Victoria H. Arrandale

Occupational contact allergens: Are they also associated with occupational asthma?†‡

BACKGROUND Workplace exposures that can potentially cause both allergic occupational contact dermatitis (AOCD) and occupational asthma (OA) are not clearly identified. METHODS Occupational contact allergens (OCAs) were identified using North American Contact Dermatitis Group (NACDG) data. Reference documents and systematic reviews were used to determine whether each OCA had been reported to potentially cause OA. The presence or absence of a sensitizer notation in occupational hygiene reference documents was also examined. RESULTS The 10 most common OCAs were: epoxy resin*, thiuram, carba mix, nickel sulfate*, cobalt chloride*, potassium dichromate*, glyceryl thioglycolate, p-phenylenediamine*, formaldehyde* and glutaraldehyde*. Seven (indicated by *) were determined to be possible causes of OA. Information on sensitizing potential from OH reference materials contained conflicting information. CONCLUSIONS Several common OCAs can also potentially cause OA. Inhalation and dermal exposures to these agents should be controlled and both OA and AOCD should be considered as possible health outcomes. Increased consistency in sensitizer notations is needed.

Exposure Assessment in Cohort Studies of Childhood Asthma

Background The environment is suspected to play an important role in the development of childhood asthma. Cohort studies are a powerful observational design for studying exposure–response relationships, but their power depends in part upon the accuracy of the exposure assessment. Objective The purpose of this paper is to summarize and discuss issues that make accurate exposure assessment a challenge and to suggest strategies for improving exposure assessment in longitudinal cohort studies of childhood asthma and allergies. Data synthesis Exposures of interest need to be prioritized, because a single study cannot measure all potentially relevant exposures. Hypotheses need to be based on proposed mechanisms, critical time windows for effects, prior knowledge of physical, physiologic, and immunologic development, as well as genetic pathways potentially influenced by the exposures. Modifiable exposures are most important from the public health perspective. Given the interest in evaluating gene–environment interactions, large cohort sizes are required, and planning for data pooling across independent studies is critical. Collection of additional samples, possibly through subject participation, will permit secondary analyses. Models combining air quality, environmental, and dose data provide exposure estimates across large cohorts but can still be improved. Conclusions Exposure is best characterized through a combination of information sources. Improving exposure assessment is critical for reducing measurement error and increasing power, which increase confidence in characterization of children at risk, leading to improved health outcomes.

Educational intervention among farmers in a community health care setting

BACKGROUND Farmers are at increased risk of developing work-related respiratory diseases including asthma, but little is known about their occupational health and safety (OHS) knowledge and exposure prevention practices. Educational interventions may improve knowledge and practice related to prevention. AIMS To determine the feasibility of an educational intervention for farmers in a community health centre setting. METHODS This was a pilot study. Farmers were recruited by the community health centre and completed a questionnaire on symptoms, OHS knowledge and exposure prevention practices. The intervention group received education on work-related asthma and exposure control strategies, and was offered spirometry and respirator fit testing. All subjects were asked to repeat the questionnaire 6 months later. RESULTS There were 68 study participants of whom 38 formed the intervention group. At baseline, almost 60% of farmers reported having received OHS training and were familiar with material safety data sheets (MSDSs); fewer (approximately 40%) reported knowledge of OHS legislation and availability of MSDSs. Approximately, two-thirds of subjects reported using respiratory protection. The response rate for repeating the questionnaire was 76% in the intervention group and 77% in the controls. Among the intervention subjects, statistically significant increases were observed in reported safety training, familiarity and availability of MSDSs and knowledge of OHS legislation. CONCLUSIONS Gaps in OHS knowledge were observed. The educational intervention on OHS knowledge and exposure prevention practices in the community health centre setting was feasible. Larger, more-controlled studies should be undertaken as this study suggests a positive effect on OHS knowledge and prevention practices.

