Chronic bronchitis in Aboriginal people--prevalence and associated factors.

INTRODUCTION: Knowledge about chronic bronchitis (CB) among Aboriginal people in Canada is limited. The aim of this study was to determine the prevalence of CB and its associated factors among Aboriginal people aged 15 years plus. METHODS: Logistic regression analysis was used on data from the cross-sectional 2006 Aboriginal Peoples Survey to determine risk factors associated with CB. RESULTS: CB prevalence was 6.6% among First Nations, 6.2% among Métis and 2.4% among Inuit. Prevalence was higher among females than males (7.2% versus 5.0%). Individuals with CB were more likely to be older, living at a lower income, with a lower educational attainment and residing in rural areas. Smoking status and body mass index were also significantly associated with CB, but their effect differed by sex. Obesity was particularly significantly associated with CB among females compared with males, and current smoking and non-smoking status was significantly associated with CB among females but not males. CONCLUSION: These findings identify factors associated with CB among Aboriginal people. As such, they may represent potentially preventable risk factors that can inform health promotion and disease prevention practices.

TITRE: La bronchite chronique chez les Autochtones ­ prévalence et facteurs associés. INTRODUCTION: On sait peu de choses sur la bronchite chronique (BC) chez les Autochtones au Canada. Le but de cette étude était de déterminer la prévalence de la BC et des facteurs qui lui sont associés chez les Autochtones de 15 ans et plus. MÉTHODOLOGIE: Une analyse de régression logistique a été appliquée à des données tirées de l'Enquête auprès des peuples autochtones de 2006 (enquête transversale) afin de déterminer les facteurs de risque associés à la BC. RÉSULTATS: La prévalence de la BC était de 6,6 % au sein des membres des Premières nations, de 6,2 % chez les Métis et de 2,4 % chez les Inuits. Elle était plus élevée chez les femmes que chez les hommes (7,2 % contre 5,0 %). Les individus atteints de BC étaient en général plus âgés et plus nombreux à avoir un revenu et un niveau d'instruction plus faibles et à habiter en milieu rural. Le tabagisme et l'indice de masse corporelle étaient également associés de façon significative à la BC, mais leur effet différait selon le sexe. L'obésité était associée de manière particulièrement significative à la BC chez les femmes, et le fait d'être fumeur ou de n'avoir jamais fumé était aussi associé de façon significative à la BC chez les femmes. CONCLUSION: Ces constatations permettent de déterminer les facteurs associés à la BC chez les Autochtones. Ce sont peut-être à ce titre des facteurs de risque potentiellement évitables qui peuvent éclairer les pratiques en matière de promotion de la santé et de prévention des maladies.

Cigarette smoking and risk of Hodgkin lymphoma and its subtypes: a pooled analysis from the International Lymphoma Epidemiology Consortium (InterLymph).

BACKGROUND: The etiology of Hodgkin lymphoma (HL) remains incompletely characterized. Studies of the association between smoking and HL have yielded ambiguous results, possibly due to differences between HL subtypes. PATIENTS AND METHODS: Through the InterLymph Consortium, 12 case-control studies regarding cigarette smoking and HL were identified. Pooled analyses on the association between smoking and HL stratified by tumor histology and Epstein-Barr virus (EBV) status were conducted using random effects models adjusted for confounders. Analyses included 3335 HL cases and 14 278 controls. RESULTS: Overall, 54.5% of cases and 57.4% of controls were ever cigarette smokers. Compared with never smokers, ever smokers had an odds ratio (OR) of HL of 1.10 [95% confidence interval (CI) 1.01-1.21]. This increased risk reflected associations with mixed cellularity cHL (OR = 1.60, 95% CI 1.29-1.99) and EBV-positive cHL (OR = 1.81, 95% CI 1.27-2.56) among current smokers, whereas risk of nodular sclerosis (OR = 1.09, 95% CI 0.90-1.32) and EBV-negative HL (OR = 1.02, 95% CI 0.72-1.44) was not increased. CONCLUSION: These results support the notion of etiologic heterogeneity between HL subtypes, highlighting the need for HL stratification in future studies. Even if not relevant to all subtypes, our study emphasizes that cigarette smoking should be added to the few modifiable HL risk factors identified.

