Respiratory disease in United States farmers

"Death by a Thousand Cuts": Agriculture Producer Resiliency in the Western United States

OBJECTIVE

Agricultural producers face a wide array of stress triggers, shocks, and long-term pressures such as drought, flooding, fire, government policies, financial insecurity, and physical injuries. Extant research has revealed that mental health stigma, lack of access to care in rural areas, and negative coping responses (alcohol abuse, suicide, prescription drugs use) exacerbate the challenge of producer responses to short and long-term adversity. Resilience, the traits, processes, and capacities of producers to adapt and transform their approach to farming or ranching, when necessary, in response to stress triggers or long-term pressures, has received less research attention, particularly in the Western United States. The purpose of the study was to apply an interactionist occupational resilience theoretical perspective to the investigation of contextual factors contributing to resilience in Western United States agricultural producers.

METHODS

Qualitative interviews (45 to 90 minutes) were conducted with agricultural producers (n=51) from Western states and territories. Applied thematic analysis with a phenomenological lens was utilized to analyze interview transcriptions. First and second level coding were conducted to derive themes.

RESULTS

The analysis revealed that resilience is based upon the interactions between traits of producers and the context of agriculture. Four themes were generated (Agricultural Life, External Stressors, Traits and Adaptations, and Supports and Resources), supported by subthemes. The themes and subthemes are depicted in an agricultural producer resiliency model. The findings shed light on the equivocal role of neighbors in providing support for each other and the double-edged sword of co-working with family.

CONCLUSIONS

The findings underscore that social capital is an important mechanism for supporting farmers and ranchers, as those with stronger social resources are more resilient. We recommend more funding to tailor stress and mental health programming to the specifics of agriculture, integration of behavioral health in primary care as a mechanism to increase access to care, and more intentional technical assistance for farmers and ranchers on strategic planning and problem solving.

A comprehensive review of microbial contamination in the indoor environment: sources, sampling, health risks, and mitigation strategies

The quality of the indoor environment significantly impacts human health and productivity, especially given the amount of time individuals spend indoors globally. While chemical pollutants have been a focus of indoor air quality research, microbial contaminants also have a significant bearing on indoor air quality. This review provides a comprehensive overview of microbial contamination in built environments, covering sources, sampling strategies, and analysis methods. Microbial contamination has various origins, including human occupants, pets, and the outdoor environment. Sampling strategies for indoor microbial contamination include air, surface, and dust sampling, and various analysis methods are used to assess microbial diversity and complexity in indoor environments. The review also discusses the health risks associated with microbial contaminants, including bacteria, fungi, and viruses, and their products in indoor air, highlighting the need for evidence-based studies that can relate to specific health conditions. The importance of indoor air quality is emphasized from the perspective of the COVID-19 pandemic. A section of the review highlights the knowledge gap related to microbiological burden in indoor environments in developing countries, using India as a representative example. Finally, potential mitigation strategies to improve microbiological indoor air quality are briefly reviewed.

Review of bioaerosols from different sources and their health impacts

The emission of bioaerosols in the ambient atmosphere from different sources is a cause of concern for human health and the environment. Bioaerosols are a combination of biotic matter like microbes and pollens. The present review emphasizes the understanding of various sources of bioaerosols (industries, municipal solid waste, and medical facilities), their components, and their impact on human health. The study of bioaerosols is of great importance as large numbers of people are estimated to be exposed on the global scale. Bioaerosols exposure in different work environments results in health issues such as infectious diseases, allergies, toxic effects, and respiratory problems. Hence, extensive research is urged to establish an effective assessment of bioaerosols exposure in the workplace, risks involved, distribution, and validation. The present review is intended to explore the relationship between bioaerosols exposure to the atmosphere and its impacts on human health. Some of the preliminary findings, based on our analysis of bioaerosols arising from municipal solid waste at a landfill site and a waste transfer station in Hyderabad, India, are also discussed herein.

A Cross Sectional Study of Respiratory and Allergy Status in Dairy Workers

INTRODUCTION

Workers on dairy farms face exposures to organic dusts and endotoxin. At the same time, a number of studies of farmers have reported a lower prevalence of asthma in farmworkers compared to persons without farm contact. The "hygiene hypothesis" suggests that early life exposures on farms could be protective against allergic disease and asthma. Such protective relationships are less well studied in adult farm workers.

METHODS

A cross-sectional analysis of respiratory function and allergy status was performed in a sample of dairy farm workers (n = 42) and community controls (n = 40). Measures of respiratory status (spirometry, exhaled nitric oxide FeNO, self-reported symptoms) and levels of total and bovine-specific IgE were compared between the groups.

RESULTS

Prevalence of self-reported asthma and most respiratory symptoms was similar in the two groups, with the exception of increased report of dyspnea among dairy workers. In the dairy workers, level of lung function was not reduced and FeNO was not increased. In unadjusted and adjusted models, dairy work was not associated with reduced lung function or increased airway inflammation. Mean IgE levels did not differ significantly between workers and controls, but elevated bovine-specific IgE was detected only among dairy workers, with an apparent association between elevated bovine IgE and increased FeNO.

CONCLUSION

While dairy workers did not demonstrate increased asthma prevalence compared to controls, sensitization to bovine antigen in several workers appeared to be associated with airway inflammation. Occupational health programs for dairy workers should consider the risk of animal allergy as part of respiratory health protection efforts.

Exposure Levels of Airborne Fungi, Bacteria, and Antibiotic Resistance Genes in Cotton Farms during Cotton Harvesting and Evaluations of N95 Respirators against These Bioaerosols

The USA is the third-leading cotton-producing country worldwide and cotton farming is common in the state of Georgia. Cotton harvest can be a significant contributor to airborne microbial exposures to farmers and nearby rural communities. The use of respirators or masks is one of the viable options for reducing organic dust and bioaerosol exposures among farmers. Unfortunately, the OSHA Respiratory Protection Standard (29 CFR Part 1910.134) does not apply to agricultural workplaces and the filtration efficiency of N95 respirators was never field-tested against airborne microorganisms and antibiotic resistance genes (ARGs) during cotton harvesting. This study addressed these two information gaps. Airborne culturable microorganisms were sampled using an SAS Super 100 Air Sampler in three cotton farms during cotton harvesting, and colonies were counted and converted to airborne concentrations. Genomic DNA was extracted from air samples using a PowerSoil^® DNA Isolation Kit. A series of comparative critical threshold (2^-ΔΔCT) real-time PCR was used to quantify targeted bacterial (16S rRNA) genes and major ARGs. Two N95 facepiece respirator models (cup-shaped and pleated) were evaluated for their protection against culturable bacteria and fungi, total microbial load in terms of surface ATP levels, and ARGs using a field experimental setup. Overall, culturable microbial exposure levels ranged between 10³ and 10⁴ CFU/m³ during cotton harvesting, which was lower when compared with bioaerosol loads reported earlier during other types of grain harvesting. The findings suggested that cotton harvesting works can release antibiotic resistance genes in farm air and the highest abundance was observed for phenicol. Field experimental data suggested that tested N95 respirators did not provide desirable >95% protections against culturable microorganisms, the total microbial load, and ARGs during cotton harvesting.

Effects of different laying periods on airborne bacterial diversity and antibiotic resistance genes in layer hen houses

Poultry farms are a complex environment for close contact between humans and animals. Accumulating evidence has indicated that pathogens and drug resistance genes in chicken houses may pose a serious threat to public health and economic concerns. However, insufficient knowledge of the indoor aerosol microbiome and resistome profiles of layer hen houses hampers the understanding of their health effects. Environmental surveillance of antibiotic resistance may contribute to a better understanding and management of the human exposure risk of bioaerosols under the environmental conditions of chicken houses. In addition, the chicken house has a long operation cycle, and the bacterial diversity and antibiotic resistance genes of aerosols in different periods may be different. In this study, air samples were collected from 18 chicken houses on three farms, including the early laying period (EL), peak laying period (PL), and late laying period (LL). 16S rRNA gene sequencing and metagenomics were used to study the composition of the bacteria and resistome in aerosols of layer hen houses and the results showed that they varied with laying period. The highest alpha diversity of bacteria was observed in PL bioaerosols. The dominant bacterial phyla included Firmicutes, Bacteroidetes and Proteobacteria. Three potential pathogenic bacterial genera (Bacteroides, Corynebacterium and Fusobacterium) were found. The most abundant ARG type was aminoglycosides in all laying periods. In total, 22 possible ARG host genera were detected. ARG subtypes and abundance were both higher in LL. Network analysis also showed higher co-occurrence patterns between the bacteria and resistome in bioaerosols. The laying period plays an important role in the bacterial community and resistome in layer house aerosols.

