Risk of asthma and/or wheezing in obese individuals with or without metabolic syndrome: From the Korea National Health and Nutrition Examination Survey data

Introduction: Obesity increases the risk of asthma; however, whether metabolic syndrome (MS), with obesity being one of its five components, is also associated with increased asthma risk remains unclear. Objective: To investigate the association between the risk of asthma and obesity, MS, and each component of MS. Methods: We performed a cross-sectional study of 41,480 Korean adults by using data from the 2007–2016 Korean National Health and Nutrition Examination Survey. Asthma was defined as a history of physician-diagnosed asthma or wheezing sound within the past 12 months. Results: The adjusted odds ratio (OR) for asthma was significantly increased in participants with obesity (OR 1.30 [95% confidence interval {CI}, 1.27–1.33]; p < 0.0001) and MS (OR 1.23 [95% CI, 1.20–1.25]; p < 0.0001). Obesity and MS showed an additive effect (OR 1.38 [95% CI, 1.34–1.41]; p < 0.001), followed by obesity(+)MS(-) (OR 1.28 [95% CI, 1.25–1.31]; p < 0.001) and obesity(-)MS(+) (OR 1.14 [95% CI, 1.10–1.18]; p < 0.001). Among each metabolic component, only abdominal obesity (OR 1.28 [95% CI, 1.24–1.32]; p < 0.001) and hypertension (OR 1.16 [95% CI, 1.12–1.20]; p < 0.001) significantly increased the risk of asthma. Unlike the female patients (OR 1.39 [95% CI, 1.35–1.43]; p < 0.001), having MS showed a lower risk of asthma in the male patients (OR 0.79 [95% CI, 0.75–0.82]; p < 0.001). Conclusion: The risk of asthma was highest when both obesity and MS were present, followed by obesity alone and MS alone. Abdominal obesity and hypertension were associated with an increased asthma risk, and there was a sex difference that MS lowered the risk of asthma in Korean male patients.