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O Vandenplas

Publications and source records attributed to O Vandenplas.

At least 19 recordsLinked to original sources
PubMed2006

[Epidemiology and etiologic agents of occupational asthma].

INTRODUCTION: Occupational asthma is, by definition, a disease that can be prevented through appropriate protective strategies. Epidemiological information is required to guide these interventions, and we here examine epidemiological data on the burden, causes, and risk factors for this condition. STATE OF THE ART: Population-based surveys indicate that approximately 15% of adult asthma is attributable to the workplace environment. The most common occupational agents implicated include flour, isocyanates, latex, and persulphate salts. The occupations in which occupational asthma has been most commonly reported are bakers, spray painters, health-care workers, hairdressers, and cleaners. The level of exposure to sensitizing agents seems to be the most relevant risk factor. Atopy is a significant risk factor only for the development of sensitization to high molecular weight agents. The role of other individual determinants, such as genetic factors, has been less consistently established. Occupational asthma is associated with a substantial adverse impact on the employment and financial status of affected workers. PERSPECTIVES: Methodological improvements are required in order to distinguish more accurately between occupational and work-exacerbated asthma. Further investigations of the effectiveness of primary and secondary preventive interventions are also needed.

Allergens↗
PubMed2005

[The epidemiology of occupational asthma in Belgium].

INTRODUCTION: A national surveillance programme of occupational asthma was set up to estimate the incidence and identify the causes of this disorder in Belgium. MATERIALS AND METHODS: The programme was based on the voluntary notification of new cases of occupational asthma by chest specialists and occupational physicians during the period 2000-2002. RESULTS: 92% of the reported cases included occupational asthma of an immunological type and 8% bronchial irritability. According to the opinion of the reporting physicians the diagnosis was considered certain in 39%, probable in 29% and possible in 32% of cases. On the basis of these notifications the mean annual incidence of occupational asthma is estimated as 23.5 cases per million workers (95% confidence interval 19.2-28.8). The most frequently incriminated substances were isocyanates (16%), cereals (12%) and latex (10%). At the time of diagnosis 38% of patients had not applied for compensation. CONCLUSION: The results of this programme of notification of occupational asthma agree with the data available from other countries and provide information complementary to the medico-legal statistics.

Adult↗
PubMed2005

What are the questionnaire items most useful in identifying subjects with occupational asthma?

The present study assessed the usefulness of key items obtained from a clinical "open" questionnaire prospectively administered to 212 subjects, referred to four tertiary-care hospitals for predicting the diagnosis of occupational asthma (OA). Of these subjects, 72 (34%) were diagnosed as OA (53% with OA due to high-molecular-weight agents) according to results of specific inhalation challenges, and 90 (42%) as non-OA. Wheezing at work occurred in 88% of subjects with OA and was the most specific symptom (85%). Nasal and eye symptoms were commonly associated symptoms. Wheezing, nasal and ocular itching at work were positively, and loss of voice negatively associated with the presence of OA in the case of high-, but not low molecular-weight agents. A prediction model based on responses to nasal itching, daily symptoms over the week at work, nasal secretions, absence of loss of voice, wheezing, and sputum, correctly predicted 156 out of 212 (74%) subjects according to the presence or absence of OA by final diagnosis. In conclusion, key items, i.e. wheezing, nasal and ocular itching and loss of voice, are satisfactorily associated with the presence of occupational asthma in subjects exposed to high-molecular-weight agents. Therefore, these should be addressed with high priority by physicians. However, no questionnaire-derived item is helpful in subjects exposed to low-molecular-weight agents.

Adult↗
PubMed2003

Comparison of FEV1 and specific airway conductance in assessing airway response to occupational agents.

BACKGROUND: There is theoretical evidence that specific airway conductance (SGaw) could be more reliable than forced expiratory volume in 1 s (FEV1) for assessing changes in airway calibre. We investigated the changes in FEV1 and SGaw when assessing bronchial responses to occupational agents. METHODS: SGaw and FEV1 were measured during inhalation challenges with various occupational agents in 174 consecutive subjects investigated for possible occupational asthma. RESULTS: A decline in SGaw of 50% or greater was documented in 77 of 90 subjects (86%) who showed a >/=20% fall in FEV1 and in 11 of 84 subjects (13%) who failed to demonstrate such a fall in FEV1. Among subjects who developed a >/=20% fall in FEV1, those who failed to develop a >/=50% decline in SGaw had a lower baseline SGaw than those who did. Among the group without a >/=20% fall in FEV1, a >/=50% decrease in SGaw was associated with either an 'intermediate' fall in FEV1 (between 15 and 17% from baseline value) (n = 4), a significant postchallenge increase in nonspecific bronchial hyper-responsiveness to histamine (n = 2), or both features (n = 3). CONCLUSIONS: A decline in SGaw of 50% or greater may provide useful complementary evidence of a bronchial response during challenges that produce equivocal results in FEV1.

