[1] Univ Ghent, Int Ctr Reprod Hlth, B-9000 Ghent, Belgium
[2] Haute Autorite Sante, Dept Econ & Publ Hlth Evaluat, La Plaine St Denis, France
[3] Ghent Univ Hosp, Dept Internal Med Infect Dis & Psychosomat Med, Ghent, Belgium
[4] Univ Porto, Sch Med, Inst Publ Hlth, P-4100 Oporto, Portugal
[5] Natl Inst Hlth Dev, Tallinn, Estonia
[6] Natl Hlth & Welf Inst, Helsinki, Finland