[1] Maastricht Univ, Dept Hlth Serv Res, Care & Publ Hlth Res Inst, POB 616, NL-6200 MD Maastricht, Netherlands
[2] Univ Leuven, Dept Publ Hlth & Primary Care, Kapucijnenvoer 33,Bus 7001, B-3000 Leuven, Belgium
[3] Vrije Univ Brussel, Dept Educ Sci, Pleinlaan 2, B-1050 Brussels, Belgium
[4] Univ Coll Ghent, Fac Educ Hlth & Social Work, Ghent, Belgium
[5] Univ Leuven, Dept Publ Hlth & Primary Care, Leuven Inst Healthcare Policy, Kapucijnenvoer 35,Bus 7001, B-3000 Leuven, Belgium
[6] Maastricht Univ, Dept Family Med, Care & Publ Hlth Res Inst, POB 616, NL-6200 MD Maastricht, Netherlands