Industrial Hog Operations Research Articles

Hurricanes, Industrial Hog Operations, and Acute Gastrointestinal Illness in North Carolina, USA

Background and aim: North Carolina (NC) is the third most hurricane-prone state and second leading hog producer. NC’s hogs are housed in industrial hog operations (IHOs) in its eastern, hurricane-prone region. Hurricanes can inundate hog waste lagoons, transporting fecal bacteria that may cause diarrhea, vomiting, and/or nausea, collectively known as acute gastrointestinal illness (AGI). Hurricanes Matthew (2016) and Florence (2018) were NC's most recent deadliest hurricanes. We aim to understand the association between hurricanes and AGI in areas with and without IHOs. Methods: We used NC ZIP code-level surveillance data to calculate rates of AGI emergency department (ED) visits during 2016-2019. Using gridded PRISM precipitation data and swine permit data, we assessed the increase in AGI rate during the three weeks after Hurricanes Matthew and Florence in ZIP codes with heavy rain (>75th percentile of storm precipitation) and ≥10 IHOs and in ZIP codes with heavy rain but no IHOs by comparing AGI rates in these areas to their AGI rates during comparable non-hurricane time periods (2017, 2019). Results: The AGI rate in ZIP codes with heavy rain and ≥10 IHOs increased 13% (RR=1.13, 95% CI: 1.00, 1.29) after Hurricane Florence and 8% (RR=1.08, 95% CI: 0.87, 1.33) after Hurricane Matthew, while the AGI rates in ZIP codes with heavy rain and no IHOs experienced no increase (Florence: RR=0.99, 95% CI: 0.88, 1.12; Matthew: RR=0.98, 95% CI: 0.82, 1.16). ZIP codes with heavy precipitation and IHOs also had a higher proportion of Black, American Indian, and Hispanic residents than the state average. Conclusions: Heavy rain from hurricanes in areas with IHOs may increase AGI rates, disproportionately harming people of color in NC. Keywords: Climate change, extreme weather, hurricane, disaster, flooding, industrial animal operations

Exposure to industrial hog and poultry operations and urinary tract infections in North Carolina, USA

An increasing share of urinary tract infections (UTIs) are caused by extraintestinal pathogenic Escherichia coli (ExPEC) lineages that have also been identified in poultry and hogs with high genetic similarity to human clinical isolates. We investigated industrial food animal production as a source of uropathogen transmission by examining relationships of hog and poultry density with emergency department (ED) visits for UTIs in North Carolina (NC). ED visits for UTI in 2016–2019 were identified by ICD-10 code from NC's ZIP code-level syndromic surveillance system and livestock counts were obtained from permit data and aerial imagery. We calculated separate hog and poultry spatial densities (animals/km2) by Census block with a 5 km buffer on the block perimeter and weighted by block population to estimate mean ZIP code densities. Associations between livestock density and UTI incidence were estimated using a reparameterized Besag-York-Mollié (BYM2) model with ZIP code population offsets to account for spatial autocorrelation. We excluded metropolitan and offshore ZIP codes and assessed effect measure modification by calendar year, ZIP code rurality, and patient sex, age, race/ethnicity, and health insurance status. In single-animal models, hog exposure was associated with increased UTI incidence (rate ratio [RR]: 1.21, 95 % CI: 1.07–1.37 in the highest hog-density tertile), but poultry exposure was associated with reduced UTI rates (RR: 0.86, 95 % CI: 0.81–0.91). However, the reference group for single-animal poultry models included ZIP codes with only hogs, which had some of the highest UTI rates; when compared with ZIP codes without any hogs or poultry, there was no association between poultry exposure and UTI incidence. Hog exposure was associated with increased UTI incidence in areas that also had medium to high poultry density, but not in areas with low poultry density, suggesting that intense hog production may contribute to increased UTI incidence in neighboring communities.

