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K J Donham

Publications and source records attributed to K J Donham.

At least 19 recordsLinked to original sources
PubMed1998

Respiratory tract inflammation in swine confinement workers studied using induced sputum and exhaled nitric oxide.

OBJECTIVE: To further define the asthma-like syndrome seen in swine confinement workers. DESIGN: A cross-sectional study was performed at a swine confinement facility in rural Nebraska and at the University of Nebraska Medical Center, Omaha, Nebraska. PARTICIPANTS: 24 swine confinement workers and 14 urban normal control subjects. All subjects completed a questionnaire concerning respiratory complaints. We performed hypertonic saline challenges on the swine confinement workers and control subjects in order to induce expectoration of sputum. Cell counts and cell differentials were determined in the induced sputum samples. Nasal, mean, and peak exhaled nitric oxide was measured in both groups. Spirometry was also done. RESULTS: Swine confinement workers were significantly more likely to report wheezing, cough, and sinusitis symptoms than controls (p = .003). Macrophages were significantly elevated in the induced sputum samples of the swine confinement workers vs the control subjects (0.59 macrophages/mL +/- 0.1 SEM vs 0.36 +/- .16; p = .006), while there was no difference in numbers of neutrophils. No eosinophils were observed. A small elevation in mean exhaled nitric oxide was seen in the swine confinement workers compared to normal controls (11.7 ppb +/- 0.6 SEM vs 10.2 +/- 1.6; p = 0.023). Spirometry values did not differ statistically between swine confinement workers and the control group. CONCLUSIONS: Swine confinement workers have signs and symptoms of lower respiratory tract inflammation when studied using induced sputum and exhaled nitric oxide. Findings in the swine confinement workers differ from those in asthmatics and chronic bronchitis.

Adult↗
PubMed1996

Longitudinal evaluation of dose-response relationships for environmental exposures and pulmonary function in swine production workers.

Studies describing respiratory health hazards for workers in swine production facilities have been published in the United States, Sweden, Canada, the Netherlands, and Denmark. Up to 50% of these workers experience bronchitis, organic dust toxic syndrome, hyper-reactive airways disease, chronic mucous membrane irritation, and other respiratory effects. These studies clearly point to the fact that this occupational environment poses a significant health risk hazard, and that control methods are needed to protect the worker. Before precise control strategies can be developed, implemented, and evaluated, dose-response studies are required to determine acceptable target levels for exposure. A previous manuscript described the development of multiple regression equations characterizing the relationships between environmental exposures and pulmonary response in a cohort of 207 swine producers. Baseline pulmonary function was included as a significant predictor of cross-shift decrements in pulmonary function in addition to personal measurements of dust, endotoxin, and ammonia concentrations. These equations were then used to predict specific exposure levels of dust and ammonia that could be expected to elicit significant decrements in cross-shift pulmonary function. This paper presents the results from analysis of follow-up data obtained on this same cohort 2 years after the initial measurements. At the second measurement period of the study (time-2), swine workers were found to have a mean cross-shift decrease in FEV1 of 2%. Cross-shift change in FEV1 was significantly correlated with personal exposures to total dust, total endotoxin, respirable endotoxin, and ammonia. The magnitude of the decrease in FEV1 was associated with increasing airborne concentrations of these environmental parameters thus confirming the dose-response relationship observed in the initial study (time-1). The correlation of dust with FEV1 changes in workers with more than 6 years of exposure (time-1 data) and more than 10 years of exposure (time-2 data) suggests that dust exposure is an important factor in chronic respiratory disease. Additionally, the correlation of endotoxins with FEV1 changes in the group with less than 6 years exposure (time-2 data) suggests endotoxins may have more significance for subacute respiratory effects. The agreement between observed cross-shift FEV1 changes measured in time-2 with changes predicted using regression equations derived from time-1 data demonstrates a consistent dose-response relationship over time for this cohort of swine production workers. This finding provides further support for conclusions of the previous study that levels of 2.5 mg/m3 (total dust) and 7.5 ppm (ammonia) are reasonable guidelines for occupational exposure limits in this environment.

Adult↗
PubMed1995

Respiratory dysfunction in swine production facility workers: dose-response relationships of environmental exposures and pulmonary function.

