Abstract
BACKGROUND:
In adults with type 2 diabetes (T2DM), sarcopenia and obesity are two common body composition issues.
OBJECTIVE:
We investigated the associated influencing factors of muscle mass loss in obese adults with T2DM, to provide a theoretical basis for the prevention of sarcopenic obesity in patients with T2DM.
METHODS:
We recruited 315 participants in this study. The participants underwent body composition assessment and clinical information was collected. Dual-energy X-ray absorptiometry was used to verify the accuracy of the body composition data. Based on their body fat percentage, 189 patients with T2DM were classified as obese. Patients with T2DM and obesity were grouped into the muscle mass loss group and non-muscle mass loss group based on gender. We collected demographic and clinical information about patients with T2DM who were obese, including their age, gender, body mass index (BMI), appendicular skeletal muscle index (ASMI), and body fat percentage (PBF).
RESULTS:
Among the participants who were obese and had T2DM, 56.61% (107/189) experienced muscle mass loss, with a detection rate of 43.42% (33/76) among females and 65.49% (74/113) among males. Body mass index, fat index, Android fat, Gynoid fat, limb fat, trunk fat, and total body bone mineral content were all lower in the muscle mass loss group compared to the non-muscle mass loss group, regardless of gender (all
CONCLUSION:
Muscle mass loss is more prevalent in adults with T2DM and a high PBF. Body mass index, body fat index, and limb fat are the protective factors of muscle mass loss in adult patients with T2DM and obesity.
Keywords
Introduction
In adults with type 2 diabetes (T2DM), sarcopenia and obesity are two common body composition issues. Sarcopenia refers to a condition characterized by a significant decrease in muscle mass, strength, and/or physical functioning. Studies indicate that low muscle mass not only aggravates metabolic abnormalities [1], but is also a strong predictor of increased disability, disability rate, and mortality [2]. Adults with T2DM experience a skeletal muscle mass loss in the early stages of the disease, and diabetes can aggravate age-related loss of muscle mass [3, 4, 5].
Obesity is a chronic nutritional metabolic disease caused by abnormal accumulation and (or) abnormal distribution of fat in the body due to an energy imbalance. Recent studies have linked obesity to a loss of muscle mass, an effect that compounds the metabolic disorder already existing in people with diabetes. Loss of muscle mass and weight gain both have negative effects on metabolism in people with diabetes [6, 7]. Patients with T2DM are more likely to be obese or overweight, but little is known about the detection rate and associated influencing factors of muscle mass loss in patients with both T2DM and obesity. The purpose of this study was to examine the prevalence of muscle mass loss in patients with T2DM and obesity and the factors influencing obesity with respect to skeletal muscle content in an effort to provide a theoretical basis for preventing sarcopenic obesity in patients with T2DM. Participants included adult patients with T2DM and obesity hospitalized in the endocrinology department.
Materials and methods
Participants
This was a cross-sectional study of adults with T2DM. Between January and December 2021, we enrolled 315 adult patients with T2DM who were admitted to the Endocrinology Department of the China Rehabilitation Research Center. The patients had a mean age of 62.18
Inclusion criteria: (1) Age
Collection of clinical data
The age, gender, height, weight, BMI, blood pres-sure, duration of diabetes, past medical history, and drug combination of all participants were recorded. After an overnight fast of 8 hours, venous blood was drawn from each participant’s elbow to measure a variety of biochemical markers. These included glycosylated hemoglobin, fasting blood glucose, aspartate transaminase, alanine transaminase, urea, creatinine, total cholesterol, and triglyceride, among others.
Body composition evaluation
Body composition data were measured using Discovery Wi Dual-energy X-ray absorptiometry manufactured by Hologic (USA), including the total body and limb skeletal muscle mass, fat mass index (FMI), Android fat, gynoid fat, Android fat/gynoid fat percentage (A/G), percentage of body fat (PBF), limb and trunk fat mass, and total body bone mineral content (BMC). All the scans were performed by a single experienced technologist.
Diagnostic criteria and grouping
Obesity was primarily diagnosed based on the PBF. When the PBF exceeded 60% of the population of the same age (that is, PBF
Statistical analysis
Data were processed and analyzed using SPSS 24.0 statistical software. The measurement data were subjected to a normal test, and the data in normal distribution are expressed as mean
Results
Screening process and results
Obesity was diagnosed in 189 of the 315 patients with T2DM included in the study, including 113 males (average age 61.42
Comparison of clinical data
Males in the muscle mass loss group were significantly older than those in the non-muscle mass loss group (
A comparison of gender-specific clinical data
A comparison of gender-specific clinical data
Values are mean
Comparison of body fat between non-muscle mass loss and muscle mass loss groups
Values are mean
FMI, Android fat, gynoid fat, limb fat, and trunk fat in the muscle mass loss group were lower than those in the non-muscle mass loss group (all
Correlation between ASMI and various influencing factors in patients with T2DM and obesity
Pearson’s correlation analysis showed that the ASMI in males was positively correlated with BMI, FMI, Android fat, gynoid fat, limb fat, and BMC (
Multiple linear regression analysis of ASMI in patients with T2DM and obesity of different genders
Using ASMI as the dependent variable and age, BMI, FMI, Android fat, gynoid fat, limb fat, and BMC as the independent variables, we developed gender-specific multiple linear regression analysis models. The results indicated that BMI, FMI, and limb fat were the influencing factors of ASMI in patients with T2DM and obesity (
Discussion
Low muscle mass is an essential indicator for diagnosing sarcopenia and is also a strong predictor of increased body disability, disability rate, and mortality [2]. Kim et al. [11] examined elderly patients with T2DM with BMI
Effect of BMI on muscle mass loss in patients with T2DM and obesity
Previous studies have confirmed that patients with T2DM with a low BMI have an increased risk of muscle mass loss and sarcopenia [12, 13, 14, 15, 16]. The results of our study revealed that the BMI of patients with T2DM and obesity in the muscle mass loss group was lower than that of the non-muscle mass loss group, irrespective of gender. Consistent with the findings of a previous study [12], BMI is a protective factor for muscle mass loss. There is a strong correlation between BMI and ASMI in this study, suggesting that BMI can be used as an indicator of muscle mass in patients with T2DM and obesity with a high PBF. The weight criteria based on BMI in China are 24.0–27.9 for overweight, and
A multiple linear regression analysis of ASMI in obese adults with T2DM
A multiple linear regression analysis of ASMI in obese adults with T2DM
BMI: body mass index; FMI: fat mass index; ASMI: appendicular skeletal muscle index.