Prevalence of High Epworth Sleepiness Scale scores in a rural population.

BACKGROUND: Increased daytime sleepiness is an important symptom of obstructive sleep apnea (OSA). OSA is frequently underdiagnosed, and the Epworth Sleepiness Scale (ESS) can be a useful tool in alerting physicians to a potential problem involving OSA. OBJECTIVE: To measure the prevalence and determinants of daytime sleepiness measured using the ESS in a rural community population. METHODS: A community survey was conducted to examine the risk factors associated with ESS in a rural population in 154 households comprising 283 adults. Questionnaire information was obtained regarding physical factors, social factors, general medical history, family medical history, ESS score, and self-reported height and weight. Multivariable binary logistic regression analysis based on the generalized estimating equations approach to account for clustering within households was used to predict the relationship between a binary ESS score outcome (normal or abnormal) and a set of explanatory variables. RESULTS: The population included 140 men (49.5%) and 143 women (50.5%) with an age range of 18 to 97 years (mean [± SD] 52.0±14.9 years). The data showed that 79.2% of the study participants had an ESS score in the normal range (0 to 10) and 20.8% had an ESS score >10, which is considered to be abnormal or high sleepiness. Multivariable regression analysis revealed that obesity was significantly associated with an abnormal or high sleepiness score on the ESS (OR 3.40 [95% CI 1.31 to 8.80). CONCLUSION: High levels of sleepiness in this population were common. Obesity was an important risk factor for high ESS score.

Changing prevalence of obesity in a rural community between 1977 and 2003: a multiple cross-sectional study.

OBJECTIVE: To determine the changes in the prevalence of obesity in a rural community between 1977 and 2003. STUDY DESIGN: A multiple cross-sectional study. METHODS: The analysis was based on data from four cross-sectional surveys of adults aged 25-59 years, conducted in the town of Humboldt, Saskatchewan in 1977, 1983, 1993 and 2003. People with a body mass index (BMI) > or =30 kg/m(2) were considered to be obese. RESULTS: Average body weight increased by 8 kg for both men and women during the study period. The increase in BMI was greater in adults aged 25-39 years compared with older age groups. The prevalence of obesity increased from 24% in 1977 to 38% in 2003 for men, and from 16% to 32% for women. The change was more pronounced from 1993 to 2003 than from 1977 to 1993, especially among younger adults. Standardized to the 2003 study population by sex, age and smoking status, the prevalence of obesity was 16.8% in 1977, 22.7% in 1983, 24.7% in 1993 and 34.5% in 2003, and was much higher than the Canadian national average (16% in 2003). CONCLUSION: There was a dramatic increase in the prevalence of obesity in rural adults, and this was greater in younger adults. Changes in cigarette smoking did not explain the increase. There is an urgent need to identify and implement effective interventions to slow if not reverse the trend, particularly in rural populations.

Prevention of agricultural injuries: an evaluation of an education-based intervention.

OBJECTIVE: To evaluate the effectiveness of an agricultural health and safety program in reducing risks of injury. DESIGN: Cross-sectional survey. SETTING: 50 rural municipalities in the Province of Saskatchewan, Canada. INTERVENTION: The Agricultural Health and Safety Network (AHSN), a mainly educational program that administered 112 farm safety interventions over 19 years. SUBJECTS: 5292 farm people associated with 2392 Saskatchewan farms. Farms and associated farm people were categorized into three groups according to years of participation in the AHSN. IMPACT: self-reported prevalence of: (1) farm safety practices; (2) physical farm hazards. OUTCOME: (1) self-reported agricultural injuries. RESULTS: After adjustment for group imbalances and clustering at the rural municipality level, the prevalence of all impact and outcome measures was not significantly different on farms grouped according to years of AHSN participation. To illustrate, the adjusted relative risk of reporting no rollover protection on tractors among farms with none (0 years) versus high (>8 years) levels of AHSN participation was 0.95 (95% CI 0.69 to 1.30). The adjusted relative risk for agricultural injuries (all types) reported for the year before the survey was 0.99 (95% CI 0.74 to 1.32). CONCLUSIONS: Educational interventions delivered via the AHSN program were not associated with observable differences in farm safety practices, physical farm hazards, or farm-related injury outcomes. There is a need for the agricultural sector to extend the scope of its injury prevention initiatives to include the full public health model of education, engineering, and regulation.

