Dietary Zinc Intakes Are Associated With Skeletal Muscle Mass and Strength in Children and Adolescents: Zinc and Muscle in Children

The purpose of this study was to evaluate the relationship between dietary zinc intakes and skeletal muscle mass and strength in children and adolescents. A retrospective study was conducted using data on United States adolescents aged 8 to 19 years. Data were extracted from the National Health and Nutrition Examination Survey 2011-2014 cycles. Subjects were divided into 3 groups based on the tertiles of dietary zinc intakes. The levels of appendicular skeletal muscle mass divided by weight (ASM/Wt, %) and grip in subjects with the highest tertile were higher than those in subjects with the middle and lowest tertiles (P < .05). Dietary zinc intakes were positively correlated with ASM/Wt (r = .221, P < .001) and grip (r = 0.169, P < .001). After a multivariate analysis, dietary zinc intakes were still significantly associated with ASM/Wt (β = 0.059, P < .001) and grip (β = 0.245, P < .001). The present study demonstrates that dietary zinc intakes were positively associated with skeletal muscle mass and strength in children and adolescents.

Leg strength and incidence of heart failure in patients with acute coronary syndrome

AIMS

The risk of developing heart failure (HF) after acute coronary syndrome (ACS) remains high. It is unclear whether skeletal muscle strength, in addition to existing risk factors, is a predictor for developing HF after ACS. We aimed to clarify the relationship between quadriceps isometric strength (QIS), a skeletal muscle strength indicator, and the risk of developing HF in patients with ACS.

METHODS

We included 1,053 patients with ACS without a prior HF or complications of HF during hospitalization. The median (IQR) age was 67 (57-74) years. The patients were classified into two groups-high and low QIS-using the sex-specific median QIS. The endpoint was HF admissions.

RESULTS

During a mean follow-up period of 4.4±3.7 years, 75 (7.1%) HF admissions were observed. After multivariate adjustment, a high QIS was associated with a lower risk of HF (hazard ratio [HR]: 0.52, 95% confidence interval [CI]: 0.32-0.87). HR (95% CI) per 5% body weight increment increase of QIS for HF incidents was 0.87 (0.80-0.95). Even when competing risks of death were taken into account, the results did not change. The inclusion of QIS was associated with increases in net reclassification improvement (0.26; 95% CI, 0.002-0.52) and an integrated discrimination index (0.01; 95% CI, 0.004-0.02) for HF.

CONCLUSION

The present study showed that a higher level of QIS was strongly associated with a lower risk of developing HF after ACS. These findings suggest that skeletal muscle strength could be one of the factors contributing to the risk of developing HF after ACS.

Association of Nutritional Status and Diet Diversity with Skeletal Muscle Strength and Quality of Life among Older Arab Adults: A Cross-Sectional Study

There is little research evaluating skeletal muscle strength, nutritional status, and quality of life in older Arab adults. This study examined the association of nutritional status with skeletal muscle strength and quality of life among older adults living in Saudi Arabia. A cross-sectional study was conducted among older adults (n = 166 older adults; 57.8% females) who visited primary outpatient clinics at King Khalid University Hospital in Riyadh City. Sociodemographic data, Mini Nutritional Assessment short-form (MNA-SF), diet variety score (DVS), and health-related quality of life (HR-QoL) were assessed. Furthermore, handgrip strength (HGS) and knee extension strength (KES) were measured to evaluate skeletal muscle strength. Malnourishment and risk of malnutrition were found in 16.9% of our sample. Nutritional status was significantly associated with muscle strength and HR-QoL (p < 0.05). The well-nourished group had higher HGS, KES, and total HR-QoL scores compared to the at risk of malnutrition or malnourished group. Moreover, there was a moderate positive correlation between MNA-SF and total HR-QoL scores (r = 0.40). The percentage of individuals in the well-nourished group categorized with a high or moderate DVS was significantly higher than those at risk of malnutrition or are malnourished; however, DVS was not associated with muscle strength and HR-QoL. The MNA-SF score had a significant positive correlation with HGS (r = 0.30) and KES (r = 0.23). An increase in the MNA-SF score was significantly associated with higher odds of being moderate/high (HGS and HR-QoL) in the crude and adjusted models. In conclusion, maintaining adequate nutritional status is beneficial for preserving skeletal muscle strength and promoting better HR-QoL among older individuals. Therefore, applications of appropriate nutritional and muscle strength assessments in geriatric care institutions are recommended.

