Detection and Characterization of COPD in Dairy Farmers
Condition: Chronic Obstructive Pulmonary Disease (COPD); Environmental Exposure
MeSH terms: Lung Diseases, Obstructive; Pulmonary Disease, Chronic Obstructive
Study type: Observational

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.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        COPD patients will be defined according to the GOLD criteria (post-bronchodilator FEV1/FVC
        ratio<70%).

        Healthy subjects must have pre-bronchodilator FEV1/FVC ratio >75% and pre-bronchodilator
        FEV1 >95% of predicted value.
      
Biospecimen description: 
      Serum for further analyses
    
Keywords: Occupational COPD; Pathophysiology; Exercise limitation; Pulmonary hyperinflation; Arterial stiffness