Adolescent↗
PubMed2003

Pathogenesis of occupational asthma.

The development of occupational asthma (OA) is likely to result from the complex interaction of environmental and host factors. This article addresses a series of issues relating to the multiple environmental factors that could affect the initiation of OA, including the intrinsic characteristics of causative agents, as well as the influence of the level, mode and route of exposure. Although the clinical and pathological features of OA caused by low molecular weight agents resemble those of immunoglobulin (Ig)E-mediated asthma, the failure to detect specific IgE antibodies against most of these agents and/or poor association with disease status have resulted in intense speculation about alternative or complementary physiopathological mechanisms leading to airway sensitisation. In this contribution, the roles of specific immunoglobulin E and G antibodies, cell-mediated immunity and inflammatory effector cells are critically reviewed. Recent advances in the characterisation of the molecular interactions between chemical sensitisers and human airway proteins provide promising avenues for elucidating the immunological basis of occupational asthma caused by low molecular weight agents.

Asthma↗
PubMed2003

Health and socioeconomic impact of work-related asthma.

There is accumulating evidence that the workplace environment contributes significantly to the general burden of asthma. The purpose of this review is to explore the respiratory health and socioeconomic consequences of work-related asthma by addressing a series of controversial issues: 1) what is the natural history of occupational asthma and in what ways does ongoing exposure to the causal agent impact clinical outcomes?; 2) how does the natural history of irritant-induced asthma differ in its health outcomes from immunologically-mediated occupational asthma?; 3) do working conditions have a significant impact on asthma regardless of the aetiology of the disease?; 4) what is the scope of work disability from work-related-asthma in social and economic terms?; 5) what is the clinician's role in reducing the respiratory health consequences of work-related asthma? 6) to what extent do existing compensation and other social insurance schemes successfully address occupational asthma and work-aggravated asthma?

Asthma↗
PubMed2003

Definitions and types of work-related asthma: a nosological approach.

The workplace can trigger or induce asthma and cause the onset of different types of work-related asthma. Analysis of previous definitions of occupational asthma (OA) led to the conclusion that evidence of a direct causal relationship between workplace exposure and the development of asthma remains the key element for defining OA. Based on clinical features and pathophysiological mechanisms, the following conditions should be distinguished in the spectrum of work-related asthma: 1) immunological OA characterised by a latency period necessary to acquire immunologically induced sensitisation; 2) nonimmunological OA characterised by the rapid onset of asthma following single or multiple exposures to high concentrations of irritant compounds; 3) work-related asthma defined by exacerbation of symptoms in workers with pre-existing or coincident asthma; and 4) variant syndromes including eosinophilic bronchitis, potroom asthma, and asthma-like disorders caused by organic dusts. The issues and controversies relating to this approach are critically reviewed in order to stimulate the consensus development of operational definitions of work-related asthma.

Asthma↗
PubMed2002

Fever and neutrophilic alveolitis caused by a vanadium based catalyst.

AIMS: To investigate a worker who experienced systemic and respiratory symptoms when exposed to a vanadium containing powder used as a catalyst in the production of maleic anhydride. METHODS: The investigation included inhalation challenge with the suspected compound combined with monitoring of lung function tests and post-challenge bronchoalveolar lavage. RESULTS: Exposure to the vanadium containing catalyst for 120 minutes resulted in a sustained decline in forced vital capacity and forced expiratory volume in one second, while the transfer factor for carbon monoxide did not change significantly. The subject developed fever and peripheral blood neutrophilia. Bronchoalveolar lavage performed 48 hours after the end of challenge exposure showed a marked increase in neutrophils (60% of total cell count). CONCLUSIONS: Exposure to vanadium can cause a metal fume fever-like syndrome associated with neutrophilic alveolitis.

