Long-term effect of asthma on the development of obesity among adults: an international cohort study, ECRHS.

Introduction: Obesity is a known risk factor for asthma. Although some evidence showed asthma causing obesity in children, the link between asthma and obesity has not been investigated in adults.
Methods: We used data from the European Community Respiratory Health Survey (ECRHS), a cohort study in 11 European countries and Australia in 3 waves between 1990 and 2014, at intervals of approximately 10 years. We considered two study periods: from ECRHS I ( t ) to ECRHS II ( t+1 ), and from ECRHS II ( t ) to ECRHS III ( t+1 ). We excluded obese (body mass index≥30 kg/m ² ) individuals at visit t . The relative risk (RR) of obesity at t+1 associated with asthma at t was estimated by multivariable modified Poisson regression (lag) with repeated measurements. Additionally, we examined the association of atopy and asthma medication on the development of obesity.
Results: We included 7576 participants in the period ECRHS I-II (51.5% female, mean (SD) age of 34 (7) years) and 4976 in ECRHS II-III (51.3% female, 42 (8) years). 9% of participants became obese in ECRHS I-II and 15% in ECRHS II-III. The risk of developing obesity was higher among asthmatics than non-asthmatics (RR 1.22, 95% CI 1.07 to 1.38), and particularly higher among non-atopic than atopic (1.47; 1.17 to 1.86 vs 1.04; 0.86 to 1.27), those with longer disease duration (1.32; 1.10 to 1.59 in >20 years vs 1.12; 0.87 to 1.43 in ≤20 years) and those on oral corticosteroids (1.99; 1.26 to 3.15 vs 1.15; 1.03 to 1.28). Physical activity was not a mediator of this association.
Conclusion: This is the first study showing that adult asthmatics have a higher risk of developing obesity than non-asthmatics, particularly those non-atopic, of longer disease duration or on oral corticosteroids.
Competing Interests: Competing interests: SM reports Long-Term Research fellowship and Young Scientist Sponsorship from the European Respiratory Society, outside the submitted work. MJA holds investigator-initiated grants for unrelated research from Pfizer and Boehringer-Ingelheim. He has undertaken an unrelated consultancy for and received assistance with conference attendance from Sanofi and has also received a speaker’s fee from GSK, outside the submitted work. PD reports personal fees from ALK, Stallergenes Greer, IQVIA, Chiesi, AstraZeneca, Thermo Fisher Scientific, Ménarini, Bausch & Lomb, Mylan, ASIT Biotech, Novartis, Sanofi, Regeneron, outside the submitted work. RJ reports grants from Estonian Research Council Personal Research Grant no 562, during the conduct of the study; personal fees from Consultancy, grants from Grants/grants pending, personal fees from Payment for lectures, personal fees from Travel/accommodations/meeting expenses, outside the submitted work. CR-S reports personal fees from ALK, Astra Zeneca, GSK, Novartis, outside the submitted work.
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