Relationship between dysphagia and motor function in community-dwelling older people

AIM

Dysphagia is a problem typically associated with aging. The aim was to investigate the relationship between dysphagia and motor function using a simple assessment method that can be performed in the community setting, and to promote the early detection and prevention of dysphagia.

METHODS

Data from the Locomotive Syndrome and Health Outcome in Aizu Cohort Study (LOHAS) were used. Those aged ≥65 years were included. Motor function was assessed using a grip strength test, single limb standing test (SLS), and timed up and go test (TUG). Swallowing function was assessed using the Japanese version of the 10-item Eating Assessment Tool (EAT-10). The association between motor function and swallowing function was analyzed.

RESULTS

In total, 1732 participants were included. In logistic regression modes in which grip strength, SLS, and TUG results were included separately, the odds ratio for dysphagia increased by 1.08 (P = 0.001) for each 1-kg decrease in grip strength, and increased by 1.15 (P < 0.001) for each 1-s increase in TUG time. No association was found for SLS. In the model in which grip strength and TUG were included simultaneously, the odds ratio for dysphagia increased by 1.06 (P = 0.01) in grip strength, and increased by 1.11 (P = 0.009) in TUG time.

CONCLUSION

Our results suggest that skeletal muscle strength and dynamic balance function are associated with dysphagia in community-dwelling older people. Geriatr Gerontol Int 2023; ••: ••-••.

Nebulized albuterol delivery is associated with decreased skeletal muscle strength in comparison with metered-dose inhaler delivery among children with acute asthma exacerbations

OBJECTIVE

Albuterol is a β2-agonist and causes an intracellular shift of potassium from the interstitium. Whole-body hypokalemia is known to cause skeletal muscle weakness, but whether this occurs as a result of hypokalemia from the intracellular shift during albuterol treatment is unknown. We sought to determine if albuterol total dose or route of administration (nebulization and/or metered-dose inhaler) is associated with skeletal muscle weakness.

METHODS

This was a prospective observational study using convenience sampling. Skeletal muscle strength was measured before and after 1 hour of albuterol treatment using a hand-grip dynamometer in participants aged 5-17 years with acute asthma exacerbation in the emergency department. We examined associations of albuterol dose and route of administration with changes in grip strength.

RESULTS

Among 50 participants, 10 received continuous albuterol by nebulizer and 40 received albuterol by metered-dose inhaler. The median (interquartile range) in change of grip was -7.8% (interquartile range, -23.3, +5.1) for those treated with a nebulizer and +2.4% (interquartile range, -5%, +12.7%) for those treated with a metered-dose inhaler (P = 0.036 for the difference). In a multiple linear regression model adjusted for the pretreatment Acute Asthma Intensity Research Score and age, participants treated with a nebulizer had a 12.9% decrease in skeletal muscle strength compared with those treated with a metered-dose inhaler.

CONCLUSION

Higher doses of albuterol administered via nebulization result in decreased skeletal muscle strength in patients with acute asthma; whereas, albuterol administration via metered-dose inhalers showed no effect on skeletal muscle strength.

Association between Skeletal Muscle Strength and Dysphagia among Chinese Community-Dwelling Elderly Adults

OBJECTIVES

Swallowing disorder is a health burden for the elderly in China. This study aimed to investigate the prevalence of dysphagia and to test the association between skeletal muscle strength and swallowing problems among community-dwelling older adults.

DESIGN

A cross-sectional study.

SETTING

Community-dwelling Chinese elderly in China.

