Associations Between Bioaerosol Exposures and Lung Function Changes Among Dairy Workers in Colorado

Airborne particulate matter exposure in male sugarcane workers at risk for chronic kidney disease in Guatemala

BACKGROUND

There is an international epidemic of chronic kidney disease of unknown cause (CKDu) in agricultural working populations. Particulate air pollution is a likely contributing factor in populations at risk for CKDu, but there is little personal breathing zone data for these workers.

METHODS

We collected 1 to 3 personal breathing zone particulate matter <5 microns (PM5) gravimetric measurements in 143 male sugarcane harvesters over 2 seasons and concurrent ambient samples using personal sampling pumps and cyclone inlets as a sampling train. Due to very high concentrations observed during a pilot of these methods, personal breathing zone sampling duration was set to 4 h, beginning either at the start of a work shift (AM) or delayed for 4 h (PM). To obtain full-shift exposure concentrations we calculated 8-h time-weighted average (TWA, in µg/m3) estimates of each worker's full-shift personal breathing zone PM5 exposure concentration by averaging their individual monitored concentration with the median concentration of the unmonitored AM or PM segment from all workers that day to obtain an 8-h TWA.

RESULTS

Median full-shift personal TWA PM5 concentrations were 449 μg/m3 (range 20.5 to 1,930 μg/m3), which were much higher than ambient concentrations in these fields (median 136, range 22.5 to 2,360 μg/m3). These findings document very high personal breathing zone PM5 exposure in workers at risk for CKDu: median concentrations for all workers were 3.5 (range <1 to 33.6) times as high as concurrent ambient concentrations.

SIGNIFICANCE

These findings suggest that ambient measurements of particulate matter are insufficient to estimate personal exposure in this population and that personal breathing zone monitoring should be used to fully explore air pollution as a risk factor for CKDu. Given that particulate matter from this source likely has multiple hazardous constituents, future research should focus on characterizing all constituents and explore associations with biomarkers of kidney injury.

Hypertonic Saline Nasal Rinse Intervention: Immunomodulatory Effects in Dairy Workers

OBJECTIVE

Increased risk of occupational exposure to bioaerosols has long been recognized in livestock operations including dairy facilities. Spanning the inhalable fraction (0-100 μm), dairy bioaerosols comprise a wide variety of inflammatory components that deposit in the nasopharyngeal region. The resultant inflammatory response from bioaerosol exposure is likely driving the increased prevalence of respiratory disease observed in dairy workers. It is also thought the microbiome of the upper respiratory system may help mediate this inflammation. We investigated the viability of a low-cost hypertonic saline nasal rinse intervention in modulating inflammatory responses in bioaerosol exposed dairy workers and its impact on microbial diversity.

METHODS

Pre- and post-shift nasal rinses were administered and collected alongside full shift inhalable personal breathing zone (PBZ) samples for each participant for up to 5 consecutive days. Treatment group participants (n = 23) received hypertonic saline rinses while control group participants (n = 22) received normotonic saline rinses. Particulate matter (PM) and endotoxin concentrations were quantified from PBZ samples using gravimetric and enzymatic analytical methods, respectively. Pre- and post-shift rinses were analyzed for pro- and anti-inflammatory markers and microbial diversity using a multiplex assay and 16S rRNA sequencing, respectively.

RESULTS

PM and endotoxin concentrations were comparable between groups indicating similar exposures. Post-shift pro-inflammatory markers were significantly higher than pre-shift for IL-13 (p = .047), IL-1β (p < .001), IL-6 (p < .001), IL-8 (p < .001), and TNF-α (p = .024). There was no evidence of a difference in log concentrations between intervention group or day among any of the measured inflammatory markers. Anti-inflammatory IL-10 concentrations increased across the 5 sample days, independent of treatment group suggesting tonicity may not be driving the change. However, this result was not significant (p = .217). Nasal microbiome alpha (within sample) and beta (between sample) diversity metrics did not differ significantly between group or day demonstrating no adverse washout intervention effects.

CONCLUSION

This study provided encouraging results that warrant future research to further evaluate saline nasal rinses as a workplace intervention.

Assessment of ventilatory functions and associated inflammatory markers among workers in slaughterhouses

OBJECTIVE

Meat processing is among the most extensive industries globally. However, data on the effects of occupational exposure on the pulmonary health of slaughterhouse workers is limited. Ascertaining the impact of the slaughterhouse atmosphere on the breathing habits of laborers exposed to it and the inflammatory markers associated with it was the aim of the current investigation.