Bioaerosol dispersion and environmental risk simulation: Method and a case study for a biopharmaceutical plant of Gansu province, China

Pathogenic bacteria pose a great threat to global public health from environmental and public health perspectives, especially regarding the impact of the COVID-19 pandemic worldwide. As a result, the increased risk of pathogenic bioaerosol exposure imposes a considerable health burden and raises specific concerns about the layout and location of vaccine manufacturers. This study proposed a grid computing method based on the CALPUFF modelling system and population-based environmental risks to reduce bioaerosol-related potential risks. We previously used the CALPUFF model to quantify the diffusion level, the spatial distribution of emissions, and potential environmental risks of bioaerosol leakage in Gansu province's Zhongmu Lanzhou biopharmaceutical plant from July 24, 2019, to August 20, 2019. By combining it with publicly available test data, the credibility was confirmed. Based on our previous research, the CALPUFF model application combined with the environmental population-based environmental risks in two scenarios: the layout and site selection, was explored by using the leakage accident of Zhongmu Lanzhou biopharmaceutical plant of Gansu province as a case study. Our results showed that the site selection method of scenario 2 coupled with the buffer area was more reasonable than scenario 1, and the final layout site selection point of scenario 2 was grid 157 as the optimal layout point. The simulation results demonstrated agreement with the actual survey. Our findings could assist global bioaerosol manufacturers in developing appropriate layout and site selection strategies to reduce bioaerosol-related potential environmental risks.

Health check-ups for the French under-consuming agricultural population: A pilot evaluation of the Instants santé MSA program

BACKGROUND

The social protection scheme in charge of farmers and agricultural employees (MSA) in France has developed a two-step health promotion program with a nurse appointment followed by a consultation with a doctor of the participant's choosing to reach its under-consuming beneficiaries and enroll them back into a care pathway. Our objective was to carry out a pilot evaluation of this program.

METHODS

The evaluation was carried out on the population invited during the second semester of 2017 using data from the program's service providers (date of invitation, of nurse appointment…), regional MSA bodies (consultation voucher), and reimbursement data (other care consumption). Participation rates were calculated overall and by participant characteristics. Medical needs were identified during the nurse appointment and new care pathways were assessed using reimbursement data. Multivariable regression models identified factors associated with participation.

RESULTS

2366 beneficiaries were included in the analysis. 1559 (65.89%) were men and mean age was 52.41 (standard deviation = 14.86). 409 (17.29%) attended the nurse appointment. There was a significant increase in participation with age, in farmers vs. employees (odds ratio = 1.905, 95% confidence interval = 1.393-2.604), and in people living in the most disadvantaged areas (odds ratio = 1.579, 95% confidence interval=1.079-2.312). Participation to the consultation following the nurse appointment was high (62.35%-73.11%). 87.53% of participants had at least one medical need, and new care pathways were more frequent among those who had attended the nurse appointment (55.50% vs. 34.80%, p < 0.0001).

CONCLUSIONS

This pilot evaluation shows promising results which need to be confirmed with a national evaluation of the program and longer-term evidence.

Typology of Iranian farmers' vulnerability to the COVID-19 outbreak

Context

Presently, farmers are faced with a new crisis caused by the outbreak of COVID-19. On the one hand, they are vulnerable to such respiratory diseases due to the nature of their farming activity. On the other hand, they will definitely be influenced by the pandemic in different aspects no matter if they do not contract the infection. So, this research aimed to study the vulnerability of farmers to the COVID-19 pandemic.

Methods

The present study was conducted using the quantitative approach and a descriptive-survey methodology. The statistical population was composed of farmers in Kermanshah province, Iran (N = 126,900). The sample (n = 382) was taken by the multistage stratified sampling technique with proportional allocation. The research instrument was a self-designed questionnaire whose face and content validity was confirmed by a panel of relevant experts and its reliability was supported in a pilot test.

Results

The main damages of the pandemic to the farmers were found to be the increased costs of production, permanent or seasonal unemployment, reduced access to crop sale markets, and reduced control over pests and diseases at farms. The results revealed that the means of environmental, agronomic-vocational, and economic vulnerability were greater than the scale mean. The results also illustrated significant differences in the means of economic, psychological-social, agronomic-vocational, and environmental dimensions of vulnerability. Among these dimensions, the variable of agronomic-vocational vulnerability had the highest mean, and the variable of psychological-social vulnerability had the lowest mean.

Conclusion

Farmers have been one of the groups most severely influenced and damaged by the pandemic in various aspects. In this regard, organizations and institutions in charge of different agriculture sections, especially the Office of Agricultural Extension and Education, must develop practical strategies to reduce the effect of the pandemic on the agricultural sector. Identifying the dimensions and parameters of farmers' vulnerability in the face of COVID-19 can provide new and appropriate solutions to relevant planners and policymakers.

Early-life farm exposures and eczema among adults in the Agricultural Lung Health Study

Background

Several studies conducted in Europe have suggested a protective association between early-life farming exposures and childhood eczema or atopic dermatitis; few studies have examined associations in adults.

Objectives

To investigate associations between early-life exposures and eczema among 3217 adult farmers and farm spouses (mean age 62.8 years) in a case-control study nested within an US agricultural cohort.

Methods

We used sampling-weighted logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (95%CIs) for associations between early-life exposures and self-reported doctor-diagnosed eczema (273 cases) and polytomous logistic regression to estimate ORs (95%CIs) for a 4-level outcome combining information on eczema and atopy (specific IgE≥0.35). Additionally, we explored genetic and gene-environment associations with eczema.

Results

Although early-life farming exposures were not associated with eczema overall, several early-life exposures were associated with a reduced risk of having both eczema and atopy. Notably, results suggest stronger protective associations among individuals with both eczema and atopy than among those with either atopy alone or eczema alone. For example, ORs (95%CIs) for having a mother who did farm work while pregnant were 1.01 (0.60-1.69) for eczema alone and 0.80 (0.65-0.99) for atopy alone, but 0.54 (0.33-0.80) for having both eczema and atopy. A genetic risk score based on previously identified atopic dermatitis variants was strongly positively associated with eczema, and interaction testing suggested protective effects of several early-life farming exposures only in individuals at lower genetic risk.

Conclusions

In utero and childhood farming exposures are associated with decreased odds of having eczema with atopy in adults.

Fast Detection of Different Water Contaminants by Raman Spectroscopy and Surface-Enhanced Raman Spectroscopy

Fast monitoring of water quality is a fundamental part of environmental management and protection, in particular, the possibility of qualitatively and quantitatively determining its contamination at levels that are dangerous for human health, fauna and flora. Among the techniques currently available, Raman spectroscopy and its variant, Surface-Enhanced Raman Spectroscopy (SERS), have several advantages, including no need for sample preparation, quick and easy operation and the ability to operate on the field. This article describes the application of the Raman and SERS technique to liquid samples contaminated with different classes of substances, including nitrates, phosphates, pesticides and their metabolites. The technique was also used for the detection of the air pollutant polycyclic aromatic hydrocarbons and, in particular, benzo(a)pyrene, considered as a reference for the carcinogenicity of the whole class of these compounds. To pre-concentrate the analytes, we applied a methodology based on the well-known coffee-ring effect, which ensures preconcentration of the analytes without any pretreatment of the sample, providing a versatile approach for fast and in-situ detection of water pollutants. The obtained results allowed us to reveal these analytes at low concentrations, close to or lower than their regulatory limits.