Exposure to industrial hog operations and gastrointestinal illness in North Carolina, USA

With 9 million hogs, North Carolina (NC) is the second leading hog producer in the United States. Most hogs are housed at concentrated animal feeding operations (CAFOs), where millions of tons of hog waste can pollute air and water with fecal pathogens that can cause diarrhea, vomiting, and/or nausea (known as acute gastrointestinal illness (AGI)). We used NC's ZIP code-level emergency department (ED) data to calculate rates of AGI ED visits (2016–2019) and swine permit data to estimate hog exposure. Case exposure was estimated as the inverse distances from each hog CAFO to census block centroids, weighting with Gaussian decay and by manure amount per CAFO, then aggregated to ZIP code using population weights. We compared ZIP codes in the upper quartile of hog exposure (“high hog exposed”) to those without hog exposure. Using inverse probability of treatment weighting, we created a control with similar demographics to the high hog exposed population and calculated rate ratios using quasi-Poisson models. We examined effect measure modification of rurality and race using adjusted models. In high hog exposed areas compared to areas without hog exposure, we observed a 11% increase (95% CI: 1.06, 1.17) in AGI rate and 21% increase specifically in rural areas (95% CI: 0.98, 1.43). When restricted to rural areas, we found an increased AGI rate among American Indian (RR = 4.29, 95% CI: 3.69, 4.88) and Black (RR = 1.45, 95% CI: 0.98, 1.91) residents. The association was stronger during the week after heavy rain (RR = 1.41, 95% CI: 1.19, 1.62) and in areas with both poultry and swine CAFOs (RR = 1.52, 95% CI: 1.48, 1.57). Residing near CAFOs may increase rates of AGI ED visits. Hog CAFOs are disproportionally built near rural Black and American Indian communities in NC and are associated with increased AGI most strongly in these populations.

Assessing Residential Exposure to Microbes from Industrial Hog Operations in Rural North Carolina: Methods and Lessons Learned.

Recent advances in molecular source tracking make answering questions from residents regarding their exposure to microbial contaminants from industrial hog operations (IHOs) possible. Associations between residential distance to IHOs and exposure can be addressed by measuring livestock-associated (Staphylococcus aureus) and pig-specific bacteria in the air, on household surfaces, and in participants' nasal and saliva swabs. Here we assess the mechanics, feasibility, capacity-building, and lessons learned during a pilot study employing this novel technology in community-based participatory research of bacterial exposure and human health. Together, our team of academics and community members designed a field- and laboratory-based pilot study. Air samples, surface and human swabs, and questionnaires from households at varying distances from IHOs were collected. Data were assessed for completeness and quality by two independent reviewers. These metrics were defined as: missingness (completeness), incorrect data type (validity), out of range (validity), and outliers (accuracy). While critical field equipment was obtained, and knowledge exchange occurred, leading to an increased capacity for future work, after review, 38 of 49 households were deemed eligible for inclusion in the study. Of eligible participants, 98% of required electronic survey questions were complete and 100% were valid; an improvement over prior work which employed paper surveys. While all human microbial and air samples were collected from eligible households (n = 231), (5%) of environmental swabs were reported missing. Using community-appropriate sampling protocols, a pilot study of residential exposure to bacteria from IHOs was completed. While high-quality data was collected from those eligible, we learned the necessity of early and continual data review.

Application of Markov models to predict changes in nasal carriage of Staphylococcus aureus among industrial hog operations workers

