Six year longitudinal study of respiratory function in dairy farmers in the Doubs province

Asthma and Chronic Obstructive Pulmonary Disease Associated With Occupational Exposure in Dairy Farmers - Importance of Job Exposure Matrices

AIM

To evaluate the prevalence of chronic respiratory symptoms, lung function impairment, and chronic obstructive respiratory diseases in dairy farmers. Our objective is to then examine their relation to exposure duration and to explore the usefulness of job exposure matrices as tools for exposure assessment, and predictors for respiratory health impairment.

METHODS

A cross-sectional study was performed, including 83 dairy farmers (mean age: 52.6 ± 8.7 years; mean exposure duration: 23.7 ± 7.6 years) and 80 office workers as a control group (mean age: 52.7 ± 8.2 years) matched for age, smoking habits, and socioeconomic status. Methods of evaluating examined subjects included a questionnaire on respiratory symptoms in the last 12 months, spirometry and histamine challenge, as well as the use of job exposure matrices (JEM).

RESULTS

Dairy farmers had a significantly higher prevalence of cough (38.5), phlegm (27.7%), and wheezing (21.7%), than controls (p < 0.05). All mean baseline spirometric parameters were lower in dairy farmers compared to the controls, but statistical significance was confirmed only for MEF25, MEF50, and MEF75% (p = 0.010, p = 0.001, and p = 0.004, respectively). The prevalence of bronchial hyperresponsiveness, asthma, and chronic obstructive pulmonary disease was higher in dairy farmers but without statistical significance. JEM were useful tools for exposure assessment and predictors of factors for asthma and COPD development.

CONCLUSION

The results suggest that occupational exposure among crop farmers is associated with a higher prevalence of respiratory symptoms, lung function impairment, and a higher prevalence of chronic respiratory diseases. JEM showed good potential for farming exposure evaluation and promoted their applicability within the diagnostic algorithm focused on respiratory health assessment.

Prevalence and risk factors of chronic obstructive pulmonary disease in dairy farmers: AIRBAg study

BACKGROUND

The AIRBAg study was designed to assess the prevalence of chronic obstructive pulmonary disease (COPD) in dairy farmers and to define its associated risk factors.

METHODS

Between March 2012 and February 2017 randomly selected dairy farmers in the French region of Brittany were asked to complete a self-administered questionnaire and undergo an occupational health check-up with electronic mini-spirometry and standard spirometry. Those having one or more of the following features: chronic cough, chronic bronchitis, wheezing, dyspnea and/or a ratio FEV₁/FEV₆ < 80% were then referred to a pulmonologist for further check-up including spirometry with a reversibility test. Each COPD case was matched with three controls (dairy farmers and non-farm employees), for sex and age ( ± 5 years). Conditional multivariate logistic regression models were used to estimate the odds ratios between COPD occurrence and various risk factors.

RESULTS

The 1203 farmers examined included 525 (43.6%) who were "at risk of bronchial obstruction" and 432 (35.9%) of these saw the pulmonologist. This screening identified 16 (1.3%) cases of COPD, including eight non-smokers and five with an FEV₁ < 80% of predicted values. Their average age was 54.6 ( ± 7.7) years and 10 of them were men. None complained of illness before the study. Multivariate analyses revealed no significant occupational risk factors for COPD.

CONCLUSIONS

This unexpected result may be because Breton dairy farms began to modernize early (1950s), giving rise to conditions with much lower exposure to airborne contaminants.

COPD, airflow limitation and chronic bronchitis in farmers: a systematic review and meta-analysis

Introduction

The current definition of chronic obstructive pulmonary disease (COPD) associates persistent airflow limitation and chronic respiratory symptoms. Agricultural work has been associated with an increased risk of developing COPD, but the prevalence and definition of the disease vary greatly between studies. This meta-analysis aimed to assess the association between agricultural work and COPD using the most widely used definitions of the disease.

Methods

Inclusion criteria were: (1) design: cross-sectional or longitudinal, (2) groups: at least one group of farmers and a control group of non-farmers, (3) outcome: prevalence or unadjusted OR of COPD, airflow limitation and/or chronic bronchitis, (4) study subjects: groups of exposed subjects comprising ≥30 individuals and with a mean age ≥40 years and (5) language: English and French language, full-length, original publications in peer-reviewed journals.