Allergic and non-allergic wheeze among farm women in the Agricultural Health Study (2005-2010)

BACKGROUND

Farms represent complex environments for respiratory exposures including hays, grains and pesticides. Little is known about the impact of these exposures on women's respiratory health. We evaluated the association of farm exposures with allergic and non-allergic wheeze among women in the Agricultural Health Study, a study of farmers and their spouses based in Iowa and North Carolina.

METHODS

We used self-reported data (2005-2010) on current use (≤12 months) of 15 pesticides (selected based on frequency of use) and occupational farm activities from 20 164 women. We defined allergic wheeze as reporting wheeze and doctor-diagnosed hay fever (7%) and non-allergic wheeze as wheeze but not hay fever (8%) in the past 12 months. Using polytomous logistic regression, we evaluated associations of wheeze subtypes with pesticides and other farm exposures (eg, raising farm animals) using no wheeze/hay fever as the referent, adjusting for age, body mass index, state, current asthma, glyphosate use and smoking.

RESULTS

Current use of any pesticide, reported by 7% of women, was associated with both allergic (OR: 1.36, 95% CI: 1.10 to 1.67) and non-allergic (OR: 1.25, 95% CI: 1.04 to 1.51) wheeze. Four pesticides were associated with at least one wheeze subtype: glyphosate, with both wheeze subtypes; diazinon and fly spray with only allergic wheeze; carbaryl with only non-allergic wheeze. Working weekly with mouldy hay was associated with allergic (OR: 1.88, 95% CI: 1.26 to 2.80) and non-allergic wheeze (OR: 1.69, 95% CI: 1.18 to 2.42).

CONCLUSION

Use of specific pesticides and certain farm activities may contribute to wheeze among farm women.

The Distribution Characteristics of Aerosol Bacteria in Different Types of Pig Houses

Simple Summary

Microbial aerosols from pig houses can be released into the environment, posing a serious threat to biosafety and public health. At present, there are few studies on the structural characteristics of aerosol bacteria in piggeries at different growth stages. It is important to understand the characteristics of aerosol bacteria in pig houses to solve the problems of air pollution and disease control in pig houses at different growth stages. In this study, bacterial aerosol concentrations and bacterial communities were compared in pig houses at different growth stages in Hebei Province, China. It was found that bacterial concentrations, community richness, and diversity in the air increased with the age of pigs. There are many pathogenic bacteria in the microbial aerosols of piggery. Our study highlights the importance of more comprehensive research and analysis of microbial aerosols in pig houses. Precautions for air pollution should be instituted in pig houses, including wearing masks, rigorous disinfection, and hygiene procedures.

Abstract

With the development of modern pig raising technology, the increasing density of animals in pig houses leads to the accumulation of microbial aerosols in pig houses. It is an important prerequisite to grasp the characteristics of bacteria in aerosols in different pig houses to solve the problems of air pollution and disease prevention and control in different pig houses. This work investigated the effects of growth stages on bacterial aerosol concentrations and bacterial communities in pig houses. Three traditional types of closed pig houses were studied: farrowing (FAR) houses, weaning (WEA) houses, and fattening (FAT) houses. The Andersen six-stage sampler and high-volume air sampler were used to assess the concentrations and size distribution of airborne bacteria, and 16S rRNA gene sequencing was used to identify the bacterial communities. We found that the airborne bacterial concentration, community richness, and diversity index increased with pig age. We found that Acinetobacter, Erysipelothrix, Streptococcus, Moraxella, and Aerococcus in the microbial aerosols of pig houses have the potential risk of causing disease. These differences lead us to believe that disinfection strategies for pig houses should involve a situational focus on environmental aerosol composition on a case-by-case basis.

A Review of Current Bacterial Resistance to Antibiotics in Food Animals

The overuse of antibiotics in food animals has led to the development of bacterial resistance and the widespread of resistant bacteria in the world. Antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) in food animals are currently considered emerging contaminants, which are a serious threat to public health globally. The current situation of ARB and ARGs from food animal farms, manure, and the wastewater was firstly covered in this review. Potential risks to public health were also highlighted, as well as strategies (including novel technologies, alternatives, and administration) to fight against bacterial resistance. This review can provide an avenue for further research, development, and application of novel antibacterial agents to reduce the adverse effects of antibiotic resistance in food animal farms.

Sex-Specific Differences in Resolution of Airway Inflammation in Fat-1 Transgenic Mice Following Repetitive Agricultural Dust Exposure

In agriculture industries, workers are at increased risk for developing pulmonary diseases due to inhalation of agricultural dusts, particularly when working in enclosed confinement facilities. Agricultural dusts inhalation leads to unresolved airway inflammation that precedes the development and progression of lung disease. We have previously shown beneficial effects of the omega-3 polyunsaturated fatty acid (ω-3 PUFA) DHA in protecting against the negative inflammatory effects of repetitive dust exposure in the lung. Dietary manipulation of pulmonary disease risk is an attractive and timely approach given the contribution of an increased ω-6 to ω-3 PUFA ratio to low grade inflammation and chronic disease in the Western diet. To prevent any confounding factors that comes with dietary supplementation of ω-3 PUFA (different sources, purity, dose, and duration), we employed a Fat-1 transgenic mouse model that convert ω-6 PUFA to ω-3 PUFA, leading to a tissue ω-6 to ω-3 PUFA ratio of approximately 1:1. Building on our initial findings, we hypothesized that attaining elevated tissue levels of ω-3 PUFA would attenuate agricultural dust-induced lung inflammation and its resolution. To test this hypothesis, we compared wild-type (WT) and Fat-1 transgenic mice in their response to aqueous extracts of agricultural dust (DE). We also used a soluble epoxide hydrolase inhibitor (sEH) to potentiate the effects of ω-3 PUFA, since sEH inhibitors have been shown to stabilize the anti-inflammatory P450 metabolites derived from both ω-3 and ω-6 PUFA and promote generation of specialized pro-resolving lipid mediators from ω-3 PUFA. Over a three-week period, mice were exposed to a total of 15 intranasal instillations of DE obtained from swine confinement buildings in the Midwest. We observed genotype and sex-specific differences between the WT vs. Fat-1 transgenic mice in response to repetitive dust exposure, where three-way ANOVA revealed significant main effects of treatment, genotype, and sex. Also, Fat-1 transgenic mice displayed reduced lymphoid aggregates in the lung following DE exposure as compared to WT animals exposed to DE, suggesting improved resilience to the DE-induced inflammatory effects. Overall, our data implicate a protective role of ω-3 FA in the lung following repetitive dust exposure.

Prevalence and Risk Factors for Pulmonary Conditions among Farmers and Ranchers in the Central United States

This study was conducted to evaluate the prevalence and risk factors for work-related respiratory conditions (asthma, farmer's lung, sinusitis, rhinitis, and environmental allergies, diagnosed by a physician) among farm and ranch operators in the central US. A survey was conducted by the Central States Center for Agricultural Safety and Health (CS-CASH) in 2018, focusing on work-related injuries, illnesses, exposures, and preventive measures in a seven-state region (Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, and South Dakota). Farms and ranches (n = 16,818) with an email address and annual sales exceeding $5,000 were randomly selected for the survey. Agricultural production and weather data were merged with survey responses. The relationship between exposures and respiratory conditions was analyzed using generalized estimating equations. We received responses from 3,268 agricultural operations (19% response rate) containing information on 4,064 individual operators. The life-time prevalence of (any) respiratory conditions among farm/ranch operators was 18%. Risk factors for respiratory conditions included exposures to grain/hay/feed dust (OR 2.41), animal confinement dust (OR 1.57), field/road dust (OR 2.11), manure/silage gasses (OR 1.66), anhydrous ammonia (OR 1.51), fuels/solvents/paints (OR 1.92), older age group >70 vs. <43 (OR 1.40), female gender (OR 1.82), and being primary vs. third operator (OR 1.61). Farmers and ranchers have a high prevalence of respiratory conditions associated with dust and gas exposures at work. More effective protective measures are needed using the hierarchy of controls, including improved use of respiratory protection.