METHODS

A cross-sectional study was performed on 82 non-smoker subjects of 41 male workers working in one of the major slaughterhouses in Cairo, Egypt, matched to 41 controls of administrative personnel. An elaborate questionnaire encompassing medical and occupational history was administered to each participant in the research. General and local systemic examinations and ventilatory function tests were carried out, and serum levels of interleukin 6 (IL-6) and high-sensitivity C-reactive protein (hsCRP) were measured.

RESULTS

Respiratory symptoms were more prevalent with a statistically significant decline in ventilatory function parameters (FVC%, FEV1%, FEV1/FVC, FEF 25%, FEF 50%, FEF 75%, and PEF%) among the exposed group compared to those of control. In addition, there was a significantly higher serum level of inflammatory markers (IL-6 and hsCRP) among the exposed group compared to the control group, with a negative correlation with ventilatory functions. Moreover, there was a positive association between levels of serum IL-6 and hsCRP and the age and duration of employment of workers.

CONCLUSION

There was a notable increase in the prevalence of respiratory disorders and inflammatory markers among slaughterhouse workers. Additionally, there was a substantial decrease in ventilatory function parameters, which could be attributed to the bioaerosols they encountered in the workplace.

Employee perception of precision technology use at the dairy farm

The adoption of precision technologies on dairy farms has increased significantly in recent decades, leading to the challenge of providing employees with resources to maximize the efficient use of these tools. The objective of this study was to explore how dairy farm employees perceive the available precision technologies and to identify possible challenges they face when adapting to their use at the farm. An online survey consisting of four sections (employee demographics, precision technologies in use, perception of these technologies, and opportunities for adapting to technology use) was completed from September to December 2022 by 266 farm employees from three dairies operated under similar management. Most of the respondents were identified as male (72.2%), Hispanic or Latino (92.5%), aged between 21 and 30 (39.1%) or 31 and 40 yr (36.8%), with a bachelor's degree (34.6%) or completion of middle school (29.3%) and having basic or no English proficiency (74%). Overall, the respondents indicated being comfortable (95.6%) with and understanding (91.8%) the technology they use. Employees recognized precision technology as a tool that helps them to be more efficient (93.7%), identifying the technologies' benefits (92.1%). However, challenges for adapting to these technologies included personal limitations, such as not knowing the language of the technology (31%), visual impairments (24%), light sensitivity (14%), and not being able to read (7%). Environmental limitations were also recognized and included cold weather (64.3%), wind (46%), and surroundings that were too dark (31%) or too bright (21%). Significant associations between perception of the technology and age, level of education, and English proficiency were identified. Respondents indicated their desire to learn more about precision technologies implemented at work, which could eventually lead to improved efficiency at the dairy operation through innovations in the way users interact with these technologies, increasing employees' motivation. This study provides insights that could assist the dairy industry in addressing challenges and enhancing opportunities for a more efficient use of precision technologies at dairy farms.

Lessons from Dairy Farmers for Occupational Allergy and Respiratory Disease

PURPOSE OF REVIEW

Exposure to bioaerosols at dairies has long been associated with allergy, respiratory disease, and decreases in lung function. Recent advancements in exposure assessments have aided our understanding on the size distribution and composition of these bioaerosols, but investigations focusing solely on exposures may overlook important intrinsic factors impacting worker's susceptibility to disease.

RECENT FINDINGS

In our review, we discuss the most recent studies examining the exposures and genetic factors that contribute to occupational disease in dairy work. We also review more recent concerns in livestock work associated with zoonotic pathogens, antimicrobial resistant genes, and the role of the human microbiome. The studies highlighted in this review demonstrate the need for further research to better understand bioaerosol exposure-response relationships in the context of extrinsic and intrinsic factors, antibiotic-resistant genes, viral pathogens, and the human microbiome to help inform effective interventions that improve respiratory health among dairy farmers.

Influenza D virus exposure among US cattle workers: A call for surveillance

Although cattle are a reservoir for influenza D virus (IDV), little is known about human exposure to IDV. We assessed IDV exposure and associated health effects among United States dairy workers, a population at heightened risk of cattle zoonoses. In prospective, cross-shift sampling of 31 workers employed at five large-herd dairy operations in two states, we found evidence of IDV in the nasal washes of 67% of participants at least once during the 5-day study period. IDV exposure was not associated with respiratory symptoms in these workers. These findings suggest that IDV is present in dairy cattle environments and can result in worker exposure.

