Obstructive sleep apnea syndrome (OSAS) is a prevalent and potentially life-threatening disease that poses a significant threat to human health1. OSAS is characterized by the partial or complete collapse of the pharynx during sleep, resulting in obstructive sleep apnea. According to surveys, there are approximately 936 million individuals worldwide with mild to severe OSAS, and nearly 425 million individuals with moderate to severe OSAS2. Frailty is a condition in which multiple systems and their reserve capacity decline in the elderly, affecting their physical, cognitive, and psychological well-being. Reduced physical activity is a key clinical manifestation of frailty. Research has indicated that there is a higher combined risk of frailty in individuals with a higher risk of OSAS3. Sarcopenia and osteoporosis are both external manifestations of frailty in older adults.

Sarcopenia is an aging syndrome characterized by a progressive decline in muscle mass and strength. This can lead to an increased risk of falls, fractures, and physical disability, greatly reducing the patient's quality of life and even leading to death. The prognosis of patients with sarcopenia combined with other diseases, such as fractures, tumors, or chronic obstructive pulmonary emphysema, is generally poor4, 5, 6. Sarcopenia has important effects on the airway, especially lung function, however, there is a lack of research on the combination of OSAS and sarcopenia heretofore7. As is known to all, osteoporosis, considered as the silent killer, is a chronic disease that seriously endangers bone health. Osteoporosis is a systemic bone disease that is prone to fractures due to multiple bone mineral density (BMD) and decreased bone quality, damage to bone microarchitecture, and increased bone fragility8. Dual-energy X-ray absorptiometry is the gold standard for the diagnosis of osteoporosis9. Currently, some researchers believe that sarcopenia and osteoporosis have a significant relationship in the elderly, and they are collectively referred to as 'sarco-osteoporosis'10. This condition is also considered a geriatric syndrome. As the global aging process accelerates, sarcopenia and osteoporosis have an increasing impact on human longevity and quality of life. Chronic persistent hypoxia, oxidative stress, and inflammatory responses in OSAS patients affect the balance of muscle and bone metabolism, thereby increasing the risk of sarcopenia and osteoporosis. However, the specific factors contributing to sarcopenia and osteoporosis in elderly patients with OSAS have not been fully understood. This study aims to explore the related risk factors of sarcopenia and osteoporosis in outpatients with OSAS, in order to provide insights for early clinical intervention and treatment of OSAS-related diseases.