Nasal cytokine responses to natural colds in asthmatic children.

BACKGROUND: The mechanisms by which viruses induce asthma exacerbations are not well understood. OBJECTIVE: We characterized fluctuations in nasal aspirate cytokines during naturally occurring respiratory viral infections in children with asthma. METHODS: Sixteen children underwent home collections of nasal aspirates when they were without cold symptoms and again during self-reported respiratory illnesses. The presence of viral infection was ascertained by multiplex PCR. Cytokines were measured using multiplex immune assay. mRNA expression for selected markers of viral infection was measured using RT-PCR. A cumulative respiratory symptom score was calculated for each day of measurement. Generalized estimated equations were used to evaluate associations between viral infection and marker elevation, and between marker elevation and symptom score. RESULTS: The 16 patients completed a total of 37 weeks of assessment (15 'well' weeks; 22 self-assessed 'sick' weeks). Viral infections were detected in 3 of the 'well' weeks and 17 of the 'sick' weeks (10 rhinovirus, three coronavirus, two influenza A, two influenza B, two respiratory syncytial virus, one parainfluenza). Compared to virus-negative well weeks, nasal aspirate IFN-γ, CXCL8/IL-8, CXCL10/IP-10, CCL5/RANTES, CCL11/eotaxin-1, CCL2/MCP-1, CCL4/MIP-1ß, CCL7/MCP-3, and CCL20/MIP3α protein levels increased during virus-positive sick weeks. Only a subset of cytokines (IFN-γ, CXCL8, CCL2, CCL4, CCL5, and CCL20) correlated with self-reported respiratory tract symptoms. While many aspirates were dilute and showed no mRNA signal, viral infection significantly increased the number of samples that were positive for IFN-λ1, IFN-λ2/3, TLR3, RIG-I, and IRF7 mRNA. CONCLUSIONS AND CLINICAL RELEVANCE: We conclude that in children with asthma, naturally occurring viral infections apparently induce a robust innate immune response including expression of specific chemokines, IFNs, and IFN-responsive genes.

Determinants of asthma phenotypes in supermarket bakery workers.

While baker's asthma has been well described, various asthma phenotypes in bakery workers have yet to be characterised. Our study aims to describe the asthma phenotypes in supermarket bakery workers in relation to host risk factors and self-reported exposure to flour dust. A cross-sectional study of 517 supermarket bakery workers in 31 bakeries used a questionnaire, skin prick tests, and specific immunoglobulin E to wheat, rye and fungal alpha-amylase and methacholine challenge testing. The prevalence of probable occupational asthma (OA, 13%) was higher than atopic (6%), nonatopic (6%) and work-aggravated asthma (WAA, 3%) phenotypes. Previous episodes of high exposure to dusts, fumes and vapours causing asthma symptoms were more strongly associated with WAA (OR 5.8, 95% CI 1.7-19.2) than OA (2.8, 1.4-5.5). Work-related ocular-nasal symptoms were significantly associated with WAA (4.3, 1.3-13.8) and OA (3.1, 1.8-5.5). Bakers with OA had an increased odds ratio of reporting adverse reactions to ingested grain products (6.4, 2.0-19.8). OA is the most common phenotype among supermarket bakery workers. Analysis of risk factors contributes to defining clinical phenotypes, which will guide ongoing medical surveillance and clinical management of bakery workers.

Interaction between ambient pollutant exposure, CD14 (-159) polymorphism and respiratory outcomes among children in Kwazulu-Natal, Durban.

The objective of this study was to determine if the association between exposure to ambient air pollutants such as sulfur dioxide, nitrogen dioxde (NO2), nitrous oxide (NO), and PM10, and variation in lung function measures was modified by genotype. A validated questionnaire was administered to 71 African children to evaluate prevalence of respiratory symptoms. Atopy was evaluated by skin-prick testing and bihourly measures of lung function (spirometry) were collected. Gaseous air pollutant concentrations were monitored continuously. CD14 polymorphism was genotyped and plasma CD14 levels were measured. There was no statistically significant association between the CD14 (159) CT+TT polymorphism with any asthma-related phenotype. There was a significant association between lung function (forced expiratory volume in 1 second intraday variability) and NO2 and NO among participants carrying the CD14 CT/TT genotype for lags 1, 2, and the 5-day average. Similarly, statistically significant gene-pollutant interactions ( p < 0.05) were found with NO and CD14 CT/TT at lag 2 and for the 5-day average. While there was no association with any respiratory phenotype (as determined by symptoms), the CD14 CT/TT genotype appeared to be protective to increased exposure to NO2 and NO.

