Predicting occupational asthma and rhinitis in bakery workers referred for clinical evaluation.

BACKGROUND: Occupational allergic diseases are a major problem in some workplaces like in the baking industry. Diagnostic rules have been used in surveillance but not yet in the occupational respiratory clinic. OBJECTIVE: To develop diagnostic models predicting baker's asthma and rhinitis among bakery workers at high risk of sensitisation to bakery allergens referred to a specialised clinic. METHODS: As part of a medical surveillance programme, clinical evaluation was performed on 436 referred Dutch bakery workers at high risk for sensitisation to bakery allergens. Multivariable logistic regression analyses were developed to identify the predictors of onset of baker's asthma and rhinitis using a self-administered questionnaire and compared using a structured medical history. Performance of models was assessed by discrimination (area under the receiver operating characteristics curve) and calibration (Hosmer-Lemeshow test). Internal validity of the models was assessed by a bootstrapping procedure. RESULTS: The prediction models included the predictors of work-related upper and lower respiratory symptoms, the presence of allergy and allergic symptoms, use of medication (last year), type of job, type of shift and working years with symptoms (≥10 years). The developed models derived from both self-administered questionnaire and the medical history showed a relatively good discrimination and calibration. The internal validity showed that the models developed had satisfactory discrimination. To improve calibrations of models, shrinkage factors were applied to model coefficients. CONCLUSION: The probability of allergic asthma and rhinitis in referred bakers could be estimated by diagnostic models based on both a self-administered questionnaire and by taking a structured medical history.

What are the benefits of medical screening and surveillance?

Pre-employment examination is considered to be an important practice and is commonly performed in several countries within the European Union. The benefits of medical surveillance programmes are not generally accepted and their structure is often inconsistent. The aim of this review was to evaluate, on the basis of the available literature, the usefulness of medical screening and surveillance. MEDLINE was searched from its inception up to March 2010. Retrieved literature was evaluated in a peer-review process and relevant data was collected following a systematic extraction schema. Pre-placement screening identifies subjects who are at an increased risk for developing work-related allergic disease, but pre-employment screening is too low to be used as exclusion criteria. Medical surveillance programmes can identify workers who have, or who are developing, work-related asthma. These programmes can also be used to avoid worsening of symptoms by implementing preventive measures. A combination of different tools within the surveillance programme, adjusted for the risk of the individual worker, improves the predictive value. Medical surveillance programmes provide medical as well as socioeconomic benefits. However, pre-employment screening cannot be used to exclude workers. They may act as a starting point for surveillance strategies. A stratified approach can increase the effectiveness and reduce the costs for such programmes.

Increased Micronodule Counts Are More Common in Occupationally Silica Dust-Exposed Smokers Than in Control Smokers.

OBJECTIVE:: To determine the prevalence of increased micronodule counts in silica dust-exposed smokers. METHODS:: We evaluated 54 male smokers with severe silica dust exposure and 54 male control smokers. Both groups underwent low-dose chest computed tomography and lung function testing. Computed tomographic scans were visually evaluated for solid micronodules (<3 mm). The 95th percentile of micronodule count was calculated for the control smokers. Prevalence of an increased micronodule count was assessed for the dust-exposed subjects. RESULTS:: Solid micronodules were present in most participants of both groups. The 95th percentile of micronodule count in the control group was 13. Increased micronodule counts were significantly more common in the exposed group than in the control group (P = 0.01). CONCLUSIONS:: A substantial number of silica-exposed heavy smokers evaluated for silicosis have increased micronodule counts on chest computed tomographic scan. This finding might represent an early stage of silicosis.

Acute respiratory effects in firefighters.

BACKGROUND: Associations between acute respiratory inflammatory responses, changes in bronchial hyperresponsiveness, serum pneumoprotein levels, and exposure to fire smoke were studied. METHODS: The study comprised 51 firefighters. Blood samples were taken within 24 hr following exposure to fire smoke, and after a week and 3 months. Sputum was induced within 5 days post-exposure and subjects underwent spirometry and methacholine provocation one week post-exposure. Exposure was registered by a questionnaire. RESULTS: No changes were observed following smoke exposure in bronchial hyperresponsiveness and serum pneumoprotein levels. Nevertheless, in a sizable proportion of the firefighters (44%) elevated sputum neutrophil levels (≥60%) were found. Serum IL-8 concentrations were higher 24 hr post-exposure compared to pre-exposure. Elevated neutrophil levels in sputum were associated with elevated serum IL-8 (ß = 0.010, P = 0.004) and TNFα (ß = 0.005, P = 0.034) levels within 24 hr post-exposure and IL-8 elevation lasted up to 3 months. CONCLUSIONS: Acute exposure to fire smoke induces acute neutrophilic airway and long-lasting systemic inflammation in healthy firefighters in the absence of bronchial hyperresponsiveness.

