Chronic Obstructive Pulmonary Disease (COPD), Environmental Exposure
Conditions
Keywords
Occupational COPD, Pathophysiology, Exercise limitation, Pulmonary hyperinflation, Arterial stiffness
Brief summary
A pilot study from the investigators group suggests that the prevalence of chronic obstructive pulmonary disease (COPD) among dairy farmers is higher than in the general population. Most characteristics of COPD in dairy farmers (smoking habits, dyspnoea, quality of life, lung function, bronchial exhaled nitric oxide, systemic inflammation, arterial stiffness and exercise capacity) are largely unknown. Although immunization against organic dusts is suspected, the pathophysiology of COPD in dairy farmers is also unknown. This study therefore aims at (i) comparing the prevalence of COPD in dairy farmers and in subjects without any occupational exposure (control arm) through a vast COPD detection program in the Franche-Comté region; (ii) comparing several characteristics (smoking habits, dyspnoea, quality of life, lung function, bronchial exhaled nitric oxide, systemic inflammation, arterial stiffness and exercise capacity) between dairy farmers with COPD and patients with COPD without any occupational exposure; (iv) identifying etiological factors of COPD in dairy farmers (comparison of exposure and specific immunoglobulin E between dairy farmers with COPD and dairy farmers with normal pulmonary function tests); and (v) constituting a cohort of COPD patients and control subjects for further longitudinal studies. Data from selected patients (either current or former smokers) with mild COPD and from matched controls will also be analyzed in an ancillary study which objectives are to compare exercise tolerance, ventilatory constraints on tidal volume expansion and dyspnoea between asymptomatic mild COPD subjects, symptomatic mild COPD and healthy controls.
Detailed description
2000 dairy workers and 2000 subjects without any occupational exposure, all aged 40 to 74 years, will take part to a COPD screening program (spirometry and bronchodilation test) between September 2011 and October 2014. Subjects with COPD and healthy matched controls will attend a second visit. If needed, COPD subjects will be asked to stop any respiratory related medication such as short and long acting bronchodilators 72 hours prior to the visit. All subjects will complete several questionnaires (quality of life, respiratory symptoms, smoking habits,…). A complete medical history will be collected, and a blood sample will be taken. Subjects thereafter will complete arterial stiffness measurement, exhaled nitric oxide and pulmonary function testing pre- and 30-min post-bronchodilator. A symptom-limited incremental cycle exercise test will be performed on the same day, at least 6 hours after the bronchodilator test and at least 4 hours after the meal. Exposure to organic dusts will be quantified through analyze of electrostatic wipes left at subjects' homes for 10 weeks.
Interventions
None listed
Sponsors
Centre Hospitalier Universitaire de Besancon
Study design
Observational model
CASE_CONTROL
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
40 Years to 74 Years
Healthy volunteers
Yes
Inclusion criteria
* subject aged 40-74 years * either dairy farmer or unexposed to any occupational risk factor for COPD
Exclusion criteria
* COPD in GOLD stage 4 * pregnancy * treatment with systemic corticosteroids * established diagnosis of asthma * established diagnosis of bronchiectasis * established diagnosis of allergic alveolitis
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| prevalence of COPD in dairy farmers and in unexposed subjects | 3-year |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| comparison of bronchial exhaled nitric oxide between dairy farmers with COPD and unexposed COPD | 4-year | — |
| comparison of arterial stiffness between dairy farmers with COPD and unexposed COPD | 4-year | — |
| comparison of exercise capacity between dairy farmers with COPD and unexposed COPD | 4-year | — |
| comparison of exposure to organic dusts between dairy farmers with and without COPD | 3-year | — |
| comparison of immunization to organic dusts between dairy farmers with and without COPD | 3-year | — |
| comparison of smoking habits between dairy farmers with COPD and unexposed COPD | 4-year | — |
| comparison of dyspnoea between dairy farmers with COPD and unexposed COPD | 4-year | , quality of life, lung function, bronchial exhaled nitric oxide, systemic inflammation, arterial stiffness and exercise capacity |
| comparison of lung function between dairy farmers with COPD and unexposed COPD | 4-year | — |
| comparison of systemic inflammation between dairy farmers with COPD and unexposed COPD | 4-year | — |
Other
| Measure | Time frame | Description |
|---|---|---|
| comparison of ventilatory constraints on tidal volume expansion between asymptomatic mild COPD subjects, symptomatic mild COPD and healthy controls | 2-year | In the relationship between tidal volume (VT) and ventilation (V'E), there is an inflection point beyond which almost no further change in VT is possible despite a continued increase in V'E. This inflection in the VT response marks the point were dyspnoea sharply raises because of mechanical constraints on VT expansion. This inflection point is determined for each patient by analyzing individual Hey plot. |
| cardiovascular risk in COPD patients either never-smokers or current/former smokers | 3-year | comparison of pulse wave velocity between smoking and non-smoking COPD |
| comparison of exercise tolerance dyspnoea between asymptomatic mild COPD subjects, symptomatic mild COPD and healthy controls | 2-year | — |
| comparison of dyspnoea between asymptomatic mild COPD subjects, symptomatic mild COPD and healthy controls | 2-year | the magnitude of their perceived breathing discomfort at rest, at the middle of warm up, every 2-minute during exercise, and at peak exercise is rated by pointing to the 10-point Borg scale |
Countries
France
Outcome results
None listed