1. Department of Family MedicineMaastricht University (CAPHRI) Maastricht the Netherlands
2. Department of Health PromotionMaastricht University (CAPHRI) Maastricht the Netherlands
3. IVO Research Institute The Hague the Netherlands
4. Department of Methodology and StatisticsMaastricht University (CAPHRI) Maastricht the Netherlands
5. Department of Public Health and Primary CareLeiden University Medical Center Leiden the Netherlands
6. Department of Health Services ResearchMaastricht University (CAPHRI) the Netherlands