Table 1.

Description of the NorTwinCan cohorts

DenmarkFinlandNorwaySweden
Birth cohorts1870–19991887–19571896–19791886–1999
Number of male twins53,07612,15412,31865,919
Number of MZ/DZ pairs6,092/11,1321,792/4,2222,392/3,0268,438/11,731
End of follow-upDecember 31, 2009December 31, 2009December 31, 2008December 31, 2009
Number of MZ/DZ pairs uncensored at follow-up1,300/2,456388/819231/2981,632/2,843
Cancer registration since1943195319531958
Number of prostate cancer cases8215473562,385