1. Department of Public Health, Occupational and Environmental Medicine, and
2. Department of Biostatistics, Katholieke Universiteit Leuven, Leuven, Belgium
3. Center for Statistics, Hasselt University, Campus Diepenbeek, Diepenbeek, Belgium
4. Belgian Interregional Environment Agency, Brussels, Belgium
5. Centre for Environmental Sciences, Hasselt University, Campus Diepenbeek, Diepenbeek, Belgium