Results

In total, 22 manuscripts were included in the meta-analysis. Eight studies assessed only the prevalence of airflow limitation, nine assessed only the prevalence of chronic bronchitis and four assessed the prevalence of both these parameters. Only one assessed the prevalence of COPD according to its current definition, and this study also provided the prevalence of airflow limitation. Ten studies showed a positive association between farming exposure and airflow limitation or chronic bronchitis, and 12 showed no association (OR (95% CI)=1.77 (1.50 to 2.08), p<0.001). Cattle, swine, poultry and crop farming were associated with either airflow limitation or chronic bronchitis.

Conclusion

Although some features of COPD are associated with some agricultural work, well-designed studies with appropriate diagnostic criteria should be conducted to draw strong conclusions about the relationship between COPD and farming.

[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.

The effect of organic dust exposure on long-term change in lung function: a systematic review and meta-analysis

Lung function is a predictor of morbidity and mortality, and the chronic nature of lung function decline allows for preventive initiatives. Proinflammatory constituents of organic dust are considered a possible cause of compromised respiratory health. The aim of this systematic review was to reveal the impact of organic dust exposure on long-term change in lung function. The literature search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. Predefined criteria concerned study design: longitudinal, ≥1 year follow-up, ≥50 exposed; exposure measures: organic dust, measured or estimated, in different occupational settings; and outcome measures: change in lung function measured by spirometry. Based on these criteria, 1580 potentially relevant publications were narrowed down to 20 included publications. Quality was evaluated and discussed based on six objectively defined criteria. Overall, 14 studies found some type of association between exposure to organic dust and long-term change in lung function. However, the results were inconsistent and no specific work exposure showed more clear associations to change in lung function. Meta-analysis revealed an overall small significant excess loss in forced expiratory volume in the 1st s for exposed compared with controls of 4.92 mL/year (95% CI 0.14 to 9.69). No significant association was seen overall for forced vital capacity. 12 studies revealed a significant exposure-response relation between organic dust and change in lung function. The results were inconsistent across varying study design and different exposure measures and outcomes. We therefore conclude that there is limited evidence of a causal association between general exposure to organic dust and long-term excess decline in lung function.

Annual decline in forced expiratory volume is steeper in aluminum potroom workers than in workers without exposure to potroom fumes

Background

Aluminum potroom exposure is associated with increased mortality of COPD but the association between potroom exposure and annual decline in lung function is unknown. We have measured lung volumes annually using spirometry from 1986 to 1996. The objective was to compare annual decline in forced expiratory volume in 1 s (dFEV1) and forced vital capacity (dFVC).

Methods

The number of aluminum potroom workers was 4,546 (81% males) and the number of workers in the reference group was 651 (76% males). The number of spirometries in the index group and the references were 24,060 and 2,243, respectively.

Results

After adjustment for confounders, the difference in dFEV1 and dFVC between the index and reference groups were 13.5 (P < 0.001) and −8.0 (P = 0.060) ml/year.

Conclusion

Aluminum potroom operators have increased annual decline in FEV1 relative to a comparable group with non‐exposure to potroom fumes and gases. Am. J. Ind. Med. 59:322–329, 2016. © 2016 The Authors. American Journal of Industrial Medicine Published by Wiley Periodicals, Inc.

Impact of farm modernity on the prevalence of chronic obstructive pulmonary disease in dairy farmers

