Background: In spite of numerous investigations, the relation between respiratory symptoms and reflux symptoms in the general population remains unclear, since population-based studies are few.
Study objectives: To investigate the relation between respiratory symptoms and reflux symptoms in the population.
Subject and methods: In a cohort of 65,363 individuals representing 71.2% of the adult population in the Norwegian county of Nord-Trøndelag, 58,596 individuals (89.6%) responded to questions concerning reflux symptoms. The 3,153 persons (5.4%) with severe and recurrent reflux symptoms constituted the case group, and the 40,210 persons (68.6%) without reflux symptoms served as the control group. Odds ratios (ORs) with 95% confidence intervals (CIs) represented relative risks. Potential confounding was tested in multivariable logistic regression analysis.
Results: Persons with asthma had reflux to a 60% greater extent than those without asthma after including adjustment for asthma medication (OR, 1.6; 95% CI, 1.4 to 1.9). There was a statistically significant dose-response association between breathlessness and reflux symptoms (p for trend < 0.0001), and the OR of severe breathlessness was 12.0 (95% CI, 9.5 to 15.2). Persons with heavy and wheezy breathing, daily cough, daily productive cough, or chronic cough showed a twofold to threefold statistically significant increase in risk of reflux symptoms. Adjustment for asthma or use of asthma medication did not substantially influence the risk estimates for any of the studied respiratory disorders.
Conclusions: Reflux symptoms commonly coexist with asthma and other respiratory symptoms on a population-based level, seemingly irrespective of asthma medication.