Childhood asthma.

Asthma prevalence in children has increased 58% since 1980. Mortality has increased by 78%. The burden of the disease is most acute in urban areas and racial/ethnic minority populations. Hospitalization and morbidity rates for nonwhites are more than twice those for whites. Asthma is characterized by recurrent wheezing, breathlessness, chest tightness, and coughing. Research in the past decade has revealed the importance of inflammation of the airways in asthma and clinical treatment to reduce chronic inflammation. Asthma is associated with production of IgE to common environmental allergens including house dust mite, animal dander, cockroach, fungal spores, and pollens. Some interventions to reduce symptoms through control of dust mite and animal dander have had positive results. Control of symptoms through interventions to reduce exposures to cockroach antigen has not been reported. Studies illustrating causal effects between outdoor air pollution and asthma prevalence are scant. Increases in asthma prevalence have occurred at the same time as general improvements in air quality. However, air quality appears to exacerbate symptoms in the child who already has the disease. Decreased pulmonary function has been associated with exposure to particulates and bronchial hyperresponsiveness to smoke, SO(2) and NO(2). Symptoms have been correlated with increased levels of respirable particulates, ozone, and SO(2). Interventions that reduce the negative outcomes in asthma associated with outdoor environmental factors have not been reported. Control of asthma in children will entail the collaborative efforts of patients, family, clinical professionals, and school personnel, as well as community-wide environmental control measures and conducive national and local policies based on sound research.

An evaluation of peer and professional trainers in a union-based occupational health and safety training program.

Social cognitive theory posits that behavior can be changed by observing others perform or describe performance of behaviors. This framework was applied to understanding health behavior change associated with workplace health and safety training. Questionnaires were developed and administered to 426 workers at a United Automobile Worker's Union health and safety training program. Participants received training from one of three trainers: (1) local union discussion leaders (LUDLs), (2) professional staff trainers, or (3) LUDLs with professional staff trainers. Data were collected in three phases: before, after, and three months post-training. Findings show that subjects trained by LUDLs identify most closely with their instructors, whereas subjects trained by staff trainers identify least closely with them. In addition, workers trained by LUDLs reported changing behavior as a result of training more often than workers trained by others.

Effect of overtime work on cognitive function in automotive workers.

OBJECTIVE: The present investigation examined whether increased overtime work predicts impairment in cognitive performance in the domains of attention, executive function, and mood. METHODS: The behavioral and cognitive functions of 248 automotive workers were measured by a neurobehavioral test performance. Overtime, defined as number of hours worked greater than 8 h a day or greater than 5 d a week, was calculated from company payroll records for the week before the test day. The number of consecutive days worked before the test day was also determined. RESULTS: Cross-sectional data analysis by multiple linear regression, after adjustment for the effects of age, education, gender, alcohol intake, repeated grade in school, acute petroleum naphtha exposure, shift worked, job type, number of consecutive days worked before the test day, and number of hours worked on the test day before the testing, demonstrated that increased overtime was significantly associated with impaired performance on several tests of attention and executive function. Increased feelings of depression, fatigue, and confusion were also associated with increased overtime work. In addition significant interaction effects were observed for job type but not for naphtha exposure. CONCLUSIONS: The findings support the hypothesis that overtime work results in impaired cognitive performance in the areas of attention and executive function and that both overtime hours and the number of consecutive days worked prior to a test day affect mood.

Ambient pollution and respiratory outcomes among schoolchildren in Durban, South Africa.

OBJECTIVE: To examine associations between ambient air pollutants and respiratory outcomes among schoolchildren in Durban, South Africa. METHODS: Primary schools from within each of seven communities in two regions of Durban (the highly industrialised south compared with the non-industrial north) were selected. Children from randomly selected grade 4 classrooms were invited to participate. Standardised interviews, spirometry, methacholine challenge testing and skin-prick testing were conducted. Particulate matter (PM), sulphur dioxide (SO2) and carbon monoxide were monitored at each school, while nitrogen oxides (NOx) and other pollutants were monitored at other sites. RESULTS: SO2 was significantly higher in the south than in the north, while PM concentrations were similar across the city. The prevalence of symptoms consistent with asthma of any severity was 32.1%. Covariate-adjusted prevalences were higher among children from schools in the south than among those from the north for persistent asthma (12.2% v. 9.6 %) and for marked airway hyperreactivity (AHR) (8.1% v. 2.8%), while SO2 resulted in a twofold increased risk of marked AHR (95% confidence interval 0.98 - 4.66; p=0.056). CONCLUSIONS: Schoolchildren from industrially exposed communities experienced higher covariate-adjusted prevalences of persistent asthma and marked AHR than children from communities distant from industrial sources. Our findings are strongly suggestive of industrial pollution-related adverse respiratory health effects among these children.

