SMOKING AND BRONCHIAL REACTIVITY IN SMALL AIRWAYS DISEASE IN A POPULATION OF BOGDANKA (POLAND) COAL-MINERS

The pathogenesis of chronic obstructive pulmonary disease (COPD) is st ill not fully understood. Smoking is the most important factor but onl y 15% of smokers develop disabling airflow obstruction and it is clear that additional predisposing factors must exist Small airways disease (SAD) and increased bronchial reactivity are considered important ris k factors for COPD development. The aim of this study was to assess an d characterise bronchial reactivity in miners presenting with SAD in c omparison with a control population. The study population was 1,456 co al miners working in the Bogdanka colliery, Poland. Body plethysmograp hy, spirometry and flow volume curves were obtained in each case befor e and after bronchoprovocation with a single dose of methacholine. The number of miners with SAD (characterised by isolated end-expiratory f low below the normal range) was 292 (20%). Bronchial reactivity manife sted by greeter airway resistance (Raw), intrathoracic gas volume and lower forced expiratory volume per second, after methacholine challeng e was more frequent in the SAD group than among controls. Higher level s of post-provocational Raw (0.3-0.6kPa/L/sec and >0.6kPa/L/sec) were significantly more frequent among workers with SAD. We consider that t hese moderate changes do not reflect 'true' hyperreactivity but reflec t cryptogenic abnormalities throughout the bronchial tree. We conclude that SAD is accompanied by moderate (but significant) increase in bro nchial reactivity and that such increase may provide an opportunity to detect abnormalities at a very early stage in the development of dise ase.