PARTICIPANTS

3361 adults aged 65 years or above were involved, among which 1740 (51.8%) were female, with average age of 72.64 (Standard deviation, SD=6.10) years old.

MEASUREMENTS

Handgrip strength (HGS) was used to evaluate skeletal muscle strength. Dysphagia assessment was performed using the Eating Assessment Tool-10 (EAT-10) and the 30mL water swallow test (WST). Binary logistic regression was used to evaluate the relationship between skeletal muscle strength and dysphagia, and covariates as age, gender, material status, etc. were adjusted.

RESULTS

The prevalence of dysphagia were 5.5% and 12.9%, screened by EAT-10 and 30mL WST respectively. Participants with dysphagia showed lower HGS (21.73 ± 9.20 vs. 25.66 ± 11.32, p<0.001, by EAT-10; 20.26 ± 9.88 vs. 26.22 ± 11.28, p<0.001, by WST). The adjusted model suggested that muscle strength is a protective factor for swallowing disorders (adjusted OR=0.974, 95%CI: 0.950-0.999, by EAT-10; adjusted OR=0.952, 95%CI: 0.933-0.972, by WST). Subgroup analyses of WST found the effects were significant among participants aged in 70-74 years group and ≥75 years group, rather than those aged under 70.

CONCLUSION

Dysphagia was significantly associated with skeletal muscle strength among the community-dwelling elderly population. Effective interventions should be taken to manage the decline of muscle strength for the older adults, especially early prevention before 70 years old.

The acute effects of decaffeinated versus caffeinated coffee on reaction time, mood and skeletal muscle strength

Background Caffeinated coffee, a psycho-stimulant, is widely consumed throughout the globe. However, its chronic consumption has deleterious effects on human health. Meanwhile, decaffeinated coffee has low content of caffeine and thus can be an alternative to caffeinated coffee. Therefore, the study was undertaken to explore and compare the acute effects of decaffeinated and caffeinated coffee on reaction time, mood and skeletal muscle strength in healthy volunteers. Methods This was a prospective, interventional, comparative type of study. The study included 70 healthy adults divided into two groups (Caffeinated coffee group and Decaffeinated coffee group). The following parameters were assessed: reaction time was assessed by digital display multiple-choice apparatus, mood by Visual Analogue Scale (VAS) and Profile of Mood States revised version (POMS) and skeletal muscle strength by hand dynamometer. All parameters in both groups were assessed pre-intervention (baseline) and 30 min post-intervention. Results In both groups (decaffeinated and caffeinated coffee) post-intervention, there was a statistically significant (p < 0.05) improvement in the reaction time (VRT) and mood (VAS, POMS) from the baseline. However, both groups did not show any significant effects on the skeletal muscle strength. Upon comparing the two groups, we found that caffeinated coffee showed higher and significant improvement of mood than decaffeinated coffee. Conclusions Decaffeinated coffee exerts an acute significant stimulatory effect on the reaction time and mood. However, these effects in comparison to caffeinated coffee are low. Further randomized control clinical trials are thus needed to validate these interesting findings.

Human Body Composition and Immunity: Visceral Adipose Tissue Produces IL-15 and Muscle Strength Inversely Correlates with NK Cell Function in Elderly Humans

