1. Institute for Prevention and Occupational Medicine of the German Social Accident Insurance Institute; Ruhr-University Bochum (IPA); Bürkle-de-la-Camp Platz 1 44789 Bochum Germany
2. Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine; Friedrich-Alexander University Erlangen-Nürnberg (FAU); Schillerstraße 25 and 29 91054 Erlangen Germany