Higher abdominal adiposity is associated with higher lean muscle mass but lower muscle quality in middle-aged and older men and women: the Framingham Heart Study

Insights Into the Role of Obesity in Heart Failure With Preserved Ejection Fraction Pathophysiology and Management

Heart failure (HF) is a significant global health issue, categorized by left ventricular ejection fraction, being either reduced (HFrEF < 0.40) or preserved (HFpEF > 0.50), or in the middle of this range. Although the overall incidence of HF remains stable, HFpEF cases are increasing, representing about 50% of all HF cases. Outcomes for HFpEF are similar to those for HFrEF, leading to substantial health-care resource use. Despite extensive research over the past 2 decades, the prognosis and mortality rates for HFpEF remain high. A key feature of HFpEF is exercise intolerance, characterized by severe exertional dyspnea and fatigue, which significantly impacts quality of life. The underlying mechanisms of exercise intolerance are not fully understood due to the complex pathophysiology and multisystem involvement. Obesity is a common comorbidity in HFpEF, especially in North America, leading to worsening symptoms, hemodynamics, and mortality rates. Increased adiposity leads to inflammation, hypertension, dyslipidemia, and insulin resistance, and impairing cardiac, vascular, pulmonary, and skeletal muscle function. Therefore, managing obesity is crucial in treating HFpEF. In this review we explore the pathophysiologic mechanisms of HFpEF, emphasizing obesity's role, and we discuss current management strategies while identifying areas needing further research.

Poor muscle quality: A hidden and detrimental health condition in obesity

Poor muscle quality (MQ) is a hidden health condition in obesity, commonly disregarded and underdiagnosed, associated with poor health-related outcomes. This narrative review provides an in-depth exploration of MQ in obesity, including definitions, available assessment methods and challenges, pathophysiology, association with health outcomes, and potential interventions. MQ is a broad term that can include imaging, histological, functional, or metabolic assessments, evaluating beyond muscle quantity. MQ assessment is highly heterogeneous and requires further standardization. Common definitions of MQ include 1) muscle-specific strength (or functional MQ), the ratio between muscle strength and muscle quantity, and 2) muscle composition (or morphological MQ), mainly evaluating muscle fat infiltration. An individual with obesity might still have normal or higher muscle quantity despite having poor MQ, and techniques for direct measurements are needed. However, the use of body composition and physical function assessments is still limited in clinical practice. Thus, more accessible techniques for assessing strength, muscle mass, and composition should be further explored. Obesity leads to adipocyte dysfunction, generating a low-grade chronic inflammatory state, which leads to mitochondrial dysfunction. Adipocyte and mitochondrial dysfunction result in metabolic dysfunction manifesting clinically as insulin resistance, dyslipidemia, and fat infiltration into organs such as muscle, which in excess is termed myosteatosis. Myosteatosis decreases muscle cell function and insulin sensitivity, creating a vicious cycle of inflammation and metabolic derangements. Myosteatosis increases the risk of poor muscle function, systemic metabolic complications, and mortality, presenting prognostic potential. Interventions shown to improve MQ include nutrition, physical activity/exercise, pharmacology, and metabolic and bariatric surgery.

Running Plus Strength Training Positively Affects Muscle Strength and Quality in Both Younger (Below 50 Years Old) and Older (Above 50 Years Old) Women

BACKGROUND/OBJECTIVES

Sarcopenia is a muscular disease characterized by loss of muscular strength and function, affecting mainly women, and associated with increased mortality risk. The aim of this study was to compare active women with inactive women of different age groups regarding muscle mass, strength, and muscle quality.

METHODS

This study included 147 women (85 runners and 62 inactive), divided into <50 and ≥50 years old. Participants were evaluated for knee flexor and extensor peak torque (PT), body composition, and training habits.