Industrial hog operation (IHO) workers can be occupationally exposed to Staphylococcus aureus and may carry the bacteria in their nares. Workers may persistently carry S. aureus or transition between different states of nasal carriage over time: no nasal carriage, nasal carriage of a human-associated strain, and nasal carriage of a livestock-associated strain. We developed a mathematical model to predict the proportion of IHO workers in each nasal carriage state over time, accounting for IHO worker mask use. We also examined data sufficiency requirements to inform development of models that produce reliable predictions. We used nasal carriage data from a cohort of 101 IHO workers in North Carolina, sampled every 2 weeks for 4 months, to develop a three-state Markov model that describes the transition dynamics of IHO worker nasal carriage status over the study period and at steady state. We also stratified models by mask use to examine their impact on worker transition dynamics. If conditions remain the same, our models predicted that 49.1% of workers will have no nasal carriage of S. aureus, 28.2% will carry livestock-associated S. aureus, and 22.7% will carry human-associated S. aureus at steady state. In stratified models, at steady state, workers who reported only occasional mask (<80% of the time) use had a higher predicted proportion of individuals with livestock-associated S. aureus nasal carriage (39.2%) compared to workers who consistently (≥80% of the time) wore a mask (15.5%). We evaluated the amount of longitudinal data that is sufficient to create a Markov model that accurately predicts future nasal carriage states by creating multiple models that withheld portions of the collected data and compared the model predictions to observed data. Our data sufficiency analysis indicated that models created with a small subset of the dataset (approximately 1/3 of observed data) perform similarly to models created using all observed data points. Markov models may have utility in predicting worker health status over time, even when limited longitudinal data are available.

Exposure to Industrial Hog Operations and Gastrointestinal Illness in North Carolina, USA

BACKGROUND AND AIM: With 9 million hogs, North Carolina (NC) is the second leading hog producer in the United States. Most hogs are housed at concentrated animal feeding operations (CAFOs), where millions of tons of hog waste can pollute the air and water with fecal pathogens that can cause diarrhea, vomiting, and/or nausea (known as acute gastrointestinal illness (AGI)). METHODS: We used NC’s ZIP code-level syndromic surveillance system to calculate rates of AGI emergency department (ED) visits during 2016-2019 and swine permit data to estimate hog exposure. Exposure was estimated as the inverse distances from each hog CAFO to census block centroids, weighting with Gaussian decay and by hogs per CAFO, then aggregated to ZIP codes using population weights. We compared ZIP codes in the upper quartile of hog exposure to those without hog exposure. Using inverse probability of treatment weighting, we created a control with similar demographics to the high hog exposed population and calculated rate ratios (RR) using quasi-Poisson models. We examined effect measure modification of rurality and race using adjusted models. RESULTS:Among the 111 high hog exposed ZIP codes, the median number of hogs per ZIP code was 50,022. In high hog exposed areas compared to areas without hog exposure, we observed a 17% increase in AGI rate (95% CI: 1.08, 1.26) and a 24% increase in rural areas (95% CI: 1.04, 1.48). The association was stronger during the weeks after heavy rain (RR=1.54, 95% CI: 1.25, 1.83). When restricted to rural areas, we found an increased AGI rate among American Indian (RR=5.26, 95% CI: 4.60, 5.91) and Black (RR=1.47, 95% CI: 1.04, 1.89) patients. CONCLUSIONS:Residing near hog CAFOs may increase rates of AGI ED visits. Hog CAFOs are disproportionally built near rural Black and American Indian communities in NC and are associated most strongly with increased AGI in these populations. KEYWORDS: Concentrated animal feeding operation (CAFO), animal production, swine, environmental pollution, gastrointestinal illness, waterborne pathogens

