Evaluation of different methods to measure muscle mass and strength in a population with class II/III obesity: A Cross-Sectional Study

Background: Weight loss therapies should aim to reduce fat mass while preserving both muscle mass and muscle strength. Consequently, there is a need for validated methods to measure muscle mass and strength. Current methods are either expensive and require trained technicians, or have not been validated in populations with class II/III obesity (BMI: 35-45 kg/m2). Therefore, the aim of this study is to validate other methods or a combination of methods to measure muscle mass in a population with class II/III obesity.
Secondary Objectives:
1. To assess which combination of methods for measuring muscle mass and muscle strength is most reliable compared to the DEXA scan in a population with class II/III obesity.
2. To assess the variance in muscle mass measured by DEXA in a population with class II/III obesity.
3. To assess the influence of nutrition, exercise and hormones on muscle mass.

Study design: This study is a prospective cross-sectional study and will take place in the Center Obesity Northern Netherlands (CON) at the Medical Center Leeuwarden (MCL).
Study population: The population will consist of 120 people, either patients scheduled for a first intake at the Center Obesity Northern Netherlands (CON) or people invited through ads in local newspapers. All patients people between 18 and 65 years of age and a body mass index (BMI) above 40 kg/m2 or above 35 kg/m2 with obesity-related comorbidities are eligible to participate in this study.
Main parameters: muscle mass measured by DEXA, ultrasound (US), bioelectrical impedance analysis (BIA), anthropometric methods and 24-hour urine creatinine.
Main endpoint: correlation between muscle mass measured by DEXA and one of the parameters.
Secondary parameters: muscle strength measured by handgrip strength; biochemical measures; protein intake; and physical activity measured with movement sensors and short questionnaire to assess health-enhancing physical activity (SQUASH).
Secondary endpoint: the correlation between multiple parameters for muscle mass and muscle strength and the muscle mass measured by DEXA.

Finding methods that are more accessible and cheaper, can be helpful in tracking changes in muscle mass during weight loss in these patients.

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