1. National Centre for Healthcare Research & Pharmacoepidemiology, University of Milano-Bicocca Milan, Milan, Italy
2. Laboratory of Healthcare Research & Pharmacoepidemiology, Unit of Biostatistics, Epidemiology and Public Health, Department of Statistics and Quantitative Methods, University of Milano-Bicocca, Milan, Italy
3. Epidemiologic Observatory, Lombardy Regional Health Service, Milan, Italy
4. University of Milano-Bicocca, Milan, Italy