1 Department of Biomedical Sciences for Health, Postgraduate School of Public Health, Via Pascal 36, University of Milan, Milan, Italy. francesca.grosso@unimi.it.
2 MRC Biostatistics Unit, University of Cambridge, East Forvie Building, Robinson way, Cambridge, UK.
3 Department of Statistics, University of Warwick, Mathematical Sciences Building, Academic Loop Road, Warwick, UK.
4 Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Via Francesco Sforza, 28, Milan, Italy.
5 Welfare General Directorate, Regione Lombardia, Piazza Città di Lombardia 1, Milan, Italy.
6 Department of Biomedical Sciences for Health, Postgraduate School of Public Health, Via Pascal 36, University of Milan, Milan, Italy.