D. Fishwick

Specific inhalation challenge in the diagnosis of occupational asthma: consensus statement

This consensus statement provides practical recommendations for specific inhalation challenge (SIC) in the diagnosis of occupational asthma. They are derived from a systematic literature search, a census of active European centres, a Delphi conference and expert consensus. This article details each step of a SIC, including safety requirements, techniques for delivering agents, and methods for assessing and interpreting bronchial responses. The limitations of the procedure are also discussed. Testing should only be carried out in hospitals where physicians and healthcare professionals have appropriate expertise. Tests should always include a control challenge, a gradual increase of exposure to the suspected agent, and close monitoring of the patient during the challenge and for at least 6 h afterwards. In expert centres, excessive reactions provoked by SIC are rare. A positive response is defined by a fall in forced expiratory volume in 1 s ≥15% from baseline. Equivocal reactions can sometimes be clarified by finding changes in nonspecific bronchial responsiveness, sputum eosinophils or exhaled nitric oxide. The sensitivity and specificity of SIC are high but not easily quantified, as the method is usually used as the reference standard for the diagnosis of occupational asthma. ERS Task Force: a statement on specific inhalation challenges in the diagnosis of occupational asthma http://ow.ly/tCvFG

Lung function in Lancashire cotton and man made fibre spinning mill operatives.

OBJECTIVES--This survey was conducted to investigate current lung function levels in operatives working with cotton and man made fibres. Dust concentrations, smoking history, and occupational details were recorded so that factors influencing lung function could be identified. METHODS--A cross sectional study of respiratory symptoms and lung function was made in 1057 textile spinning operatives of white caucasian extraction. This represented 96.9% of the total available working population to be studied. Most (713) worked currently with cotton. The remainder worked with man made fibre. Lung function was assessed by measuring forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). Exposure to cotton dust was measured in the work area and personal breathing zones, and retrospective exposure to cotton dust over a working life was estimated with accurate work history and best available hygiene data. RESULTS--3.5% of all operatives had byssinosis, 55 (5.3%) chronic bronchitis, 36 (3.5%) work related persistent cough, 55 (5.3%) non-byssinotic work related chest tightness, and 56 (5.3%) work related wheeze. A total of 212 static work area dust samples (range 0.04-3.23 mg/m3) and 213 personal breathing zone samples (range 0.14-24.95 mg/m3) were collected. Percentage of predicted FEV1 was reduced in current smokers (mean 89.5, 95% confidence interval (95% CI) 88-91) in comparison with non-smokers (93.1, 90.5-94.1) and FVC was reduced in operatives currently working with man made fibre (95.3, 93.8-96.9) in comparison with cotton (97.8, 96.6-99.0). Regression analysis identified smoking (P < 0.01), increasing age (P < 0.01), increasing time worked in the waste room (P < 0.01), and male sex (P < 0.05) as being associated with a lower FEV1 and FVC. Current and retrospective cotton dust exposures did not appear as predictor variables in the regression analysis although in a univariate analysis, FEV1 was reduced in those operatives exposed to high dust concentrations assessed by personal and work area sampling. DISCUSSION--This study has documented loss of lung function in association with exposure to cotton dust. Those operatives with work related symptoms had significantly lower FEV1 and FVC than asymptomatic workers. Although lung function seemed to be affected by high dust exposures when operatives were stratified into high and low exposure groups, regression analysis did not identify current dust concentrations as an independent factor influencing loss. Smoking habit was found to explain most of the measured change in FEV1 and FVC. It is likely that smoking and dust exposure interact to cause loss of lung function in cotton textile workers.

A Comparison of Performance of Two Personal Sampling Heads for Cotton Dust

Cotton dust sampling for monitoring worker exposure was traditionally performed by work area sampling. A change to an exposure limit based on personal sampling has recently been agreed. The choice of sampling head for personal monitoring exposure was hampered by the use of two different sampling heads in the major epidemiological studies of textile workers which had incorporated personal sampling techniques. The purpose of this study was to compare the results of exposure measurements using these two sampling heads. This study has examined the performance of the two sampling heads, by performing dual sampling on cotton operatives during normal working activities. Each operative included wore two samplers randomly allocated to left or right side. A minimum of 200 minutes of sampling was accepted and the relative concentrations calculated. The IOM total dust sampler produced repeatedly higher measurements than the Manchester head. The ratio overall was 1.33 (95% C.I. 1.20-1.49). The performance was similar across the ranges of dust exposure from low (< 1 mg/m3-ratio 1.28), medium (1-3 mg/m3-ratio 1.43) to high exposure (> 3 mg/m3-ratio 1.24). The two heads give reproducibly proportionate dust measurements with approximately 30% greater results obtained with the IOM total dust sampler. Either dust sampling head could be used for worker monitoring and the results adjusted accordingly for reference to the Maximum Exposure Limit.

Hypersensitivity pneumonitis and metalworking fluids contaminated by mycobacteria

To the Editors:nnWe read with interest the article published by Tillie-Leblond et al. [1] relating to hypersensitivity pneumonitis (HP) in French automobile workers exposed to metalworking fluids (MWFs). Our group was involved in the UK outbreak investigation referenced in their article [2, 3], and have a clinical and research interest in this area.nnWhilst Tillie-Leblond et al. [1] are correct in stating that the majority of MWF-HP outbreaks have occurred in the USA, the UK Powertrain and French outbreaks are not the only ones to have occurred in Europe. We have provided scientific support to three other similar outbreaks in the UK, all with confirmed cases of MWF-HP [4, 5]. In addition, we have diagnosed single cases of MWF-HP or asthma in workers from at least five other workplaces close to our occupational lung disease clinic. We are also aware of a published respiratory outbreak from Croatia [ …

A review of the use of CD14: a biomarker for workplace airborne endotoxin exposure?

Abstract Occupational exposure to endotoxin, a component of Gram-negative bacteria, causes short-term illness and contributes to long-term illness. There are currently no recognised objective markers of endotoxin exposure. Such a biomarker could be used to distinguish between symptoms caused by inhaled endotoxin or by other contaminants of organic aerosols and to demonstrate a cause and effect relationship between endotoxin exposure and impairment of respiratory function. Flow cytometry has been used to measure CD14, an endotoxin receptor on monocytes, which may be a useful biomarker of endotoxin exposure. An in vitro model was developed, CD14 expression on monocytes was significantly upregulated in response to endotoxin. In cotton dust workers exposed to 1– 400 EU / m 3 air, CD14 expression significantly increased after 6 h and at 72 h levels had fallen to baseline or lower. We propose that CD14 expression on monocytes may be used to monitor workers exposure to endotoxin.