Dairy farming is associated with an excess of chronic obstructive pulmonary disease (COPD). The dairy industry has been changing for the past three decades with larger, more efficient farms and potentially less exposure to agents involved in COPD development. However, the impact of farm modernisation on COPD prevalence is unknown. We studied respiratory symptoms, respiratory function by spirometry and tobacco smoking in 575 male dairy farmers working either in traditional or in modern farms in the French Doubs region. COPD was defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criterion (forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) <0.70) and by the Quanjer reference equation (FEV1/FVC<lower limit of normal (LLN)). Modern farms were defined either as having a separation between the house and the cowshed (model 1) or as having a loose housing system for the animals (model 2). The prevalence of COPD in dairy farmers was 12.0 ± 2.7% (GOLD), and 5.6 ± 4.1% (LLN definition). By multivariate analysis using the LLN definition, tobacco smoking (OR (95% CI) 3.96 (1.53 to 10.3) and 3.42 (1.32 to 8.84) for models 1 and 2, respectively) and characteristics of traditional farms (1.97 (1.02 to 4.47) and 5.20 (1.73 to 15.64) for models 1 and 2, respectively) were associated with higher COPD prevalence. Working in a traditional farm plus current smoking had an additive effect on COPD prevalence in model 1 and a synergistic effect in model 2. These findings support a positive impact of farm modernity on COPD prevalence in dairy farmers. Occupational and smoking-related risk factors are of nearly the same magnitude.

Prevalence and risk factors for COPD in farmers: a cross-sectional controlled study

There are conflicting data regarding the magnitude and determinants of chronic obstructive pulmonary disease (COPD) risk in farmers.In a cross-sectional study of 917 nonfarming working controls and 3787 farmers aged 40-75 years, we assessed respiratory symptoms, tobacco exposure, job history (without direct exposure measurement) and lung function. COPD was defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criterion (post-bronchodilator forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) <0.70) and by the Quanjer reference equation (post-bronchodilator FEV1/FVC <lower limit of normal (LLN)).The prevalence (95% CI) of COPD according to the GOLD criterion was 5.1% (4.4-5.8%) and 2.9% (1.8-4.0%) in farmers and controls, respectively (p=0.005), and 3.1% (2.5-3.6%) and 1.5% (0.7-2.3%), respectively, for the LLN criterion (p<0.01). For both COPD criteria after adjustment for age, sex and smoking status, COPD prevalence was similar in controls and crop farmers. Compared to controls, four job categories had a higher prevalence of COPD according to the GOLD criterion, namely, cattle breeders, swine breeders, poultry breeders and breeders of two or more livestock types. Among cattle breeders, only those from Franche-Comté had higher prevalence of COPD according to both GOLD and LLN criteria.The prevalence of COPD in farmers is higher than in nonfarming working controls, and depends on the farming activity, the region and the criterion used to define COPD.

Farm environment during infancy and lung function at the age of 31: a prospective birth cohort study in Finland

OBJECTIVES

Farming as an occupation is considered a risk factor for asthma and reduced lung function. By contrast, living on a farm during infancy has been reported to be associated with lower risk of asthma in adulthood. However, little is known about the association between farming environment during infancy and lung function in adulthood. We aimed to study the prospective longitudinal association between farming environment during infancy and lung function in adulthood.

DESIGN

A prospective birth cohort study.

SETTING

Northern Finland.

PARTICIPANTS

5666 participants born in 1966 were followed up at the age of 31 years.

PRIMARY OUTCOME MEASURES

Spirometry at the age of 31 years.

RESULTS

To be born into a farmer's family was associated with higher forced expiratory volume in 1 s (FEV1) (36 mL; 95% CI 6 to 67 mL) and forced vital capacity (FVC) (40 mL; 95% CI 5 to 75 mL) at the age of 31 years. Contact with farm animals during infancy was associated with higher FEV1. No associations were seen with FEV1/FVC (FEV1/FVC ratio). Having dogs in childhood revealed similar associations. There was a suggestive dose-dependent association with the number of animal species during childhood and higher FEV1 and FVC at adulthood, especially among women.

CONCLUSIONS

Farming environment in early life may have a positive impact on lung function in adulthood.

[Occupational chronic obstructive pulmonary diseases. Legal aspects and practical management]

The existence of occupational chronic obstructive pulmonary diseases (COPD) is now well established. Since 1989, several regulations have been progressively introduced, allowing compensation for some cases of occupational COPD. Following a brief review of the main occupational causes of COPD, the authors describe the present context for compensation in France and the procedures to be followed to ensure that patient's interests are supported.

