[1] Karolinska Inst, Dept Global Publ Hlth, Stockholm, Sweden
[2] Aarhus Univ, Dept Clin Med, Dept Clin Epidemiol, Aarhus, Denmark
[3] Norwegian Univ Sci & Technol, Dept Publ Hlth & Nursing, Trondheim, Norway
[4] Karolinska Inst, Inst Environm Med, Stockholm, Sweden