[1] Univ Copenhagen, Bispebjerg & Frederiksberg Hosp, Dept Occupat & Environm Med, Bispebjerg Bakke 23, DK-2400 Copenhagen NV, Denmark
[2] Univ Copenhagen, Fac Hlth & Med Sci, Dept Publ Hlth, Oster Farimagsgade 5, DK-1014 Copenhagen K, Denmark
[3] Natl Res Ctr Working Environm, Lerso Pk Alle 105, DK-2100 Copenhagen O, Denmark
[4] Aarhus Univ Hosp, Dept Clin Epidemiol, Olof Palmes Alle 43-45, DK-8200 Aarhus N, Denmark
[5] Aarhus Univ, Dept Publ Hlth, Res Unit Epidemiol, Bartholins Alle 2, DK-8000 Aarhus C, Denmark