Association of lung function with visceral adiposity and skeletal muscle mass considering myosteatosis

<bold>Rationale:</bold> Changes in body composition, such as loss of muscle mass and obesity, have a negative impact on lung function. <bold>Objects:</bold> To investigate the association of lung function with visceral adiposity and skeletal muscle mass measured by CT scans in middle-aged Korean adults. <bold>Methods:</bold> We reviewed 15,827 subjects (9237 men and 6590 women) with mean ages of 52.5 ± 8.3 years who underwent comprehensive health examinations, including abdominal CT and spirometry. Selected CT images were automatically segmented to estimate the total abdominal muscle area (TAMA) and visceral fat area (VFA). For muscle quality evaluation, TAMA was divided into three categories based on CT density: good-quality muscle areas (normal attenuation muscle area; NAMA), fatty muscle areas (low attenuation muscle area; LAMA), and inter/intramuscular fat areas. Low lung function was defined as FVC% and FEV₁% < 80% of the predicted value. <bold>Results:</bold> NAMA was positively correlated with FVC and FEV₁, while VFA was negatively correlated with FVC and FEV₁. In men, low FVC and FEV1 were significantly associated with low NAMA and high VFA. In women with BMI ≥ 25 kg/m², low FVC and FEV₁ showed positive associations with VFA; in women with BMI < 25 kg/m², low FVC and FEV₁ were negatively correlated to NAMA. <bold>Conclusion:</bold> Lung function showed significant associations with both visceral adiposity and skeletal muscle quality, which varied according to sex and BMI. Tailored management for improving lung function may be necessary, which involves reducing visceral adiposity and/or increasing high-quality skeletal muscle based on CT-body composition analysis.