[1] Karolinska Inst, Div Environm Epidemiol, Inst Environm Med, SE-17177 Stockholm, Sweden
[2] Stockholm Cty Council, Dept Environm Hlth, Stockholm, Sweden
[3] Huddinge Univ Hosp, Dept Renal Med, S-14186 Huddinge, Sweden
[4] Karolinska Inst, Dept Med Epidemiol, Stockholm, Sweden
[5] Cty Council Kalmar, Dept Publ Hlth, Oskarshamn, Sweden
[6] Univ London Imperial Coll Sci & Technol, Dept Epidemiol & Publ Hlth, London, England