Systematic review of respiratory health among dairy workers

The dairy industry is changing on a global scale with larger, more efficient operations. The impact of this change on worker health and safety, specifically, associations between occupational lung disease and inhalation exposures, has yet to be reported in a comprehensive review of the scientific literature. Therefore, a three-tier process was used to identify information using a keyword search of online databases of scientific literature. Of the 147 citations reviewed, 52 met initial screening criteria, and 30 were included in this review. Dairy workers experience lung conditions such as asthma, chronic obstructive pulmonary disease, hypersensitivity pneumonitis, chronic bronchitis, and cancer. Recent pulmonary function studies have identified obstructive lung changes among dairy farm workers. The increased scale of dairy production with significant changes in technology and work practices has altered inhalation exposure patterns among dairy workers. The inhalation exposure in the dairy work environment may elicit differing inflammatory responses in relation to timing of initial exposure as well as to repeated exposures. Few studies have measured inhalation exposure while simultaneously assessing the impact of the exposure on lung function of dairy farm workers. Even fewer studies have been implemented to assess the impact of aerosol control technology to reduce inhalation exposure. Future research should evaluate worker exposure to aerosols through a task-based approach while utilizing novel methods to assess inhalation exposure and associated inflammatory responses. Finally, potential solutions should be developed and tested to reduce inhalation exposure to inflammatory agents and respiratory diseases in the dairy farm work environment.

Acute pulmonary function change associated with work on large dairies in California

OBJECTIVE

To study whether dairy workers in California have lower baseline and greater cross-shift decrements in lung function than control employees.

METHODS

A cross-sectional study of 210 dairy and 47 control workers who completed questionnaires and spirometry before and after the work shift.

RESULTS

Dairy work was associated with mean baseline differences of -0.132 L (P = 0.07) and -0.131 L (P = 0.13) in forced expiratory volume in 1 second and forced vital capacity, respectively, compared with control employees, adjusting for age, height, smoking status, and days back at work since last day off. Dairy work was associated with a mean cross-shift difference of -65.2 mL (P = 0.02) and -103.1 mL (P < 0.01) in forced expiratory volume in 1 second and forced vital capacity, respectively, adjusting for smoking status and work-shift time.

CONCLUSIONS

Dairy work in California was associated with mild acute airway obstruction. The unclear long-term effect of dairy work in California merits further investigation.

Predictors of early cessation of dairy farming in the French Doubs province: 12-year follow-up

BACKGROUND

A healthy worker effect due to respiratory disability has been noted in the farming population, but other factors may also interfere. Little has been published about factors influencing the early cessation of work in self-employed dairy farmers.

METHODS

Two hundred and nineteen dairy farmers were included from a cohort constituted in eastern France in 1993-1994 with a 12-year follow-up. Spirometric data, personal, and farm characteristics were registered. Cox models with delayed entry in which age was the time-scale were applied to identify the baseline predictive factors of the early cessation of dairy farming.

RESULTS

Working in a modern farm was protective against early cessation of dairy farming (hazard ratio: 0.36 [95% CI: 0.16-0.81]), especially in men. Having asthma was a predictive factor of early cessation, especially in women (hazard ratio: 16.12 [95% CI: 3.28-79.12]).

CONCLUSIONS

The most predictive factors of early cessation of dairy farming were health related in women and farm related in men.

Four-year prospective study of lung function in workers in a high altitude (4000 m) mine

The aim of this study was to determine if work at high altitude is associated with accelerated lung function decline and if smoking could further accelerate this decline. Subjects working at high altitude (3800 to 4500 m) in a gold mine on shift-rotation basis were included, and 7320 spirometry reports were obtained throughout a 4-yr observation period (2005-2009). Out of 3368 selected reports with acceptable quality, for 842 patients aged 38.9 ± 8.6 yr we analyzed annual decline in vital capacity (VC), forced vital capacity (FVC), and forced expiratory volume during the first second (FEV(1)). VC was reduced by 46.5 mL, FVC by 67.8 mL, and FEV(1) by 74.5 mL a year, greater than in historical controls. In those having initial FEV(1)/FVC below 70%, yearly VC decline was 59.4 mL, FEV(1) -58.6 mL. In long-term workers with no initial obstruction, FEV(1) declined slower (67.2 vs. 101.3 mL/yr (p < 0.001); but VC and FVC decline did not differ. Work at high altitude for years may be a factor that accelerates lung function decline, and the rate of decline along with confounding factors should be the subject of future studies.

