1254Comorbidity of atopic diseases and gastroesophageal reflux in adults: a co-twin control study. (2nd September 2021) - Brew, Bronwyn
Abstract: Background: Gastroesophageal reflux disease (GERD) is the most common non-allergic comorbidity in adults with asthma, however comorbidity with other atopic diseases such as eczema and hayfever is unclear. The objective was to assess the comorbidity of GERD with atopic diseases in adults, and to investigate possible mechanisms including genetic and affective factors. Methods: A co-twin control study harnessing 46 583 adult Swedish twins. Questionnaires on health status were linked to national patient and prescribed drug register data. Within twin-pair comparisons were made between unpaired, monozygotic (MZ) and dizygotic (DZ) twins to assess common genetic liability. Affective traits (depression, anxiety and neuroticism) were added to models to assess their role in comorbidity. Results: The risk of GERD in those with asthma was OR1.52 (95% CI 1.38, 1.68); hayfever OR1.22 (95%CI 1.12, 1.34); and eczema OR1.23 (95%CI 1.10, 1.38). Within twin-pair associations attenuated in decreasing order of shared genetics for all atopic diseases e.g. self-report asthma with GERD: DZ twins adjOR1.41 (95%CI 0.96, 2.08), MZ twins adjOR1.24 (95%CI 0.82, 1.87). Adjusting for affective traits only slightly attenuated the comorbidity associations. Conclusions: GERD is a common comorbidity in adults with asthma, hayfever and/or eczema. We found evidence for shared genetic factors but not for affective traits. Key messages: GERD is a common comorbidity not only in adults with asthma, but also in adults with eczema or hayfever. Twin research has revealed evidence for a common genetic liability to explain comorbidity.