Contact allergy to thiurams: multifactorial analysis of clinical surveillance data collected by the IVDK network

PURPOSE: To analyse the association between occupation (represented by job title) and contact allergy to thiuram vulcanising agents based on data of a clinical registry (IVDK, www.ivdk.org). METHODS: Clinical, demographic and allergy patch test data of all patients tested between 1992 and 2006 with the thiuram mix (1% in petrolatum) as part of the baseline series was analysed (n = 121,051). Poisson regression analysis was used to quantify the association between different occupations (and other relevant factors) and a positive patch test reaction to the thiuram mix. Furthermore, the time trend of sensitisation prevalence was analysed in high-risk occupational subgroups identified. RESULTS: In comparison to a largely unexposed reference group (office workers and teachers), rubber manufacturers had a significantly elevated risk (prevalence ratio (PR): 5.1, 95% confidence interval (CI) 2.0–10.5). However, health care workers such as physicians and dentists (PR: 3.8, 95% CI: 3.0–4.8) or nursing staff (PR: 3.0, 95% CI: 2.5–3.6) as well as meat and fish processors (PR 3.5, 95% CI: 2.2–5.3) and cleaners (PR 3.1, 95% CI: 2.5–3.8) were found to have a high sensitisation risk as well. In case of health care workers, a significant downward trend during the study period was observed; while in food processors and cleaners, sensitisation prevalence remained largely stable. CONCLUSION: The adjusted multifactorial analysis identified occupations yet unknown to be associated with elevated thiuram contact allergy risk, e.g., food processors and cleaners. Thus, (i) further in-depth research can be targeted and (ii) efforts to prevent sensitisation to thiurams focussed, e.g., by limiting thiuram concentrations in products to a residual level which is technically inevitable.