In vitro production of tumor necrosis factor-alpha by human monocytes stimulated with lipopolysaccharide is positively correlated with increased blood monocytes after exposure to a swine barn.

Recently there has been interest in the air quality in and around intensive livestock production facilities, such as modern swine production barns, where agricultural workers and surrounding residents may be exposed to elevated levels of organic dusts. The health effects of these exposures are not completely understood. The study that is reported here is a component of a larger investigation of the relationships among the acute effects of high-concentration endotoxin exposure (swine barn dust), polymorphisms in the TLR4 gene, and respiratory outcomes following exposure to swine confinement buildings. The relationships among a mediator of acute lung inflammation, tumor necrosis factor alpha (TNF-alpha), and clinical responses to acute swine barn exposure were characterized. Analysis of the results showed that in vitro stimulation of human monocytes with as little as 1 ng/ml of lipopolysaccharide (LPS) produced a significant increase in the monocytes that produced TNF-alpha. Although the proportion of TNF-alpha-positive monocytes after in vitro stimulation with 1 ng/ml of LPS was not associated with gender or TLR4 genotype, it was positively associated with the concentration of monocytes in blood after barn exposure. Thus, these two responses to different forms of LPS exposure are significantly correlated, and more responsive monocytes in vitro indicate a forthcoming relative monocytosis, post barn exposure, which may initiate a cascade of chronic inflammation.

The development of the Canadian Rural Health Research Society: creating capacity through connection.

CONTEXT: The organization of rural health research in Canada has been a recent development. Over the past 8 years, rural and remote researchers from more than 15 universities and agencies across Canada have engaged in a process of research capacity building through the development of a network, the Canadian Rural Health Research Society (CRHRS) among the scientifically and geographically diverse researchers and their community partners. The purpose of this article is to discuss the development of the CRHRS as well as the challenges and lessons learned about creating networks and building capacity among rural and remote health researchers. ISSUE: Key elements of network development have included identifying and developing multidisciplinary research groupings, maintaining ongoing connections among researchers, and promoting the sharing of expertise and resources for research training. The focus has been on supporting research excellence among networks of researchers in smaller centres. Activities include a national annual scientific meeting, the informal formation of several regional and national research networks in specific areas, and the development of training opportunities. Challenges have included the issues of sustaining communication, addressing a range of networking and capacity-enhancement needs, cooperating in an environment that rewards competition, obtaining resources to support a secretariat and research activities, and balancing the demands to foster research excellence with the needs to create infrastructure and advocate for adequate research funding. LESSONS LEARNED: The CRHRS has learned how to begin to support researchers with diverse interests and needs across sectors and wide geographical areas, specifically by: (1) focusing on research development through creating and supporting trusting connections among researchers; (2) building the science first, followed by infrastructure development; (3) making individual researchers the nodes in the network; (4) being inclusive by accommodating a wide variety of researchers and researcher strengths; (5) emphasizing social exchange, knowledge exchange, and mentoring in annual scientific meetings; (6) taking opportunities to develop separate projects while finding ways to link them; (7) finding a balance between advancing the science and advocating for adequate funding and appropriate peer review; (8) developing a network organizational structure that is both stable and flexible; and (9) maintaining sustained visionary leadership.

Respiratory response to endotoxin and dust predicts evidence of inflammatory response in volunteers in a swine barn.