Respiratory disorders are not more common in farmers. Results from a study on Icelandic animal farmers

RATIONALE

The current prevalence of respiratory disorders and symptoms in Icelandic farmers is unknown, but a high prevalence of respiratory symptoms has been reported in the past. Modern farming practices have been implemented in Iceland in the past decade and the processing of hay has changed markedly leading to less organic dust exposure.

OBJECTIVE

The aim was to estimate the prevalence of respiratory disorders and symptoms in a nationwide study of Icelandic farmers.

METHODS

We conducted a questionnaire-based study of all Icelandic farmers with a comparison group randomly selected from the national citizen registry of Iceland. The questionnaire included items regarding respiratory symptoms and disorders.

RESULTS

Out of 2042 farmers invited to participate, 1107 responded (54%), as did 689 of 1500 controls (46%). Farmers were slightly older and more likely to be male (87% vs. 47%). Smoking rates were significantly lower among farmers than among controls. The prevalence of asthma was not significantly different between the two groups, with a lifetime prevalence of 9.4% (n=104) among farmers compared to 10.2% (n=70) among controls. Medication use for asthma was not significantly different. The prevalence of self-reported, physician-diagnosed chronic bronchitis and emphysema likewise did not significantly differ between the groups, but self-reported hay fever was significantly more prevalent among farmers.

CONCLUSION

The prevalence of respiratory disorders and symptoms among Icelandic farmers is currently similar to non-farmers. This may suggest that modernization of the agricultural environment has had a positive effect on workers' health.

Feedlot dust stimulation of interleukin-6 and -8 requires protein kinase Cepsilon in human bronchial epithelial cells

Individuals exposed to dusts from concentrated animal feeding operations report increased numbers of respiratory tract symptoms, and bronchoalveolar lavage samples from such individuals demonstrate elevated lung inflammatory mediators, including interleukin (IL)-8 and IL-6. We previously found that exposure of bronchial epithelial cells to hog barn dusts resulted in a protein kinase C (PKC)-dependent increase in IL-6 and IL-8 release. We hypothesized that cattle feedlot dusts would also generate bronchial epithelial interleukin release in vitro. To test this, we used interleukin ELISAs and direct PKC isoform assays. We found that a dust extract from cattle feedlots [feedlot dust extract (FLDE)] augments PKC activity of human bronchial epithelial cells in vitro. A 5-10% dilution of FLDE stimulated a significant release of IL-6 and IL-8 at 6-24 h in a PKC-dependent manner vs. control medium-treated cells. An increase in PKCalpha activity was observed with 1 h of FLDE treatment, and PKCepsilon activity was elevated at 6 h of FLDE exposure. The PKCalpha inhibitor, Gö-6976, did not inhibit FLDE-stimulated IL-8 and IL-6 release. However, the PKCepsilon inhibitor, Ro 31-8220, effectively inhibited FLDE-stimulated IL-8 and IL-6 release. Inhibition of FLDE-stimulated IL-6 and IL-8 was confirmed in a dominant-negative PKCepsilon-expressing BEAS-2B cell line but not observed in a PKCalpha dominant negative BEAS-2B cell line. These data support the hypothesis that FLDE exposure stimulates bronchial epithelial IL-8 and IL-6 release via a PKCepsilon-dependent pathway.