Upper and lower limb fat content are indicative of subcutaneous fat accumulation, while FMI adjusts for the impact of height on body fat content to provide an accurate reflection and representation of obesity as a whole. Although the PBF was comparable between the two groups, the FMI and the fat content of upper and lower limbs were significantly lower in the muscle mass loss group than in the non-muscle mass loss group. ASMI was positively correlated with FMI and the fat content of the upper and lower limbs in this study. FMI and the fat content of the upper and lower limbs are protective factors of muscle mass loss, which is consistent with the conclusion of a previous study conducted by Cheng et al. [17], namely that adipose tissues protect muscles. Moreover, Perna et al. [18] concluded that subcutaneous adipose tissue may have a protective effect on poor prognosis. The results of this study indicated that the peripheral fat content of limbs was closely related to the decrease in skeletal muscle content in adult patients with T2DM and obesity, highlighting the importance of protecting limb fat during weight loss.
Currently, PBF is the most widely used criterion for assessing obesity in the sarcopenic obese population. We observed that total and local PBFs were comparable between the muscle mass loss group and the non-muscle mass loss group, irrespective of gender. In the muscle mass loss group, not only did the FMI and limb fat content decrease, but the android fat reflecting the central obesity decreased as well; ASMI was not correlated with total and local PBFs but was positively correlated with the total and local fat content. Previous studies concluded that an increase in adipose tissue, especially visceral fat, facilitated muscle mass loss [19, 20]. Contrary to previous findings, the results of our study revealed that patients with diabetes and obesity with muscle mass loss had lower and total fat content than those without muscle mass loss. Adipose tissue is closely associated with muscle, and the coexistence of obesity and sarcopenia is not a simple combination, but rather the result of the interaction of multiple factors including ageing, lifestyle (nutritional and exercise status), insulin resistance, chronic inflammation, and hormones (corticosteroids, growth hormone, insulin-like growth factor, muscle somatostatin, and sex hormone) [21, 22]. The precise mechanism of the interaction between muscle and adipose tissue must be further clarified by additional research.
Patients with diabetes are at increased risk for the development of sarcopenic obesity when they have high PBF but low muscle mass. Such patients can mitigate the negative effects of sarcopenic obesity through proper nutrition and sports rehabilitation management. Other rehabilitation interventions have also been shown to improve muscle properties, according to a few studies [23, 24]. Our findings suggest that future efforts to prevent sarcopenic obesity should prioritize early screening and identification of such patients, as well as the active implementation of rehabilitation strategies to reduce fat and increase muscle mass.
Limitations
One of the limitations of the present study is the small sample size. In addition, our sample was only selected from the China Rehabilitation Research Center, so the results cannot be generalizable to the broader T2DM population. Important clinical implications for understanding the mechanism of action between skeletal muscle content and adipose tissue in patients with diabetes can be gleaned from measuring abdominal subcutaneous fat, visceral fat, and intramuscular fat deposition using computed tomography or magnetic resonance imaging scans in the follow-up study.
Conclusion
Patients with T2DM and obesity who have a high PBF, have a disproportionately low percentage of muscle mass. Protective factors of ASMI in adult patients with T2DM and obesity include BMI, FMI, and limb fat content. As the clinical manifestations of patients with T2DM with fat accumulation and muscle mass loss are hidden, early screening and identification of such patients, as well as formulating an intervention strategy of actively reducing fat and increasing muscle mass through a combination of caloric restriction with nutrition and exercise training may be the most important tasks in the future for preventing sarcopenic obesity.
Ethics statement
The study was approved by the Ethics Committee of China Rehabilitation Research Center (Approval no. 2020-059-1) and conducted in accordance with the Declaration of Helsinki.
Funding
The study was funded by the Scientific Research Fund Project of China Rehabilitation Research Center (No. 2020-09).
Informed consent
Written informed consent was obtained from all participants.
Author contributions
LNB and XZ conceived the idea and conceptualised the study. LNB, YYQ, SH, CL and YZ collected the data. LNB, XZ, YYQ, SH, CL and YZ analysed the data. LNB obtained the financing. LNB drafted the manuscript, then LNB, XZ, YYQ, SH, CL and YZ reviewed the manuscript. All authors read and approved the final draft.
Footnotes
Acknowledgments
The authors would like to acknowledge the hard and dedicated work of all staff that implemented the intervention and evaluation components of the study.
Conflict of interest
The authors declare that they have no competing interests.
