Study objective: Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease of unknown etiology. The incidence of IPF increases with age. Aging contributes to lifestyle-related diseases, including diabetes mellitus (DM); therefore, it is possible that lifestyle-related diseases may affect either the initiation or progression of IPF.
Design: Case-control study.
Setting: Nippon Medical School and Omiya City Clinic.
Patients and participants: Sixty-five consecutive patients with IPF who were admitted to Nippon Medical School Hospital from 1995 to 2000, and 184 control subjects selected from 15,798 subjects who were admitted to Omiya City Clinic for routine medical examination between September 1999 and August 2000.
Measurements: Age, sex, smoking history, and results of physical examinations, blood examinations, and lung function testing were extracted from medical records and were compared with the diagnostic criteria for lifestyle-related diseases.
Results: The adjusted odds ratios for cigarette smoking were 5.40 (95% confidence interval [CI], 2.30 to 12.66) and 4.06 (95% CI, 1.80 to 9.15) for diabetes. There were no differences in clinical characteristics of patients with IPF that could be related to the presence of DM.
Conclusion: DM may be a risk factor for IPF.