Skin and respiratory symptoms among workers with suspected work-related disease

BACKGROUND Many workers are exposed to chemicals that can cause both respiratory and skin responses. Although there has been much work on respiratory and skin outcomes individually, there are few published studies examining lung and skin outcomes together. AIMS To identify predictors of reporting concurrent skin and respiratory symptoms in a clinical population. METHODS Patients with possible work-related skin or respiratory disease were recruited. An interviewer- administered questionnaire collected data on skin and respiratory symptoms, health history, smoking habits, workplace characteristics and occupational exposures. Predictors of concurrent skin and respiratory symptoms were identified using multiple logistic regression models adjusted for age, sex and atopy. RESULTS In total, 204 subjects participated; 46% of the subjects were female and the mean age was 45.4 years (SD = 10.5). Most subjects (n = 167, 82%) had possible work-related skin disease, compared with 37 (18%) subjects with possible work-related respiratory disease. Subjects with a history of eczema (OR 3.68, 95% CI 1.7-7.8), those from larger workplaces (OR 2.82, 95% CI 1.8-7.4) and those reporting respirator use at work (OR 2.44, 95% CI 1.2-4.8) had significantly greater odds of reporting both work-related skin and respiratory symptoms. Current smoking was also associated with reporting concurrent skin and respiratory symptoms (OR 2.57, 95% CI 1.2-5.8). CONCLUSIONS Workers reported symptoms in both systems, and this may be under-recognised both in the workplace and the clinic. The association between history of eczema and concurrent skin and respiratory symptoms suggests a role for impaired barrier function but needs further investigation.

Historical occupational isocyanate exposure levels in two Canadian provinces

ABSTRACT Isocyanates such as toluene 2, 4-diisocyanate (TDI), methylene bisphenyl isocyanate (MDI), and hexamethylene diisocyanate (HDI) are known sensitizers and exposure to these chemicals can result in isocyanate-induced asthma—the leading cause of occupational asthma. A newly created exposure database was available containing occupational isocyanate measurements spanning 1981–1996 from Ontario and British Columbia (BC)—two of the largest provinces in Canada. The aim was to describe the historical measurements relative to exposure thresholds, ascertain differences in the data between provinces, and identify time trends. Descriptive statistics of the observations were summarized and stratified by isocyanate species and province. Chi-square tests and Students t-test were performed to determine differences between provinces. To investigate time trends in the odds of a measurement exceeding the limit of detection (LOD) and time-weighted average (TWA), mixed effects logistic regression models were constructed. In total, 6,984 isocyanate measurements were analyzed, the majority of which were below the LOD (79%). Overall, 8.3% of samples were in excess of the 2014 TLV-TWA of 0.005 ppm. Comparing the two provinces, the proportion of samples exceeding the LOD and TLV-TWA was greater in BC for all isocyanate species. Differences in time trends were also observed between provinces—the odds of a sample exceeding the TLV-TWA decreased over time in the case of MDI (Ontario only), TDI (both Ontario and BC), and other isocyanates (BC only). Our finding that a majority of the exposure measurements was below the LOD is similar to that reported by others. Differences between provinces may be due the fact that isocyanates are classified as a designated substance in Ontario and must adhere to specific exposure control regulations. Limitations of the database, such as finite number of variables and measurements available until 1996 only, presents challenges for more in-depth analysis and generalization of results. An argument is made that a Canadian occupational exposure database be maintained to facilitate risk assessments as well as for occupational epidemiology research.

Preventing Occupational Skin Disease: A Review of Training Programs

Occupational contact dermatitis (OCD) is a common occupational disease that impacts a variety of worker groups. Skin protection and disease prevention training programs have shown promise for improving prevention practices and reducing the incidence of OCD. This review details the features of training programs for primary prevention of OCD and identifies gaps in the literature. Twelve studies were identified for in-depth review: many studies included wet workers employed in health care, hairdressing, cleaning, and food preparation; 1 program featured manufacturing workers. Few programs provided content on allergic contact dermatitis, and only 1 was evaluated for long-term effectiveness. Effective programs were similar in content, delivery method, and timing and were characterized by industry specificity, multimodal learning, participatory elements, skin care resource provision, repeated sessions, and management engagement. Long-term effectiveness, generalizability beyond OCD, workplace health and safety culture impact, and translation of programs in the North American context represent areas for future research.

Workers with hand dermatitis and workplace training experiences: A qualitative perspective

BACKGROUND Workplace training may help to prevent contact dermatitis, a common work-related disease. Information on the characteristics of existing workplace training programs and worker perceptions of this training is limited. METHODS Fourteen workers with suspected occupational contact dermatitis participated in one-on-one, semi-structured interviews. An inductive thematic analysis approach was used to identify interview themes. RESULTS Workers expressed a desire for hands-on training with content relevant to their job tasks, favored training from supervisors who had practical experience, and were conflicted about employer motivations for providing training. Few workers had received training on skin protection. In many cases, the training workers had received differed greatly from their desired training. CONCLUSIONS Although, workers with contact dermatitis describe having received workplace training, some question its value and effectiveness. This perspective may be attributed not only to the content and methods of training but also the health and safety culture of the workplace. Am. J. Ind. Med. 60:69-76, 2017.

