[COPD in dairy farmers: screening, characterization and constitution of a cohort. The BALISTIC study]

Never-smokers with occupational COPD have better exercise capacities and ventilatory efficiency than matched smokers with COPD

Chronic obstructive pulmonary disease (COPD) in never-smokers exposed to organic dusts is still poorly characterized. Therapeutic strategies in COPD are only evaluated in smoking-related COPD. Understanding how never-smokers with COPD behave during exercise is an important prerequisite for optimal management. The objective of this study was to compare physiological parameters measured during exercise between never-smokers with COPD exposed to organic dusts and patients with smoking-related COPD matched for age, sex, and severity of airway obstruction. Healthy control subjects were also studied. Dyspnea (Borg scale), exercise tolerance, and ventilatory constraints were assessed during incremental cycle cardiopulmonary exercise testing in COPD patients at mild to moderate stages [22 exposed to organic dusts: postbronchodilator forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) z score -2.44 ± 0.72 and FEV₁ z score -1.45 ± 0.78; 22 with smoking-related COPD: FEV₁/FVC z score -2.45 ± 0.61 and FEV₁ z score -1.43 ± 0.69] and 44 healthy control subjects (including 22 never-smokers). Despite the occurrence of similar significant dynamic hyperinflation, never-smoker COPD patients exposed to organic dusts had lower dyspnea ratings than those with smoking-related COPD. They also had better ventilatory efficiency, higher peak oxygen consumption and peak power output than smoking-related COPD patients, all these parameters being similar to control subjects. Differences in exercise capacity between the two COPD groups were mainly driven by better ventilatory efficiency stemming from preserved diffusion capacity. Never-smokers exposed to organic dusts with mild to moderate COPD have better exercise capacities, better ventilatory efficiency, and better diffusion capacity than matched patients with smoking-related COPD.NEW & NOTEWORTHY It is unknown whether or not never-smokers with chronic obstructive pulmonary disease (COPD) behave like their smoking counterparts during exercise. This is the first study showing that never-smokers with mild to moderate COPD [defined by a postbronchodilator forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) < lower limit of normal] have preserved exercise capacities. They also have lower exertional dyspnea than patients with smoking-related COPD. This suggests that the two COPD groups should not be managed in the same way.

Characterization of chronic obstructive pulmonary disease in dairy farmers

BACKGROUND

Although farming is often considered a risk factor for COPD, data regarding the burden and characteristics of COPD in dairy farmers are sparse and conflicting.

OBJECTIVES

To characterize COPD in dairy farmers.

METHODS

4788 subjects entered two parallel COPD screening programs, one in agricultural workers and one in general practice from 2011 to 2015. Subjects with COPD were invited to participate in the characterization phase of the study. Those who accepted were included in two subgroups: dairy farmers with COPD (DF-COPD) (n = 101) and non-farmers with COPD (NF-COPD) (n = 85). Patients with COPD were frequency-matched with subjects with normal spirometry for age, sex and tobacco smoking (pack-years and status) (DF-controls n = 98, NF-controls n = 89). All subjects from these four groups underwent lung function and exercise testing, questionnaires and blood analysis.

RESULTS

The frequency of COPD in dairy farmers was 8.0% using the GOLD criterion and 6.2% using the lower limit of normal criterion and was similar in non-farming subjects (7.3% and 5.2%, respectively) although dairy farmers had lower tobacco consumption (screening phase). DF-COPD had better pulmonary function, exercise capacity and quality of life, fewer symptoms and comorbidities than NF-COPD, and higher levels of some Th2 biomarkers (MCP-2, periostin) (characterization phase). In farmers, COPD was not related to occupational exposure factors, supporting the role of host factors.

CONCLUSION

COPD secondary to organic dust exposure (dairy farming) appears less severe and associated with fewer comorbidities than COPD secondary to tobacco smoking.

In Patients with Mild-to-Moderate COPD, Tobacco Smoking, and Not COPD, Is Associated with a Higher Risk of Cardiovascular Comorbidity

Background

Comorbidities including cardiovascular diseases are very common in chronic obstructive pulmonary disease (COPD) secondary to tobacco smoking and contribute to the overall severity of the disease. In non-smoking COPD, which accounts for about 25% of COPD cases worldwide, current knowledge on the frequency and determinants of comorbidities remains scarce. The aims of the current study were to assess the frequency of major comorbidities and to evaluate their determinants in a group of non-selected patients with mild-to-moderate COPD who were exposed to organic dust (dairy farmers), to tobacco smoking, or to both, and in controls without COPD who were exposed to organic dust (dairy farmers), or to tobacco smoking, or to both, or who were without exposure.

Patients and Methods

A total of 4665 subjects (2323 dairy farmers and 2342 non-farmers) including 355 patients with COPD and 4310 controls with normal spirometry were recruited through a large COPD screening program. Self-reported physician-diagnosed diseases with plausible links to COPD were recorded in this cross-sectional study.

Results

Whatever the exposure, cardiovascular comorbidities were not more frequent in patients with COPD than their counterparts without airflow limitation. A higher risk of major cardiovascular comorbidities was associated with tobacco smoking and a lower risk was associated with exposure to organic dusts.

