Rates and occupational characteristics of international seafarers with mental illness.

BACKGROUND: Seafarers enable 90% of global commerce, working in isolation from social support and medical care. While occupational conditions of isolation may suggest possible excess risk of mental illness and suicide, research on seafarer mental illness is limited. AIMS: To describe seafarers with mental illness and associated incidence rates in a large population of international seafarers. METHODS: We used mental illness claims data from a large international marine insurance provider arising from working seafarers during the years 2007-15. We used descriptive statistics and calculated mental illness incidence rates in this seafarer population. RESULTS: There were 278 seafarer mental illness claims in the study data. Claims were more often reported in deck workers (46%) and ratings (58%). The crude mental illness rate was 3.9 per 100 000 person-years. CONCLUSIONS: Using objective data on a large seafaring population, our analysis highlights the important issue of mental illness in this isolated and underserved international workforce. The low observed mental illness claims rate is likely due to the high threshold for claims reporting.

Surveillance for isocyanate asthma: a model based cost effectiveness analysis.

AIMS: Because logistical and financial obstacles impede using large prospective cohort studies, surveillance decisions in occupational settings must often be made without evidence of relative benefits and costs. Using the example of isocyanate induced asthma, the most commonly reported immune mediated occupational asthma, the authors developed a model based approach to evaluate the costs and benefits of surveillance from both an employer and a societal perspective. METHODS: The authors used a mathematical simulation model of isocyanate asthma to compare annual surveillance to passive case finding. Outcome measures included symptom free days (SFD), quality adjusted life years (QALY), direct costs, productivity losses, and incremental cost effectiveness ratio (CER), measured from the employer and the societal perspectives. Input data were obtained from a variety of published sources. RESULTS: For 100,000 exposed workers, surveillance resulted in 683 fewer cases of disability over 10 years. Surveillance conferred benefits at an incremental cost of 24,000 dollars/QALY (employer perspective; 13.33 dollars/SFD) and was cost saving from the societal perspective. Results were sensitive to assumptions about sensitisation rate, removal rates, and time to diagnosis, but not to assumptions about therapy costs and disability rates. CONCLUSIONS: Baseline results placed the CER for surveillance for isocyanate asthma within the acceptable range. Costs from the societal and employer perspective differed substantially with a more attractive CER from the societal perspective, suggesting opportunities for employer/societal cost sharing. The analysis demonstrates the value of a model based approach to evaluate the cost effectiveness of surveillance programmes for isocyanate asthma, and to inform shared decision making among clinicians, patients, employers, and society. Such a modeling approach may be applicable to surveillance programmes for other work related conditions.

Development of immunoassays for biomonitoring of hexamethylene diisocyanate exposure.

Hexamethylene diisocyanate (HDI) is used widely to manufacture polyurethanes for paints and coatings. It is an irritant and a chemical asthmagen. The U.S. Occupational Safety and Health Administration time-weighted average permissible exposure limit is 5 ppb and the ceiling limit is 20 ppb. We sought to develop a sensitive and specific immuno-bioassay to supplement workplace air monitoring and detect recent HDI exposure. For this, we produced rabbit antiserum to HDI-adducted keyhole limpet hemocyanin (HDI-KLH). The specificity of the antiserum was demonstrated by its reaction with a variety of HDI-conjugated proteins and the absence of reactions with conjugates of other diisocyanates, namely toluene diisocyanate and diphenyl methylene diisocyanate. Four immunoassays were developed and compared for their ability to detect decreasing quantities of HDI-adducted human serum albumin (HSA) containing 2 mol HDI adduct per mol HSA (HDI(2)-HSA) as determined by matrix-assisted laser desorption time-of-flight (MALDI-TOF) mass spectrometry. The sensitivities of some of the assays are within the range (0.82-45 nM) of current analytic methods. A Western analysis procedure has a sensitivity of 600 nM HDI adduct on HSA. ELISA inhibition assay, in which microtiter plates are coated with the HDI(2)-HSA antigen, has a sensitivity of 300 nM HDI adduct. An immunoblot assay has a sensitivity of 9 nM HDI adduct. The most sensitive bioassay (1.8 nM HDI adduct) is a three-antibody sandwich ELISA in which wells of microtiter plates are coated with the IgG fraction of the anti-HDI-KLH antisera. Compared with analytic methods for HDI biomonitoring, the immunoassays are faster and less costly and accommodate numerous samples simultaneously. The assays have the potential to affect industrial biomonitoring programs significantly.

Qualitative assessment of isocyanate skin exposure in auto body shops: a pilot study.

BACKGROUND: Little is known about the extent of human isocyanate skin exposure in auto body shops and the effectiveness of personal protective equipment. Animal studies have suggested that skin exposure to isocyanates may be an important risk factor for respiratory sensitization leading to asthma. This study provides initial data on hexamethylene diisocyanate skin exposure in three auto body shops. METHODS: Three auto body shops of different size which use different paint systems were examined for the presence of aliphatic isocyanates on environmental surfaces and workers' skin and for breakthrough of personal protective equipment. Qualitative detection of contamination by isocyanates was conducted using a wipe-sampling technique. Assessment focused on the painters and their tasks, although other auto body repairers were also evaluated. RESULTS: Environmental surfaces such as painters' workbenches, spray equipment, and cleaning tools were found contaminated with isocyanates. Painters had frequent contact with contaminated surfaces, often without wearing gloves. Moderate to heavy contamination of some skin surfaces was found with painters from two of the three auto body shops. Latex gloves used for skin protection showed significant penetrations by isocyanates even after a single painting session. CONCLUSIONS: Contaminated environmental surfaces and skin exposure to isocyanates were documented in several auto body shops. Latex gloves were not adequate protection for workers using isocyanate paints. Further research which would better quantify skin exposure, and its potential relationship to respiratory sensitization and asthma is warranted.