Lung function, bronchial hyperresponsiveness, and atopy among firefighters.

OBJECTIVES: The aim of this study was to determine associations between lung function, bronchial hyperresponsiveness (BHR), and atopy with exposure to fire smoke among firefighters. METHODS: The study was comprised of 402 firefighters, a randomly chosen subset of a previous survey among firefighters in the Netherlands. Subjects underwent spirometry and methacholine provocation, and blood samples were taken to assess atopy. Exposure to fire smoke was registered by a questionnaire. RESULTS: Hyperresponsiveness expressed as dose-response slope (DRS) was positively and significantly associated with the number of fires fought in the last 12 months with and without adjustments for smoking, gender, atopy, age, and exposure in the main job held. Limiting the analysis to firefighters without exposure within 7 days of testing did not change any of the associations. The association between the number of fires and the DRS was stronger among atopics, and hyperresponsiveness expressed as PD (20)was also significantly associated, indicating that atopics are at higher risk of developing BHR as a result of smoke exposure. Respiratory protection devices were not optimally used. CONCLUSIONS: It is recommended that awareness be heightened among firefighters to avoid exposure to all fire smoke and that management be sensitive to the adequate use of self-contained breathing apparatuses by their personnel.

Respiratory symptoms in firefighters.

BACKGROUND: The aim of the present study was to determine the prevalence and risk factors associated with respiratory symptoms in common firefighters in the Netherlands. METHODS: A total of 1,330 firefighters from the municipal fire brigades of three provinces of the Netherlands were included in the study. All subjects were administered a Dutch web-based version of the European Community Respiratory Health Survey questionnaire. RESULTS: General respiratory symptoms were associated with the number of fires fought in the last 12 months with odds ratios between 1.2 (95% CI 1.0-1.4) and 1.4 (95% CI 1.2-1.7) per 25 fires. A strong association was found between an inhalation incident and present respiratory symptoms with odds ratios between 1.7 (95% CI 1.1-2.7) and 3.0 (95% CI 1.9-4.7). Adjustments for smoking, sex, atopy, and age did not change any of the associations. After stratification, atopics showed elevated odds ratios. CONCLUSIONS: It is recommended that firefighters are aware of these elevated healthcare risks associated with exposure to fire smoke and that they increase as much as possible the use of self-contained breathing apparatus.

[Sleep disorders and the ability to drive, revision of legislation]. / Slaapstoornissen en rijgeschiktheid: herziening van de regelgeving.

Professional truck drivers suffering from obstructive sleep apnoea syndrome (OSAS) are more often involved in traffic accidents. OSAS can be treated successfully and the effects of treatment are visible almost immediately. Treatment of OSAS has shown a significant reduction in the number of traffic accidents. Based on criteria for effective treatment, the requirements for the ability to drive have recently been modified by ministerial decree. The period during which persons with OSAS were not allowed to drive was formerly at least 1 year for a passenger car and 5 years for a truck or bus. The period has now been reduced to 2 and 3 months respectively. Legislation has also been adjusted for drivers with narcolepsy and idiopathic hypersomnia for whom the use of psychostimulant drugs is allowed. The modified legislation is intended to prevent underdiagnosis, may improve driving safety and is in the public interest.

Bronchiolitis obliterans syndrome in chemical workers producing diacetyl for food flavorings.

RATIONALE: Workers in microwave popcorn plants are at risk of developing bronchiolitis obliterans associated with exposure to butter flavoring volatiles, including diacetyl. OBJECTIVES: To investigate the risk of bronchiolitis obliterans for chemical workers producing diacetyl, with exposure to less complex mixtures of chemicals. METHODS: We interviewed and conducted spirometry on 175 of 196 workers from a chemical production plant that produced diacetyl between 1960 and 2003. We used all available historical exposure data to classify all workers into three exposure groups with varying exposure profiles to diacetyl, based on frequency and level of exposure. MEASUREMENTS AND MAIN RESULTS: Workers with fixed airway obstruction underwent further pulmonary function testing (including diffusing capacity and lung volumes) and paired inspiratory and expiratory high-resolution computed tomography studies. We identified three cases consistent with bronchiolitis obliterans syndrome with air trapping on high-resolution computed tomography of the lungs, in the highest exposure group of 102 process operators. Two of these cases were lifelong nonsmokers. Potential exposures included acetoin, diacetyl, acetaldehyde, and acetic acid, with diacetyl exposures in the range previously reported to be associated with fixed airway obstruction in the microwave popcorn industry. CONCLUSIONS: Exposure to an agent during diacetyl production appears to be responsible for causing bronchiolitis obliterans syndrome in chemical process operators, consistent with the suspected role of diacetyl in downstream food production.