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Dennis Nowak

Publications and source records attributed to Dennis Nowak.

At least 37 records · Page 2Linked to original sources
PubMed2004

Childhood visits to animal buildings and atopic diseases in adulthood: an age-dependent relationship.

BACKGROUND: Several studies reported protective effects of farming environments against atopic diseases. Therefore, we aimed to establish the relevant timing of exposure in early life. METHODS: A cross-sectional study was carried out in a rural town. Overall, 4,537 inhabitants aged 18-44 years were eligible. Of these, 3,112 (69%) responded to a postal questionnaire on atopic diseases, life-time exposure to farming environments, and potential confounders. RESULTS: Those with regular childhood exposure to animal buildings had a significantly reduced risk of nasal allergies. The greatest reduction in risk was seen for respondents starting regular visits to animal stables during the 1st year of life or between ages 3 and 5. Participants reporting start of exposure after age 5 remained at a lower risk for nasal allergies (0.70, 0.49-1.01). CONCLUSIONS: The preventive effect of animal buildings' exposure against atopic respiratory diseases continues into adulthood. The magnitude of the effect appears to be age-dependent.

Adult↗
PubMed2004

Working Group report 1: tools for the diagnosis of organic dusts-induced disease.

This paper describes the outcomes of the discussion of Working Group 1. The tasks of the workgroup were to: i) review current methods for the clinical diagnosis of organic dust induced disease, and ii) suggest how further research in this field should proceed. The working group proceeded on the paradigm that for diagnosis specific and precise tests are needed, where outcomes can be related to the risk for disease. The different methods available for the investigation of individuals and groups exposed to organic dusts are summed and graded according to scientific or diagnostic values. Many of the tools should be used in experimental research only, but can be used diagnostically for evaluation during follow up of patients when treated or removed from exposure. These techniques may also be employed for investigations of outbreaks, however, only after comparison with a proper control group. Future research should focus on associations between markers of inflammation and symptoms or clinical outcomes and dose-response relationships both for short-term and long-term health effects.

Airway Obstruction↗
PubMed2004

Chronic obstructive pulmonary disease in never-smoking animal farmers working inside confinement buildings.

BACKGROUND: In animal farming, respiratory disease has been associated with indoor air contaminants and an excess in FEV1 decline. Our aim was to determine the characteristics and risk factors for chronic obstructive pulmonary disease (COPD) in never-smoking European farmers working inside animal confinement buildings. METHODS: A sample of participants in the European Farmers' Study was selected for a cross-sectional study assessing lung function and air contaminants. Dose-response relationships were assessed using logistic regression models. RESULTS: COPD was found in 18 of 105 farmers (45.1 SD 11.7 years) (17.1%); 8 cases (7.6%) with moderate and 3 cases (2.9%) with severe disease. Dust and endotoxin showed a dose-response relationship with COPD, with the highest prevalence of COPD in subjects with high dust (low=7.9%/high=31.6%) and endotoxin exposure (low=10.5%/high=20.0%). This association was statistically significant for dust in the multivariate analysis (OR 6.60, 95% CI 1.10-39.54). CONCLUSION: COPD in never-smoking animal farmers working inside confinement buildings is related to indoor dust exposure and may become severe.

Adult↗
PubMed2004

Toll-like receptor 2 as a major gene for asthma in children of European farmers.

BACKGROUND: The finding that the prevalence of asthma and allergies is less frequent in children raised on animal farms has led to the conjecture that exposure to microbial products modifies immune responses. The toll-like receptors (TLRs) represent an evolutionarily conserved family of innate immunity receptors with microbial molecules as ligands. OBJECTIVES: We reasoned that polymorphisms in genes encoding TLRs might modulate the protective effects observed in farming populations. METHODS: Farmers' and nonfarmers' children living in rural areas in Austria and Germany and who were enrolled in the cross-sectional ALEX study were genotyped for single nucleotide polymorphisms in the TLR2 and TLR4 genes. The frequencies of asthma, allergic rhinitis, and atopic sensitization were compared between the genotypes in relation to exposure to farming and endotoxin. RESULTS: Among farmers' children, those carrying a T allele in TLR2/-16934 compared with children with genotype AA were significantly less likely to have a diagnosis of asthma (3% vs 13%, P = .012), current asthma symptoms (3% vs 16%, P = .004), atopic sensitization (14% vs 27%, P = .023), and current hay fever symptoms (3% vs 14%, P = .01). The association between TLR2/-16934 and asthma among children of farmers was independent of atopy. No such association was found among children from the same rural communities but not living on farms. CONCLUSION: Our results suggest that genetic variation in TLR2 is a major determinant of the susceptibility to asthma and allergies in children of farmers.

