Contact dermatitis in the construction industry: the role of filaggrin loss-of-function mutations.

BACKGROUND: A high prevalence of contact dermatitis (CD) and respiratory symptoms has been observed in the construction industry, probably due to widespread exposure to irritants and allergens. It is unknown whether carriers of loss-of-function mutations in the gene encoding filaggrin (FLG), a known risk gene for eczema and asthma, are at increased risk. OBJECTIVES: To investigate associations of FLG mutations with CD and respiratory symptoms in Dutch construction workers. METHODS: A questionnaire including items on dermal and respiratory symptoms such as wheeze, shortness of breath and asthma was administered to construction workers. Total and specific serum IgE was analysed by enzyme immunoassays. Four FLG loss-of-function mutations were genotyped. CD was diagnosed by a team of a dermatologist and a clinical occupational medicine specialist using photographs of the subjects' hands and self-reported questionnaire data. RESULTS: Of the 506 participating workers, 6·3% carried at least one FLG mutation. Mild CD was diagnosed by the specialists in 34·0%, and severe CD in an additional 24·3%. CD was considered work related in 282 of 295 subjects (95·6%). Carriers of FLG variants had an increased risk of CD compared with subjects carrying wild-type alleles [mild CD: odds ratio (OR) 5·71, 95% confidence interval (CI) 1·63-20·06; severe CD: OR 8·26, 95% CI 2·32-29·39]. FLG variants and the presence of CD were not associated with respiratory symptoms and atopy. CONCLUSIONS: Contact dermatitis prevalence in construction workers is high. FLG loss-of-function mutations increase the risk of CD even further. FLG mutations were not associated with respiratory symptoms or atopy.

Determinants of exposure to respirable quartz dust in the construction industry.

Because most masonry building materials contain quartz and because these materials are subjected to a variety of treatments during the building process, quartz is encountered everywhere in building operations. The level of exposure to respirable quartz has been measured for some highly exposed groups of employees. At 30 construction sites personal air sampling (PAS) measurements of respirable dust and quartz have been performed and 171 samples have been taken. Both respirable dust and quartz levels were high. Respirable quartz exposures of more than ten times the Dutch limit value of 0.075 mg/m(3) TWA were common, but exposures up to 200 times the Dutch limit value were also found. The measurements were task oriented. By statistical analysis the contribution of the different determinants to the total exposure has been identified. With this approach, directions for an effective control measures programme can be given.

Effect of respiratory protective equipment on exposure to asbestos fibres during removal of asbestos insulation.

Asbestos concentrations were measured within powered respirators used by workers involved in the removal of asbestos-containing insulation. Fibre concentrations within the protective gear appeared to be above the Dutch threshold limit value for crocidolite (0.2 f cm-3). Possible sources of exposure were analysed and measures were taken to improve the situation. After this, the fibre concentrations in the breathing area were reduced and were below the Dutch concentration limit.

Lead exposure during demolition of a steel structure coated with lead-based paints. I. Environmental and biological monitoring.

Demolition of a steel railway bridge was carried out by nine workers using flame-torch cutting. The air in the breathing zone of the workers contained from 2 to 38 mg of lead/m3, which is a very high level in comparison with the Dutch exposure limit of 0.15 mg/m3 (8-h time-weighted average). Without very effective respiratory protection these concentrations may result in acute lead poisoning. Upwind of the flame-torch exposure the level was below the exposure limit, whereas downwind lead concentrations of up to ten times the exposure limit were observed. Although filtering facepieces were used by the workers, average blood lead concentrations of about 4.5 mumol/l were rapidly attained. Possibly under these work conditions this value represents a maximum concentration attainable in blood. After termination of the exposure, there was a fast decrease of lead in the blood. This finding indicates that lead was mainly present in rapidly exchangeable compartments like blood. No stable correlation between the concentration of lead in blood and the concentration of zinc protoporphyrin in blood was found.

Evaluation of an ISO draft proposal for sampling and analysis of chlorinated hydrocarbon solvent vapors in workplace atmospheres.

The ISO draft proposal for sampling and analysis of chlorinated hydrocarbon solvent vapors in workplace atmospheres (ISO/TC 146/SC 2/WG4 N41) has been evaluated by means of a round-robin test. For this purpose, the repeatability and reproducibility for the determination of tetrachloromethane, trichloromethane, 1,1,1-trichloroethane, trichloroethene were determined at three concentration levels. Furthermore, parameters such as breakthrough and loss on storage were determined. Samples were taken by 11 participants from six countries. After statistical evaluation of the results, it appeared that improvements were necessary for the determination of tetrachloromethane and trichloromethane. For the other three compounds, repeatability and reproducibility were sufficient. Possible error sources and possibilities for improvements are discussed.