0386 Exposure Registries as a Tool for Epidemiology

Objectives In Canada, there is growing interest in the use of registries for hazard and disease surveillance because they provide an opportunity for primary prevention. Registry data can also be a valuable tool for epidemiology. Here we report the strengths and limitations of using exposure registry data for epidemiology. Method Eight exposure registries were reviewed: five from Canada, two from the USA and one from Finland. They were compared based on overall goals, exposure information, registration, recruitment, and health information collected. The potential use of registry data in epidemiology was evaluated. Key considerations for designing a registry that facilitates secondary data use were identified. Results The eight registries varied significantly. Data from four had been previously used in epidemiology. In three cases exposure measurements were available within the registry; in one, health information was also collected. Registries that have mandatory registration are more likely to contain sufficient data for use in epidemiological studies in contrast to voluntary registries that may fail to capture a large or representative portion of the exposed population. In order to permit later linkage of registry data with health information, consent must be obtained in advance and privacy legislation must be taken into consideration. Conclusions Most exposure registries are not designed with secondary data uses in mind and, as a result, the use of exposure registry data in epidemiological studies can be problematic. Given the large investment involved in launching a new registry, opportunities to leverage the data for epidemiological purposes should be explored in the planning stages.

Examining lung cancer risks across different industries and occupations in Ontario, Canada: the establishment of the Occupational Disease Surveillance System

Background The Occupational Disease Surveillance System (ODSS) was established in Ontario, Canada by linking a cohort of workers with data created from Workplace Safety and Insurance Board (WSIB) claims to administrative health databases. The aim of this study was to use ODSS to identify high-risk industry and occupation groups for lung cancer in Ontario. Methods Workers in the WSIB lost time claims database were linked to the Ontario Cancer Registry using subjects’ health insurance numbers, name, sex, birthdate and death date (if applicable). Several occupations and industries known to be at increased risk were outlined a priori to examine whether ODSS could replicate these associations. Age-adjusted, sex-stratified Cox proportional hazard models compared the risk of lung cancer within one industry/occupation versus all other groups in the cohort. Workers with a lung cancer diagnosis prior to cohort entry were excluded for analysis, leaving 2 187 762 workers for analysis. Results During the 1983 to 2014 follow-up, 34 661 workers in the cohort were diagnosed with lung cancer. Among expected high-risk industries, elevated risks were observed among workers in quarries/sand pits and construction industries for both sexes, and among males in metal mines, iron foundries, non-metallic mineral products industries and transportation industries. Excess risk was also observed among occupations in drilling/blasting, other mining/quarrying, mineral ore treating, excavating/grading/paving, truck driving, painting, bus driving and construction. Conclusions This current surveillance system identified several established high-risk groups for lung cancer and could be used for ongoing surveillance of occupational lung cancer in Ontario.

0387 Smoking and allergic contact dermatitis: causation or correlation?

Objectives Contact dermatitis (CD) is the most common occupational skin disease and includes both irritant and allergic forms (ICD and ACD). Smoking has been associated with all of CD, hand eczema and sensitisation in previous studies, but never explored in relation to work-related ACD and ICD specifically. This abstract describes differences in patients who have a work-related diagnosis of ICD, ACD or both ICD and ACD. Method Data from a study of patients with possible work-related skin or respiratory disease were used. Data included demographics, symptoms, smoking history and physician diagnoses. Differences between diagnosis groups (ICD, ACD, both) were investigated using chi square and ANOVA. Results In total 163 subjects were diagnosed with work-related CD. Of these, 44% were female, approximately half (51%) were ever smokers and 30% were atopic; the mean age was 44.9 years. ICD was diagnosed in 57% of subjects, ACD in 43% and both ICD and ACD in 14%. Current smoking was more common among subjects with ACD (40%) and those with both ACD and ICD (35%) compared to those with ICD (17%) (p = 0.02); no difference in pack-years was observed. Conclusions The rate of smoking in this sample was similar to the Canadian population. Age, sex and atopy did not differ between diagnosis groups. Current smokers were more common among those with ACD and those with ACD and ICD. The mechanism by which smoking may be related to the development of allergic skin disease remains unclear (e.g., systemic inflammation, contact, behavioural differences) but deserves further attention.