Adult↗
PubMed2004

Microbial exposure of rural school children, as assessed by levels of N-acetyl-muramic acid in mattress dust, and its association with respiratory health.

BACKGROUND: Endotoxin exposure has been shown to be associated with a decreased prevalence of atopic sensitization and symptoms. Yet endotoxin represents only a part of the indoor microbial exposure. Muramic acid, a constituent of peptidoglycan, is present in gram-negative and gram-positive bacteria in the environment and may therefore serve as an additional marker of microbial exposure. OBJECTIVE: To study the factors determining the level of indoor exposure to muramic acid/peptidoglycan, as well as its potential association with respiratory health. METHODS: In 553 farm and nonfarm school children from Austria, Switzerland, and Germany, mattress dust muramic acid concentrations were determined, and health was assessed by using IgE measurements and questionnaire information. RESULTS: The muramic acid concentration was found to be significantly higher in dust from farm children's mattresses than in dust from nonfarm children's mattresses (157 vs 131 ng/mg). Children with higher mattress dust muramic acid concentrations had a significantly lower prevalence of wheezing (odds ratio of highest vs lowest tertile of muramic acid concentration, 0.3; 95% CI, 0.1-0.9), regardless of farming status and endotoxin exposure. The association for asthma was similar, and no association was found with atopic sensitization. CONCLUSION: Next to endotoxin, muramic acid provides us with an independent marker of microbial exposure. Unlike endotoxin, muramic acid was inversely associated with wheezing rather than with atopic sensitization.

Asthma↗
PubMed2004

Rethinking Th2 antibody responses and allergic sensitization.

Human Th2 cytokines (interleukins 4 and 13) induce co-expression of IgE and IgG4 through sequential switching. The regulation of IgG4 responses and the role of these responses in the pathogenesis of allergy have not been characterized. We are addressing these issues by comparing and contrasting the expression of allergen-specific IgE and IgG4 in a population of European children thoroughly defined for lifestyle, environmental exposures and allergic phenotypes. The current analysis focused exclusively on children from non-farming families (n=493) in order to avoid potential effects of exposure to microbial products abundant in farming environments. We found that allergens induce Th2-mediated IgG4 and/or IgE responses in the majority of the population. Approximately two-thirds of the children had allergen-specific IgG4 but not IgE, only a minority had both IgG4 and IgE, only a few were negative for both, and virtually none had only IgE. The prevalence of asthma and hay fever was dramatically higher in children with high IgG4 and IgE compared to children who only mounted IgG4 or low IgG4 and IgE responses. These results appear to recapitulate different stages of in vivo Th2-dependent sequential switching from IgG4 to IgE. These patterns of Th2-induced antibody responses may warrant a redefinition of the notion of allergen sensitization.

Agriculture↗
PubMed2004

Livestock odours and quality of life of neighbouring residents.

Neighbours of intensive livestock production facilities frequently complain of odour annoyance. They are also concerned about potential negative health effects of environmental exposures to livestock emissions. Quality of life (QoL) was assessed in residents of a rural community neighbouring an area with high concentration of animal farms. A postal cross-sectional survey was carried out among the 4,537 residents, aged 18-44 years. Of these, 3,112 (69 %) responded to questions on annoyance by livestock odours (4-point scale), on QoL (assessed by the short form 12, SF-12), and on potential confounders (age, gender, respiratory symptoms, smoking, living on or close to a farm, and employment status). SF-12 scores were available for 2745 (88 %) subjects. Sixty-one percent of the respondents complained about unpleasant odours, 91 % of these accused livestock as source of these odours. Physical and emotional SF-12 scores were inversely related to annoyance scores. Better risk communication might improve QoL in concerned neighbours of intensive livestock production facilities.

Adaptation, Psychological↗
PubMed2003

Working in permanent hypoxia for fire protection-impact on health.

