1. Disease Risk Unit, Department of Chronic Disease Prevention, National Institute for Health and Welfare (THL), P.O. Box 30, FI-00300 Helsinki, Finland
2. Population Studies Unit, Department of Chronic Disease Prevention, National Institute for Health and Welfare (THL), Peltolantie 3, FI-20720 Turku, Finland
3. Agrifood Research Finland (MTT), FI-31600 Jokioinen, Finland