Are body fat and inflammatory markers independently associated with age-related muscle changes?

Association Between Handgrip Strength and Type 2 Diabetes: A Prospective Cohort Study and Systematic Review With Meta-analysis

BACKGROUND

Both absolute (kg) and relative (kg per kg of body weight) handgrip strength (HGS) have been used as indicators of HGS. Multiple studies have explored HGS associations with type 2 diabetes (T2DM); however, prognostic values were inconsistent. We aimed to examine the associations between both absolute and relative HGS and incident T2DM.

METHODS

A total of 12,957 participants aged 40 years and older (mean age 51.0 years, 58.4% men) were followed and enrolled in the Tianjin Chronic Low-grade Systemic Inflammation and Health (TCLSIH) Cohort Study. Cox proportional hazards regression models were used to examine the association of HGS with incident T2DM. Other prospective studies on HGS and risk of T2DM were identified by searching several electronic databases up to November 31, 2021. Meta-analysis was performed by combining the results from the TCLSIH study and previous prospective cohort studies.

RESULTS

From the TCLSIH Cohort study, after adjustment, relative HGS was inversely associated with T2DM (hazard ratio per 0.1 higher relative HGS 0.667, 95% confidence interval [CI] 0.616, 0.722). However, no significant association between absolute HGS and incident T2DM was found. The meta-analyses showed that per 5 kg higher HGS was associated with a 5% (95% CI 2%, 8%) lower risk of T2DM and each 0.1 higher relative HGS was associated with a 22% (95% CI 14%, 29%) lower risk of T2DM.

CONCLUSION

The results from our cohort study and meta-analysis suggest that relative HGS was better than absolute HGS in predicting incident T2DM. Adiposity was an important factor that mediates the association between HGS and T2DM.

Contribution of skeletal muscle to cancer immunotherapy: A focus on muscle function, inflammation, and microbiota

Sarcopenia, characterized by degenerative and systemic loss of skeletal muscle mass and function, is a multifactorial syndrome commonly observed in individuals with cancer. Additionally, it represents a poor nutritional status and indicates possible presence of cancer cachexia. Recently, with the extensive application of cancer immunotherapy, the effects of sarcopenia/cachexia on cancer immunotherapy, have gained attention. The aim of this review was to summarize the influence of low muscle mass (sarcopenia/cachexia) on the response and immune-related adverse events to immunotherapy from the latest literature. It was revealed that low muscle mass (sarcopenia/cachexia) has detrimental effects on cancer immunotherapy in most cases, although there were results that were not consistent with this finding. This review also discussed potential causes of the paradox, such as different measure methods, research types, muscle indicators, time point, and cancer type. Mechanically, chronic inflammation, immune cells, and microbiota may be critically involved in regulating the efficacy of immunotherapy under the condition of low muscle mass (sarcopenia/cachexia). Thus, nutritional interventions will likely be promising ways for individuals with cancer to increase the efficacy of immunotherapy in the future, for low muscle mass (sarcopenia/cachexia) is an important prognostic factor for cancer immunotherapy.

High Adherence to the Mediterranean Diet is Associated with Higher Physical Fitness in Adults: a Systematic Review and Meta-Analysis

Although prior research has synthesized the relationships between the Mediterranean diet (MD) and components of physical fitness (PF) in adults, they are limited and inconclusive. This study aimed to synthesize the associations between high (compared with low) MD adherence and PF levels with each of its components (cardiorespiratory, motor, and musculoskeletal) in adulthood. We conducted a systematic search in 5 databases from inception to January 2022. Observational studies and randomized controlled trials were included. Pooled odds ratios (ORs) and effect sizes (Cohen d index) with their 95% CIs were calculated via a random effects model. A total of 30 studies were included (19 cross-sectional in young, middle-aged, and older adults; 10 prospective cohort in older adults; and 1 randomized controlled trial in young adults) involving 36,807 individuals (mean age range: 20.9-86.3 y). Pooled effect sizes showed a significant cross-sectional association between higher MD adherence scores (as a continuous variable) and overall PF (d = 0.45; 95% CI: 0.14, 0.75; I2 = 91.0%, n = 6). The pooled ORs from cross-sectional data showed that high adherence to MD was associated with higher cardiorespiratory fitness (OR: 2.26; 95% CI: 2.06, 2.47; I2 = 0%, n = 4), musculoskeletal fitness (OR: 1.26; 95% CI: 1.05, 1.47; I2 = 61.4%, n = 13), and overall PF (OR: 1.44; 95% CI: 1.20, 1.68; I2 = 83.2%, n = 17) than low adherence to MD (reference category: 1). Pooled ORs from prospective cohort studies (3- to 12-y follow-up) showed that high adherence to MD was associated with higher musculoskeletal fitness (OR: 1.20; 95% CI: 1.01, 1.38; I2 = 0%, n = 4) and overall PF (OR: 1.14; 95% CI: 1.02, 1.26; I2 = 9.7%, n = 7) than low adherence to MD (reference category: 1). Conversely, no significant association was observed between MD and motor fitness. High adherence to MD was associated with higher PF levels, a crucial marker of health status throughout adulthood. This trial was registered at PROSPERO as CRD42022308259.