BACKGROUND: It has been shown that exposure in intense exposure in swine barn facilities is associated with increased respiratory symptoms and reduction in pulmonary functions. This study investigated if systemic response could be predicted by FEV(1) response following swine barn exposure. METHODS: Naïve males were tested at baseline, low and high endotoxin and dust levels. Subjects were classified as "more responsive" (n = 9) or "less responsive" (n = 11) based on FEV(1) reduction following high endotoxin exposure. Health measures included pulmonary function testing, blood samples and nasal lavage. Environmental samples were collected from the barn. RESULTS: White blood cells and blood lymphocytes at low exposure were significantly greater in those who were "more responsive" compared to those who were "less responsive". There was a significant increase in blood lymphocytes, serum IL6, total nasal lavage cells and nasal IL8 at high exposure among "more responsive" subjects compared to "less responsive" subjects. CONCLUSIONS: Respiratory response to high-level endotoxin and dust exposure predicts evidence of inflammatory response throughout a range of endotoxin and dust exposures.

Total dust and endotoxin in poultry operations: comparison between cage and floor housing and respiratory effects in workers.

OBJECTIVE: The objective of this study was to assess respiratory outcomes and environmental exposure levels of workers in cage-housed and floor-housed poultry operations. METHODS: Poultry operations were evaluated for total dust, endotoxin, and ammonia, and respiratory symptoms and lung function tests of workers were conducted. RESULTS: Workers in floor-housed poultry operations had significantly greater exposures to total dust and ammonia, whereas workers from cage-housed poultry operations reported greater frequency of current and chronic symptoms overall and significantly greater current and chronic phlegm (39% vs 18% and 40% vs 11%, respectively). Endotoxin concentration (EU/mg) was a significant predictor (P = 0.05) of chronic phlegm for all poultry workers. CONCLUSIONS: Greater endotoxin concentration in the presence of significantly lower total dust, in conjunction with greater respiratory symptoms in workers from cage-housed poultry operations, as compared with workers from floor-housed poultry operations, appears to indicate that differences in environmental exposures may impact respiratory outcomes of workers.

Longitudinal analysis of pulmonary dysfunction in the initial years of employment in the grain industry.

The negative health effects of exposure to grain dust have previously been examined, but few studies have observed the effects on newly hired employees. Young grain workers are of interest because changes in pulmonary function may occur after a short duration of employment, and because older grain workers may represent a survivor population. The New Grain Workers Study (NGWS), a longitudinal study of 299 newly hired male grain industry workers, was conducted between 1980 and 1985. The objectives were to determine the effects of employment in the grain industry on pulmonary function. Pre-employment physical examinations and pulmonary function tests were conducted on subjects at the Division of Respiratory Medicine, Department of Medicine, Royal University Hospital, University of Saskatchewan. The Grain Dust Medical Surveillance Program (GDMSP) was a Labour Canada program that began in 1978. All subjects were grain workers employed in the grain industry in Saskatchewan. All subjects completed a respiratory symptoms questionnaire and underwent pulmonary function testing. Baseline observations were recorded every three years between 1978 and 1993. Data were available on 2184 grain workers. Generalized estimating equations were used to fit marginal and transitional multivariable regression models to determine the effects of grain dust exposure on pulmonary function. Marginal and transitional models were then compared. Height, exposure weeks, and previous FVC were predictive of FVC in the NGWS, while exposure weeks and previous FEV1 were predictive of FEV1. These models, as well as a transitional regression model built using the GDMSP data, were used to compute predicted mean annual decline inpulmonary function. Non-smoking grain workers in the NGWS had the highest pulmonary function test values, but also had the greatest predicted annual decline in pulmonary function. Ever-smoking grain workers in the GDMSP had the lowest pulmonary function test values. Non-smoking grain workers in the GDMSP had the least predicted annual decline in pulmonary function.

Gender, environmental tobacco smoke, and pulmonary function in rural children and adolescents: the Humboldt study.

