decremental serum vitamin D levels. Compared with the high vitamin D group (as reference), the low 33% group exhibited a higher OR for DMS (OR 2.776, <i>p</i> = .02). Similarly, compared with the vitamin D ≥20 ng/mL group (as reference), the <20 ng/mL group had a higher OR for DMS (OR 2.486, <i>p</i> = .002).CONCLUSIONS: Findings of this study suggest higher serum vitamin D levels through promoting outdoor physical activity and a healthy diet are key components protecting older adults against DMS.

Utilizing nomograms to predict prevalent vertebral fracture risk: An analysis of dysmobility syndrome in a community-dwelling population

BACKGROUND

To determine a reliable method to predict prevalent vertebral fractures (VF) by assessing the association between dysmobility syndrome (DS) and VF in a community-dwelling population.

METHODS

This cross-sectional study enrolled 518 participants from fracture-prevention educational activities held in multiple communities in Taiwan. Assessments included questionnaires, fracture risk assessment tool (FRAX), bone mineral density (BMD) and body composition using dual-energy x-ray absorptiometry (DXA), lateral thoracolumbar spine x-rays (specifically T8-S1), grip strength (GS), walking speed, and fall history.

RESULTS

DS was noted in 257 participants (49.6%) and VF was identified in 196 participants (37.8%). A higher prevalence of VF was noted in those with DS. The prevalence of VF was significantly associated with age, gender, FRAX both with and without BMD, osteoporosis, low GS, and DS. In multivariate models accounting for age and sex, the c-index was greater in those with low GS plus osteoporosis as compared to DS alone. Low GS, osteoporosis, and pre-BMD FRAX all had similar c-indexes. Pre-BMD FRAX plus low GS and osteoporosis was superior in predicting VF compared to pre-BMD FRAX plus low GS or osteoporosis alone. Besides the inclusion of age and gender, the nomogram with pre-BMD FRAX major osteoporosis fracture probability (MOF) plus low GS had improved correlation between the estimated and actual VF probability than those with pre-BMD FRAX MOF plus osteoporosis.

CONCLUSIONS

The constructed nomogram containing pre-BMD FRAX MOF plus low GS may be considered as a first-line prevalent VF screening method. Those with high-risk scores should subsequently undergo vertebral radiography and/or BMD.

The impact of sarcopenia on low back pain and quality of life in patients with osteoporosis

PURPOSE

Osteoporosis combined with sarcopenia contributes to a high risk of falling, fracture, and even mortality. However, sarcopenia's impact on low back pain and quality of life (QOL) in patients with osteoporosis is still unknown. The purpose of this study is to investigate low back pain and QOL in osteoporosis patients with sarcopenia.

METHODS

We assessed 100 ambulatory patients who came to our hospital for osteoporosis treatment. Low back pain was evaluated using the Visual Analogue Scale (VAS) with 100 being an extreme amount of pain and 0 no pain. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) score was used to assess QOL after adjustment for age, history of vertebral fracture, and adult spinal deformity. Differences in low back pain intensity assessed by VAS between groups were evaluated by the Willcoxon rank-sum test. Covariance analysis was used to assess QOL. All data are expressed as either median, interquartile range, or average, standard error.

RESULTS

Patients were classified into the sarcopenia group (n = 32) and the non-sarcopenia group (n = 68). Low back pain intensity assessed by VAS was significantly higher in the sarcopenia group than in the non-sarcopenia group (33.0 [0-46.6] vs. 8.5 [0-40.0]; p < 0.05). The subscales of the JOABPEQ for low back pain were significantly lower in the sarcopenia group than in the non-sarcopenia group (65.0 ± 4.63 vs. 84.0 ± 3.1; p < 0.05).

CONCLUSION

In this cross-sectional study, sarcopenia affected low back pain and QOL in ambulatory patients with osteoporosis. Sarcopenia may exacerbate low back pain and QOL.