Increased susceptibility to organic dust exposure-induced inflammatory lung disease with enhanced rheumatoid arthritis-associated autoantigen expression in HLA-DR4 transgenic mice

Immunogenetic as well as environmental and occupational exposures have been linked to the development of rheumatoid arthritis (RA), RA-associated lung disease, and other primary lung disorders. Importantly, various inhalants can trigger post-translational protein modifications, resulting in lung autoantigen expression capable of stimulating pro-inflammatory and/or pro-fibrotic immune responses. To further elucidate gene-environment interactions contributing to pathologic lung inflammation, we exploited an established model of organic dust extract (ODE) exposure with and without collagen-induced arthritis (CIA) in C57BL/6 wild type (WT) versus HLA-DR4 transgenic mice. ODE-induced airway infiltration driven by neutrophils was significantly increased in DR4 versus WT mice, with corresponding increases in bronchoalveolar lavage fluid (BALF) levels of TNF-⍺, IL-6, and IL-33. Lung histopathology demonstrated increased number of ectopic lymphoid aggregates comprised of T and B cells following ODE exposure in DR4 mice. ODE also induced citrullination, malondialdehyde acetaldehyde (MAA) modification, and vimentin expression that co-localized with MAA and was enhanced in DR4 mice. Serum and BALF anti-MAA antibodies were strikingly increased in ODE-treated DR4 mice. Coupling ODE exposure with Type II collagen immunization (CIA) resulted in similarly augmented pro-inflammatory lung profiles in DR4 mice (relative to WT mice) that was accompanied by a profound increase in infiltrating lung CD4⁺ and CD8⁺ T cells as well as CD19⁺CD11b⁺ autoimmune B cells. Neither modeling strategy induced significant arthritis. These findings support a model in which environmental insults trigger enhanced post-translational protein modification and lung inflammation sharing immunopathological features with RA-associated lung disease in the selected immunogenetic background of HLA-DR4 mice.

CC16 polymorphisms in asthma, asthma subtypes, and asthma control in adults from the Agricultural Lung Health Study

BACKGROUND

The club cell secretory protein (CC16) has anti-inflammatory and antioxidant effects and is a potential early biomarker of lung damage. The CC16 single nucleotide polymorphism (SNP) rs3741240 risk allele (A) has been inconsistently linked to asthma; other tagging SNPs in the gene have not been explored. The aim was to determine whether CC16 tagging polymorphisms are associated with adult asthma, asthma subtypes or asthma control in the Agricultural Lung Health Study (ALHS).

METHODS

The ALHS is an asthma case-control study nested in the Agricultural Health Study cohort. Asthma cases were individuals with current doctor diagnosed asthma, likely undiagnosed asthma, or asthma-COPD overlap defined by questionnaire. We also examined asthma subtypes and asthma control. Five CC16 tagging SNPs were imputed to 1000 Genomes Integrated phase 1 reference panel. Logistic regression was used to estimate associations between CC16 SNPs and asthma outcomes adjusted for covariates.

RESULTS

The sample included 1120 asthma cases and 1926 controls of European ancestry, with a mean age of 63 years. The frequency of the risk genotype (AA) for rs3741240 was 12.5% (n = 382). CC16 rs3741240 was not associated with adult asthma outcomes. A tagging SNP in the CC16 gene, rs12270961 was associated with uncontrolled asthma (n = 208, OR_adj= 1.4, 95% CI 1.0, 1.9; p = 0.03).

CONCLUSION

This study, the largest study to investigate associations between CC16 tagging SNPs and asthma phenotypes in adults, did not confirm an association of rs3741240 with adult asthma. A tagging SNP in CC16 suggests a potential relationship with asthma control.

Distribution characteristics of bioaerosols inside pig houses and the respiratory tract of pigs

Particulate matter (PM) is a carrier of many substances. Microorganisms are vital constituents contained in PM, and their varieties and concentrations are closely connected to human health and animal production. This study aimed to investigate the distribution characteristics of bioaerosols inside a pig house and in the respiratory tract of pigs. Environmental indices inside a nursery pig house were monitored in winter, including temperature, relative humidity, total suspended particulate (TSP), PM₁₀, PM_2.5, NH₃, CO₂, CO and NO. The concentrations of airborne culturable bacteria, fungi and Escherichia coli were detected. Then, 16S rRNA sequencing technology was applied to identify different-sized bioaerosols and bacteria in the respiratory tract of piglets. The results showed that the concentration of airborne culturable bacteria inside the pig house was significantly higher than that outside, and no significant difference was found among culturable fungi and Escherichia coli. The 16S rRNA results showed that the bacterial aerosols presented high similarity to the bacteria in the respiratory tract of piglets. The airborne bacterial aerosols within the size range of 1.1-3.3 µm showed high similarity to the bacteria in the lower respiratory tract (bronchus and lung) of piglets. In addition, four potential pathogenic bacterial genera (Escherichia-Shigella, Streptococcus, Acinetobacter, Pseudomonas) were identified both in the bacterial aerosols and the respiratory tract of piglets. These results will provide a significant scientific basis for exploring the potential risk of aerosols from animal houses to human and animal health.

Indoor Airborne Microbial Concentration and Dry Eye

PURPOSE

To examine associations between indoor airborne microbial concentration and dry eye (DE) measures.

DESIGN

Prospective, observational, cross-sectional study.

METHODS

A total of 157 individuals with normal external ocular anatomy were recruited from the Miami Veterans Affairs eye clinic. Subjects underwent a clinical evaluation that included assessment of DE symptoms and signs. Indoor air was sampled using bioaerosol impactors with nutrient and soy media, and samples were incubated for 48 hours at 37 C with 5% CO₂. Number of microbial colonies (CFU) was recorded. Outcome measures were DE symptoms and signs.

RESULTS

A total of 157 unique subjects participated in home and clinical visits and of these, 93 completed a 6-month follow-up of home and clinical visits. Older homes were found to have higher CFU compared to newer homes. A 1% increase in humidity was associated with a 3% increase in nutrient CFU (95% confidence interval [CI] = 0.01 to 0.04; P < .001). Instrumented CFU significantly associated with 2 DE measures: corneal epithelial disruption and lower eyelid meibomian gland (MG) dropout, adjusted for age and sex (odds ratio [OR] = 28.07, 95% CI =1.8, 443.8, P < .05; OR = 39.6, CI = 1.8, 875.2, P < .05 for soy, respectively). After adjusting for other confounders, CFU and age remained significantly associated with MG dropout. Other DE measures did not significantly associate with CFU.

CONCLUSIONS

Individuals with higher CFU counts in the home had more severe MG dropout, after adjusting for age and other confounders. This finding suggests that home CFU exposure may impact MG dropout, one of the DE measures, and may be a target for intervention.

Contribution of Primary Biological Aerosol Particles to airborne particulate matter in indoor and outdoor environments

The atmospheric concentration of bioparticles was determined in some outdoor and indoor sites by using a commercial low-volume sampler and a detection method based on particle collection on polycarbonate filters, propidium iodide staining, observation by fluorescence microscopy and image analysis. Outdoor sampling was continuously carried out from May 2015 to October 2016 by cumulating monthly samples over individual filters. PBAPs contribution to PM₁₀ concentration was in the range 0.7-13%. Seasonal differences were found in PBAPs concentration, shape and mass distribution. Higher concentrations were recorded during the warm period, when the bioparticles were more numerous, larger and more elongated. Simultaneous indoor and outdoor daily samples were collected during the spring of 2014 and 2017 in domestic environments. In indoor sites PBAPs were much higher in concentration than outdoors and showed a different visual appearance, with very wide polyhedral-shaped particles identifiable as skin flakes. Indoor/outdoor ratio (I/O) of PBAPs was in the range 6-16. Indoors, PBAPs contributed 21-77% to organic matter and 16-68% to PM₁₀. When sampling into a sealed room, I/O was only 0.01 for individual bioparticles heavier than100 ng, while it was in the range 0.24-0.43 for PBAPs below 20 ng. This suggests that the infiltration factor of wide bioparticles was very low and that their concentration increase in indoor environments was due to indoor sources, namely the presence of human beings. Samplings carried out in different rooms of an apartment showed that most of the PBAPs mass was due to particles heavier than 100 ng, particularly in the bedroom.