Environmental exposure characterization of fish processing workers.

BACKGROUND: Aerosolization of seafood and subsequent inhalation, during processing is a potential high-risk activity for allergic respiratory disease. OBJECTIVES: To quantify total thoracic particulate, protein concentration and specific fish (pilchard, anchovy) antigen concentrations in fish processing plants; to determine the correlation between these exposure metrics; and to identify the major determinants of variability and the optimal grouping strategies for establishing dose-response relationships for fish antigen exposures. METHODS: Exposure assessments were conducted on randomly selected individuals within each of the identified 'exposure groups' (EGs) in two fish processing factories. Personal time-integrated sampling was conducted with a thoracic fraction sampler and analysed for particulate mass, total protein and specific fish antigens. Exposure metrics were developed on the basis of individually measured exposures and average levels of these personal samples within EGs. The main components of the exposure variability were determined using ANOVA techniques. RESULTS: A total of 198 full-shift personal aerosol samples were collected and analysed. Twenty-two percent of the samples were below the limit of detection (LOD) for pilchard and 23% for anchovy assays. Personal sampling revealed wide variations across EGs in arithmetic mean concentrations of thoracic particulate 0.61 mg m(-3) (range: LOD-11.3), total protein 0.89 microg m(-3) (LOD-11.5), pilchard antigen 150 ng m(-3) (LOD-15 973) and anchovy antigen 552 ng m(-3) (LOD-75 748) levels. The fishmeal loading and bagging sections of both plants showed consistently high thoracic particulate mass (0.811-2.714 mg m(-3)), total protein (0.185-1.855 microg m(-3)), pilchard antigen (538-3288 ng m(-3)) and anchovy antigen (1708-15 431 ng m(-3)). The a priori strategy that grouped workers according to EGs produced reasonably satisfactory summary exposure metric statistics. An alternative grouping strategy based on department revealed comparable elasticity (exposure contrast). While the correlation between the log-transformed thoracic particulate mass and fish antigen concentrations were generally modest (Pearson's r = 0.32-0.35, P < 0.001), a high correlation was found between pilchard and anchovy antigen concentrations (Pearson's r = 0.71, P < 0.001). Models using factory and department grouping strategies accounted for a significant portion of the variability (adjusted r(2) = 0.18, P = 0.043) in pilchard antigen levels. Grouping strategies using a combination of factory and department yielded the highest degree of elasticity for thoracic particulate (0.38) and pilchard antigen (0.42) levels. CONCLUSIONS: Workers involved in bony fish processing are at risk of inhaling aerosols containing pilchard and anchovy fish antigens. Antigen exposures are highest during fishmeal production and bagging. Grouping strategies based on department and factory may provide a more efficient approach than a priori classification of EGs for evaluating fish antigen exposures.

Respiratory morbidity in workers exposed to asbestos in the primary manufacture of building materials.

Former employees (214) of a plant that manufactured asbestos-containing building materials (wallboard and acoustic tile) from 1958 through 1974 were screened for asbestos-related pulmonary disease. Results are presented on 182 union members whose names appeared on a 1966 seniority list in one of six departments believed to have had substantial asbestos exposure. The study population demonstrated a high frequency of pulmonary abnormalities often associated with asbestos exposure: low mean forced vital capacity percent of predicted (FVC % predicted), low mean forced expiratory volume at one second percent of predicted (FEV1 % predicted), presence of parenchymal abnormalities (40.1% with profusion scores of 1/0 or higher), and 30.5% with bilateral pleural abnormalities on chest roentgenograms. In addition, râles in two or more locations were found in 22.8% on examination of the chest, 30.6% gave a history of chronic bronchitis, and 34.8% of dyspnea grade two or higher. Calculated asbestos exposure scores, based upon participant recall, were not found to be associated with these abnormalities. The abnormal findings were not adequately explained by potential confounders such as cigarette smoking. Other notable findings in this study include the presence of smoking-adjusted decrements in pulmonary function associated with moderate profusion scores (i.e., 1/0 and 1/1) and the presence of a substantial degree of obstructive lung disease (19.2%) in this population.