Human respiratory health hazards for people working in livestock confinement buildings have been recognized since 1974. However, before comprehensive control programs can be implemented, more knowledge is needed of specific hazardous substances present in the air of these buildings, and at what concentrations they are harmful. Therefore, a medical epidemiological and exposure-response study was conducted on 207 swine producers using intensive housing systems (108 farms). Dose-response relationships between pulmonary function and exposures are reported here. Positive correlations were seen between change in pulmonary function over a work period and exposure to total dust, respirable dust, ammonia, respirable endotoxin, and the interactions of age-of-producer and dust exposure and years-of-working-in-the-facility and dust exposure. Relationships between baseline pulmonary function and exposures were not strong and therefore, not pursued in this study. The correlations between exposure and response were stronger after 6 years of exposure. Multiple regression models were used to identify total dust and ammonia as the two primary environmental predictors of pulmonary function decrements over a work period. The regression models were then used to determine exposure concentrations related to pulmonary function decrements suggestive of a health hazard. Total dust concentrations > or = 2.8 mg/m3 were predictive of a work period decrement of > or = 10% in FEV1. Ammonia concentrations of > or = 7.5 ppm were predictive of a > or = 3% work period decrement in FEV1. These predictive concentrations were similar to a previous dose-response study, which suggested 2.5 mg/m3 of total dust and 7 ppm of NH3 were associated with significant work period decrements. Therefore, dust > or = 2.8 mg/m3 and ammonia > or = 7.5 ppm should be considered reasonable evidence for guidelines regarding hazardous exposure concentrations in this work environment.

Adult↗
PubMed1995

Determinants of longitudinal changes in spirometric function among swine confinement operators and farmers.

To assess whether working in a swine confinement facility causes an excess or accelerated decline in lung function, we conducted a population-based study to evaluate the determinants of longitudinal changes in airflow in a population of swine confinement operators. Spirometric measures of lung function were compared between swine confinement operators (N = 168) and neighborhood farmer control subjects (N = 127). Study subjects were randomly selected from a cohort of swine confinement operators in eastern Iowa. The control farming population was matched by geographic location, age, and sex to the swine confinement operators. On average, the follow-up time was approximately 2 yr, with a range of follow-up between 56 and 1,900 d. Although swine confinement operators and neighborhood farmers had similar demographic characteristics (age, gender, racial background, smoking history, and atopy status), swine confinement operators tended to have less farming experience and were more extensively followed (more measures of lung function and longer periods of observation) than the neighborhood farmer control group. Swine confinement operators were also exposed to higher environmental dust concentrations and other irritants than the farmer control subjects. Interestingly, the cross-sectional data indicated that swine confinement operators tended to have slightly lower measures of airflow and greater workshift declines in forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and mid-expiratory flow (FEF25-75) than the neighborhood farmer control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Peak flow as a measure of airway dysfunction in swine confinement operators.

To evaluate the usefulness of a portable peak flow meter in predicting airway dysfunction in symptomatic swine confinement workers, we conducted a study using an established cohort of swine workers in Iowa. Participants were randomly selected from a group of 207 swine confinement workers and a group of nonconfinement farmers who had been followed longitudinally. Swine confinement workers with work-related symptoms were identified, and two control groups (swine confinement workers and nonconfinement workers) without work-related symptoms were frequency matched by age, sex, and smoking status to the symptomatic swine confinement workers. Peak flow measures were obtained for 7 days using a mini-Wright peak flow meter and comparisons were made between the symptomatic swine confinement farmers (n = 24) and both groups of asymptomatic workers: swine confinement workers (n = 21) and neighborhood farmer controls (n = 25). Peak flow readings were recorded by subjects five times per day for 7 days, initially on awakening, then after chores, before lunch, before dinner, and before bedtime. The actual hour of day for each measurement of peak flow was similar between the three groups. Percent changes from initial AM peak flow did not significantly differ between subject groups. However, symptomatic swine confinement workers consistently exhibited significantly lower initial and subsequent mean peak flow values compared with asymptomatic swine confinement workers and neighborhood control farmers, controlling for age, height, gender, and smoking status. These differences occurred on most of the measures of peak flow throughout the work day. The persistence of these lower values throughout the work day is remarkably consistent during the study period and is suggestive of airway disease in the symptomatic swine confinement workers. Our findings suggest that peak flow meters are a useful indicator of potential airway injury and offer an additional portable, diagnostic tool in the assessment of symptomatic workers.

Adult↗
PubMed1994

Agents in organic dust: criteria for a causal relationship.

Identification of agents of disease causation in organic dust is complicated by the fact that multiple agents may be involved, and these agents may act in a synergistic or additive fashion and cause a number of conditions resulting from chronic toxic or inflammatory effects. A new systematic approach to evaluating available data for evidence of disease-causing agents in organic dust is proposed. It combines, in a matrix fashion, principles of Koch's postulates, River's postulates, principles of epidemiologic determinants, and weight of evidence theory. By applying these principles in a systematic fashion, the strength of the scientific evidence for a specific agent can objectively be evaluated.

