Anxiety and depression among dairy farmers: the impact of COPD

Background: Chronic obstructive pulmonary disease (COPD) and farming are two conditions that have been associated with an increased risk of anxiety and depression. Dairy farming is an independent risk factor for COPD. Objective: To test the hypotheses that the prevalence of anxiety and/or depression is higher in dairy farmers with COPD than in farmers without COPD, and higher in dairy farmers with COPD than in non-farmers with COPD. Methods: Anxiety and depression were evaluated using the Hospital Anxiety and Depression Scale in 100 dairy farmers with COPD (DF-COPD), 98 dairy farmers without COPD (DF-controls), 85 non-farming patients with COPD (NF-COPD) and 89 non-farming subjects without COPD (NF-controls), all identified by screening in the Franche-Comte region of France. Anxiety and depression were considered present when the Hospital Anxiety and Depression Scale score was >8. COPD was defined by a post-bronchodilator forced expiratory volume in 1 second/forced vital capacity ratio <0.7. Results: The crude prevalence of anxiety did not differ between the four groups, ranging from 36% in NF-controls to 47% in NF-COPD (p=0.15 between groups). Similarly, the prevalence of depression did not differ significantly between the four groups (p=0.16 between groups). In dairy farmers (n=198), the only factors associated with anxiety were quality of life and current smoking. Depression in dairy farmers was associated with airflow limitation (lower forced expiratory volume in 1 second and COPD grade 2 or more) as well as with some COPD-related features (dyspnea severity, current smoking, and poorer quality of life). In non-farmers, both anxiety and depression were associated with airflow limitation and COPD-related features. Conclusion: In our population, the prevalence of anxiety and/or depression was similar in dairy farmers with and without COPD and in non-farmers with COPD. Nevertheless, the degree of airway obstruction and some COPD-related features were associated with depression among dairy farmers, whereas these factors were not associated with anxiety.