1. Institute of Clinical Medicine, Department of Internal Medicine and Biocenter Oulu, University of Oulu and Clinical Research Center, Oulu University Hospital, Oulu, Finland.
2. Department of Medicine, Kuopio University Hospital, Kuopio, Finland.
3. Department of Clinical Physiology, Tampere University Hospital and University of Tampere, Tampere, Finland.
4. Department of Medicine, University of Helsinki, Helsinki, Finland.
5. Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland.
6. Department of Chronic Disease Prevention, National Institute for Health and Welfare, Turku, Finland.