Getting ahead of antibiotic-resistant Staphylococcus aureus in U.S. hogs

Antibiotic-resistant strains of Staphylococcus aureus, an opportunistic bacterial pathogen, have emerged in industrial livestock operations and agricultural settings. In the United States, there is limited access to industrial livestock operations and farm-level antibiotic use data. As a result, studies often rely on retail meat as a proxy for direct animal sampling. To move beyond this limitation and assess S. aureus colonization in hogs, we purchased the heads of recently-slaughtered hogs and compared S. aureus populations in those raised on industrial hog operations versus those raised without antibiotics. S. aureus isolates were analyzed for antibiotic resistance and putative genotypic markers of livestock adaptation. Although methicillin-resistant S. aureus (MRSA) was not detected in this study, all of the hogs from industrial hog operations (n = 9/9) carried multidrug-resistant S. aureus (MDRSA) with two livestock-adaptation markers (scn-negative and clonal complex (CC) 9 or 398) compared to 11% of hogs raised without antibiotics (n = 1/9). Hogs from industrial operations were 9.0 times (95% confidence interval (CI): 1.4–57.1) as likely to carry livestock-adapted S. aureus and 4.5 times (95% CI: 1.3–15.3) as likely to carry MDRSA as hogs raised without antibiotics. In contrast, the majority of antibiotic-free hogs (67%, n = 6/9) contained human-adapted S. aureus (i.e. scn-positive, CC1) compared to 11% (n = 1/9) of IHO hogs. These results indicate that antibiotic use in IHO hogs may make them more conducive hosts to antibiotic-resistant, livestock-adapted S. aureus strains when compared to hogs raised without antibiotics. Our results are important, as they provide strong evidence that antibiotic use practices influence the S. aureus populations carried by U.S. hogs, supporting the need for increased access to routine monitoring of hog operations for antibiotic resistance management using a One Health framework.

Transmission of Antimicrobial-Resistant Staphylococcus aureus Clonal Complex 9 between Pigs and Humans, United States.

Transmission of livestock-associated Staphylococcus aureus clonal complex 9 (LA-SA CC9) between pigs raised on industrial hog operations (IHOs) and humans in the United States is poorly understood. We analyzed whole-genome sequences from 32 international S. aureus CC9 isolates and 49 LA-SA CC9 isolates from IHO pigs and humans who work on or live near IHOs in 10 pig-producing counties in North Carolina, USA. Bioinformatic analysis of sequence data from the 81 isolates demonstrated 3 major LA-SA CC9 clades. North Carolina isolates all fell within a single clade (C3). High-resolution phylogenetic analysis of C3 revealed 2 subclades of intermingled IHO pig and human isolates differing by 0–34 single-nucleotide polymorphisms. Our findings suggest that LA-SA CC9 from pigs and humans share a common source and provide evidence of transmission of antimicrobial-resistant LA-SA CC9 between IHO pigs and humans who work on or live near IHOs in North Carolina.

Piloting the use of mobile devices in community-driven research to assess occupational and environmental exposures from industrial hog operations in rural eastern North Carolina, USA

Piloting the use of mobile devices in community-driven research to assess occupational and environmental exposures from industrial hog operations in rural eastern North Carolina, USA

Occurrence of Staphylococcus aureus in swine and swine workplace environments on industrial and antibiotic-free hog operations in North Carolina, USA: A One Health pilot study

Occupational exposure to swine has been associated with increased Staphylococcus aureus carriage, including antimicrobial-resistant strains, and increased risk of infections. To characterize animal and environmental routes of worker exposure, we optimized methods to identify S. aureus on operations that raise swine in confinement with antibiotics (industrial hog operation: IHO) versus on pasture without antibiotics (antibiotic-free hog operation: AFHO). We associated findings from tested swine and environmental samples with those from personal inhalable air samplers on worker surrogates at one IHO and three AFHOs in North Carolina using a new One Health approach. We determined swine S. aureus carriage status by collecting swab samples from multiple anatomical sites, and we determined environmental positivity for airborne bioaerosols with inhalable and impinger samplers and a single-stage impactor (ambient air) cross-sectionally. All samples were analyzed for S. aureus, and isolates were tested for antimicrobial susceptibility, absence of scn (livestock marker), and spa type. Seventeen of twenty (85%) swine sampled at the one IHO carried S. aureus at >1 anatomical sites compared to none of 30 (0%) swine sampled at the three AFHOs. All S. aureus isolates recovered from IHO swine and air samples were scn negative and spa type t337; almost all isolates (62/63) were multidrug resistant. S. aureus was recovered from eight of 14 (67%) ambient air and two (100%) worker surrogate personal air samples at the one IHO, whereas no S. aureus isolates were recovered from 19 ambient and six personal air samples at the three AFHOs. Personal worker surrogate inhalable sample findings were consistent with both swine and ambient air data, indicating the potential for workplace exposure. IHO swine and the one IHO environment could be a source of potential pathogen exposure to workers, as supported by the detection of multidrug-resistant S. aureus (MDRSA) with livestock-associated spa type t337 among swine, worker surrogate personal air samplers and environmental air samples at the one IHO but none of the three AFHOs sampled in this study. Concurrent sampling of swine, personal swine worker surrogate air, and ambient airborne dust demonstrated that IHO workers may be exposed through both direct (animal contact) and indirect (airborne) routes of transmission. Investigation of the effectiveness of contact and respiratory protections is warranted to prevent IHO worker exposure to multidrug-resistant livestock-associated S. aureus and other pathogens.