Deep neural network for automatic volumetric segmentation of whole-body CT images for body composition assessment

BACKGROUND & AIMS

Body composition analysis on CT images is a valuable tool for sarcopenia assessment. We aimed to develop and validate a deep neural network applicable to whole-body CT images of PET-CT scan for the automatic volumetric segmentation of body composition.

METHODS

For model development, one hundred whole-body or torso ¹⁸F-fluorodeoxyglucose PET-CT scans of 100 patients were retrospectively included. Two radiologists semi-automatically labeled the following seven body components in every CT image slice, providing a total of 46,967 image slices from the 100 scans for training the 3D U-Net (training, 39,268 slices; tuning, 3116 slices; internal validation, 4583 slices): skin, bone, muscle, abdominal visceral fat, subcutaneous fat, internal organs with vessels, and central nervous system. The segmentation accuracy was assessed using reference masks from three external datasets: two Korean centers (4668 and 4796 image slices from 20 CT scans, each) and a French public dataset (3763 image slices from 24 CT scans). The 3D U-Net-driven values were clinically validated using bioelectrical impedance analysis (BIA) and by assessing the model's diagnostic performance for sarcopenia in a community-based elderly cohort (n = 522).

RESULTS

The 3D U-Net achieved accurate body composition segmentation with an average dice similarity coefficient of 96.5%-98.9% for all masks and 92.3%-99.3% for muscle, abdominal visceral fat, and subcutaneous fat in the validation datasets. The 3D U-Net-derived torso volume of skeletal muscle and fat tissue and the average area of those tissues in the waist were correlated with BIA-derived appendicular lean mass (correlation coefficients: 0.71 and 0.72, each) and fat mass (correlation coefficients: 0.95 and 0.93, each). The 3D U-Net-derived average areas of skeletal muscle and fat tissue in the waist were independently associated with sarcopenia (P < .001, each) with adjustment for age and sex, providing an area under the curve of 0.858 (95% CI, 0.815 to 0.901).

CONCLUSIONS

This deep neural network model enabled the automatic volumetric segmentation of body composition on whole-body CT images, potentially expanding adjunctive sarcopenia assessment on PET-CT scan and volumetric assessment of metabolism in whole-body muscle and fat tissues.

The diagnostic value of phase angle, an integrative bioelectrical marker, for identifying individuals with dysmobility syndrome: the Korean Urban-Rural Elderly study

Low phase angle, a non-invasive bioimpedance marker, is associated with elevated odds of dysmobility syndrome and its components. Phase angle (estimated cutoffs: < 4.8° in men; < 4.5° in women) can be used to detect dysmobility syndrome in community-dwelling older adults as a simple, integrative screening tool.

INTRODUCTION

Dysmobility syndrome uses a score-based approach to predict fracture risk that incorporates the concepts of osteoporosis, sarcopenia, and obesity. Low phase angle (PhA), a simple, non-invasive bioelectrical impedance marker, was associated with low lean mass, high fat mass, and poor muscle function. We aimed to investigate the association between PhA and dysmobility syndrome, with the exploration of the diagnostic cutoffs.

METHODS

In a community-dwelling Korean older adult cohort, dysmobility syndrome was defined as the presence of ≥ 3 of the following components: osteoporosis, low lean mass, falls in the preceding year, low grip strength, high fat mass, and poor timed up and go performance.

RESULTS

Among the 1825 participants (mean age 71.6, women 66.7%), subjects were classified into sex-stratified PhA tertiles. The prevalence of dysmobility syndrome increased from the highest PhA tertile group to the lowest (15.50 to 2.45% in men; 33.41 to 12.25% in women, P for trend < 0.001). The mean PhA values decreased as the dysmobility score increased (5.33° to 4.65° in men; 4.76° to 4.39° in women, P for trend < 0.001). Low PhA (cutoff: < 4.8° in men; < 4.5° in women) was associated with twofold elevated odds of dysmobility syndrome after adjusting for age, sex, and conventional risk factors. Low PhA improved the identification of individuals with dysmobility syndrome when added to the conventional risk model (area under the curve, 0.73 to 0.75, P = 0.002).