Hazard communication in a large U.S. manufacturing firm: the ecology of health education in the workplace.

This article describes the design, implementation, and evaluation of a workplace health and safety education program intended to bring a large U.S. manufacturing firm into compliance with a Federal regulation, the Hazard Communication Standard. The methods of program delivery and levels of resources allocated were decided by local plant management and union representatives resulting in marked variations among the five plants studied. These differences in program delivery were associated with differences in employee assessment of the training's usefulness, changes in employee work practices, working conditions, and organizational handling of health and safety problems. In all five plants, the program evidenced indirect beneficial effects on the use of hazard control measures and organizational approaches to health and safety issues which went beyond the requirements of the federal Standard. The results appear well-explained by an ecological model which views health and disease as outcomes of a complex system of interactions between the individual worker and multiple levels of environmental influences. Implications of these findings for health educators are discussed.

Chronic noise exposure, high-frequency hearing loss, and hypertension among automotive assembly workers.

The prevalence of hypertension and mean blood pressure was studied in 150 white men and 119 black men exposed to industrial noise of 85 dBA or greater for a minimum of 5 years. Mean decibel loss at 4000 Hz was 28.3 among the black workers and 45.3 among the white workers. 31.9% of the black men and 22.0% of the white men had hypertension, defined as diastolic blood pressure greater than 90 mm Hg and/or currently taking hypertensive medication. After controlling for several potential confounding factors, hearing loss at 4000 Hz and years worked in high-noise departments were significantly associated with mean blood pressure and hypertension among the black workers. No correlation between mean blood pressure or the presence of hypertension and hearing loss at 4000 Hz or years worked in high-noise departments was found among the white workers.

Renal function in dry cleaning workers exposed to perchloroethylene.

Perchloroethylene (PCE) is a widely used dry cleaning and degreasing solvent. Although there is evidence in animals and humans for renal effects at extremely high doses, there are few studies of its potential renal toxicity at typical occupational concentrations. This study reports on the relationship of PCE in breath and estimates of chronic exposure with the urinary ratios of total urinary protein, albumin, and n-acetyl-glucosaminidase (NAG) to creatinine in dry cleaning workers exposed to PCE. Regression models including one or more exposure variables, demographic variables, mean arterial blood pressure (MAP), and the presence of diseases affecting kidney function were examined. Urine samples, breath samples, exposure histories, and medical histories were obtained from 192 dry cleaning workers. The results failed to demonstrate any consistent relationship between exposure and renal outcome variables. However, protein/creatinine and albumin/creatinine were significantly, although weakly and positively, associated with MAP; NAG/creatinine was weakly but significantly positively associated with age; mean NAG/creatinine was also higher in non-whites. The reasons why an association between exposure and renal outcome was not found are discussed.

Relationship of cumulative trauma disorders of the upper extremity to degree of hand preference.

The degree of hand preference, ie, the extent to which the use of one upper extremity is obligate, has not been studied previously as a possible risk factor for the development of upper extremity cumulative trauma disorders (UECTDs). This case-control study was designed to test the hypothesis that strong hand preference, whether left or right, would be associated with UECTDs in a working population. Case subjects were drawn from workers who presented to one of two acute care clinics for treatment of work-related cumulative trauma disorders of the upper extremity. Control subjects were drawn from job applicants presenting for preplacement examinations at the same two clinics. The degree of hand preference was determined by the Edinburgh Handedness Inventory of Oldfield. The 48 case subjects evidenced a higher absolute value of the mean handedness score (indicative of a stronger degree of hand preference) than the 134 control subjects (P = .01). As a dichotomized variable, being "strong"-handed versus "weak"-handed was a significant risk factor for UECTD (P = .01, odds ratio = 2.48). Among the 48 case subjects, 83% had a UECTD ipsilateral to the side of hand preference. This study found that workers who develop cumulative trauma disorders of the upper extremity are more likely to exhibit a strong hand preference than a group of applicants entering the work force. These findings suggest that the endogenously determined obligate use of one extremity may be a significant risk factor for the development of upper extremity cumulative trauma disorders.

Assessment of a screening protocol for occupational renal disease.

