BACKGROUND: Little is known about the long-term natural history of @entity565 and the long-term clinical and functional consequences in non-smoking @entity1 . From a functional point of view, non-smoking @entity748 @entity1 may have a significantly greater decline in forced expiratory volume in one second (FEV1) compared with non- @entity748 subjects and may develop chronic irreversible (fixed) airflow limitation. This has been related to the physiological consequences of chronic airway inflammation causing airway remodeling. However these lesions are all potentially reversible and there is little radiological evidence indicating @entity358 ( @entity2542 ), which is potentially irreversible, in non-smoking asthmatics. Severe @entity1576 is the major cause of mortality in @entity1 with severe chronic @entity358 . Domiciliary long-term @entity26 therapy (LTOT) is an accepted treatment for @entity1 with severe @entity1576 . Our reasoning, therefore, was that if @entity565 is a cause of severe @entity1576 in non-smokers we should be able to find non-smoking asthmatics within a large population of @entity1 on LTOT. The aim of our study (Asthma and Long-term @entity26 Therapy, "ALOT") was to investigate the prevalence of non-smoking asthmatics in @entity1 on LTOT in a multi-centre, cross-sectional study. METHODS: Between June and September 2003 we screened all subjects on long-term domiciliary @entity26 therapy in three different hospitals in the North-East area of Italy (within the provinces of Ferrara and Bologna). Taken collectively, we have found one-hundred and eighty-four @entity1 on LTOT. We have reviewed their clinical data (age, sex, smoking, history and physical examination, arterial blood gas analysis, pulmonary function). RESULTS: 114 @entity1 (all smokers) fulfilled the diagnostic criteria for @entity1030 . Seventy @entity1 (all smokers) had other diseases. We were unable to find any non-smokers in our screened population of subjects on long-term domiciliary @entity26 therapy. Furthermore, there was no past history of @entity565 and/or acute wheezing episodes in either of the @entity1 groups. CONCLUSIONS: This data suggests that @entity565 is an uncommon cause of severe @entity1576 necessitating long-term domiciliary @entity26 therapy in non-smokers and supports the current consensus that @entity565 and @entity1030 are different diseases with differing stages of severity and the concept that long-term avoidance of active smoking is fundamental for the prevention of severe @entity1576 .

Asthma is not a common cause of severe XXXX in non-smokers: ALOT study.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity748 :: ('MESH:D013224', 'Disease') :: ['asthmatic'] @entity565 :: ('MESH:D001249', 'Disease') :: ['asthma'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen', 'Oxygen'] @entity358 :: ('MESH:D008171', 'Disease') :: ['lung destruction', 'lung diseases'] @entity1576 :: ('MESH:D012131', 'Disease') :: ['chronic respiratory failure'] @entity1030 :: ('MESH:D029424', 'Disease') :: ['COPD'] @entity2542 :: ('MESH:D011656', 'Disease') :: ['pulmonary emphysema']
@entity1576 :: (MESH:D012131,Disease) :: ['chronic respiratory failure']
