Sun YQ, et al. - In this bidirectional one-sample Mendelian randomisation study, researchers looked at the potential causal links of adiposity with asthma overall, asthma by atopic status or by levels of symptom control in a large adult population (n = 56,105) and stratified by gender. The participants were from the Norwegian Nord-Trøndelag Health Study. They also examined the potential for reverse causation between asthma and risk of adiposity. As instrumental variables for body mass index (BMI) and waist-to-hip ratio (WHR), they included 73 and 47 genetic variants, respectively. In this study, a causal link of BMI with asthma in adults, especially with non-atopic asthma, was evident. No clear evidence was found for a causal association between WHR and asthma or for reverse causation.