Work-related and personal risk factors for occupational contact dermatitis: A systematic review of the literature with meta-analysis.

The objective of this review is to identify work-related and personal risk factors for contact dermatitis (CD), and assess their association with this frequently occurring occupational disease. A systematic review of the literature from 1990 to June 2, 2020, was conducted using Medline and Embase. Prospective cohort and case-control studies were included, and meta-analyses were conducted when feasible. Quality of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation. Twenty-nine studies were identified, comprising 26 study populations and with a total of 846 209 participants investigating 52 risk factors for CD. Meta-analyses were performed for five risk factors, all of them for irritant contact dermatitis (ICD). Moderate-quality evidence was found for associations between wet work and ICD (OR: 1.56, 95%CI: 1.21-2.01). High-quality evidence was found for the association between atopic dermatitis and ICD (OR: 2.44, 95%CI: 1.89-3.15). There was no evidence for an association between ICD and sex or history of hand dermatitis, respiratory and mucosal atopy. In conclusion, several work-related and personal risk factors associated with CD were identified. Our data emphasize the need for the assessment of both, work-related and personal, risk factors to prevent occupational CD.

Chronic 14-day exposure to insecticides or methylmercury modulates neuronal activity in primary rat cortical cultures.

There is an increasing demand for in vitro test systems to detect neurotoxicity for use in chemical risk assessment. In this study, we evaluated the applicability of rat primary cortical cultures grown on multi-well micro-electrode arrays (mwMEAs) to detect effects of chronic 14-day exposure to structurally different insecticides or methylmercury on neuronal activity (mean spike rate; MSR). Effects of chronic exposure to α-cypermethrin, endosulfan, carbaryl, chlorpyrifos(-oxon), methylmercury or solvent control [14days exposure, initiated after baseline recording at day in vitro (DIV)7] were studied in five successive recordings between DIV10 and DIV21. The results were compared to effects of acute exposure to these same compounds (activity recorded immediately after the start of exposure after baseline recording at DIV10-11). Chronic 14-day exposure to methylmercury, chlorpyrifos and α-cypermethrin inhibited MSR, all with a lowest-observed effect concentration (LOEC) of 0.1µM, while exposure to endosulfan increased MSR [LOEC: 1µM]. No significant effects were observed for chlorpyrifos-oxon and carbaryl. Similar to the observations in the chronic 14-day exposure studies, MSR was inhibited by acute 30-min exposure to methylmercury, chlorpyrifos, and α-cypermethrin [LOECs: 1µM, 10µM, and 1µM, respectively], whereas endosulfan increased MSR [LOEC: 0.3µM]. While not observed in the chronic 14-day exposure study, acute exposure to chlorpyrifos-oxon and carbaryl resulted in inhibition of MSR [LOECs: 10µM, and100 µM, respectively]. Effects on median interspike intervals (mISI; a measure for neuronal firing pattern) were not detected following chronic 14-day or acute 30-min exposure, except for increased mISI at acute chlorpyrifos and α-cypermethrin exposures at concentrations that also inhibited MSR. These data indicate that the effects of chronic 14-day exposures to methylmercury and insecticides at low concentrations on spontaneous neuronal activity in vitro can be predicted in rapid acute screening studies using mwMEAs.