1. Institute for Risk Assessment Sciences, Utrecht University, the Netherlands
2. Netherlands Institute for Health Services Research, Utrecht, the Netherlands
3. Netherlands Expertise Centre for Occupational Respiratory Disorders, Utrecht, the Netherlands
4. Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, the Netherlands
5. Department of General Practice & Elderly Care Medicine, Amsterdam Public Health Research Institute, Vrije Universiteit, University Medical Center, Amsterdam, the Netherlands; and
6. Julius Center for Health Sciences and Primary Care, University Medical Center, Utrecht, the Netherlands