Role of diabetes mellitus and gastro-oesophageal reflux in the aetiology of idiopathic pulmonary fibrosis.
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 40 years 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.
Gribbin
Jonathan
J
Division of Epidemiology and Public Health, University of Nottingham, Respiratory Medicine, Clinical Sciences Building, City Hospital, Hucknall Road, Nottingham NG5 1PB, UK. mcxjg@nottingham.ac.uk
Hubbard
Richard
R
Smith
Chris
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000493:Allopurinol / Q000627:therapeutic use; D000863:Antacids / Q000627:therapeutic use; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D048909:Diabetes Complications; D003920:Diabetes Mellitus / Q000188:drug therapy; D004812:Epidemiologic Methods; D005194:Family Practice / Q000706:statistics & numerical data; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications* / Q000188:drug therapy; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D054990:Idiopathic Pulmonary Fibrosis / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011239:Prednisolone / Q000627:therapeutic use; D012907:Smoking / Q000453:epidemiology; D006113:United Kingdom
D000863:Antacids; D000893:Anti-Inflammatory Agents; D007004:Hypoglycemic Agents; D000493:Allopurinol; D011239:Prednisolone