OBJECTIVES: A new technique to prevent fires is continuous exchange of oxygen with nitrogen which leads to an oxygen concentration of between 15% and 13% in the ambient air. This paper reviews the effect of short-term, intermittent hypoxia on health and performance of people working in such atmospheres. METHODS: We reviewed the effect of ambient air hypoxia on human health in the literature using Medline, as well as reference lists of articles and handbooks. Articles were assessed from the perspective of working conditions in fire-protected rooms. RESULTS: Oxygen reduced to 15% and 13% in normobaric atmospheres is equivalent to the hypobaric atmospheres found at 2,700 and 3,850-m altitudes. When acutely exposed, a healthy person responds within minutes to hours with increased ventilation, stimulation of the sympathetic system, increased heart rate, increased pulmonary-circulation resistance, reduced plasma volume, and stimulation of erythropoesis. Acute mountain sickness occurs frequently at these oxygen partial pressures, but the full syndrome is rare if continuous exposure is limited to 6 h. Mood, cognitive, and psychomotor functions may be mildly impaired in these conditions, but data are inconclusive. Persons suffering from cardiac, pulmonary, or hematological diseases should consult a specialist in order for their individual risk to be assessed, and medical screening for any of these diseases is strongly recommended prior to exposure. CONCLUSION: Preliminary evidence suggests that working environments with low oxygen concentrations to a minimum of 13% and normal barometric pressure do not impose a health hazard, provided that precautions are observed, comprising medical examinations and limitation of exposure time. However, evidence is limited, particularly with regard to workers performing strenuous tasks or having various diseases. Therefore, close monitoring of the health problems of people working in low oxygen atmospheres is necessary.

Altitude↗
PubMed2003

Environmental ozone effects in different population subgroups.

The study objective was to get more information on characteristics of ozone risk groups. We performed repeated (on average 16 times) lung function tests and interviews with 171 persons belonging to four different population subgroups (44 healthy children, 43 juvenile asthmatics, 43 athletes, and 41 elderly). The environmental half hour mean ozone concentrations ranged from 8 to 99 ppb. For two groups there was significant NO2 co-pollution. The asthmatics showed statistically significant ozone related increased ORs for eye irritations, the elderly for nose irritations. Significant lung function decrements (increase in ozone by 50 ppb) were found for asthmatics (FVC -4.3% afternoon one day lag, -4.9% afternoon two day lag, -3.6% morning one day lag) and children (FVC -3.2% same morning, PEF -11.9% same morning, PEF -4.6% morning one day lag). In the group of elderly, however, there were also some significant FVC and PEF increments. Ozone responders were found more often in the groups of asthmatics and children (21% resp. 18%) compared with elderly and athletes (both 5%). The results suggest that children and asthmatics have a higher risk of being ozone sensitive showing more ozone related acute lung function decrements than other population groups.

Adolescent↗
PubMed2002

Uptake of antineoplastic agents in pharmacy and hospital personnel. Part I: monitoring of urinary concentrations.

OBJECTIVES: There is a risk of adverse health effects for personnel with occupational exposure to antineoplastic agents. The aim of the present longitudinal study was to identify, quantify, and evaluate potential health hazards of occupationally exposed workers in pharmaceutical and oncological departments with central processing units for drug preparation. METHODS: One hundred operatives in 14 German hospital pharmacies and oncological departments underwent biological monitoring by providing urine samples up to four times over a period of 3 years. RESULTS: All antineoplastic agents that were considered (cyclophosphamide, ifosfamide, doxorubicin, epirubicin and platinum from cisplatin and carboplatin), were found in urine samples in up to 40% of participants. CONCLUSIONS: Despite standard safety precautions, such as the use of vertical laminar air flow safety cabinets, and personal protective clothing, incorporation of drugs was detected. Therefore, an environmental monitoring strategy should be developed in order to detect contamination and attempt to improve hygiene during work.

Adult↗
PubMed2002

Uptake of antineoplastic agents in pharmacy personnel. Part II: study of work-related risk factors.

