The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology
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Smokers are assessed for chronic obstructive pulmonary disease (COPD) using spirometry, with COPD defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) as airflow limitation that is not fully reversible with bronchodilators. There is a subset of smokers with normal spirometry (by GOLD criteria), who have a low diffusing capacity of the lung for carbon monoxide (DLCO), a parameter linked to emphysema and small airway disease. The natural history of these "normal spirometry/low DLCO" smokers is unknown. ⋯ In the normal spirometry/normal DLCO group assessed over 45±20 months, 3% developed GOLD-defined COPD. In contrast, in the normal spirometry/low DLCO group, followed over 41±31 months, 22% developed GOLD-defined COPD. Despite appearing "normal" according to GOLD, smokers with normal spirometry but low DLCO are at significant risk of developing COPD with obstruction to airflow.
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Several studies have investigated the effect of livestock farm emissions on the respiratory health of local residents, but results are inconsistent. This study aims to explore associations between the presence of livestock farms and respiratory health in an area of high-density livestock farming in the Netherlands. We focused especially on associations between farm exposures and respiratory symptoms within subgroups of potentially susceptible patients with a pre-existing lung disease. ⋯ Using general practitioners' electronic medical records, we demonstrated that selection bias did not affect the observed associations. Our data suggest a protective effect of livestock farm emissions on the respiratory health of residents. Nonetheless, COPD patients living near livestock farms reported more respiratory symptoms, suggesting an increased risk of exacerbations.