Methacholine induced airway contraction in porcine precision cut lung slices from indoor and outdoor reared pigs

Repetitive exposure to bioaerosols in swine production facilities (SPF) promotes respiratory dysfunction in workers and animals. An adequate understanding of the impact of the SPF environment on pulmonary physiology is needed. However, there is currently no sufficient ex vivo model to investigate the cause for agriculture-related lung disease. The precision cut lung slices (PCLS) technique represents a practical and useful procedure for ex vivo studies. Our goal was to use the PCLS technique to develop a model of agriculture-related lung diseases using a physiologically relevant animal model, the domesticated pig. Freshly prepared pig lung tissue cores were sectioned into 300 µm slices and viability was measured by lactate dehydrogenase activity and live/dead staining. Airway contractility in response to a methacholine (MCh) dose gradient (10^-7-10^-4 M) was measured. After the last MCh dose, PCLS were incubated with 1 mM chloroquine to allow airways to relax. Time-lapse images were taken every minute for 35 minutes and used to determine airway lumen area changes. Porcine PCLS remained viable and demonstrated metabolic activity for three days. PCLS from indoor and outdoor pigs contracted in response to MCh exposure and relaxed when incubated with chloroquine. Notably, PCLS of indoor pigs showed greater airway constriction in response to 10^-5 M MCh exposure compared to outdoor pig PCLS (P<0.05). These data suggest that exposure to the indoor pig production environment may be associated with hyperresponsiveness in swine airways, and support future studies to investigate lung response to inflammatory substances using the porcine PCLS model.

Gender differences in respiratory health outcomes among farming cohorts around the globe: findings from the AGRICOH consortium

Purpose: Respiratory hazards of farming have been identified for centuries, with little focus on gender differences. We used data from the AGRICOH consortium, a collective of prospective cohorts of agricultural workers, to assess respiratory disease prevalence among adults in 18 cohorts representing over 200,000 farmers, farm workers, and their spouses from six continents.Methods: Cohorts collected data between 1992 and 2016 and ranged in size from 200 to >128,000 individuals; 44% of participants were female. Farming practices varied from subsistence farming to large-scale industrial agriculture. All cohorts provided respiratory outcome information for their cohort based on their study definitions. The majority of outcomes were based on self-report using standard respiratory questionnaires; the greatest variability in assessment methods was associated with chronic obstructive pulmonary disease (COPD).Results: For all three respiratory symptoms (cough, phlegm, and wheeze), the median prevalence in men was higher than in women, with the greatest difference for phlegm (17% vs. 10%). For asthma, women had a higher prevalence (7.8% vs 6.5%), with the difference associated with allergic asthma. The relative proportion of allergic asthma varied among cohorts. In two of eight cohorts for women and two of seven cohorts for men, allergic asthma was more common than non-allergic asthma.Conclusions: These findings indicate that respiratory outcomes are common among farmers around the world despite differences in agricultural production. As women in the general population are at higher risk of asthma, exploring gender differences in occupational studies is critical for a deeper understanding of respiratory disease among agricultural workers.

Seasonal variations of microbial assemblage in fine particulate matter from a nursery pig house

The microorganisms contained in PM_2.5 from livestock houses can spread over long distances through airborne transmission. As such, the potential bacterial pathogens and fungal allergens within can pose a formidable threat to nearby residents' health and the overall environment. However, little is known about the microbial assemblage contained in PM_2.5 from pig houses. In this study, 16S and 18S rRNA gene sequencing was employed to analyze the bacterial and fungal assemblage contained in PM_2.5 from a nursery pig house across four seasons, respectively. The results showed that alpha diversity was higher in summer and autumn compared to the spring and winter. The bacterial and fungal assemblage varied according to season. At the phylum level, the dominant bacteria and fungi were Firmicutes and Basidiomycota, respectively, across the four seasons. At the genus level, a total of five potential bacterial pathogen and 20 potential fungal allergen genera were identified across the samples. The most abundant bacterial pathogen and fungal allergen genera were observed in summer and autumn, respectively, but neither had a significant correlation with PM_2.5 concentration. Moreover, microbial diversity and the relative abundance of fungal allergen genera were positively correlated with temperature and relative humidity. It can be concluded that microbial diversity and assemblage varied significantly among the seasons in a nursery pig house, and this can be useful in exploring the potential risks of PM_2.5 from pig houses across all four seasons.

Assessing Health and Safety Concerns and Psychological Stressors among Agricultural Workers in the U.S. Midwest

There is limited research exploring agricultural workers' own perspectives on the relative importance of the hazards and stressors they experience. There is also a lack of evidence on whether this reporting differs by method of elicitation. Finally, very little research exists on how to improve mail survey response rates among agricultural workers. We examined health and safety concerns and psychological stressors among Midwestern farmers. We assessed whether these reports varied by survey mode (mail survey versus in-person survey). The efficacy of two different types of incentives to enhance mail survey response rates among agricultural workers was also investigated. In 2018, a needs assessment survey was developed and mailed to a random sample of farm owner-operators in Iowa, Ohio, and Missouri, with randomly assigned prepaid or promised monetary incentives. In-person surveys were conducted among farm owner-operators and hired workers at three regional farm shows in Iowa, Minnesota, and Nebraska. The mail survey response rates were compared by incentive type. Content analysis was used to generate themes associated with health and safety concerns and psychological stressors, which were then ranked by frequency counts. Chi-square tests were used to analyze variation in the distribution of these themes by survey mode. The response rate for the $1 prepaid incentive was double that of the $10 promised incentive. Content analysis identified 13 health and safety concerns and eight psychological stressors. Chemicals, equipment/tools, and health outcomes were the most frequently noted health and safety concerns. Finances, climate/weather, and farm workload and management were the most frequently noted psychological stressors. Although there was considerable overlap in survey responses across mail and in-person respondents, important differences by sample and survey mode characteristics were observed. The results can support a variety of stakeholders in prioritizing and developing interventions and educational resources to address health and safety concerns and psychological stressors among Midwestern farmers. Our findings also contribute to the evidence base on primary data collection methods for agricultural workers.

Profiling of cell stress proteins reveals decreased expression of enzymatic antioxidants in tracheal epithelial tissue of pigs raised indoors

Exposure to indoor swine production facilities (SPF) environments causes airway inflammation and diseases including asthma, chronic bronchitis and chronic obstructive pulmonary disease (COPD) in facility workers. However, less is known about the impact of SPF exposures on the respiratory health of pigs. Respiratory symptoms are associated with repeat exposure to SPF, specifically inhalation of organic dust and other air pollutants therein. A thorough understanding of the molecular pathways regulated by SPF exposure is needed to understand airway inflammation and chronic inflammatory lung disease. The present study measured the expression of proteins associated with oxidative stress and antioxidant defenses in the tracheal epithelial tissues of pigs reared in SPF or on pasture. Proteome profiler cell stress arrays, western blotting and enzyme activity assays were utilized to measure protein expression and activity levels in tracheal epithelial tissue extracts of pigs. It was determined that pigs raised in SPF express significantly less enzymatic antioxidants, including superoxide dismutase (SOD), within their tracheal epithelial tissues compared to pasture raised pigs. Concomitantly, tracheal epithelial tissues of SPF raised pigs had lower SOD and catalase antioxidant activity levels compared to pasture raised pigs. The observations summarized herein provide evidence that exposure to swine production environments influence endogenous enzymatic antioxidant defenses within the tracheal epithelial tissues of pigs. This study offers insight for understanding the effect of continuous exposure to SPF pollutants on endogenous antioxidant defenses in the airway epithelial and may be helpful in understanding human airway responses to swine barn exposures.