We examined the gender-related association between household exposure to environmental tobacco smoke (ETS) and pulmonary function among 862 children and adolescents aged 6 to 17 years living in the town of Humboldt, Saskatchewan, in 1993. Pulmonary function tests included forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximum mid-expiratory flow rate (FEF25-75), and flow rates at 75%, 50%, and 25% of vital capacity (Vmax75, Vmax50, and Vmax25). Each pulmonary function test variable was regressed on age, height, weight, and their quadratic and cubic polynomials, with the terms significant at the alpha level of 0.10 being retained. Residuals for the pulmonary function test variables, which are the differences between the observed and predicted values, were calculated. Estimations of ETS exposure were parental smoking status, number of household smokers, total daily cigarette consumption, and number of cigarettes smoked daily at home by household members. Maternal smoking status was significantly related to residual FEF25-75, Vmax75, Vmax50, and Vmax25. Number of household smokers and daily cigarette consumption by household members were significantly associated with FEV1, FEF25-75, Vmax75, Vmax50, and Vmax25, and the association between ETS exposure and pulmonary function was stronger in girls than in boys. Interaction of gender and number of cigarettes smoked daily at home was significantly related to FEF25-75, Vmax75, Vmax50, and Vmax25 among the non-smoking subjects. We concluded that ETS exposure had a larger effect on pulmonary function in girls than in boys.

Occupational asthma in newly employed workers in intensive swine confinement facilities.

Respiratory symptoms, reductions in pulmonary function and increased bronchial responsiveness have been described in exposed workers and in naïve volunteers exposed to intensive swine production facilities. Typically, this occurs in persons who have been employed for a long duration or in previously unexposed, naïve volunteers. The current authors describe four cases, all female, who developed acute onset of wheezing and cough suggestive of asthma within weeks of commencing full-time employment in intensive swine production facilities. None of the workers were aware of any previous asthma, allergies or hay fever. All four employees reported improvement of symptoms on cessation of work in the facilities and consequent withdrawal from exposure. However, when seen at the respiratory clinic, cases 1 and 3 continued to be either mildly symptomatic or were taking medications with continued borderline airways responsiveness, as measured by methacholine challenge test up to 4 and 5 months, respectively, following work cessation. Case 2 continued to have symptoms for > or =3 months after work cessation. Only case 1, however, was seen at repeated visits in the respiratory clinic. One worker participated in a work re-entry trial and experienced profound coughing and chest tightness within an hour of entry, after which, the trial had to be terminated. Provocative concentration causing a 20% fall in forced expiratory volume in one second (PC20) measured 5 h later was lower than pre-trial PC20. No acute exposure event was recorded in the workers prior to the onset of symptoms. To the current authors' knowledge, this is the first report of occupational asthma occurring in newly employed full-time intensive swine production workers after a short-term exposure and should raise awareness that previously unexposed workers may be at risk of developing what would appear to be long-term asthma after relatively short-term exposure.

Effect of age on hospitalized machine-related farm injuries among the Saskatchewan farm population.

Machinery-related injuries are the leading cause of fatal and hospitalized injuries on Canadian farms. In Saskatchewan, the proportion of all farm injuries related to farm machinery exceeds that reported for all of Canada. This project examined the relationship between age and various factors associated with farm machine-related injuries in Saskatchewan. A retrospective review of hospital discharge data from the administrative data set of Saskatchewan Health was conducted using external cause of injury codes to identify cases of farm machinery injury that occurred in Saskatchewan during the period April 1, 1990, to March 31, 2000. Log linear estimates of association of various factors in four age groups were derived. There were 1,493 hospitalizations attributed to farm machinery-related injuries. Among the injured cohort, age was a predictor of the rate of injury. Significant association for nature of injury, mechanism of injury, and type of machine varied by age group. These data provide insights for a case-control study of farm machinery-related injuries with the objective of determining personal, environmental, and machine-related factors that are responsible for this serious public health issue.

Case reports of on-site investigations of auger-related farm injuries.

Previous reports have indicated that injuries involving augers (screw conveyors) are a serious problem in agriculture, but to date on-site engineering inspections linking injuries to mechanical and procedural aspects have not been available. This article details four events involving injuries as the result of being entangled in auger flighting. In each report, the circumstances surrounding the injury event are outlined, and the machinery involved is evaluated in terms of its compliance with current safety standards. In three of the four instances, the machinery did not conform to current guarding standards or to safety sign standards. In these three cases, injuries were preventable with improved guarding according to ASAE Standards. In the other case, the machine complied with ASAE Standards, but the injury could have been prevented with improved guarding of the auger flighting.