Work Activities, Self-Reported Symptoms, and Diminished Lung Function in a Population of Predominantly Hispanic Industrial Hog Operation Workers in North Carolina, United States

Background/Aim: Although swine worker respiratory disease is established, evidence is mainly from predominantly Caucasian farm-owner-operator cohorts whose work exposures may differ from laborers hired to perform day-to-day intensive swine production jobs in confinement barns. The Rural Empowerment Association for Community Help (REACH) has initiated community-based participatory research (CBPR) with Hispanic laborers hired to work in industrial hog operations (IHOs) in eastern North Carolina. Together with REACH, we investigated whether such IHO workers’ occupational exposures were related to respiratory health outcomes. Methods: During 2013-14, we completed a 4-month CBPR panel study, involving baseline and 8 bi-weekly visits to collect demographic, personal, and work exposure data and spirometry measurements. We assessed the relation of IHO work activities with respiratory outcomes at baseline (linear regression) and longitudinally (fixed-effects ordinal logistic regression), adjusting for potential confounders. Results: One hundred and three IHO workers were enrolled (88% Hispanic; 46% male; age mean[±SD] 38±11 years) and completed 782 bi-weekly visits. Asthma prevalence was 8.7% and 92.6% were non-smokers. At baseline, total number of years of IHO work was negatively associated with forced expiratory volume (L) in the first second (FEV1) (ß=-0.031; 95% confidence interval [CI]: -0.060, -0.001). Longitudinally, positive associations were observed between pressure washing barns and coughing (odds ratio [OR]=3.8; 95%CI: 1.2, 12.3), herd changes and nasal congestion (OR=7.4; 95%CI: 1.2, 44.6) and confinement barn ventilation fans turned off and difficulty breathing (OR=11.2; 95% CI: 2.8, 44.4), eye irritation (OR=5.8; 95%CI: 1.1, 30.7), and chills (OR=5.1; 95%CI: 3.0, 8.9). Conclusions: In a predominantly Hispanic cohort of IHO workers, we observed relations between IHO work activities and adverse respiratory outcomes, particularly prolonged IHO employment and activities that aerosolize and keep waste in-barn. Challenges in exposure assessment from lack of on-IHO access and worker reluctance to enroll in cohorts can be mitigated using an empowering CBPR approach.

In Memoriam: Steve Wing

In Memoriam: Steve Wing

The Prevalence of Antibiotic-Resistant Staphylococcus aureus Nasal Carriage among Industrial Hog Operation Workers, Community Residents, and Children Living in Their Households: North Carolina, USA.