OBJECTIVES: This study aimed to find working conditions related to internal exposure of substances handled in centralised cytostatic drug preparation units in hospitals. Recommendations to avoid this uptake should be deduced from the results. METHOD: In a longitudinal study over 3 years, 87 pharmacy technicians and pharmacists of 14 different hospitals in Germany provided 24-h urine samples separately up to three times (three sampling cycles: cycles 1-3) at the end of a working week. Additional samples were taken after 2 days and after at least 3 weeks of absence. Cyclophosphamide and ifosfamide, doxo-, dauno- epi-, and idarubicin, and platinum deriving from cis- and carboplatin were determined in urine samples by gas chromatography/mass spectrometry, liquid chromatography (HPLC) and voltammetry. The following working conditions were assessed by questionnaire: working tasks, different ways that the workbenches were run, cleaning conditions, waste disposal, number of preparations, amount of substances handled, and use of gloves (material, thickness and changing interval). RESULTS: Two-thirds of the subjects showed at least one positive result with regard to all three cycles (56 of initially 87 subjects). Employees who only pass material that is needed for processing are affected, just as are those who only prepare administrations and those alternating in both functions (25% vs. 24.1% vs. 50.6%, respectively). The storage of waste in containers that could be opened to add waste tends to increase the risk of internal exposure of ifosfamide and cyclophosphamide (odds ratios (95% confidence interval): 0.08 (0.013-0.5) and 0.19 (0.03-1.12), respectively). The amount handled and number of preparations of cyclophosphamide for "manufacturers" were associated with internal exposure of cyclophosphamide (28.04 (1.75-448.74) and 1.22 (1.03-1.44), respectively). The total number of preparations handled by assistants seemed to increase the risk of intake of any of the substances under study [1.04 (1.00-1.08)]. CONCLUSION: Since employees who pass materials are affected in the same way as those who prepare administrations, both have to be included in reviewing protective measures. Further studies must be carried out to verify the generated hypotheses of factors related to internal exposure found in this study.

Adult↗
PubMed2002

Environmental exposure to endotoxin and its relation to asthma in school-age children.

BACKGROUND: In early life, the innate immune system can recognize both viable and nonviable parts of microorganisms. Immune activation may direct the immune response, thus conferring tolerance to allergens such as animal dander or tree and grass pollen. METHODS: Parents of children who were 6 to 13 years of age and were living in rural areas of Germany, Austria, or Switzerland where there were both farming and nonfarming households completed a standardized questionnaire on asthma and hay fever. Blood samples were obtained from the children and tested for atopic sensitization; peripheral-blood leukocytes were also harvested from the samples for testing. The levels of endotoxin in the bedding used by these children were examined in relation to clinical findings and to the cytokine-production profiles of peripheral-blood leukocytes that had been stimulated with lipopolysaccharide and staphylococcal enterotoxin B. Complete data were available for 812 children. RESULTS: Endotoxin levels in samples of dust from the child's mattress were inversely related to the occurrence of hay fever, atopic asthma, and atopic sensitization. Nonatopic wheeze was not significantly associated with the endotoxin level. Cytokine production by leukocytes (production of tumor necrosis factor alpha, interferon-gamma, interleukin-10, and interleukin-12) was inversely related to the endotoxin level in the bedding, indicating a marked down-regulation of immune responses in exposed children. CONCLUSIONS: A subject's environmental exposure to endotoxin may have a crucial role in the development of tolerance to ubiquitous allergens found in natural environments.

Adolescent↗
PubMed2002

Web-based training in occupational medicine.

OBJECTIVES: The aim of our project was to develop and evaluate an interactive computer-based approach to teach medical students in occupational medicine. To enhance interest in occupational medicine the major focus was on clinical and practical aspects of occupational medicine. METHODS: The computer program was designed in HTML and JavaScript. It presents a guided tour of the patient's case history followed by information on practice and theory of occupational medicine. The program was integrated into the curriculum during the summer term of 1999 and the following winter term. To assess the effectiveness and acceptability of the program we asked students to rate the program on an 18-item questionnaire. RESULTS: Overall, 287 students participated in the evaluation of the program. The participants highly recommended the program structure and had no difficulties in handling the program. This was independent of the computer experience of the students. The evaluation showed that it was possible to enhance interest in occupational medicine by using "virtual patients". CONCLUSION: The program represents a student-orientated learning tool that points out clinical and practical aspects of occupational medicine. The availability via the Internet allows the application as a self-learning tool as well as a teaching tool for the medical curriculum.

Humans↗
PubMed2002

Expression of CD14 and Toll-like receptor 2 in farmers' and non-farmers' children.

