The primary aim of this study is to identify the composition and characteristics of the gut microbiota in patients with sarcopenia in older adults, and compare these with the gut microbiota characteristics of older adults and young control groups to determine differences. Secondary purpose of this study is to provide data on the characteristics of gut microbiota for the development of probiotics effective in treating sarcopenia in older adults.

Sarcopenia is a condition characterized by the loss of skeletal muscle mass and decline in physical function associated with aging. It is closely related to chronic diseases and geriatric disease and it is known to increase the risk of frailty, disability, falls, fractures, and mortality. The microbiome is closely associated with a wide range of human diseases, including metabolic disorders, cancer, infectious diseases, and immune-related conditions, and is considered one of the most valuable biomarkers for disease prevention and diagnosis. This indicates growing global interest and research activity on the connection between sarcopenia and gut microbiota. Through this study, we expect to elucidate the relationship between age-related sarcopenia and gut microbiota, which may provide important clues for the diagnosis and treatment of this condition.

Inclusion criteria

1. Sarcopenia patient group

   • Individuals aged 65 to 90 years

   • Meet the diagnostic criteria for sarcopenia based on the 2019 Asian Working Group for Sarcopenia (AWGS) guidelines:

   • Low appendicular skeletal muscle mass

     • DEXA: <7.0 kg/m² (men), <5.4 kg/m² (women)
     • BIA: <7.0 kg/m² (men), <5.7 kg/m² (women)

   • Low muscle strength

     • Handgrip strength: <28 kg (men), <18 kg (women) or

   • Low physical performance

     • 6-meter walk speed <1.0 m/s
     • 5-chair stand test ≥12 seconds
     • Short Physical Performance Battery (SPPB) score ≤9

   • Voluntarily agree to participate in the clinical study and sign the informed consent form

2. Older adult control group

   • Individuals aged 65 to 90 years
   • Voluntarily agree to participate in the clinical study and sign the informed consent form

3. Young adult control group

   • Individuals aged 20 to 50 years
   • Voluntarily agree to participate in the clinical study and sign the informed consent form

Exclusion criteria

• Individuals currently under treatment for severe diseases of the cardiovascular, immune, respiratory, gastrointestinal/hepatic and biliary, renal/urinary, neurological, psychiatric systems, infectious diseases, or malignant tumors (Exception: skin tumors other than melanoma are excluded; cancer survivors may participate if more than 5 years have passed since complete remission).
• Individuals who have difficulty performing independent activities of daily living due to musculoskeletal or neurological diseases, or cognitive impairment (e.g., those with spinal disorders requiring surgery or having walking limitations).
• Individuals who regularly consume alcohol according to WHO daily intake standards (≥ 40 g/day for men, ≥ 20 g/day for women).
• Heavy smokers (≥ 20 cigarettes/day).
• Individuals with AST (GOT) or ALT (GPT) levels ≥ 3 times the upper limit of normal established by the testing institution.
• Patients with uncontrolled hypertension (systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg, measured after the subject has rested for 10 minutes).
• Patients with uncontrolled diabetes mellitus (HbA1c > 7.0%).
• Individuals with TSH ≤ 0.1 μIU/mL or ≥ 10 μIU/mL.
• Individuals deemed unsuitable for other reasons at the discretion of the investigator.

tertiary general hospital