Background:Antibiotic use in industrial hog operations (IHOs) can support the emergence of antibiotic-resistant (ABR) Staphylococcus aureus. The extent of ABR S. aureus exposure in IHO workers and children living in their households remains unclear.Objective:We investigated ABR S. aureus nasal carriage prevalence among adults with versus without occupational exposure to IHOs and among children living in their households.Methods:In total, 198 IHO worker–child household pairs and 202 community referent (CR) adult–child household pairs completed a questionnaire and provided a nasal swab which was analyzed for S. aureus, methicillin-resistant S. aureus (MRSA), multidrug-resistant S. aureus (MDRSA), absence of scn (putative marker of livestock association), and spa type.Results: S. aureus nasal carriage prevalence was higher among IHO (53%) compared with CR (31%) adults [adjusted prevalence ratio (aPR): 1.40; 95% confidence interval (CI): 1.07, 1.83], but MRSA nasal carriage prevalence was uncommon (2–3%) in IHO and CR adults. MDRSA nasal carriage prevalence was similar among IHO workers and CR adults (12% vs. 8%; aPR: 1.14; 95% CI: 0.56, 2.29). Nasal carriage prevalence was higher among IHO compared with CR children for S. aureus (49% vs. 31%; aPR: 1.50; 95% CI: 1.13, 1.99), MRSA (14% vs. 6%; aPR: 2.37; 95% CI: 1.14, 4.92), and MDRSA (23% vs. 8%; aPR: 2.64; 95% CI: 1.47, 4.75). We also found suggestive evidence of a higher prevalence of S. aureus, MRSA, and MDRSA among children living with an IHO worker who did versus did not report taking personal protective equipment (PPE) home from the IHO. Livestock-associated S. aureus nasal carriage predominated among IHO workers.Conclusion:Our findings support the importance of further research on the prevalence and potential sources of exposure to ABR S. aureus among children living with IHO workers.Citation:Hatcher SM, Rhodes SM, Stewart JR, Silbergeld E, Pisanic N, Larsen J, Jiang S, Krosche A, Hall D, Carroll KC, Heaney CD. 2017. The prevalence of antibiotic-resistant Staphylococcus aureus nasal carriage among industrial hog operation workers, community residents, and children living in their households: North Carolina, USA. Environ Health Perspect 125:560–569; http://dx.doi.org/10.1289/EHP35

Occurrence of methicillin-resistant Staphylococcus aureus in surface waters near industrial hog operation spray fields

Industrial hog operations (IHOs) have been identified as a source of antibiotic-resistant Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). However, few studies have investigated the presence of antibiotic-resistant S. aureus in the environment near IHOs, specifically surface waters proximal to spray fields where IHO liquid lagoon waste is sprayed. Surface water samples (n=179) were collected over the course of approximately one year from nine locations in southeastern North Carolina and analyzed for the presence of presumptive MRSA using CHROMagar MRSA media. Culture-based, biochemical, and molecular tests, as well as matrix-assisted laser desorption/ionization-time of flight mass spectrometry were used to confirm that isolates that grew on CHROMagar MRSA media were S. aureus. Confirmed S. aureus isolates were then tested for susceptibility to 16 antibiotics and screened for molecular markers of MRSA (mecA, mecC) and livestock adaptation (absence of scn). A total of 12 confirmed MRSA were detected in 9 distinct water samples. Nine of 12 MRSA isolates were also multidrug-resistant (MDRSA [i.e., resistant to ≥3 antibiotic classes]). All MRSA were scn-positive and most (11/12) belonged to a staphylococcal protein A (spa) type t008, which is commonly associated with humans. Additionally, 12 confirmed S. aureus that were methicillin-susceptible (MSSA) were recovered, 7 of which belonged to spa type t021 and were scn-negative (a marker of livestock-adaptation). This study demonstrated the presence of MSSA, MRSA, and MDRSA in surface waters adjacent to IHO lagoon waste spray fields in southeastern North Carolina. To our knowledge, this is the first report of waterborne S. aureus from surface waters proximal to IHOs.

Pig-2-Bac as a biomarker of occupational exposure to pigs and livestock-associated Staphylococcus aureus among industrial hog operation workers

Over 50 million hogs are raised annually in the United States for consumption, mostly on industrial hog operations (IHOs). Workers at IHOs are exposed to airborne particulates, zoonotic pathogens, and other workplace hazards, but lack of access to IHOs can hinder exposure assessment in epidemiologic studies. Here, we demonstrate the utility of pig-specific Bacteroidales (Pig-2-Bac) as a biomarker of exposure to pigs and pig waste and to help identify sources of Staphylococcus aureus carriage among IHO workers.