Canadian male farm residents, pesticide safety handling practices, exposure to animals and non-Hodgkin's lymphoma (NHL).

BACKGROUND: A majority of published studies indicate that farmers have an elevated risk of developing non-Hodgkin's lymphoma (NHL) compared to other workers. METHODS: We evaluated accidental exposure to pesticides, the use of personal protective equipment, and exposure to animals among male farm residents in a Canadian population-based, multi-centre, NHL-control questionnaire study. RESULTS: In a multivariate model, the following variables had statistically significant adjusted odds ratios (OR) using 95% confidence intervals (95% CI) (a) higher risk: having more than 13 head of swine, raising bison, elk or ostriches, a personal history of cancer, > 4 and < or = 15 years of farm residence and occupational exposure to diesel fuel and exhaust; (b) lower risk: raising cattle and a personal history of measles. CONCLUSIONS: Future multidisciplinary studies of NHL should include a comprehensive review of exposure to animals in sufficient detail to assess etiological mechanisms to explain the putative associations between exposure to farm animals and NHL.

Segregation analyses of asthma and respiratory allergy: the Humboldt family study.

We performed segregation analyses of asthma and respiratory allergy based on data from 309 nuclear families comprising 1,053 individuals living in the town of Humboldt, Saskatchewan, in 1993, using the REGD program of the S.A.G.E. program package. For adults, information on asthma and history of respiratory allergy was provided by the subjects themselves, and for children by their parents. When asthma was considered as the trait in segregation analysis, models of no major effect, with or without familial effects, were rejected, but they were not rejected after adjusting for history of respiratory allergy. The major gene hypothesis was not rejected before adjusting for history of respiratory allergy. When respiratory allergy was analyzed as the trait, both major gene and multifactorial models fitted the data well, regardless of whether there was adjustment for asthma or not. Other covariates adjusted for in the segregation analyses were age, sex, number of household smokers, current smoking, number of household members, generation, and house type. The data suggest that a major gene related to respiratory allergy may explain the familial aggregation of asthma.

Non-Hodgkin's lymphoma and specific pesticide exposures in men: cross-Canada study of pesticides and health.

Our objective in the study was to investigate the putative associations of specific pesticides with non-Hodgkin's Lymphoma [NHL; International Classification of Diseases, version 9 (ICD-9) 200, 202]. We conducted a Canadian multicenter population-based incident, case (n = 517)-control (n = 1506) study among men in a diversity of occupations using an initial postal questionnaire followed by a telephone interview for those reporting pesticide exposure of 10 h/year or more, and a 15% random sample of the remainder. Adjusted odds ratios (ORs) were computed using conditional logistic regression stratified by the matching variables of age and province of residence, and subsequently adjusted for statistically significant medical variables (history of measles, mumps, cancer, allergy desensitization treatment, and a positive history of cancer in first-degree relatives). We found that among major chemical classes of herbicides, the risk of NHL was statistically significantly increased by exposure to phenoxyherbicides [OR, 1.38; 95% confidence interval (CI), 1.06-1.81] and to dicamba (OR, 1.88; 95% CI, 1.32-2.68). Exposure to carbamate (OR, 1.92; 95% CI, 1.22-3.04) and to organophosphorus insecticides (OR, 1.73; 95% CI, 1.27-2.36), amide fungicides, and the fumigant carbon tetrachloride (OR, 2.42; 95% CI, 1.19-5.14) statistically significantly increased risk. Among individual compounds, in multivariate analyses, the risk of NHL was statistically significantly increased by exposure to the herbicides 2,4-dichlorophenoxyacetic acid (2,4-D; OR, 1.32; 95% CI, 1.01-1.73), mecoprop (OR, 2.33; 95% CI, 1.58-3.44), and dicamba (OR, 1.68; 95% CI, 1.00-2.81); to the insecticides malathion (OR, 1.83; 95% CI, 1.31-2.55), 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT), carbaryl (OR, 2.11; 95% CI, 1.21-3.69), aldrin, and lindane; and to the fungicides captan and sulfur compounds. In additional multivariate models, which included exposure to other major chemical classes or individual pesticides, personal antecedent cancer, a history of cancer among first-degree relatives, and exposure to mixtures containing dicamba (OR, 1.96; 95% CI, 1.40-2.75) or to mecoprop (OR, 2.22; 95% CI, 1.49-3.29) and to aldrin (OR, 3.42; 95% CI, 1.18-9.95) were significant independent predictors of an increased risk for NHL, whereas a personal history of measles and of allergy desensitization treatments lowered the risk. We concluded that NHL was associated with specific pesticides after adjustment for other independent predictors.

