Asthmatic patients with normal body mass index and high body fat percentage

<bold>Backgrounds:</bold> Obesity is a risk factor for severe asthma, and research into the pathophysiology of obesity-associated asthma has advanced considerably. However, many studies use body mass index (BMI) to define obesity. In the field of obesity research, individuals with a normal BMI but a high body fat percentage (BF) are reported to be at a higher risk for obesity-related diseases. This indicates that BF might be a more critical factor than BMI in asthma severity. We investigated the characteristics of asthma in patients with a normal BMI but excessive BF. <bold>Methods:</bold> A total of 70 asthmatic patients were enrolled, categorized into three groups: those with normal BMI and BF (NBF, n=20), those with normal BMI and high BF (HBF, n=22), and those with high BMI and high BF (HBF&BMI, n=28). Clinical data and peripheral blood samples were collected from the enrolled patients. <bold>Results:</bold> Asthma exacerbations were more frequent in HBF and HBF&BMI than in NBF, but the frequency was identical between HBF and HBF&BMI. Steroid sensitivity, evaluated by the IC₅₀-Dex of peripheral blood mononuclear cells, significantly varied across the groups. Pairwise comparisons indicated that steroid sensitivity in the HBF and HBF&BMI groups was lower than in NBF, although no significant difference was observed in steroid sensitivity between the HBF and HBF&BMI. Similarly, oxidative stress levels, indicated by serum 8-OHdG levels, was significantly higher in the HBF and HBF&BMI than in the NBF, with the levels between HBF and HBF&BMI showing no significant difference. <bold>Conclusions:</bold> This study highlights the importance of BF over BMI in assessing obesity-related modification of asthma severity and treatment response in obese patients.