Adult↗
PubMed2002

Socioeconomic outcome of subjects experiencing asthma symptoms at work.

The aim of this study was to investigate the socioeconomic outcomes of subjects who experienced work-related asthma symptoms in the absence of demonstrable occupational asthma (OA) and to compare these outcomes with those found in subjects with documented OA. Subjects (n=157) who were being investigated for work-related asthma, were surveyed. Of these 86 had OA, ascertained by a positive specific inhalation challenge (SIC), and 71 subjects had a negative SIC response. After a median interval of 43 months (range 12-85 months), the subjects were interviewed to collect information on employment status, income changes, and asthma-related work disability. Rates of work disruption and income loss at follow-up were similar in subjects with negative SIC (46% and 59%, respectively) and in those with OA (38% and 62%). The median loss as a percentage of initial income was 23% in subjects with negative SIC and 22% in subjects with OA. Asthma-related work disability, defined as any job change or work loss due to asthma, was slightly more common in subjects with OA (72%) than in those with negative SIC (54%). This study shows that, even in the absence of demonstrable occupational asthma, work-related asthma symptoms are associated with considerable socioeconomic consequences.

Adult↗
PubMed2002

[Diagnostic approach occupational asthma].

Occupational asthma is associated with significant medical and socioeconomic consequences. Therefore, the diagnosis should be based on objective and accurate evidence. Available diagnostic procedures include the clinical history, measurement of non-specific bronchial hyperresponsiveness, monitoring of expiratory peak flows at work, and specific inhalation challenges in the laboratory. Advantages and limitations of these tests are discussed in order to propose a pragmatic diagnostic approach where specific inhalation challenges play a central role.

Algorithms↗
PubMed2001

Occupational asthma in symptomatic workers exposed to natural rubber latex: evaluation of diagnostic procedures.

BACKGROUND: Natural rubber latex (NRL) has been increasingly identified as a cause of occupational asthma (OA). OBJECTIVE: We sought to examine the accuracy of the clinical history, immunologic tests, and assessment of nonspecific bronchial hyperresponsiveness in diagnosing OA caused by latex compared with that of the specific inhalation challenge (SIC). METHODS: Forty-five consecutive patients referred for investigation of possible OA caused by latex underwent a diagnostic protocol, including an open medical questionnaire, skin prick testing against latex, measurement of bronchial responsiveness to histamine, and inhalation challenge with latex gloves. Recorded clinical history was judged retrospectively by 4 physicians who were blinded for the results of other objective tests. RESULTS: The clinical history, skin prick testing against NRL, and assessment of nonspecific bronchial hyperresponsiveness showed a high sensitivity (87%, 100%, and 90%, respectively) but a low specificity (14%, 21%, and 7%, respectively) when compared with the results of the SIC. Logistic regression analysis showed that combining the results of skin prick tests against latex with the clinical history enhanced the negative predictive value from 50% to 71%, whereas the positive predictive value remained virtually unchanged (75% vs 76%). CONCLUSION: The clinical history and immunologic tests were the most useful procedures in diagnosing NRL-induced asthma, although combining the 2 procedures remained less accurate than SIC. Further examination of the predictive values of available tests is warranted to recommend diagnostic strategies that are specific to the various agents causing OA.

Adult↗
PubMed2001

Frequency of cystic fibrosis transmembrane conductance regulator gene mutations and 5T allele in patients with allergic bronchopulmonary aspergillosis.

STUDY OBJECTIVE: To assess the frequency of cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations in patients with allergic bronchopulmonary aspergillosis (ABPA). DESIGN: Case-control study. All subjects in the study were screened for the presence of 13 mutations in the CFTR gene (R117H, 621 + 1G(-)>T, R334 W, Delta F508, Delta I507, 1717-1G(-)>A, G542X, R553X, G551D, R1162X, 3849 + 10kbC(-)>T, W1282X, and N1303K). Moreover, they were also screened for the presence of the 5T variant in intron 8. SETTING: University hospital and community-based hospital. PATIENTS: Twenty-one white patients with ABPA participated in the study. The presence of CFTR mutations was also investigated in 43 white subjects with allergic asthma who did not show sensitization to Aspergillus fumigatus and in 142 subjects seeking genetic counseling for diseases other than cystic fibrosis (CF). RESULTS: Six patients with ABPA were found to be heterozygous for one CFTR mutation, including Delta F508 (n = 2), G542X (n = 1), R1162X (n = 1), 1717-1G(-)>A (n = 1), and R117H (n = 1). The 5T allele was not detected in ABPA patients. None of the ABPA patients showed sweat chloride concentrations > 60 mEq/L. The frequency of CFTR mutation carriers was significantly higher in ABPA patients (6 of 21 patients; 28.5%) than in control asthmatic subjects (2 of 43 subjects; 4.6%; p = 0.01) and in subjects seeking genetic counseling (6 of 142 subjects; p < 0.001). CONCLUSION: These findings indicate that in patients without a clinical diagnosis of CF, CFTR gene mutations could be involved in the development of ABPA, in association with other genetic or environmental factors.

