[1] Aarhus Univ, Inst Publ Hlth, Dept Nursing Sci, DK-8000 Aarhus C, Denmark
[2] Cvu Vita, Sch Nursing, DK-7500 Holstebro, Denmark
[3] Aarhus Univ, Inst Publ Hlth, Dept Biostat, DK-8000 Aarhus, Denmark
[4] Univ Calif Los Angeles, Sch Publ Hlth, Dept Epidemiol, Los Angeles, CA 90095 USA
[5] Aarhus Univ, Inst Publ Hlth, Dept Epidemiol, Danish Epidemiol Sci Ctr, DK-8000 Aarhus, Denmark
[6] Muusmann Res & Consulting, DK-1210 Copenhagen, Denmark