Recent Research Activities from the EOM Working Groups

Regulation and practice of workers' protection from chemical exposures during container handling

by Randi Nørgaard Fløe Pedersen, Jørgen Riis Jepsen and Balázs Ádám. Journal of Occupational Medicine and Toxicology 2014, 9:33 doi:10.1186/s12995-014-0033-6 [Full text PDF]

Background: Fumigation of freight containers to prevent spread of pests and off-gassing of freight are sources of volatile chemicals that may constitute significant health risks when released. The aim of the study was to investigate the regulation and practice of container handling in Denmark with focus on preventive measures to reduce risk of chemical exposure. 

Methods: A comprehensive systematic search of scientific literature, legislation and recommendations related to safe work with transport containers from international and Danish regulatory bodies was performed. The practice of handling containers was investigated in a qualitative study based on a series of semi-structured interviews with key informants, including managers and health and safety representatives of organizations that handle containers. 

Results: Although several international and national regulations and local safety instructions relate to container handling, the provided information is not sufficiently detailed to conduct safe practice in many aspects. In accordance with the scientific literature, the interviewees estimate that there is a high frequency (5 to 50%) of containers with hazardous chemical exposure that are regarded as potentially damaging to health, although recognisable health effects are rare. There is limited knowledge about the types of chemicals, which mostly cannot be measured by available devices at the worksite. Aeration and use of personal protective equipment are typical preventive measures in practice, but their use is not consistent and does not necessarily ensure adequate protection. 

Conclusions: Managers, workers, even occupational health professionals have limited knowledge about the hazardous chemicals that can be released from containers. Detailed risk assessment and specific instructions on risk management are needed for safe handling of transport containers.

Allergens causing occupational asthma: an evidence-based evaluation of the literature by Xaver Baur and Prudence Bakehe (Int Arch Occup Environ Health)

Purpose: The aim of this work is to provide an evidence based evaluation and overview of causative substances in order to improve disease management.

Methods: We conducted a database search with MEDLINE via PubMed, screened reference lists of relevant reviews and matched our findings with a list of agents denoted as ‘‘may cause sensitisation by inhalation’’ by the phrase H334 (till 2011 R42). After exclusion of inappropriate publications, quality of the selected studies was rated with the Scottish Intercollegiate Guideline Network (SIGN) grading system. The evidence level for each causative agent was graded using the modified Royal College of General Practitioners (RCGP) three-star system. 

Results: A total of 865 relevant papers were identified, which covered 372 different causes of allergic work-related asthma. The highest level achieved using the SIGN grading system was 2?? indicating a high-quality study with a very low risk of confounding or bias and a high probability of a causal relationship.According to the modified RCGP three-star grading system, the strongest evidence of association with an individual agent, profession or worksite (‘‘***’’) was found to be the co-exposure to various laboratory animals. An association with moderate evidence level (‘‘**’’) was obtained for a-amylase from Aspergillus oryzae, various enzymes from Bacillus subtilis, papain, bakery (flour, amylase, storage mites), western red cedar, latex, psyllium, farming (animals, cereal, hay, straw and storage mites), storage mites, rat, carmine, egg proteins, atlantic salmon, fishmeal, norway lobster, prawn, snow crab, seafood, trout and turbot, reactive dyes, toluene diisocyanates and platinum salts. 

Conclusion: This work comprises the largest list of occupational agents and worksites causing allergic asthma. For the first time, these agents are assessed in an evidence based manner. The identified respiratory allergic agents or worksites with at least moderate evidence for causing work-related asthma may help primary care physicians and occupational physicians in diagnostics and management of cases suffering from work-related asthma. Furthermore, this work may possibly provide a major contribution to prevention and may also initiate more detailed investigations for broadening and updating these evidence-based evaluations.

Is specific IgE antibody analysis feasible for the diagnosis of methylenediphenyl diisocyanate-induced occupational asthma?

by Lygia Therese Budnik, Alexandra M. Preisser, Hjalmar Permentier, Xaver Baur (Int Arch Occup Environ Health).