Association Between Inflammatory Biomarkers and Mental Health Symptoms in Middle Eastern Refugees in the US

Introduction: Refugees are at increased risk for trauma-related mental health disorders, including anxiety, depression, and post-traumatic stress disorder (PTSD). The underlying biological mechanisms linking trauma to mental disorders need additional study, and the possible pathophysiological role of the immune system is attracting increasing interest. In this study, we investigated whether two well-known pro-inflammatory cytokines (interleukin (IL-8) and IL-6) are associated with mental health symptoms in Middle Eastern refugees displaced to the United States.

Methods: Refugees (n=64, mean age=37.6 years) ages ranged from 21 to 74 years (mean=37.62, SD=11.84) were interviewed one month after arrival in Michigan, United States, using a validated survey in Arabic. Questions covered pre-displacement trauma, current anxiety, depression, and PTSD symptoms. Blood, collected immediately following the interview, was analyzed for the levels of interleukins. Multivariate linear regression was used to determine the association between mental health symptoms and IL-6 and IL-8.

Results: In multivariate modeling, older age (β=0.37; p<0.01) and anxiety (β=0.31; p<0.05) were positively associated with IL-8. Age (β=0.28; p<0.05) and pre-displacement trauma (β=0.40; p<0.05) were positively associated with IL-6. Depression (β=-0.38) was negatively associated with IL-6.

Conclusion/relevance: This study of inflammatory biomarkers suggests the possibility of differential associations between mental health symptoms (anxiety and depression) and pro-inflammatory markers (IL-6 and IL-8). To enhance our ability to prevent and more effectively treat trauma-exposed refugees, we need to better understand the neuroinflammatory mechanisms contributing to mental disorders.

Inflammation and sarcopenia: A focus on circulating inflammatory cytokines

Sarcopenia is an aged-related syndrome that is progressive and can be accelerated by other concomitant disease states. Sarcopenia, characterized by loss of skeletal muscle mass, reduced muscle strength, and/or reduced physical performance, is one of the main reasons for limitation of daily activities in the elderly. It is associated with an increased incidence of many adverse events, such as dysfunction, falls, weakness, hospitalization, disability and even death. Sarcopenia justifies one of the most widely accepted theories that low-grade chronic inflammation associated with aging, known as inflammatory aging, is important to the pathogenesis of many age-related diseases. Currently, the diagnosis of sarcopenia is based on a comprehensive assessment of three aspects: muscle mass, muscle strength and physical performance. The measurement of muscle mass is complicated, as the measurement of muscle strength and gait speed is easily affected by the physical conditions of the subjects. This makes the measurements inaccurate and prospective, and it is difficult to achieve continuous, purposeful monitoring. In addition, serum levels of inflammatory cytokines change as inflammatory states develop in the elderly population. This manuscript focuses on the correlation between serum inflammatory cytokines and sarcopenia in recent years, plus the possible underlying mechanisms.

Is lifelong endurance training associated with maintaining levels of testosterone, interleukin-10, and body fat in middle-aged males?

Background:

Aging is associated with a gradual physiological decline, including an imbalance in hormone profile, increased adiposity, and reduced anti-inflammatory cytokines. However, lifelong physical exercise mitigates aging, as observed in endurance-trained middle-aged athletes (EMA).

Aim:

We compared and associated testosterone, interleukin 10 (IL-10), and body fat in EMA and untrained age-matched individuals (UAM).

Methods:

Participants were EMA (n=25; 51.48±9.49 years) and UAM (n=23; 46.0±9.37 years). Both groups underwent body composition measurements (evaluated by a skinfold protocol) and blood sampling for IL-10 (assessed through ELISA^® kit) and testosterone (assessed with Roche Diagnostics^® kit, Mannheim, Germany, by chemiluminescence technique in a third-party laboratory).

Results:

EMA had lower body fat (14.15±3.82% vs. 23.42±4.95%; P<0.05), higher testosterone (751.68±191.45 ng/dL vs. 493.04±175.15 ng/dL; P<0.05), and higher IL-10 (8.00±1.21 pg/mL vs. 5.89±1.16 pg/mL; P<0.05) compared to UAM. A significant linear correlation was found between testosterone and IL-10 (r=0.56; P=0.001), whereas significant inverse correlations were observed between body fat and testosterone (r=–0.52; P=0.001) and body fat and IL-10 (r=–0.69; P=0.001).

Conclusions:

EMA had higher levels of IL-10 and testosterone and lower body fat in comparison with UAM. In addition, higher IL-10 was associated with increased levels of circulating testosterone and lower body fat.

Relevance for Patients:

The adoption of endurance training as part of a healthy lifestyle may contribute to decreasing age-related testosterone reduction, besides reducing markers of inflammaging, preventing the occurrence of chronic age-related diseases, and thus contributing to healthy aging. For people who already have chronic diseases, physical exercise can shift the immune system toward a more anti-inflammatory profile and, thus, improve their pathological condition. In both cases, physical exercise can help attenuate the decline in testosterone, decrease body fat, and increase anti-inflammatory levels.

Mobility speed predicts new-onset hypertension: a longitudinal study

The aim of this study was to investigate whether declining mobility and muscle strength predict new-onset hypertension in suburban-dwelling elderly individuals.