Association between visceral adipose tissue and asthma based on the NHANES and Mendelian randomization study

Background Obesity is a crucial risk factor for asthma. Observational studies have examined the association between abdominal obesity and asthma symptoms. This study aimed to investigate the causal relationship between visceral adipose tissue (VAT) and asthma and its potential as an independent indicator.Methods This study utilized data from the National Health and Nutrition Examination Survey spanning 2011-8. Multivariable logistic regression and stratified variable selection were employed to identify associations between asthma and VAT. Moreover, a two-sample Mendelian randomization analysis, using 221 genetic variants as instrumental variables, was conducted to assess this relationship further.Results Our findings indicated that individuals with higher VAT levels were more likely to develop asthma. Visceral obesity remained a significant risk factor for asthma after adjusting for demographic characteristics. Genetic predictions suggest a positive association between VAT and an elevated risk of asthma (odds ratio [OR] = 1.393, 95% confidence interval [CI]: 1.266-1.534, and P = 1.43E-11). No significant polymorphisms were detected using the Mendelian randomization-Egger intercept test.Conclusions This study presents potential evidence supporting the causal role of VAT in asthma development. Furthermore, the findings from the Mendelian randomization analysis further reinforce the relationship between VAT and asthma risk. Key message What is already known on this topic Obesity is a well-established risk factor for asthma, with previous observational studies examining the association between abdominal obesity and asthma symptoms. What this study adds Individuals with higher visceral fat are more likely to develop asthma. Furthermore, even after adjusting for demographic factors, visceral obesity remains a significant risk factor for asthma. How this study might affect research, practice, or policy This study offers additional evidence associating visceral fat with asthma and further validates the causal relationship between the two conditions.