1 Department of Research, Cancer Registry of Norway, and Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
2 Department of Research, Cancer Registry of Norway, and Section for Colorectal Cancer Screening, Cancer Registry of Norway, Cancer Registry of Norway, Oslo, Norway. Electronic address: edoardo.botteri@kreftregisteret.no.