CAFOs and Environmental Justice: The Case of North Carolina

On the coastal plain of eastern North Carolina, families in certain rural communities daily must deal with the piercing, acrid odor of hog manure—reminiscent of rotten eggs and ammonia—wafting from nearby industrial hog farms. On bad days, the odor invades homes, and people are often forced to cover their mouths and noses when stepping outside. Sometimes, residents say, a fine mist of manure sprinkles nearby homes, cars, and even laundry left on the line to dry.1 Today’s industrial-scale farms—called concentrated animal feeding operations (CAFOs)—house thousands of animals whose waste is periodically applied to “spray fields” of Bermuda grass or feed crops.2,3 The waste can contain pathogens, heavy metals, and antibiotic-resistant bacteria,4,5 and the spray can reach nearby homes and drinking water sources. The odor plume, which often pervades nearby communities, contains respiratory and eye irritants including hydrogen sulfide and ammonia.6,7,8 A growing body of research suggests these emissions may contribute not only to mucosal irritation9 and respiratory ailments10 in nearby residents but also decreased quality of life,11 mental stress,12,13 and elevated blood pressure.14 The home of a minority family in Kenansville, North Carolina, situated next to a concentrated animal feeding operation, or CAFO. Dust, odors, and manure from CAFOs can reach nearby residents’ homes, including their laundry. Although the Midwest is the traditional home for hogs, with Iowa still the top-producing state, North Carolina went from fifteenth to second in hog production between the mid-1980s and mid-1990s.15 This explosive growth resulted in thousands of CAFOs located in the eastern half of the state—squarely in the so-called Black Belt, a crescent-shaped band throughout the South where slaves worked on plantations.16,17 After emancipation many freed slaves continued to work as sharecroppers and tenant farmers. A century later, black residents of this region still experience high rates of poverty, poor health care, low educational attainment, unemployment, and substandard housing.18,19 The clustering of North Carolina’s hog CAFOs in low-income, minority communities—and the health impacts that accompany them—has raised concerns of environmental injustice and environmental racism.20 As one pair of investigators explained, “[P]eople of color and the poor living in rural communities lacking the political capacity to resist are said to shoulder the adverse socio-economic, environmental, or health related effects of swine waste externalities without sharing in the economic benefits brought by industrialized pork production.”21 Although North Carolina is not the only area with environmental justice concerns vis-a-vis CAFOs, it has become one of the best studied.

A LONGITUDINAL STUDY OF EXPOSURE TO LIVESTOCK ODOR AND SYMPTOM REPORTS IN CHILDREN

Background and Aims: Industrial livestock operations are sources of dusts and gasses that can affect respiratory health. Associations between school proximity to industrial hog operations and prevalence of asthma-related illness in children have been seen in cross-sectional studies. We conducted a longitudinal study of air pollution from industrial hog operations and symptom reports. Methods: 340 children aged 11-15 attending schools near industrial hog operations completed daily diaries in science class for 3-5 weeks in February-November 2009. Odor was reported for the previous 24 hours in each diary record. Participants recorded the current strength of eleven symptoms on a five-point scale (none, barely there, present, strong, or very strong). Logistic fixed effects models were used to examine within-person associations between livestock odor and binary symptoms with adjustment for concurrent reported odors of vehicle exhaust and smoke from fires. Results: Livestock odor was reported by 255 participants (75%) during follow-up. The median proportion of study days participants reported livestock odor and strong livestock odor was 29% and 12%, respectively. Reported livestock odor in the previous 24 hours was associated with increased symptom reports for respiratory and irritation symptoms. Log odds (±standard error) following exposure to livestock odor were 0.44±0.25 for chest tightness, 0.57±0.26 for shortness of breath, 0.40±0.13 for cough, 0.36±0.15 for sore throat, and 0.46±0.18 for burning eyes or nose. Children reporting current wheeze at baseline (N=65) experienced stronger effects of livestock odor on chest tightness, shortness of breath, and wheeze than children not reporting current wheeze. Among participants with allergies (N=83), logs odds for burning eyes or nose increased to 0.97±0.29, while other associations were similar. Conclusions: These associations are consistent with cross-sectional studies of respiratory conditions in children and a previous longitudinal study of symptoms in adults living near industrial hog operations.

