RT Journal Article
SR Electronic
T1 Adiposity and asthma in adults: a bidirectional Mendelian randomisation analysis of The HUNT Study
JF Thorax
JO Thorax
FD BMJ Publishing Group Ltd and British Thoracic Society
SP 202
OP 208
DO 10.1136/thoraxjnl-2019-213678
VO 75
IS 3
A1 Yi-Qian Sun
A1 Ben Michael Brumpton
A1 Arnulf Langhammer
A1 Yue Chen
A1 Kirsti Kvaløy
A1 Xiao-Mei Mai
YR 2020
UL http://thorax.bmj.com/content/75/3/202.abstract
AB Background We aimed to investigate the potential causal associations of adiposity with asthma overall, asthma by atopic status or by levels of symptom control in a large adult population and stratified by sex. We also investigated the potential for reverse causation between asthma and risk of adiposity.Methods We performed a bidirectional one-sample Mendelian randomisation (MR) study using the Norwegian Nord-Trøndelag Health Study population including 56 105 adults. 73 and 47 genetic variants were included as instrumental variables for body mass index (BMI) and waist-to-hip ratio (WHR), respectively. Asthma was defined as ever asthma, doctor-diagnosed asthma and doctor-diagnosed active asthma, and was further classified by atopic status or levels of symptom control. Causal OR was calculated with the Wald method.Results The ORs per 1 SD (4.1 kg/m2) increase in genetically determined BMI were ranged from 1.36 to 1.49 for the three asthma definitions and similar for women and men. The corresponding ORs for non-atopic asthma (range 1.42–1.72) appeared stronger than those for the atopic asthma (range 1.18–1.26), but they were similar for controlled versus partly controlled doctor-diagnosed active asthma (1.43 vs 1.44). There was no clear association between genetically predicted WHR and asthma risk or between genetically predicted asthma and the adiposity markers.Conclusions Our MR study provided evidence of a causal association of BMI with asthma in adults, particularly with non-atopic asthma. There was no clear evidence of a causal link between WHR and asthma or of reverse causation.