Sorrel Extract Reduces Oxidant Production in Airway Epithelial Cells Exposed to Swine Barn Dust Extract In Vitro

Exposure to hog barn organic dust contributes to occupational lung diseases, which are mediated by inflammatory and oxidative stress pathways. Isoprostanes-a family of eicosanoids produced by oxidation of phospholipids by oxygen radicals-are biomarkers of pulmonary oxidative stress. Importantly, 8-isoprostane has been implicated as a key biomarker and mediator of oxidative stress because it is a potent pulmonary vasoconstrictor. Antioxidants found in fruits and vegetables hold promise for preventing or reducing effects of oxidative stress-related diseases including chronic bronchitis and chronic obstructive pulmonary disease (COPD). Here, we investigated 8-isoP and oxidant production by organic dust-exposed airway epithelial cells and the inhibitory effects of an extract from calyces of the sorrel plant, Hibiscus sabdariffa, on oxidant-producing pathways. Confluent cultures of normal human tracheobronchial epithelial cells were pretreated or not with 1% sorrel extract prior to 5% dust extract (DE) exposure. Following DE treatments, live cells, cell-free supernatants, or cell extracts were evaluated for the presence of 8-isoprostane, superoxide, hydrogen peroxide, nitric oxide, hydroxyl radical, peroxynitrite, and catalase activity to evaluate sorrel's inhibitory effect on oxidative stress. The well-known radical scavenging antioxidant, N-acetyl cysteine (NAC), was used for comparisons with sorrel. DE exposure augmented the production of all radicals measured including 8-isoprostane (p value < 0.001), which could be inhibited by NAC or sorrel. Among reactive oxygen and nitrogen species generated in response to DE exposure, sorrel had no effect on H2O2 production and NAC had no significant effect on NO· production. The observations reported here suggest a possible role for sorrel in preventing 8-isoprostane and oxidant-mediated stress responses in bronchial epithelial cells exposed to hog barn dust. These findings suggest a potential role for oxidative stress pathways in mediating occupational lung diseases and antioxidants within sorrel and NAC in reducing dust-mediated oxidative stress within the airways of exposed workers.

Differences among Thai Agricultural Workers' Health, Working Conditions, and Pesticide Use by Farm Type

More than 11 million Thai people (38%) work in agriculture, but since most are in the informal sector, government enforcement and support are very limited. As a result, working conditions on Thai farms vary greatly, putting the health of many agricultural workers at risk. A cross-sectional study in three Thai provinces collected information on the work activities and conditions of 424 farmers representing five farm types: rice, vegetable, flower, rice/vegetable, and flower/vegetable. The agricultural workers were mainly women (60%); their average age was 53 but ranged from 18 to 87 years. More than 64% worked more than 5 days/week. Seventy-four percent of them had only primary school education. A number of the health and hazardous working conditions surveyed were significantly different by farm type. Rice farmers were found to have the highest prevalence of allergies, nasal congestion, wheezing, and acute symptoms after pesticide use, while flower farmers had the lowest prevalence of these health outcomes. Rice farmers reported the highest prevalence of hazardous working conditions including high noise levels, working on slippery surfaces, sitting or standing on a vibrating machine, spills of chemicals/pesticides, and sharp injuries. The lowest prevalence of these working conditions (except noise) was reported by flower farmers. Vegetable farmers reported the highest prevalence knee problems, while rice farmers had the lowest prevalence. Among these farmers, more than 27 different types of pesticides were reported in use during the past year, with the majority reporting use once a month. The flower/vegetable farming group reported the highest frequency of good exposure prevention practices during pesticide use. They were the most likely to report using cotton or rubber gloves or a disposable paper masks during insecticide spraying. Those farmers who only grew vegetables had the lowest frequency of good exposure prevention practices, including use of personal protective equipment. The economic cost of work-related injuries and illnesses among informal sector agricultural workers in Thailand is unknown and in need of study. Gaps in the regulations covering pesticide sales allow farmers to purchase pesticides without adequate training in their safe use. Training targeted to farm type regarding safe pesticide use and the prevention of accidents and musculoskeletal disorders is needed. Studies of chronic health effects among Thai farmers are needed, with special emphasis on respiratory, metabolic disease and cancer.

Difference in Accidents, Health Symptoms, and Ergonomic Problems between Conventional Farmers Using Pesticides and Organic Farmers

Organic farming has been promoted in Thailand by King Rama the ninth. In addition to being healthier for consumers, organic farming is healthier for agricultural workers. The cross-sectional study was conducted to investigate the frequency of chronic disease conditions, accidents, health symptoms, and ergonomic problems among 243 conventional (pesticide using) farmers and 235 organic farmers. Data were collected using questionnaires in face-to-face interviews. The results indicated symptoms that could be related to pesticide exposure (skin rashes, water blisters, headache, dizziness, and loss of appetite) were significantly higher among conventional farmers than organic farmers. The organic farmers reported significantly more health symptoms such as hives, chest pain, mild fever, flatulence, and frequent urination than the conventional farmers. The organic farmers reported significantly more pain, numbness, or weakness in the wrists/hands, fingers, upper back, hips, and ankles/feet than conventional farmers.

MyD88 controls airway epithelial Muc5ac expression during TLR activation conditions from agricultural organic dust exposure

Inflammation from airborne microbes can overwhelm compensatory mucociliary clearance mechanisms, leading to mucous cell metaplasia. Toll-like receptor (TLR) activation via myeloid differentiation factor 88 (MyD88) signaling is central to pathogen responses. We have previously shown that agricultural organic dust extract (ODE), with abundant microbial component diversity, activates TLR-induced airway inflammation. With the use of an established model, C57BL/6J wild-type (WT) and global MyD88 knockout (KO) mice were treated with intranasal inhalation of ODE or saline, daily for 1 wk. ODE primarily increased mucin (Muc)5ac levels relative to Muc5b. Compared with ODE-challenged WT mice, ODE-challenged, MyD88-deficient mice demonstrated significantly increased Muc5ac immunostaining, protein levels by immunoblot, and expression by quantitative PCR. The enhanced Muc5ac levels in MyD88-deficient mice were not explained by differences in the differentiation program of airway secretory cells in naïve mice. Increased Muc5ac levels in MyD88-deficient mice were also not explained by augmented inflammation, IL-17A, or neutrophil elastase levels. Furthermore, the enhanced airway mucins in the MyD88-deficient mice were not due to defective secretion, as the mucin secretory capacity of MyD88-KO mice remained intact. Finally, ODE-induced Muc5ac levels were enhanced in MyD88-deficient airway epithelial cells in vitro. In conclusion, MyD88 deficiency enhances airway mucous cell metaplasia under environments with high TLR activation.

Mechanisms of organophosphorus pesticide toxicity in the context of airway hyperreactivity and asthma

Numerous epidemiologic studies have identified an association between occupational exposures to organophosphorus pesticides (OPs) and asthma or asthmatic symptoms in adults. Emerging epidemiologic data suggest that environmentally relevant levels of OPs may also be linked to respiratory dysfunction in the general population and that in utero and/or early life exposures to environmental OPs may increase risk for childhood asthma. In support of a causal link between OPs and asthma, experimental evidence demonstrates that occupationally and environmentally relevant OP exposures induce bronchospasm and airway hyperreactivity in preclinical models. Mechanistic studies have identified blockade of autoinhibitory M2 muscarinic receptors on parasympathetic nerves that innervate airway smooth muscle as one mechanism by which OPs induce airway hyperreactivity, but significant questions remain regarding the mechanism(s) by which OPs cause neuronal M2 receptor dysfunction and, more generally, how OPs cause persistent asthma, especially after developmental exposures. The goals of this review are to 1) summarize current understanding of OPs in asthma; 2) discuss mechanisms of OP neurotoxicity and immunotoxicity that warrant consideration in the context of OP-induced airway hyperreactivity and asthma, specifically, inflammatory responses, oxidative stress, neural plasticity, and neurogenic inflammation; and 3) identify critical data gaps that need to be addressed in order to better protect adults and children against the harmful respiratory effects of low-level OP exposures.

A review on recent progress in observations, and health effects of bioaerosols

Bioaerosol is a particulate mixture of solid and semi-solid matter combined with biotic matter like pollens, microbes and their fragments. The present review stresses on a cumulative understanding of sources, components, quantification and distribution of bioaerosols with respect to size, and its significant impacts on human health. The present review will be instrumental in devising strategies to understand and manage bioaerosols and reducing their human exposure and associated health hazards. The present review aims explore the relationship between particle and associated biological agents responsible for behaviours like dispersal, total potential health hazards and toxicology level during exposure to bioaerosol.