PURPOSE: Early recognition improves the prognosis of isocyanate asthma. A major unanswered question is whether IgE-dependent mechanisms are of diagnostic value? Our objective was to appraise serological methods using various methylenediphenyl diisocyanate (MDI)-albumin conjugates and weigh up the data versus the outcome of standardized comprehensive clinical diagnostics to evaluate the viability of immunological analysis in supportive MDI-asthma diagnosis (OAI).

METHODS: Specific IgE (sIgE) and IgG (sIgG) binding was measured with fluorescence enzyme immunoassay in 43 study subjects (using conjugates prepared in-vapor, in-solution and commercial preparations). The differential clinical diagnosis included standardized measurement of pulmonary function, non-specific bronchial hyper-responsiveness, specific MDI-prick test (MDI-SPT) and specific inhalation challenge (MDI-SIC). 

RESULTS: Detailed diagnostic scheme allows the differential OAI and MDI-induced hypersensitivity pneumonitis (PI). The presumed OAI diagnoses were confirmed in 84 % (45 % cases having demonstrable sIgE antibodies) with RR 5.7, P > 0.001, when OAI diagnosis is correlated with MDI-SIC/MDI-SPT (RR 1.28 for MDI-SIC alone); sIgG antibodies were clinically relevant for PI and not for the OA diagnosis. MDI-specific IgE data generated with commercial ImmunoCAP preparations show high correlation with our in-vapor generated MDI conjugates. 

CONCLUSIONS: Isocyanate-specific IgE antibodies are not always detectable but their presence is strongly predictive of OAI and supportive for the diagnosis. MDI-SPT can be a valuable parameter differentiating OAI and PI. We have confirmed and extended published data showing that isocyanate-albumin conjugates perform better in specific antibody assays when prepared with volatile phase formulations and would like to stress additionally the necessity for further refinements and standardization in clinical diagnostics procedures.

Prostate cancer and toxicity from critical use exemptions of methyl bromide: Environmental protection helps protect against human health risks

Lygia T Budnik, Stefan Kloth, Marcial Velasco-Garrido and Xaver Baur

Background: Although ozone-depleting methyl bromide was destined for phase-out by 2005, it is still widely applied as a consequence of various critical-use-exemptions and mandatory international regulations aiming to restrict the spread of pests and alien species (e.g. in globalized transport and storage). The withdrawal of methyl bromide because of its environmental risk could fortuitously help in the containment of its human toxicity. 

Methods: We performed a systematic review of the literature, including in vitro toxicological and epidemiological studies of occupational and community exposure to the halogenated hydrocarbon pesticide methyl bromide. We focused on toxic (especially chronic) or carcinogenic effects from the use of methyl bromide, on biomonitoring data and reference values. Eligible epidemiological studies were subjected to meta-analysis. 

Results: Out of the 542 peer reviewed publications between 1990-2011, we found only 91 referring to toxicity of methyl bromide and 29 using the term “carcinogenic”, “neoplastic” or “mutagenic”. Several studies provide new additional data pertaining to the mechanistic aspects of methyl bromide toxicity. Few studies have performed a detailed exposure assessment including biomonitoring. Three evaluated epidemiological studies assessed a possible association between cancer and methyl bromide. Overall, exposure to methyl bromide is associated with an increased risk of prostate cancer OR, 1.21; 95% CI (0,98-1.49), P = 0.076. Two epidemiological studies have analyzed environmental, non-occupational exposure to methyl bromide providing evidence for its health risk to the general public. None of the epidemiological studies addressed its use as a fumigant in freight containers, although recent field and case reports do refer to its toxic effects associated with its use in shipping and storage. Conclusions: Both the epidemiological evidence and toxicological data suggest a possible link between methyl bromide exposure and serious health problems, including prostate cancer risk from occupational and community exposure. The environmental risks of methyl bromide are not in doubt, but also its health risks, especially for genetically predisposed subjects, should not be underestimated.

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