Volumetric assessment of airborne fungi in two sections of a rural indoor dairy cattle shed

There is increasing concern about the exposure to fungal aerosols in occupational environments and associated respiratory allergic diseases and asthma. A large number of people work in cattle sheds around the world, pulmonary function impairments and higher frequency of respiratory symptoms have been reported in dairy farmers; however, it appears that adequate information on the fungal aerosols from the cattle sheds are largely lacking. Volumetric assessment of airborne culturable and nonculturable fungal spores was performed in two sections of a large rural indoor cattle shed of West Bengal, India for 2 consecutive years. An Andersen Two Stage Viable Sampler was used for sampling culturable fungi and a Burkard Personal Slide Sampler was used to collect the total airborne fungal spores including both the culturable and nonculturable types. A total of 31 spore types and 35 types of viable colony-forming units were recorded. Average concentration range of total fungal spores was 233-2985/m(3) and concentration of viable colony-forming units ranged between 165 and 2225 CFU/m(3). Burkard Sampler showed higher frequencies of Aspergilli/Penicilli, Cladosporium, Alternaria, and smut spores. Andersen Sampler showed the prevalence of Aspergillus niger, Aspergillus flavus and Cladosporium cladosporioides colonies. Some recorded fungi were earlier reported as allergenic, toxic, and pathogenic for occupational workers as well as cattle population. Higher concentration levels of airborne total and culturable fungal spores were recorded during the months of November through February (winter) and June through September (late summer and rainy season).

Respiratory status in dairy farmers in France; cross sectional and longitudinal analyses

AIMS

To compare respiratory status in dairy farmers with that of non-farming controls.

METHODS

Longitudinal study in the Doubs (France). From a cohort constituted in 1994 (T1), 215 (81.1%) dairy farmers and 110 (73.8%) controls were reevaluated in 1999 (T2). The protocol comprised a medical and occupational questionnaire, spirometric tests at both evaluations, allergological tests at T1, and a non-invasive measure of blood oxygen saturation (SpO2) at T2.

RESULTS

In 1999 analyses, the prevalence of chronic bronchitis was higher (p = 0.013), and FEV1/VC (p < 0.025) and SpO2 (-0.7%, p < 0.01) lower in dairy farmers than in controls. In a multiple linear regression model, farming, age, and smoking were significantly and inversely correlated with SpO2. In the whole population, the mean annual decline in FEV1 and FEV1/VC was -13.4 ml and -0.30%, respectively. Farming was associated with an accelerated decline in FEV1/VC (p < 0.025) after adjustment for covariates. No relation between allergy and respiratory function changes was observed, except for FEF25-75.

CONCLUSIONS

This prospective study shows that dairy farming is associated with an excess of chronic bronchitis, with a moderate degree of bronchial obstruction and a mild decrease in SpO2.

Agricultural lung disease

Agricultural work is associated with high rates of injury, disability, and illness. Agricultural workers are at increased risk for a variety of illnesses including respiratory disorders, dermatologic conditions, and cancer. The recognition of ODTS led to increased understanding of acute illness in farmers and grain workers. Previously, many cases of acute illness were probably erroneously called farmer's lung. The same agents that are responsible for ODTS are responsible for the high prevalence of bronchitis in certain agricultural workers. The recent description of the innate immune system is very exciting because it will lead to increased understanding of the pathogenesis of organic dust induced disorders.

Rapid declines in FEV1 and subsequent respiratory symptoms, illnesses, and mortality in coal miners in the United States

Coal mine dust exposure is associated with accelerated loss of lung function. We assessed long-term health outcomes in two groups of underground coal miners who during previous mine surveys had shown either high rates of FEV1 decline (cases, n = 310) or relatively stable lung function (referents, n = 324). Cases and referents were matched initially for age, height, smoking status, and FEV1. We determined vital status for 561 miners, and obtained a follow-up questionnaire for 121 cases and 143 referents. Responses on the follow-up questionnaire were compared with those on the last previous mine health survey questionnaire. Cases showed a greater incidence of symptoms than did referents for cough, phlegm production, Grades II and III dyspnea, and wheezing, and greater incidences than referents of chronic bronchitis and self- reported asthma and emphysema. More cases than referents (15% versus 4%) left mining before retirement because of chest illnesses. After controls were applied for age and smoking, cases had twice the risk of dying of cardiovascular and nonmalignant respiratory diseases and a 3.2-fold greater risk of dying of chronic obstructive pulmonary disease than did referents. Rapid declines in FEV1 experienced by some coal miners are associated with subsequent increases in respiratory symptoms, illnesses, and mortality from cardiovascular and nonmalignant respiratory diseases.