Natural killer (NK) lymphocyte-mediated cytotoxicity and cytokine secretion control infections and cancers, but these crucial activities decline with age. NK cell development, homeostasis, and function require IL-15 and its chaperone, IL-15 receptor alpha (IL-15Rα). Macrophages and dendritic cells (DC) are major sources of these proteins. We had previously postulated that additional IL-15 and IL-15Rα is made by skeletal muscle and adipose tissue. These sources may be important in aging, when IL-15-producing immune cells decline. NK cells circulate through adipose tissue, where they may be exposed to local IL-15. The objectives of this work were to determine (1) if human muscle, subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) are sources of IL-15 and IL-15 Rα, and (2) whether any of these tissues correlate with NK cell activity in elderly humans. We first investigated IL-15 and IL-15Rα RNA expression in paired muscle and SAT biopsies from healthy human subjects. Both tissues expressed these transcripts, but IL-15Rα RNA levels were higher in SAT than in skeletal muscle. We also investigated tissue obtained from surgeries and found that SAT and VAT expressed equivalent amounts of IL-15 and IL-15Rα RNA, respectively. Furthermore, stromal vascular fraction cells expressed more IL-15 RNA than did adipocytes. To test if these findings related to circulating IL-15 protein and NK cell function, we tested 50 healthy adults aged > 70 years old. Plasma IL-15 levels significantly correlated with abdominal VAT mass in the entire cohort and in non-obese subjects. However, plasma IL-15 levels did not correlate with skeletal muscle cross-sectional area and correlated inversely with muscle strength. Plasma IL-15 did correlate with NK cell cytotoxic granule exocytosis and with CCL4 (MIP-1β) production in response to NKp46-crosslinking. Additionally, NK cell responses to K562 leukemia cells correlated inversely with muscle strength. With aging, immune function declines while infections, cancers, and deaths increase. We propose that VAT-derived IL-15 and IL-15Rα is a compensatory NK cell support mechanism in elderly humans.

Association between ultrasound measurements of muscle thickness, pennation angle, echogenicity and skeletal muscle strength in the elderly

The increase of elderly in our society requires simple tools for quantification of sarcopenia in inpatient and outpatient settings. The aim of this study was to compare parameters determined with musculoskeletal ultrasound (M-US) with muscle strength in young and elderly patients. In this prospective, randomised and observer blind study, 26 young (24.2 ± 3.7 years) and 26 old (age 67.8 ± 4.8 years) patients were included. Muscle thickness, pennation angle and echogenicity of all muscles of musculus quadriceps were measured by M-US and correlated with isometric maximum voluntary contraction force (MVC) of musculus quadriceps. Reproducibility of M-US measurements as well as simple and multiple regression models were calculated. Of all measured M-US variables the highest reproducibility was found for measurements of thickness (intraclass correlation coefficients, 85-97%). Simple regression analysis showed a highly significant correlation of thickness measurements of all muscles of musculus quadriceps with MVC in the elderly and in the young. Multiple regression analysis revealed that thickness of musculus vastus medialis had the best correlation with MVC in the elderly. This study showed that measurement of muscle thickness, especially of musculus vastus medialis, by M-US is a reliable, bedside method for monitoring the extent of sarcopenia.

Supplemental vitamin D and physical performance in COPD: a pilot randomized trial

Background

Low 25-hydroxyvitamin D (25[OH]D) levels, commonly observed in chronic obstructive pulmonary disease (COPD), are associated with muscle weakness in elderly populations, and vitamin D supplementation appears to improve muscle strength and decrease falls in older individuals. We tested the effect of vitamin D supplementation on physical performance in patients with COPD.

Methods

Patients were randomized to daily cholecalciferol (2000 IU) or placebo for 6 weeks. The primary outcome was the 6-week change in Short Physical Performance Battery (SPPB) score. Secondary outcomes included changes in the St George’s Respiratory Questionnaire (SGRQ) score, and serum 25(OH)D.

Results

Thirty-six participants (mean age 68 years, all Caucasian males, mean forced expiratory volume in one second 33% of predicted) completed the study. Despite an increase in 25(OH)D levels in the intervention arm to a mean of 32.6 ng/mL (versus 22.1 ng/mL in the placebo arm), there was no difference in improvements in either SPPB scores (0.3 point difference; 95% confidence interval −0.8 to 1.5; P = 0.56) or SGRQ scores (2.3 point difference; 95% confidence interval −2.3 to 6.9; P = 0.32).

Conclusion

Among patients with severe COPD, 2000 IU of daily vitamin D for 6 weeks increased 25(OH)D to a level widely considered as normal. However, compared with placebo, short-term vitamin D supplementation had no discernible effect on a simple measure of physical performance.