David P. Johns

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BACKGROUND Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality. Although the main risk factor is smoking, 15-19% of COPD even in smokers has been attributed to occupational exposures. The aim of this study was to investigate the association between occupational exposure and risk of COPD. METHODS Participants were part(More)
Given that the apnea-ventilation cycle length during central sleep apnea (CSA) with congestive heart failure (CHF) is approximately 70 s, we hypothesized that rapidly responsive peripheral CO(2) ventilatory responses would be raised in CHF-CSA and would correlate with the severity of CSA. Sleep studies and single breath and rebreathe hypercapnic ventilatory(More)
BACKGROUND There are few data in asthma relating airway physiology, inflammation and remodelling and the relative effects of inhaled corticosteroid (ICS) treatment on these parameters. A study of the relationships between spirometric indices, airway inflammation, airway remodelling, and bronchial hyperreactivity (BHR) before and after treatment with high(More)
BACKGROUND The association between allergic rhinitis and asthma is well documented, but the temporal sequence of this association has not been closely examined. OBJECTIVE We sought to assess the associations between childhood allergic rhinitis and (1) asthma incidence from preadolescence to middle age and (2) asthma persistence to middle age. METHODS(More)
BACKGROUND Asthma is accepted as a disease characterized by airway inflammation, with evidence that airway structural changes, or 'remodelling' occurs. There are few studies relating airway physiology, inflammation and remodelling, however. We have carried out a study of inter-relationships between airway inflammation, airway remodelling, reticular basement(More)
The aims of this study were to document the effect terrain has on the physiological responses and work demands (power output) of riding a typical mountain bike cross-country course under race conditions. We were particularly interested in determining whether physiological measures relative to mass were better predictors of race performance than absolute(More)
BACKGROUND In patients with cystic fibrosis (CF), it has been proposed that hypoxemia and hypercapnia occur during episodes of stress, such as exercise and sleep, and that respiratory muscle weakness because of malnutrition may be responsible. METHODS Pulmonary function, respiratory muscle strength, and nutrition were assessed and correlated with the(More)
BACKGROUND AND OBJECTIVE There are few data on the short-term natural history of airway inflammation during severe episodes of acute exacerbation of COPD (AECOPD). An observational study was performed to determine how rapidly conventional treatment improves airway inflammation in patients admitted to hospital with AECOPD. METHODS Twenty-four consecutive(More)