[1] Erasmus MC, Dept Internal Med, NL-3000 CA Rotterdam, Netherlands
[2] Erasmus MC, Dept Epidemiol & Biostat, NL-3000 CA Rotterdam, Netherlands
[3] Erasmus MC, Dept Clin Chem, NL-3000 CA Rotterdam, Netherlands
[4] Erasmus MC, Div Reprod Med, Dept Obstet & Gynaecol, NL-3000 CA Rotterdam, Netherlands
[5] Vrije Univ Amsterdam Med Ctr, Inst Res Extramural Med, NL-1081 BT Amsterdam, Netherlands
[6] Vrije Univ Amsterdam Med Ctr, Dept Endocrinol, NL-1007 MB Amsterdam, Netherlands