Persistence of respiratory symptoms in ex-underground iron ore miners.

Aims: To assess the persistence of respiratory symptoms in ex-miners after cessation of mining exposure.

Methods: Population-based cross-sectional study using a postal questionnaire comparing prevalence of symptoms between ex-miners who had stopped mining at least 1 year before the study and referents not occupationally exposed to irritants or dust. Age, smoking and a family history of asthma were considered as possible confounders in the analysis.

Results: A total of 206 ex-miners and 4,560 referents participated. Ex-miners had on average been working as miners for 13 years and had stopped mining 16 years before the study. Chronic productive cough and physician-diagnosed chronic bronchitis were significantly more common among ex-miners (P < 0.05 and <0.01, respectively). Furthermore, there was a trend that other respiratory symptoms were more common in ex-miners.

Conclusion: Ex-miners had an increased risk of chronic productive cough and physician-diagnosed chronic bronchitis many years after they had stopped working as a miner.