Air Pollutants↗
PubMed1994

Animal models.

Explore the source record for details and available documents.

Animals↗
PubMed1992

Comparison of bioaerosol sampling methods in barns housing swine.

The air in livestock buildings contains bioaerosol levels that are sufficiently high to cause adverse health effects in animals and workers. These bioaerosols are complex mixtures of live and dead microorganisms and their products as well as other aeroallergens. The effectiveness of sampling methods used for quantifying the very high concentrations of microorganisms in these environments has not been well studied. To facilitate an accurate assessment of respiratory hazards from viable organisms in agricultural environments, three bioaerosol sampling methods were investigated: the Andersen microbial sampler method (AMS), the all-glass impinger method (AGI), and the Nuclepore filtration-elution method (NFE). These methods were studied in a parallel fashion in 24 swine confinement buildings. Measurements were taken in two seasons with three types of culture media in duplicate to assess total bacteria, gram-negative enteric bacteria, and total fungi. Methods were analyzed for the proportion of samples yielding data within the limits of detection, intraclass reliability, and correlation between methods. For sampling viable bacteria, the AMS had a poor data yield because of overloading and demonstrated weak correlation with the AGI. Conversely, the AGI and NFE gave sufficient numbers of valid data points (90%), yielded high intraclass reliabilities (alpha greater than or equal to 0.92), and were highly correlated with each other (r = 0.86). The AGI and the NFE were suitable methods for assessing bacteria in this environment, but the AMS was not. The AMS was the only method that consistently recovered enteric bacteria (73% data yield). For sampling fungi, the AGI and AMS both yielded sufficient data and all three methods demonstrated high intraclass reliability.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗
PubMed1992

Lung dysfunction in animal confinement workers--chairman's report to the Scientific Committee of the Third International Symposium: issues in health, safety and agriculture, held in Saskatoon, Saskatchewan, Canada, May 10-15, 1992.

The session traced the course of health hazards in livestock confinement from anticipation of an emerging health hazard in 1974 to its full recognition as a significant health hazard in 1992. The session documented the major health hazards including hydrogen sulfide toxicity, bronchitis, non-allergic asthma, organic dust toxic syndrome, and mucus membrane irritation. In regard to exposures, bioaerosols seem to be the most significant hazard, with endotoxin evident as at least one of the major specific atiologic agents. Other agents were suspected, as newly recognized agents, specifically 1,3 beta-glucan. Previous epidemiological studies have revealed mild decrements in pulmonary function, however symptoms have always been excessively prevalent relative to controls. Recent results of a longitudinal observation showed a 12% drop out of workers with profound decrement in pulmonary function. In summary, the health hazard of livestock confinement workers is now well substantiated in North America and Europe and further work regarding prevention is highly indicated.

Animal Husbandry↗
PubMed1991

Association of environmental air contaminants with disease and productivity in swine.

A cross-sectional epidemiologic study associating air quality with swine health was conducted on 28 swine farms in southern Sweden. Correlation of housing air environment to swine diseases and productivity (data collected over the preceding 12 months) were investigated. The most prevalent swine health problems detected at slaughter were pneumonia and pleuritis. In farrowing and nursery operations, the most prevalent problem was neonatal pig mortality. Several air contaminants (dust, ammonia carbon dioxide, and microbes) were found to be correlated with these swine health problems. Maximal safe concentrations of air contaminants were estimated on the basis of dose-response correlation to swine health or human health problems. Recommended maximal concentrations of contaminant were: dust, 2.4 mg/m3; ammonia, 7 ppm; endotoxin, 0.08 mg/m3; total microbes, 10(5) colony-forming units/m3; and carbon dioxide, 1,540 ppm. The overall quality of the ventilation system was correlated with lower concentration of ammonia, carbon dioxide, microorganisms, and endotoxin, but not with dust concentrations. High animal density was related to high ammonia and air microbe concentrations. Animal density measured as kilograms of swine per cubic meter (compared with kilograms of pig weight or swine per square meter) had the highest correlation to animal health and air contaminants.

Aerosols↗
PubMed1990

Health effects from work in swine confinement buildings.