CONCLUSION

Low PhA was associated with dysmobility syndrome and its components, independent of age, sex, body mass index, nutritional status, and inflammation.

Integrating Muscle Health in Predicting the Risk of Asymptomatic Vertebral Fracture in Older Adults

Background: The utility of muscle health for predicting asymptomatic vertebral fracture (VF) is uncertain. We aimed to determine the effects of muscle health on bone quantity and quality in the older adults and to integrate these factors into a predictive model for VF. Methods: We prospectively recruited participants with a body mass index <37 kg/m². The total lean mass (TLM), appendicular skeletal muscle index, presence of sarcopenia, and bone mineral density were determined by dual-energy X-ray absorptiometry, and bone quality by the trabecular bone score (TBS). VF was diagnosed based on spine radiography. Results: A total of 414 females and 186 males were included; 257 participants had VF. Lower TLM was significantly associated with poorer bone quantity and quality in both males and females. A low TBS (OR: 11.302, p = 0.028) and sarcopenia (Odds ratio (OR): 2.820, p = 0.002) were significant predictors of VF in males, but not bone quantity. Moreover, integrating TBS and sarcopenia into the predictive model improved its performance. Conclusions: Although TLM was associated with bone quantity and quality in both sexes, sarcopenia and a low TBS were significant predictors of asymptomatic VF only in male participants.

Defining an international cut-off of two-legged countermovement jump power for sarcopenia and dysmobility syndrome

We aimed to establish jump power cut-offs for the composite outcome of either sarcopenia (EWGSOP2) or dysmobility syndrome using Asian and Caucasian cohorts. Estimated cut-offs were sex specific (women: < 19.0 W/kg; men: < 23.8 W/kg) but not ethnicity specific. Jump power has potential to be used in definitions of poor musculoskeletal health.

PURPOSE

Weight-corrected jump power measured during a countermovement jump may be a useful tool to identify individuals with poor musculoskeletal health, but no cut-off values exist. We aimed to establish jump power cut-offs for detecting individuals with either sarcopenia or dysmobility syndrome.

METHODS

Age- and sex-matched community-dwelling older adults from two cohorts (University of Wisconsin-Madison [UW], Korean Urban Rural Elderly cohort [KURE], 1:2) were analyzed. Jump power cut-offs for the composite outcome of either sarcopenia defined by EWGSOP2 or dysmobility syndrome were determined.

RESULTS

The UW (n = 95) and KURE (n = 190) cohorts were similar in age (mean 75 years) and sex distribution (68% women). Jump power was similar between KURE and UW women (19.7 vs. 18.6 W/kg, p = 0.096) and slightly higher in KURE than UW in men (26.9 vs. 24.8 W/kg, p = 0.050). In UW and KURE, the prevalence of sarcopenia (7.4% in both), dysmobility syndrome (31.6% and 27.9%), or composite of either sarcopenia or dysmobility syndrome (32.6% and 28.4%) were comparable. Low jump power cut-offs for the composite outcome differed by sex but not by ethnicity (< 19.0 W/kg in women; < 23.8 W/kg in men). Low jump power was associated with elevated odds of sarcopenia (adjusted odds ratio [aOR] 4.07), dysmobility syndrome (aOR 4.32), or the composite of sarcopenia or dysmobility syndrome (aOR 4.67, p < 0.01 for all) independent of age, sex, height, and ethnicity.

CONCLUSION

Sex-specific jump power cut-offs were found to detect the presence of either sarcopenia or dysmobility syndrome in older adults independent of Asian or Caucasian ethnicity.

Impact of Bone Fracture on Muscle Strength and Physical Performance-Narrative Review

PURPOSE OF REVIEW

Low muscle strength and poor physical performance are associated with high risk of fracture. Many studies assessed clinical and functional outcomes of fractures. Fewer studies analyzed the impact of fractures on muscle strength and physical performance.

