[1] Vrije Univ Amsterdam, Med Ctr, Dept Clin Genet, Sect Community Genet,EMGO Inst Hlth & Care Res, NL-1007 MB Amsterdam, Netherlands
[2] Vrije Univ Amsterdam, Med Ctr, Dept Midwifery Sci, EMGO Inst Hlth & Care Res, NL-1007 MB Amsterdam, Netherlands
[3] Radboud Univ Nijmegen, Med Ctr, Dept Primary Care & Community Care, NL-6525 ED Nijmegen, Netherlands
[4] Vrije Univ Amsterdam, Med Ctr, Dept Publ & Occupat Hlth, EMGO Inst Hlth & Care Res, NL-1007 MB Amsterdam, Netherlands