Respiratory Findings in Herd Dairy Farmworkers from the Nile Delta Region

BACKGROUND

Dairy farmworkers are exposed to a variety of respiratory hazards, including organic and inorganic dust, allergens, disinfectants, and gases emitted by cows and their wastes resulting in a range of adverse health effects. In Egypt, large herd dairy farms (>1000 cattle) are growing in both size and number and thereby more workers are employed. However, there is a lack of studies on the respiratory health status of these workers. Accordingly, the present study aimed to determine the prevalence of respiratory problems, assess ventilatory functions, and highlight the predictors of abnormal spirometry patterns among Egyptian dairy farmworkers.

METHODS

A cross-sectional study was carried out on 282 male workers, of whom 141 were dairy farmworkers and the other 141, not involved in livestock handling, were enrolled as controls. Full history, clinical examination, and ventilatory function measurements were done for both groups.

RESULTS

Dairy farmworkers had a significantly higher prevalence of respiratory symptoms (throat irritation and/or sore throat, cough, sputum production, and difficulty breathing) than controls as well as bronchitis, wheezes on chest auscultation, and obstructive ventilatory patterns. Older age (>37 years), longer smoking duration (>10 years), and longer working duration (>4 years) were independent predictors of abnormal spirometry patterns, particularly obstructive patterns, in dairy farmworkers.

CONCLUSIONS

Large herd dairy farms, despite being open and naturally ventilated, are hazardous to workers' respiratory health. Hence, the provision of personal protective equipment, periodic spirometry examinations as well as mandatory breaks and days off, are highly urged.

Preliminary investigation of a hypertonic saline nasal rinse as a hygienic intervention in dairy workers

Livestock workers experience an increased burden of bioaerosol-induced respiratory disease including a high prevalence of rhinosinusitis. Dairy operations generate bioaerosols spanning the inhalable size fraction (0-100 μm) containing bacterial constituents such as endotoxin. Particles with an aerodynamic diameter between 10 and 100 μm are known to deposit in the nasopharyngeal region and likely affect the upper respiratory tract. We evaluated the effectiveness of a hypertonic saline nasal lavage in reducing inflammatory responses in dairy workers from a high-volume dairy operation. Inhalable personal breathing zone samples and pre-/post-shift nasal lavage samples from each participant over five consecutive days were collected. The treatment group (n = 5) received hypertonic saline while the control group (n = 5) received normotonic saline. Personal breathing zone samples were analyzed for particulate concentrations and endotoxin using gravimetric and enzymatic methods, respectively. Pro- and anti-inflammatory cytokines (i.e., IL-8, IL-10, and TNF-α) were measured from nasal lavage samples using a multiplex assay. Inhalable dust concentrations ranged from 0.15 to 1.9 mg/m3. Concentrations of both pro- and anti-inflammatory cytokines, specifically IL-6, IL-8, and IL-10, were significantly higher in the treatment group compared to the control group (p < 0.02, p < 0.04, and p < 0.01, respectively). Further analysis of IL-10 anti-inflammatory indicates a positive association between hypertonic saline administration and IL-10 production. This pilot study demonstrates that hypertonic saline nasal lavages were successful in upregulating anti-inflammatory cytokines to support larger interventional studies.

Systematic Review of Ozone Effects on Human Lung Function, 2013 through 2020

Background

Ozone effects on lung function are particularly important to understand in the context of the air pollution-health outcomes epidemiologic literature, given the complex relationships between ozone and other air pollutants with known lung function effects.

Research Question

What has been learned about the association between ozone exposures and lung function from epidemiology studies published from 2013 through 2020?

Study Design and Methods

On March 18, 2018, and September 8, 2020, PubMed was searched using the terms health AND ozone, filtering to articles in English and about humans, from 2013 or later. An additional focused review searching for ozone AND (lung function OR FEV₁OR FVC) was performed June 26, 2021. Articles were selected for this review if they reported a specific relationship between a lung function outcome and ozone exposure.

Results

Of 3,271 articles screened, 53 ultimately met criteria for inclusion. A systematic review with assessment of potential for bias was conducted, but a meta-analysis was not carried out because of differences in exposure duration and outcome quantification. Consistent evidence exists of small decreases in children’s lung function, even associated with very low levels of short-term ozone exposure. The effects on adult lung function from exposure to low-level, short-term ozone are less clear, although ozone-associated decrements may occur in the elderly. Finally, long-term ozone exposure decreases both lung function and lung function growth in children, although few new studies have examined long-term ozone and lung function in adults.

Interpretation

Much of this literature involves concentrations below the current US Environmental Protection Agency’s National Ambient Air Quality Standard of 70 parts per billion over an 8-h averaging time, suggesting that this current standard may not protect children adequately from ozone-related decrements in lung function.