Malodor as a Trigger of Stress and Negative Mood in Neighbors of Industrial Hog Operations

We evaluated malodor and air pollutants near industrial hog operations as environmental stressors and negative mood triggers. We collected data from 101 nonsmoking adults in 16 neighborhoods within 1.5 miles of at least 1 industrial hog operation in eastern North Carolina. Participants rated malodor intensity, stress, and mood for 2 weeks while air pollutants were monitored. Reported malodor was associated with stress and 4 mood states; odds ratios (ORs) for a 1-unit change on the 0-to-8 odor scale ranged from 1.31 (95% confidence interval [CI] = 1.16, 1.50) to 1.81 (95% CI = 1.63, 2.00). ORs for stress and feeling nervous or anxious were 1.18 (95% CI = 1.08, 1.30) and 1.12 (95% CI = 1.03, 1.22), respectively, for a 1 ppb change in hydrogen sulfide and 1.06 (95% CI = 1.00, 1.11) and 1.10 (95% CI = 1.03, 1.17), respectively, for a 1 microg/m(3) change in semivolatile particulate matter less than 10 microm in aerodynamic diameter (PM(10)). Hog odor, hydrogen sulfide, and semivolatile PM(10) are related to stress and negative mood in disproportionately low-income communities near industrial hog operations in eastern North Carolina. Malodor should be considered in studies of health impacts of environmental injustice.

Data Completeness and Quality in a Community-Based and Participatory Epidemiologic Study

The principles of community-based participatory (CBPR) research challenge traditional scientific standards of objectivity and neutrality. Little work has been done to evaluate the quality of data obtained from CBPR studies. We examined factors associated with the completeness and quality of data that participants collected for the Community Health Effects of Industrial Hog Operations (CHEIHO) study, a community-based, participatory, longitudinal, epidemiologic investigation. Twice daily for 2 weeks, 101 eastern North Carolina residents collected data on odor from industrialized hog operations, physical health, and mood. Data collected at a single point in time constitute a record. For each record, participant responses were classified as error free or not and missing or not. We used mixed models to quantify associations between errors or missing values and time of day, odor rating, week-in-participation, and presence of a person to assist with data collection. Participants collected data out of order in 2% of 2,949 total records. On average, individual variables were incomplete in 2% of records. Errors and missing data were most common for lung function measurements. Missing data for lung function and blood pressure were less common after the first week of participation (odds ratio [OR], 0.41; 95% confidence interval [CI], 0.20-0.84). Saliva samples were more frequently missing when participants reported odor than when they did not (OR, 1.59; 95% CI, 0.97-2.59). For women, the odds that yes/no variables were missing in week 2 records were higher relative to week 1 (OR, 1.46; 95% CI, 1.01-2.12). Community members collected relatively complete and consistent data. Better training in use of mechanical devices and more frequent input from researchers could help to improve data quality in CBPR studies.

Integrating Epidemiology, Education, and Organizing for Environmental Justice: Community Health Effects of Industrial Hog Operations

The environmental justice movement has stimulated community-driven research about the living and working conditions of people of color and low-income communities. We describe an epidemiological study designed to link research with community education and organizing for social justice. In eastern North Carolina, high-density industrial swine production occurs in communities of low-income people and people of color. We investigated relationships between the resulting pollution and the health and quality of life of the hog operations' neighbors. A repeat-measures longitudinal design, community involvement in data collection, and integration of qualitative and quantitative research methods helped promote data quality while providing opportunities for community education and organizing. Research could affect policy through its findings and its mobilization of communities.