RECENT FINDINGS

Vertebral fractures (especially multiple and severe ones) are associated with back pain, back-related disability, lower grip strength, lower strength of lower limbs, lower gait speed, and poor balance. Patients with hip fracture have slower gait and lower quadriceps strength. Non-vertebral fractures were associated with lower strength of the muscles adjacent to the fracture site (e.g., grip strength in the case of distal radius fracture, knee extensors in the case of patellar fracture) and poor physical function dependent on the muscles adjacent to the fracture site (e.g., limited range of motion of the shoulder in the case of humerus fracture, gait disturbances in the case of the ankle fracture). Individuals with a fracture experience a substantial deterioration of muscle strength and physical performance which exceeds that related to aging and is focused on the period close to the fracture occurrence. After fracture, muscle strength increased and physical performance improved. The rate of normalization depended partly on the therapeutic approach and on the rehabilitation program. A subgroup of patients, mainly the elderly, never returns to the pre-fracture level of physical performance. The permanent decline of physical function after fracture may be related to the limitation of movements due to pain, low physical activity, poor health before the fracture, and reduced efficacy of retraining after immobilization.

Dysregulated Autophagy Mediates Sarcopenic Obesity and Its Complications via AMPK and PGC1α Signaling Pathways: Potential Involvement of Gut Dysbiosis as a Pathological Link

Sarcopenic obesity (SOB), which is closely related to being elderly as a feature of aging, is recently gaining attention because it is associated with many other age-related diseases that present as altered intercellular communication, dysregulated nutrient sensing, and mitochondrial dysfunction. Along with insulin resistance and inflammation as the core pathogenesis of SOB, autophagy has recently gained attention as a significant mechanism of muscle aging in SOB. Known as important cellular metabolic regulators, the AMP-activated protein kinase (AMPK) and the peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1α) signaling pathways play an important role in autophagy, inflammation, and insulin resistance, as well as mutual communication between skeletal muscle, adipose tissue, and the liver. Furthermore, AMPK and PGC-1α signaling pathways are implicated in the gut microbiome-muscle axis. In this review, we describe the pathological link between SOB and its associated complications such as metabolic, cardiovascular, and liver disease, falls and fractures, osteoarthritis, pulmonary disease, and mental health via dysregulated autophagy controlled by AMPK and/or PGC-1α signaling pathways. Here, we propose potential treatments for SOB by modulating autophagy activity and gut dysbiosis based on plausible pathological links.

Cohort profile: Korean Urban Rural Elderly (KURE) study, a prospective cohort on ageing and health in Korea

PURPOSE

The Korean Urban Rural Elderly (KURE) cohort was initiated to study the epidemiologic characteristics, physical performance, laboratory and imaging biomarkers and incidence of age-related diseases in an elderly population with respect to both clinical and social aspects to develop preventive and therapeutic strategies for combatting age-related diseases.

PARTICIPANTS

A total of 3517 adults aged 65 or older participated in the cohort at baseline from 2012 to 2015, recruited from three urban districts and one rural district in Korea. The second-wave follow-up survey is now being conducted at a 4-year interval from baseline (2016-2019; follow-up rate 71.5%). The data set included detailed information on anthropometric and socioeconomic factors, functional assessments, image scans (plain radiography, dual-energy X-ray absorptiometry and CT), biospecimens (ie, serum, urine and DNA) and social support networks along with the feasibility of linkage to a national claims database.

FINDINGS TO DATE

Mean age of participants at entry was 71.9±4.6 years and 67% were women. From the KURE participants enrolled in baseline recruitment, several studies were published in the fields of cardiometabolic diseases, musculoskeletal health and the association between social support network and diseases in ageing.

FUTURE PLANS

Participants will be observed actively and passively every 4-5 years and the first follow-up will be completed in 2020. The KURE data set has strength in comprehensive physical function assessments, quantifiable imaging data sets using CT and detailed information regarding the social support networks of participants from a large community-based elderly Korean population.