Association Between Visceral Fat and Lung Function Impairment in Overweight and Grade I Obese Women: A Cross-Sectional Study

Beyond the common comorbidities related to obesity, such as type 2 diabetes and cardiovascular diseases, impaired lung function is already known, but whether the fat distribution (sub-cutaneous, visceral) affects the lung function and pulmonary immune response are poorly known. Few evidence has shown that visceral fat is associated with insulin resistance, low-grade inflammation, and reduced lung function. In the present study, the body composition and fat distribution were evaluated by multi-frequency octopolar bioimpedance. This study demonstrated a possible association of increased visceral fat with impaired lung function in obesity grade I (n = 28; 45.46 ± 10.38 years old) women that was not observed in normal weight (n = 20; 43.20 ± 10.78 years old) and in overweight women (n = 30; 47.27 ± 10.25 years old). We also identified a negative correlation in FVC% (R² = 0.9129; <i>p</i> < 0.0236), FEV1% (R² = 0.1079; <i>p</i> < 0.0134), PEF% (R² = 0.1673; <i>p</i> < 0.0018), and VC IN% (R² = 0.1330; <i>p</i> < 0.0057) in the obesity grade I group, clearly demonstrating that higher levels of visceral fat correlate with reduced lung function, but not with sub-cutaneous fat. In addition, for the first time, a negative correlation among anti-fibrotic protein klotho (R² = 0.09298; <i>p</i> < 0.0897) and anti-inflammatory IL-10 (R² = 0.1653; <i>p</i> < 0.0487) in plasma was observed, in contrast to increased visceral fat. On the contrary, in breath condensate, a positive correlation for adiponectin (R² = 0.5665; <i>p</i> < 0.0120), IL1-Ra (R² = 0.2121; <i>p</i> < 0.0544), and IL1-Beta (R² = 0.3270; <i>p</i> < 0.0084) was found. Thus, increased visceral fat directly influences the impairment of lung function and the systemic and pulmonary immune response of women with obesity grade I.