A total of 14 epidemiologic studies from four countries, involving 2,786 workers is reviewed for respiratory symptoms, pulmonary function, antibodies to swine house allergens, and exposure-response variables. Cough and phlegm were the most common symptoms (ranging from 12 to 55%). Tightness of chest and wheezing were frequently reported (12 to 33%) as well as episodes of organic dust toxic syndrome. Acute symptoms, directly associated with work, were from 1.5 to 2 times more prevalent than chronic symptoms. Baseline pulmonary function generally revealed decrements in flow rates, but not volumes; over-shift changes showed small decrements in both flows and volumes. IgG antibodies to swine house antigens were common; no relation to symptoms could be found. Exposure response studies were limited, but relationships were seen between endotoxin and pulmonary function decrements, or respiratory symptoms.

Agricultural Workers' Diseases↗
PubMed1990

Bronchial hyperreactivity among pig and dairy farmers.

The presence of work-related symptoms, pulmonary functions, and bronchial reactivity were studied in farmers working with dairy animals or pigs. An increased incidence of the organic dust toxic syndrome, cough, and throat irritation was found. Pulmonary function baseline values were close to normal, and no significant decreases occurred over the work period. Bronchial reactivity was increased.

Animal Husbandry↗
PubMed1990

Prologue: agricultural occupational and environmental health: policy strategies for the future.

The conference "Agricultural Occupational and Environmental Health: Policy Strategies for the Future" documented for the public record the epidemic of occupational and environmental deaths, diseases, and injuries experienced by America's farm families and agricultural workers. The conference also gave life to a process aimed at reducing those hazards. The outcome of long-range objectives of lowering death, injury, and disease rates in our agricultural population will not be known for several years. However, there was unanimous consensus that the major short-range objectives were achieved. Extensive regional and national media coverage helped meet the goal of facilitating public awareness of the issues. In addition, a prioritized policy agenda, soundly based on recent scientific information, was produced. This agenda was the product of collaboration between the scientific community, farm constituency groups, farm equipment and chemical manufacturers, and representatives from state and federal governments. Primary changes resulting from the conference include an increase in general awareness and a sense of urgency that agricultural health problems must be addressed. In addition, the conference spawned a new organization called the National Coalition for Agricultural Safety and Health (N-CASH) to help assure a vibrant continuation of conference issues. This coalition will live on to help disseminate the spirit, information, and specific policy recommendations of the conference to the public sector and private institutions. Two years of planning and work by 18 individuals occurred even before the start of the conference. During the conference, 176 individuals put in an equivalent of three and a half person years of work. However, the work is just beginning. This effort is justified if it results in one less death or serious injury in a farm family.

Accidents, Occupational↗
PubMed1990

Preventing respiratory disease in swine confinement workers: intervention through applied epidemiology, education, and consultation.

A combined epidemiological and intervention study was conducted on 207 swine confinement farmers with matched comparison subjects. The objectives of the study were to define, in detail, the nature and disease determinants in this exposed group and to explore methods of disease prevention. This 5 year prospective study included three annual medical assessments of workers and complementary work environment assessments. Between the first and second assessment periods, an in-depth educational intervention was conducted. An industrial hygiene consultation intervention was conducted between the second and third measurement periods. Outcome measurements included changes in knowledge, attitudes, and behavior following educational intervention. Additionally, the outcomes measured included changes in medical and environmental assessment over the 3 year assessment periods. Results of the baseline respiratory symptoms assessment are reported here. Nearly 20% of swine confinement workers reported chronic cough, and 25% reported phlegm (American Thoracic Society questionnaire). Both symptoms were significantly more prevalent in the confinement workers compared to a blue collar comparison group, but only phlegm production was more prevalent compared to nonconfinement farmers. Work-related symptoms were reported much more frequently than chronic symptoms (e.g., 87% of confinement workers reported work-related cough). Bronchitis as well as airways reactivity were all significantly more prevalent in confinement workers compared to nonconfinement workers. Smoking seemed to have an additive effect with confinement exposure. Bronchitis and chest tightness symptoms were reported to be more severe upon return to work after an absence of 7 days or more. Finally, 34% of workers reported episodes of organic dust toxic syndrome.

Adult↗
PubMed1990

Iowa Agricultural Health and Safety Service Project.

A model community-based comprehensive agricultural occupational health and safety service program has been implemented in Iowa. The functional center of coordination is based in the College of Medicine at the University of Iowa. The community-based hub of the service is the community hospital, where the majority of the direct client services originate. The University provides training of hospital staff, programming, direction, consultation, and referral. The services offered include primary care, health surveillance, industrial hygiene and safety, and education. Through a detailed evaluation of the project's objectives we will be able to evaluate, modify, and disseminate a model agricultural health and safety services delivery program. This model should be effective in changing the farming population's health and safety attitudes and behaviors through a community-based program.

Accidents, Occupational↗