RESULTS

For knee extensor muscles, there was an age group effect (F(2.146) = 40.5; p < 0.001) on absolute PT (Nm); an age group effect (F(2.146) = 44.1; p < 0.001) and a physical activity group effect (F(2.146) = 113.0; p < 0.001) on PT adjusted by body mass (Nm/kg); and an age group effect (F(2.146) = 36.9; p < 0.001) and a physical activity group effect (F(2.146) = 6.1; p = 0.014) on PT adjusted by lean mass (Nm/kgLM). There was no interaction effect.

CONCLUSION

In both age groups, active women had greater strength and higher muscle quality than inactive women, but the difference in strength, muscle mass, and muscle quality between younger and older women were the same among runners and inactive women.

Association between the age-adjusted visceral adiposity index (AVAI) and female infertility status: a cross-sectional analysis of the NHANES 2013-2018

BACKGROUND

Obesity stands as an essential factor contributing to infertility in women. Early identification of obese individuals leads to favorable results for female infertility. The objective of this research is to assess the association between the age-adjusted visceral adiposity index (AVAI) and female infertility.

METHODS

This study was conducted using NHANES data from 2013 to 2018, in which 1,231 women aged 20-45 were selected. Infertility was defined by survey questions. AVAI was calculated using anthropometric and serum data. Covariates included demographics and lifestyle factors. Statistical analysis with R, adjusting for covariates, and assessing nonlinearity and cutoff effects.

RESULTS

The study of 1,231 women from the NHANES database revealed that 11.94% were diagnosed with infertility. Individuals with higher AVAI scores showed increased age, WC, BMI, and reduced HDL levels, with a positive correlation between AVAI and female infertility (OR = 1.42, 95%CI: 1.26-1.60). AVAI quartiles showed a pronounced relationship with female infertility risk, with the highest quartile showing the greatest risk(OR = 9.35,95% CI: 2.96-29.55). Nonlinear and threshold effects in the relationship between AVAI and female infertility were identified, with an inflection point at -9.70. Subgroup analyses indicated significant interactions between AVAI and educational status and BMI, particularly in women with a BMI below 25 kg/m2, where a high AVAI level was closely related to increased infertility risk(OR = 1.92, 95%CI: 1.44-2.58).

CONCLUSION

The study identifies a strong association between elevated AVAI scores and female infertility risk, especially in women with a BMI under 25 kg/m2. This suggests that AVAI could be a valuable predictor in female fertility assessments.

Current Perspectives: Obesity and Neurodegeneration - Links and Risks

Obesity is increasing in prevalence across all age groups. Long-term obesity can lead to the development of metabolic and cardiovascular diseases through its effects on adipose, skeletal muscle, and liver tissue. Pathological mechanisms associated with obesity include immune response and inflammation as well as oxidative stress and consequent endothelial and mitochondrial dysfunction. Recent evidence links obesity to diminished brain health and neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Both AD and PD are associated with insulin resistance, an underlying syndrome of obesity. Despite these links, causative mechanism(s) resulting in neurodegenerative disease remain unclear. This review discusses relationships between obesity, AD, and PD, including clinical and preclinical findings. The review then briefly explores nonpharmacological directions for intervention.

The causal relationship between sarcopenic obesity factors and benign prostate hyperplasia

Background

Both benign prostatic hyperplasia (BPH) and sarcopenic obesity (SO) are common conditions among older adult/adults males. The prevalent lifestyle associated with SO is a significant risk factor for the development of BPH. Therefore, we investigated the causal relationship between SO factors and BPH.

Method

The instrumental variables for SO factors were selected using the inverse variance-weighted method, which served as the primary approach for Mendelian randomization analysis to assess the causal effect based on summary data derived from genome-wide association studies of BPH.

Result

The increase in BMR (OR = 1.248; 95% CI = (1.087, 1.432); P = 0.002) and ALM (OR = 1.126; 95% CI = (1.032, 1.228); P = 0.008) was found to be associated with an elevated risk of BPH. However, no genetic causality between fat-free mass distribution, muscle mass distribution, and BPH was observed.

Conclusion

Our findings indicate that a genetic causal association between BMR, ALM and BPH. BMR and ALM are risk factors for BPH. The decrease in BMR and ALM signified the onset and progression of SO, thus SO is a protective factor for BPH.