[1] State Univ Ghent, Heymans Inst Pharmacol, B-9000 Ghent, Belgium
[2] Vrije Univ Amsterdam, Med Ctr, Inst Res Extramural Med, Dept Social Med, Amsterdam, Netherlands
[3] Free Univ Brussels, Dept Human Ecol, Brussels, Belgium
[4] State Univ Ghent, Ctr Environm Philosophy & Bioeth, B-9000 Ghent, Belgium
[5] Free Univ Brussels, Dept Med Sociol & Hlth Sci, Brussels, Belgium