Using 10 guidelines for medical screening programs, this review assesses a screening protocol that seeks to identify presymptomatic occupational renal disease among workers with nephrotoxin exposure. The protocol uses urinary markers of early renal dysfunction for the screening test. The review reveals that arguments for screening are the clinical significance of renal disease, worker acceptance of urine collection, the availability of exposure reduction as an intervention, and the availability of diagnostic and treatment facilities. Obstacles to screening are the lack of an effective intervention, the lack of strong evidence to indicate that an elevation in the urinary markers represents a preclinical stage of occupational renal disease, and the absence of firm numbers to demarcate normal from elevated concentrations of urinary markers. Given these obstacles, screening for occupational renal disease is not recommended.

The use of geometric and arithmetic mean exposures in occupational epidemiology.

In constructing quantitative measures of exposure for the study of chronic occupational disease, researchers have generally used a cumulative exposure calculated as the sum of the products of period-specific exposure concentrations and the time each individual spent in each exposure category. There has been some disagreement and lack of clarity about the use of the geometric or arithmetic mean of exposure for this calculation. This paper explores the difference in the use of the two measures and defines a relative bias introduced with the geometric vs. the arithmetic mean. The magnitude of the bias is calculated in two linear models of possible exposure-response relationships. The theoretical basis for the choice of one mean over the other is then explored. It is suggested that when adopting a linear exposure response model, the arithmetic mean is the more appropriate measure. In other models, such as a linear-log (outcome is proportional to the logarithm of exposure) model, the geometric mean would be more appropriate.

Solvent nephrotoxicity in humans and experimental animals.

Evidence from human case reports, epidemiologic studies and animal experiments have suggested that exposure to organic solvents is associated with a wide spectrum of renal disorders, including tubular necrosis, interstitial disease, glomerulonephritis and neoplasia. This review summarizes what is known about solvent-induced renal damage in humans and experimental animals, with emphasis on hypothesized mechanisms by which this broad range of disorders may occur.

Perchloroethylene exposure assessment among dry cleaning workers.

Perchloroethylene (Perc), the most widely used solvent in dry cleaning, is toxic to the liver, kidneys, and central nervous system and may be a human carcinogen. In the Detroit area, as part of a project investigating the health status of dry cleaning workers, an exposure assessment was carried out in dry cleaning plants using perchloroethylene. Breath samples were obtained from each participant, and time-weighted average (TWA) breathing zone air samples were obtained using passive dosimeters on a subset expected to experience a range of exposures. Perc in breath and Perc in air were highly correlated (r2 = 0.75, p less than 0.0001). On average, operators of dry cleaning equipment experienced significantly more exposure than nonoperators. Also, employees working in shops that use transfer equipment (requiring physical transfer of Perc-saturated clothing from washers to dryers) showed significantly higher exposure than those in shops utilizing dry-to-dry machinery (permitting washing and drying in one machine in a single cycle). One or more air samples in every transfer shop exceeded the recently revised Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) of 25 ppm, while no air samples in dry-to-dry shops exceeded this limit. The results suggest concern for exposures to operators in transfer shops and that compliance with the PEL is achievable by engineering controls with presently existing technology.

Lymphocytopenia, T-lymphocyte subsets, and colorectal polyps in automotive pattern and model makers.

Several studies have found pattern and model makers to be at increased risk for colorectal polyps and colorectal cancers. One study found an increased prevalence of lymphocytopenia. The association of total lymphocyte, CD4 (T-helper cell), CD8 (T-suppressor cell), CD2 (total T-cell), and CD16 (natural killer cell) counts with biopsy-proved colorectal polyp status was investigated in 70 patternmakers participating in one or more of four sequential screenings. In logistic regression analyses after adjusting for age or trade years, pack-years smoked, and material worked with most, a history of any type of polyp was significantly associated with total lymphocyte count (odds ratio of 2.01 for a 500 cell/cc decrease, P = 0.03), and somewhat associated with decreased CD4 and CD2 counts (P values of 0.06 and 0.07, respectively). In linear regression models adjusted for age, pattern and model makers had (regardless of polyp status) significantly lower CD4, CD8, CD2, and CD16 counts than did laboratory reference controls (P value less than 0.01 for each comparison). These findings appear consistent with a sequence of carcinogenesis initiated by pattern and model makers' work-place exposures that depress immune surveillance thus promoting the development of colorectal polyps as a precursor of carcinoma.