Positive human health effects of wearing a respirator in a swine barn.

STUDY OBJECTIVES: A study was conducted to evaluate the acute health effects of wearing an N-95 disposable respirator in a swine confinement facility. DESIGN: A crossover trial design was used in the study. SETTING: The study was carried out at the research facilities of the Centre for Agricultural Medicine, the Royal University Hospital, and the Prairie Swine Centre Inc, Saskatoon, Saskatchewan, Canada. PARTICIPANTS: Twenty-one nonsmoking healthy male subjects with no previous swine barn exposure participated in the study. INTERVENTIONS: The subjects participated in a laboratory session (baseline day), a 4-h exposure in a traditional swine room wearing the respirator (intervention day), and a 4-hour exposure in a traditional swine room without a respirator (nonintervention day). MEASUREMENTS: Lung function, methacholine challenge tests, blood counts, nasal lavage, and cytokines in serum and nasal lavage fluid. RESULTS: Mean (+/- SE) shift change in FEV(1), from preexposure to postexposure, was highest on nonintervention day (-8.1+/-1.01%) and was significantly different from intervention day (0.32+/-0.62%; p<0.0001) and baseline day (1.57+/-0.51%; p<0.0001). Similar patterns were observed in the mean values of the provocative concentration of a substance (methacholine) causing a 20% fall in FEV(1) (nonintervention day, 130.4+/-36.9 mg/mL; intervention day, 242.0+/-38.0 mg/mL; and baseline day, 328.0 mg/mL +/-34.1 mg/mL). Significant increases in serum neutrophil levels and nasal cell counts were observed on the nonintervention day in comparison to the baseline and intervention days. Significant increases also were found in the levels of cytokines interleukin (IL)-6 and IL-8 in nasal lavage fluid and in the levels of IL-6 in serum for the nonintervention day in comparison to the other 2 days. CONCLUSIONS: The results demonstrate that an N-95 disposable respirator can help to significantly reduce acute negative health effects in subjects not previously exposed to a swine barn environment.

Seasonal changes in lung function in a farming population.

OBJECTIVE: To assess the changes in respiratory health from winter to summer seasons in a rural population. DESIGN: A longitudinal design was used in the study. SETTING: A population-based study was conducted as part of the Environmental Pesticide Exposure and Human Health component of the Prairie Ecosystem Study (PECOS) in southwestern Saskatchewan. PATIENTS: In the winter season, 358 patients participated in the study. Of these patients, 234 returned for the second assessment during the summer season. After excluding 34 children aged 17 years and under, 200 adult patients were available for analysis. MEASUREMENTS: Questionnaires were used to obtain information on demographic factors, smoking habits, occupational and environmental exposures, and respiratory conditions. Pulmonary function measurements were obtained using a volume displacement spirometer. RESULTS: Mean ages (+/- SD) of the 106 men and 94 women participating in the study were 50.1+/-13.3 and 49.0+/-13.1 years, respectively. Mean percentage changes in maximal midexpiratory flow rate from winter to summer assessments indicated an improvement for town residents and a decline for farm residents. Mean percentage changes in the ratio of forced expiratory volume in 1 s to forced vital capacity indicated an improvement for town residents who were not engaged in farming, and increasing declines for town residents engaged in farming, farm residents not engaged in farming and farm residents engaged in farming. CONCLUSIONS: Seasonal changes occurred in measurements of pulmonary function between winter and summer seasons; these changes may be related to the environmental or occupational exposures experienced by the participants during the study.