Sarcopenia, Obesity, and Sarcopenic Obesity: Relationship with Skeletal Muscle Phenotypes and Single Nucleotide Polymorphisms

Abstract

Obesity may aggravate the effects of sarcopenia on skeletal muscle structure and function in the elderly, but no study has attempted to identify the gene variants associated with sarcopenia in obese women. Therefore, the aims of the present study were to: (1) describe neuromuscular function in sarcopenic and non-sarcopenic women with or without obesity; (2) identify gene variants associated with sarcopenia in older obese women. In 307 Caucasian women (71 ± 6 years, 66.3 ± 11.3 kg), skeletal muscle mass was estimated using bioelectric impedance, and function was tested with a 30 s one-leg standing-balance test. Biceps brachii thickness and vastus lateralis cross-sectional area (VLACSA) were measured with B-mode ultrasonography. Handgrip strength, maximum voluntary contraction elbow flexion (MVCEF), and knee extension torque (MVCKE) were measured by dynamometry, and MVCKE/VLACSA was calculated. Genotyping was performed for 24 single-nucleotide polymorphisms (SNPs), selected based on their previous associations with muscle-related phenotypes. Based on sarcopenia and obesity thresholds, groups were classified as sarcopenic obese, non-sarcopenic obese, sarcopenic non-obese, or non-sarcopenic non-obese. A two-way analysis of covariance was used to assess the main effects of sarcopenia and obesity on muscle-related phenotypes and binary logistic regression was performed for each SNP to investigate associations with sarcopenia in obesity. There were no significant obesity * sarcopenic status interactions for any of the investigated muscle-related phenotypic parameters. Neither sarcopenia nor obesity had a significant effect on biceps brachii thickness, but sarcopenia was associated with lower VLACSA (p = 0.003). Obesity was associated with lower MVCEF (p = 0.032), MVCKE (p = 0.047), and MVCKE/VLACSA (p = 0.012) with no significant effect of sarcopenia. Adjusted for age and height, three SNPs (ACTN3 rs1815739, MTHFR rs1801131, and MTHFR rs1537516) were associated with sarcopenia in obese participants. Sarcopenia was associated with a smaller muscle size, while obesity resulted in a lower muscle quality irrespective of sarcopenia. Three gene variants (ACTN3 rs1815739, MTHFR rs1801131, and MTHFR rs1537516) suspected to affect muscle function, homocysteine metabolism, or DNA methylation, respectively, were associated with sarcopenia in obese elderly women. Understanding the skeletal muscle features affected by sarcopenia and obesity, and identification of genes related to sarcopenia in obese women, may facilitate early detection of individuals at particular risk of sarcopenic obesity.

Effect of vitamin D monotherapy on indices of sarcopenia in community‐dwelling older adults: a systematic review and meta‐analysis

“… 71 Equally, an association with attenuated physical function and lower muscle quality have all been observed in individuals with obesity and related co‐morbidities. 72 , 73 , 74 This suggests that mineral co‐supplementation and co‐morbidity status may potentially influence effects of vitamin D supplementation on muscle health. Moreover, to achieve the aim of our study, we utilized clinically reliable measurements of physical performance and muscle strength that have little bias in their determination among older populations.…”

“…Increased calcium intake has been associated with lower odds of sarcopenia, 69,70 elevated ALM, 69,70 and greater gait speed 71 . Equally, an association with attenuated physical function and lower muscle quality have all been observed in individuals with obesity and related co‐morbidities 72–74 . This suggests that mineral co‐supplementation and co‐morbidity status may potentially influence effects of vitamin D supplementation on muscle health.…”

Sarcopenia, Obesity, Sarcopenic Obesity and Risk of Poor Nutritional Status in Polish Community-Dwelling Older People Aged 60 Years and Over

“…Comparing our results with data from earlier studies further confirms methodological gaps in the field. For example, Khanal et al [ 52 ] assessed older women living in the community (n = 307, mean age 71 ± 6 years). They divided participants into four groups based on body composition phenotype assessed with the BIA method, similarly to our study.…”

“…Subjects without sarcopenia or obesity were classified as non-sarcopenia, non-obese (healthy) phenotype. The prevalence of sarcopenia, obesity, SO, and non-sarcopenia non-obese phenotype in Khanal et al [ 52 ] was 2.3%, 57.3%, 25.1%, and 15.3%, respectively. Obesity was twice more prevalent and SO three times more prevalent than in our study, while sarcopenia was much sparser (2.3% vs. 7.9%).…”

Deep Learning-Based Muscle Segmentation and Quantification of Full-Leg Plain Radiograph for Sarcopenia Screening in Patients Undergoing Total Knee Arthroplasty

“…Secondly, due to fatty infiltration of skeletal muscle in patients with sarcopenic obesity, the estimated muscle mass of patients may not always represent the actual muscle mass [54]. Features such as radio-opacity of the plain radiographs, which may reflect fatty infiltration, will be incorporated in future studies.…”