Conclusion

Tobacco smoking (but not COPD) is associated with higher frequency of cardiovascular comorbidities. By contrast, being a dairy farmer exposed to organic dusts is associated with a lower frequency of the same comorbidities. This reinforces the crucial need for controlling established cardiovascular risk factors even in patients with mild-to-moderate COPD.

Quantitative and qualitative evaluation of spirometry for COPD screening in general practice

INTRODUCTION

Proper diagnosis of COPD remains a challenge. Spirometry testing in primary care may help to reduce misdiagnosis, but its reliability as a diagnostic instrument needs to be assessed.

OBJECTIVES

To investigate (1) the validity of spirometry testing performed in primary care and (2) the accuracy of the diagnostic of airflow limitation obtained by these tests.

METHODS

Subjects attending a COPD screening programme had screening spirometry performed either by general practitioners (GPs) or by trained nurses or technicians, who had all received two 3-hour training sessions. Subjects with airflow limitation and a subset of subjects with normal spirometry at screening were invited to undergo confirmatory spirometry performed by trained nurses in a pulmonary function laboratory.

RESULTS

Of the 4610 subjects who attended the screening sessions, 96.5% had a valid screening spirometry test. A total of 392 subjects attended the confirmatory sessions. Values measured by screening spirometry were satisfactory compared with those of confirmatory spirometry (r_c=0.83). Taking confirmatory spirometry as reference, the positive predictive value of screening spirometry for the diagnosis of persistent airflow limitation was 93% with a specificity of 95%. Agreement for the diagnosis of persistent airflow limitation was substantial (k=0.80).

CONCLUSION

Spirometry performed in primary care by trained personnel reliably identifies persistent airflow limitation. This may encourage pulmonologists to collaborate with primary care providers with the aim of improving appropriate diagnosis of COPD.

Dietary Patterns and Prevalence of Post-bronchodilator Airway Obstruction in Dairy Farmers Exposed to Organic Dusts

Exposure to organic dusts is an independent causative factor of chronic obstructive pulmonary disease (COPD). Unhealthy dietary patterns have been associated with poor lung function in smokers. This study investigated whether dietary patterns were associated with post-bronchodilator airway obstruction, a hallmark of COPD, in dairy farmers exposed to organic dusts. All subjects were identified by screening programs and patients with airflow obstruction were matched with subjects with normal spirometry. Six groups were compared, defined by their exposures (non-smoking dairy farmers, smokers ≥ 10 pack-years with no occupational exposure, and smoking dairy farmers) and the presence or absence of post-bronchodilator airflow obstruction, resulting in 321 study subjects. The Alternative Healthy Eating Index (AHEI) score was calculated based on an adapted food frequency questionnaire. Mean total AHEI scores were similar in all groups. Comparison between smokers with post-bronchodilator airway obstruction and subjects with post-bronchodilator airway obstruction related to occupational exposure found minimal differences in dietary patterns: dairy farmers had lower scores for the ratio of white to red meat and higher scores for cereal fiber consumption. As in previous studies, smokers with post-bronchodilator airway obstruction exhibited higher lipid intakes and lower carbohydrate intakes than their counterparts with normal spirometry. No evidence of any meaningful difference in dietary patterns was found between subjects with post-bronchodilator airway obstruction detected by screening and healthy controls, either in dairy farmers or in smokers with no occupational exposure.

Is atopy a risk indicator of chronic obstructive pulmonary disease in dairy farmers?

Abstract

Allergic mechanisms related to environmental and occupational exposure have been suggested to contribute to the development of chronic obstructive pulmonary disease (COPD).

Objectives

To investigate the relationships between atopy markers, persistent airflow limitation (PAL) and occupational exposure in dairy farmers.

Methods

Clinical and biological (total IgE and 21 allergen specific IgE) markers of atopy were assessed in 101 dairy farmers with PAL (DF-PAL), 85 non-farmers with PAL (NF-PAL) (both groups were prospectively included from a screening program performed between 2011 and 2015), and matched controls, i.e. 98 farmers without PAL (DF-controls) and 89 non-farming subjects without PAL (NF-controls). Occupational exposure in farmers was estimated using a validated questionnaire.

Results

Prevalence of allergy history was significantly higher in DF-PAL and in NF-PAL than in controls. Polysensitization, and sensitization to seasonal and food allergens were more frequent in DF-PAL than in DF-controls, respectively: 13.8% vs 1% (adjusted odds ratio (aOR): 17.5 (2.2–134), 11.9% vs 3.1% (aOR: 4.4 (1.2–7.2) and 16.8% vs 4.1% (aOR: 5.2 (1.7–7.2)). The prevalence of atopy markers was similar between NF-PAL patients and NF-controls.

Conclusions

PAL in farmers is associated with a high rate of markers of atopy, supporting atopy as a risk indicator.

Clinical trial registered with ClinicalTrials.gov (NCT02540408).

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1082-2) contains supplementary material, which is available to authorized users.

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-Comté 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.

[Differences and similarities between occupational and tobacco induced COPD]

Chronic obstructive pulmonary disease (COPD) most often results from the inhalation of toxic agents. Cigarette smoking still remains the principal cause but the pertinence of occupational COPD is now clearly established. After a brief overview of the epidemiology of this "other COPD", the clinical and functional characteristics are summarized, taking into account recent advances in this field. The combined effects of occupational exposure and tobacco are also considered, providing evidence of the need to continuously reinforce campaigns of education and prevention in occupational COPD.