Rural Residence and Chronic Obstructive Pulmonary Disease Exacerbations. Analysis of the SPIROMICS Cohort

Rationale: Rural residence is associated with poor outcomes in several chronic diseases. The association between rural residence and chronic obstructive pulmonary disease (COPD) exacerbations remains unclear.Objectives: In this work, we sought to determine the independent association between rural residence and COPD-related outcomes, including COPD exacerbations, airflow obstruction, and symptom burden.Methods: A total of 1,684 SPIROMICS (Subpopulations and Intermediate Outcome Measures in COPD Study) participants with forced expiratory volume in 1 second/forced vital capacity < 0.70 had geocoding-defined rural-urban residence status determined (N = 204 rural and N = 1,480 urban). Univariate and multivariate logistic and negative binomial regressions were performed to assess the independent association between rurality and COPD outcomes, including exacerbations, lung function, and symptom burden. The primary exposure of interest was rural residence, determined by geocoding of the home address to the block level at the time of study enrollment. Additional covariates of interest included demographic and clinical characteristics, occupation, and occupational exposures. The primary outcome measures were exacerbations determined over a 1-year course after enrollment by quarterly telephone calls and at an annual research clinic visit. The odds ratio (OR) and incidence rate ratio (IRR) of exacerbations that required treatment with medications, including steroids or antibiotics (total exacerbations), and exacerbations leading to hospitalization (severe exacerbations) were determined after adjusting for relevant covariates.Results: Rural residence was independently associated with a 70% increase in the odds of total exacerbations (OR, 1.70 [95% confidence interval (CI), 1.13-2.56]; P = 0.012) and a 46% higher incidence rate of total exacerbations (IRR 1.46 [95% CI, 1.02-2.10]; P = 0.039). There was no association between rural residence and severe exacerbations. Agricultural occupation was independently associated with increased odds and incidence of total and severe exacerbations. Inclusion of agricultural occupation in the analysis attenuated the association between rural residence and the odds and incidence rate of total exacerbations (OR, 1.52 [95% CI, 1.00-2.32]; P = 0.05 and IRR 1.39 [95% CI, 0.97-1.99]; P = 0.07). There was no difference in symptoms or airflow obstruction between rural and urban participants.Conclusions: Rural residence is independently associated with increased odds and incidence of total, but not severe, COPD exacerbations. These associations are not fully explained by agriculture-related exposures, highlighting the need for future research into potential mechanisms of the increased risk of COPD exacerbations in the rural population.

Airborne bioaerosols and their impact on human health

Bioaerosols consist of aerosols originated biologically such as metabolites, toxins, or fragments of microorganisms that are present ubiquitously in the environment. International interests in bioaerosols have increased rapidly to broaden the pool of knowledge on their identification, quantification, distribution, and health impacts (e.g., infectious and respiratory diseases, allergies, and cancer). However, risk assessment of bioaerosols based on conventional culture methods has been hampered further by several factors such as: (1) the complexity of microorganisms or derivatives to be investigated; (2) the purpose, techniques, and locations of sampling; and (3) the lack of valid quantitative criteria (e.g., exposure standards and dose/effect relationships). Although exposure to some microbes is considered to be beneficial for health, more research is needed to properly assess their potential health hazards including inter-individual susceptibility, interactions with non-biological agents, and many proven/unproven health effects (e.g., atopy and atopic diseases).

Assessing the Potential for Bias From Nonresponse to a Study Follow-up Interview: An Example From the Agricultural Health Study

Prospective cohort studies are important tools for identifying causes of disease. However, these studies are susceptible to attrition. When information collected after enrollment is through interview or exam, attrition leads to missing information for nonrespondents. The Agricultural Health Study enrolled 52,394 farmers in 1993-1997 and collected additional information during subsequent interviews. Forty-six percent of enrolled farmers responded to the 2005-2010 interview; 7% of farmers died prior to the interview. We examined whether response was related to attributes measured at enrollment. To characterize potential bias from attrition, we evaluated differences in associations between smoking and incidence of 3 cancer types between the enrolled cohort and the subcohort of 2005-2010 respondents, using cancer registry information. In the subcohort we evaluated the ability of inverse probability weighting (IPW) to reduce bias. Response was related to age, state, race/ethnicity, education, marital status, smoking, and alcohol consumption. When exposure and outcome were associated and case response was differential by exposure, some bias was observed; IPW conditional on exposure and covariates failed to correct estimates. When response was nondifferential, subcohort and full-cohort estimates were similar, making IPW unnecessary. This example provides a demonstration of investigating the influence of attrition in cohort studies using information that has been self-reported after enrollment.

Early-life farm exposures and adult asthma and atopy in the Agricultural Lung Health Study

BACKGROUND

Previous studies, mostly from Europe, suggest that early-life farming exposures protect against childhood asthma and allergy; few data exist on asthma and allergy in adults.

OBJECTIVE

We sought to examine associations between early-life farming exposures and current asthma and atopy in an older adult US farming population.

METHODS

We analyzed data from 1746 farmers and 1555 spouses (mean age, 63) from a case-control study nested within the Agricultural Health Study. Current asthma and early-life farming exposures were assessed via questionnaires. We defined atopy based on specific IgE > 0.70 IU/mL to at least 1 of 10 allergens measured in blood. We used logistic regression, adjusted for age, sex, race, state (Iowa or North Carolina), and smoking (pack years), to estimate associations between early-life exposures and asthma (1198 cases and 2031 noncases) or atopy (578 cases and 2526 noncases).

RESULTS

Exposure to the farming environment in utero and in early childhood had little or no association with asthma but was associated with reduced odds of atopy. The strongest association was seen for having a mother who performed farm activities while pregnant (odds ratio, 0.60; 95% CI, 0.48-0.74) and remained significant in models with correlated early-life exposures including early childhood farm animal contact and raw milk consumption.

CONCLUSIONS

In a large US farming population, early-life farm exposures, particularly maternal farming activities while pregnant, were strongly associated with reduced risk of atopy in adults. These results extend previous work done primarily on childhood outcomes and suggest that protective associations of early-life farming exposures on atopy endure across the life course.

Emphysema in active farmer's lung disease

BACKGROUND

Farmer's lung (FL) is a common type of hypersensitivity pneumonitis. It is often considered that fibrosis is the most frequent finding in chronic FL. Nevertheless, three cohort studies have suggested that some patients with chronic FL may develop emphysema. We aimed to evaluate the current prevalence of emphysema in active FL, to describe the radiological and functional features of emphysema in active FL, and to identify risk factors associated with emphysema in this population.

METHODS

Patients aged over 18 years with active FL were prospectively recruited through the SOPHIA study (CPP Est; P-2009-521), between 2007 and 2015. Each patient had complete medical history screening, clinical examination, high resolution computed tomodensitometry, bronchoalveolar lavage, pulmonary function tests and serum precipitins.

RESULTS

Among 33 patients with active FL, the prevalence of emphysema in this series of incident active FL cases was higher (48.5%) than that of fibrosis (12%) and was not dependent on smoking habits. Most patients with emphysema did not have lung hyperinflation. The possible risk factors for emphysema in active FL were a longer duration of exposure to organic dusts, and at a higher level.

CONCLUSION

Emphysema is found in half of patients with active FL and may be influenced by exposure patterns.

