Role of diabetes mellitus and gastro-oesophageal reflux in the aetiology of idiopathic pulmonary fibrosis
Received 7 August 2008; accepted 6 November 2008. published online 09 December 2008.
Summary
Background
The aetiology of idiopathic pulmonary fibrosis remains poorly understood, but recent studies have suggested that diabetes mellitus and gastro-oesophageal reflux may be risk factors.
Objective
To test possible associations between diabetes mellitus and gastro-oesophageal reflux with idiopathic pulmonary fibrosis in the general population.
Methods
We designed a case–control study in the setting of UK general practices contributing data to The Health Improvement Network primary care database (THIN). We selected patients over 40years of age with a first diagnosis of idiopathic pulmonary fibrosis, and up to 4 controls per case matched by age, gender, and general practice. We estimated odds ratios for exposure to gastro-oesophageal reflux, gout, hypercholesterolaemia and diabetes mellitus using conditional logistic regression. We explored the role of confounding by smoking habit, socio-economic status, and medication with prednisolone.
Results
Amongst our 920 cases we found increased risks of use of insulin (odds ratio (OR) 2.36; 95% confidence interval (CI) 1.46–3.83) and use of ulcer drugs (OR 2.20; 95% CI 1.88–2.58). These were almost unchanged when we excluded cases and controls who had been prescribed prednisolone. We found no association with hypercholesterolaemia or gout, nor with smoking status or socio-economic status.
Conclusions
The study provides further evidence of an association between idiopathic pulmonary fibrosis and both diabetes mellitus and gastro-oesophageal reflux.
Division of Epidemiology and Public Health, University of Nottingham, Respiratory Medicine, Clinical Sciences Building, City Hospital, Hucknall Road, Nottingham NG5 1PB, UK
ABSTRACT