Written informed consent, according to the current edition of the Declaration of Helsinki, was obtained from all subjects who were interviewed and/or gave DNA samples before the beginning of the studies. The collection of blood samples followed the recommendations given in the Declaration of Helsinki and its amendments. For the FinnTwin12, FinnTwin16, and NAG-FIN studies, data collection has been approved by the hospital district of Helsinki and Uusimaa, the ethics committee for epidemiology and public health (HUS-113-E3-01, HUS-346-E0-05, HUS 136/E3/01). FinnTwin12 and FinnTwin16 have also been approved by the IRB of Indiana University at Bloomington, Indiana, while NAG-FIN was also approved by the IRB of Washington University (St. Louis). Young Finns Study data collection has been approved by the hospital district of Southwest Finland ethics committee (ETMK: no. 88/180/2010). The ethics approvals for FINRISK have been obtained from the Coordinating Ethics Committee of Helsinki and Uusimaa Hospital District.