Children of farmers are at decreased risk of developing allergies. Results of epidemiological studies suggest increased exposure to microbial compounds might be responsible for this reduced risk. Alterations in adaptive immune response are thought to be the underlying mechanism. We measured expression of receptors for microbial compounds known to trigger the innate immune response. We showed that blood cells from farmers' children express significantly higher amounts of CD14 (0.96 vs 0.43, p=0.0013), and Toll-like receptor 2 (0.11 vs 0.04, p<0.0001) than those from non-farmers' children. We propose that the innate immune system responds to the microbial burden in the environment and modulates the development of allergic disease.

Agriculture↗
PubMed2002

Occupational asthma in greenhouse flower and ornamental plant growers.

The objective of this study was to determine the prevalence of occupational asthma and sensitization to workplace allergens in greenhouse flower and/or ornamental plant growers. A random sample of 40 growers who cultivated such crops and had participated in the European Farmers' Study was selected for a cross-sectional study that included (1) greenhouse characteristics and air contaminants (dust, endotoxin, and microorganisms), (2) respiratory symptoms, (3) occupational asthma diagnosed by bronchial provocation challenge, and (4) sensitization to workplace flowers or molds. Associations among respiratory symptoms, sensitization, greenhouse characteristics, and air contaminants were analyzed by logistic regression modeling. Thirty-nine growers agreed to participate (response rate, 97.5%). Bronchial provocation challenge confirmed occupational asthma in three workers (7.7%), all of them sensitized to workplace flowers or molds. No cases of occupational asthma were found among nonsensitized growers. Poor ventilation proved to be a marginal risk factor for wheezing (air velocity: odds ratio, 0.11; 95% confidence interval, 0.01-1.04). Sensitization to flowers or molds was found in 13 of 38 growers (34.2%) but was not related to greenhouse characteristics. We conclude that one-fourth of greenhouse flower and/or ornamental plant growers sensitized to workplace flowers or molds have occupational asthma, a disease that is suffered by 8% of the growers who cultivate these crops.

Air Pollutants, Occupational↗
PubMed2002

Chemosensory irritation and the lung.

Airway irritation involves a variety of reflex mechanisms. Tracheal and bronchial C fibres and rapidly adapting fibres mediate cough, bronchoconstriction, and mucosal vasodilation. Workplace respiratory irritants can have a variety of effects in relation to asthma. Very high exposures can cause new-onset asthma, clinically presenting as reactive airways dysfunction syndrome or irritant-induced asthma. Symptoms after exposure to irritants depend on aggregate characteristics, water solubility and dose. Measurement of pulmonary function in response to irritants includes baseline spirometry, monitoring of across-shift changes and changes in non-specific bronchial responsiveness as well as bronchial responsiveness to inhaled allergens. Following irritant exposure, inflammatory changes within the airways are monitored by bronchoalveolar lavage or - less invasively - by sputum markers. A completely non-invasive approach not limited in repeatability is the investigation of inflammatory markers in exhaled air. However, the diagnostic and prognostic values of these novel markers have still to be demonstrated.

Animals↗
PubMed2002

Passive smoking exposure: a risk factor for chronic bronchitis and asthma in adults?

OBJECTIVE: The effects of passive smoke exposure on respiratory health are still under debate. Therefore, we examined the risk of respiratory symptoms related to passive smoke exposure among German adults within the European Community Respiratory Health Survey. METHODS: The questionnaire data of the population-based sample (n = 1,890) were analyzed. Multiple logistic regression models were carried out for current asthma (asthma symptoms or medication), chronic bronchitis (cough with phlegm for > or = 3 months per year), and wheezing as dependent variables, and self-reported exposure to passive smoke at home and at the workplace as independent variables after adjusting for city, age, gender, active smoking, and socioeconomic status as well as occupational exposure to dusts and/or gases. RESULTS: The relative odds for chronic bronchitis were significantly higher in subjects reporting involuntary tobacco smoke exposure in the workplace (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.16 to 3.11). Likewise, the adjusted OR for asthma was slightly elevated (OR, 1.51; 95% CI, 0.99 to 2.32). The risk of chronic bronchitis (OR, 3.07; 95% CI, 1.56 to 6.06), asthma (OR, 2.06; 95% CI, 1.07 to 3.97), and wheezing (OR, 2.12; 95% CI, 1.25 to 3.58) increased significantly with a daily exposure of > 8 h. CONCLUSION: The control of passive smoke exposure in the workplace might reduce the risk of respiratory symptoms independently of exposure to other airborne contaminants.

Adult↗