Smoking does not prevent the onset of respiratory failure in sarcoidosis.

It has been suggested that smoking prevents the development of pulmonary sarcoidosis. If this is the case, it might also be expected to prevent or postpone the onset of respiratory failure caused by sarcoidosis. During the period January 1st 1987 to October 1st 1991, 28 patients (16 never-smokers, 11 ex-smokers and one current smoker) were registered in the Swedish Oxygen Register when starting long-term domiciliary oxygen therapy (LTO) for chronic hypoxia caused by sarcoidosis. The register covers 85-90% of all patients starting LTO for respiratory failure in a population of 8.5 million. Ex-smokers were significantly younger at the start of LTO than never-smokers (p < 0.05), regardless of whether chronic airways disease was present or not. We found no indication that smoking exerts a preventive effect on the development of chronic hypoxia in sarcoidosis.