Serum cytokine levels related to exposure to volatile organic compounds and PM2.5 in dwellings and workplaces in French farmers - a mechanism to explain nonsmoking COPD

Although French farmers smoke less on average than individuals from the general population, they suffer more from COPD. Exposure to biological and chemical air pollutants in the farm may be the cause of these higher COPD rates. This study investigates the role of bio-contaminants, including the relationship of exposure to volatile organic compounds (VOCs) and fine particulate matter (of diameter of 2.5 µm [PM_2.5]) objectively measured in the farm settings (dwellings and workplaces) to serum cytokines involved in COPD, in a sample of 72 farmers from 50 farms in the Auvergne region, France. Mean concentrations of VOCs were highest inside the home, while levels of PM_2.5 were highest in workplaces (stables and granaries). After adjusting for confounders, high exposure to PM_2.5 was significantly associated with a decreased level of serum cytokines (among others, IL13: β: −0.94, CI: −1.5 to −0.2, P-value =0.004; IL8: β: −0.82, CI: −1.4 to −0.2, P-value =0.005) and high exposure to VOCs according to a VOC global score with a decreased IL13 level (β: −0.5, CI: −0.9 to −0.1, P-value =0.01). Moreover, respiratory symptoms and diseases, including COPD, were associated with a decreased level of serum cytokines significantly in the case of IL5. An alteration of immune response balance in terms of cytokine levels in relation to indoor chemical air pollution exposure may contribute to respiratory health impairment in farmers.

United Airway Disease Among Crop Farmers

Although there are observed relationships between agriculture and respiratory health problems, little attention has been given to relationship between lower and upper airway problems among farmers in the United States. The objective was to investigate the possible relationship between occupational risk factors and "united airway disease" among farmers in eastern North Carolina. Farmers and farm workers were selected from eastern North Carolina by using a cluster sampling method. A total of 180 farmers and farm workers completed the questionnaire. Data analyses were conducted to test associations and correlations between working conditions and symptoms. Lower airway symptom prevalence was 35%, and 66% had upper airway symptoms. Only 1% of farmers had physician-diagnosed rhinitis. Self-reported rhinitis and asthma symptoms were significantly correlated (r = .228, P = .003) among farmer/farm workers. Upper airway diseases are prevalent yet overlooked among farmer/farm workers. Early management of upper airway symptoms may prevent severe lower airway diseases, which will lead to increased productivity in the agricultural workforce.

Pesticides are Associated with Allergic and Non-Allergic Wheeze among Male Farmers

BACKGROUND

Growing evidence suggests that pesticide use may contribute to respiratory symptoms.

OBJECTIVE

We evaluated the association of currently used pesticides with allergic and non-allergic wheeze among male farmers.

METHODS

Using the 2005-2010 interview data of the Agricultural Health Study, a prospective study of farmers in North Carolina and Iowa, we evaluated the association between allergic and non-allergic wheeze and self-reported use of 78 specific pesticides, reported by ≥ 1% of the 22,134 men interviewed. We used polytomous regression models adjusted for age, BMI, state, smoking, and current asthma, as well as for days applying pesticides and days driving diesel tractors. We defined allergic wheeze as reporting both wheeze and doctor-diagnosed hay fever (n = 1,310, 6%) and non-allergic wheeze as reporting wheeze but not hay fever (n = 3,939, 18%); men without wheeze were the referent.

RESULTS

In models evaluating current use of specific pesticides, 19 pesticides were significantly associated (p < 0.05) with allergic wheeze (18 positive, 1 negative) and 21 pesticides with non-allergic wheeze (19 positive, 2 negative); 11 pesticides were associated with both. Seven pesticides (herbicides: 2,4-D and simazine; insecticides: carbaryl, dimethoate, disulfoton, and zeta-cypermethrin; and fungicide pyraclostrobin) had significantly different associations for allergic and non-allergic wheeze. In exposure-response models with up to five exposure categories, we saw evidence of an exposure-response relationship for several pesticides including the commonly used herbicides 2,4-D and glyphosate, the insecticides permethrin and carbaryl, and the rodenticide warfarin.

CONCLUSIONS

These results for farmers implicate several pesticides that are commonly used in agricultural and residential settings with adverse respiratory effects.

Smoking habits in French farmers: a cross-sectional study

Background

Farmers are exposed to multiple air contaminants that may interact with tobacco smoking in the development of respiratory diseases. Farmers are currently considered to smoke less than non-farmers, but precise data in different categories of age and farming activities are lacking.

Methods

Smoking habits were studied in a cross-sectional study involving 4105 farmers and 996 non-farming controls aged 40–74 years in 9 French departments between October 2012 and May 2013. Three age groups were defined (40–54, 55–64 and 65-74years). Farmers were divided into four activity groups, namely cattle breeders, livestock farmers working in confined spaces, crop farmers and others. Smoking prevalence was compared between farmers and controls, and odds ratios (ORs) for smoking adjusted for age were calculated.

Results

The adjusted OR for ever-smoking was lower among farmers than among non-farmers in all age categories, but the ORs for current smoking were similar in farmers and controls. Smoking prevalence varied according to the type of farming activity, and was lower than in non-farming controls only among cattle breeders and confined livestock farmers. In farmers, the proportion of smokers was higher in the youngest age categories compared with the older age classes.

Conclusions

Our results confirm that the prevalence of ever-smokers is lower in farmers than in non-farmers. Nevertheless, our data show that active smoking prevalence is similar in farmers and in non-farmers. This suggests that farmers, just like non-farmers, should be targeted by primary prevention campaigns against smoking.

Assessment of occupational exposure to pesticides in a pooled analysis of agricultural cohorts within the AGRICOH consortium

BACKGROUND

This paper describes methods developed to assess occupational exposure to pesticide active ingredients and chemical groups, harmonised across cohort studies included in the first AGRICOH pooling project, focused on the risk of lymph-haematological malignancies.

METHODS

Three prospective agricultural cohort studies were included: US Agricultural Health Study (AHS), French Agriculture and Cancer Study (AGRICAN) and Cancer in the Norwegian Agricultural Population (CNAP). Self-reported pesticide use was collected in AHS. Crop-exposure matrices (CEMs) were developed for AGRICAN and CNAP. We explored the potential impact of these differences in exposure assessment by comparing a CEM approach estimating exposure in AHS with self-reported pesticide use.

RESULTS

In AHS, 99% of participants were considered exposed to pesticides, 68% in AGRICAN and 63% in CNAP. For all cohorts combined (n=316 270), prevalence of exposure ranged from 19% to 59% for 14 chemical groups examined, and from 13% to 46% for 33 active ingredients. Exposures were highly correlated within AGRICAN and CNAP where CEMs were applied; they were less correlated in AHS. Poor agreement was found between self-reported pesticide use and assigned exposure in AHS using a CEM approach resembling the assessment for AGRICAN (κ -0.00 to 0.33) and CNAP (κ -0.01 to 0.14).

CONCLUSIONS

We developed country-specific CEMs to assign occupational exposure to pesticides in cohorts lacking self-reported data on the use of specific pesticides. The different exposure assessment methods applied may overestimate or underestimate actual exposure prevalence, and additional work is needed to better estimate how far the exposure estimates deviate from reality.

High prevalence of obstructive lung disease in non-smoking farmers: The Irish farmers lung health study

BACKGROUND

Mortality rates within the Irish farming community are increasing, whilst that of the general population falls. The aim of this cross-sectional study was to determine the prevalence of respiratory disease amongst Irish farmers.

METHODS

All study participants were farming volunteers attending an agricultural exhibition. Data collected by questionnaire included baseline demographics, respiratory history, presence of respiratory symptoms and occupational exposures. Spirometry was performed on all participants.

RESULTS

Data from 372 farmers was analysed. The majority were male (76%) with median age of 55 years. 61% were never smokers. 13% were previously diagnosed with airway disease (Chronic Obstructive Pulmonary Disease(COPD)/Asthma/Inhaler use) with 14% reporting hayfever/allergies. Almost two-thirds reported one or more chronic respiratory symptom. Forty-four (12%) had obstructive spirometry using fixed FEV1/FVC < 0.70 criterion and 29 (7.8%) using FEV1/FVC < 5% lower limit of normal. The majority, two-thirds, were never smokers. Amongst never smokers with obstruction (13%), there was a significantly higher proportion with a prior diagnosis of airway disease and hayfever/allergies. There was no significant association between specific occupational exposures and obstruction.

CONCLUSION

The majority of Irish farmers are never smokers. They have a high prevalence of respiratory symptoms. 13% of never smokers have airflow obstruction (FEV1/FVC < 0.70). The presence of airflow obstruction is significantly associated with self-reported allergy history and prior airway disease. Further studies are needed to identify the workplace factors accounting for these findings.