Adult↗
PubMed1999

Comparison of peak expiratory flows and FEV1 in assessing immediate asthmatic reactions due to occupational agents.

BACKGROUND: FEV1 is more sensitive than PEF in assessing late asthmatic responses (LAR) after specific inhalation challenges (SIC) with occupational agents. As immediate asthmatic reactions (IAR) mainly involve proximal airways, PEF may, however, be as valid as FEV1. METHODS: Thirty-seven subjects who experienced an immediate fall in FEV1 of > or =20% during SIC with occupational agents and 20 subjects with fall of < or =10% in FEV1 were included. Both FEV1 and PEF were measured in a random order every 10 min for 1 h after exposure. We corrected PEF (PEFc) for inaccuracies of the mini-Wright meters by the Miller equation. RESULTS: Maximum changes in PEFc (30+/-11%) were not significantly different from changes in FEV1 (27+/-5%) (P=0.13). Their timings after exposure were 14+/-11 min and 17+/-17 min, respectively (P=0.4). High sensitivity (92%), specificity (95%), accuracy (93%), and positive predictive value (97%) were found for a 20% fall in PEFc to detect a significant IAR. Results were better and not influenced by meter inaccuracies with a cutoff point of 15% change in noncorrected PEF (PEFnc). An absolute decrease in PEF of 70 l/min gave a good discrimination between reactions with and without an asthmatic response. CONCLUSIONS: PEF is as satisfactory as FEV1 for detecting a significant IAR after exposure to an occupational agent if one considers a cutoff point of 1) 15% fall in PEF 2) 20% fall in PEFc 3) 20% fall and/or 70 l/min decrease in PEFnc.

Adult↗
PubMed1999

Pulmonary effects of short-term exposure to low levels of toluene diisocyanate in asymptomatic subjects.

Isocyanates may be involved in the development of chronic obstructive airway disease among exposed workers. A short-term exposure to toluene diisocyanate (TDI) at concentrations near the permissible levels was investigated to examine whether there was an association with changes in pulmonary function tests and in potential markers of airway injury and inflammation in bronchial lavage (BL) and bronchoalveolar lavage (BAL). Seventeen subjects without respiratory symptoms (eight smokers and nine nonsmokers) were exposed once to ambient air and once to TDI (5 parts per billion (ppb) for 6 h followed by 20 ppb for 20 min) in a randomized, single-blind sequence. Pulmonary function tests were repeatedly assessed during exposure and BAL was performed 1 h after each exposure. Biochemical studies on lavage fluids included albumin, immunoglobulins, antiproteases (alpha2-macroglobulin and alpha1-proteinase inhibitor), potential indicators of epithelial cell function (secretory component and Clara cell protein), and cytokines (tumour necrosis factor-alpha, interleukin (IL)-4, IL-5, IL-6, and IL-8). Exposure to TDI caused a modest decrease in specific airway conductance (sGaw) (p=0.053) and in maximal expiratory flow at 25% of forced vital capacity (MEF25%) (p=0.015) when compared with ambient air. Exposure to TDI resulted in a slight increase in BAL albumin level (TDI: 26.4+/-12.5 versus air: 21.8+/-8.6 microg x mL(-1), p=0.044) and in BL alpha2-macroglobulin concentration (TDI: 0.07+/-0.061 versus air: 0.05+/-0.04 microg x mL(-1), p=0.021). This study suggests that exposure to low toluene disocyanate concentrations is associated with minimal but detectable changes in airway calibre and in epithelial barrier permeability. The pulmonary effects of long-term exposure to low levels of isocyanates require further investigation.

Adult↗