Standardizing serum 25-hydroxyvitamin D data from four Nordic population samples using the Vitamin D Standardization Program protocols: Shedding new light on vitamin D status in Nordic individuals

Kevin D Cashman, Kirsten G Dowling, Zuzana Škrabáková, Mairead Kiely, Christel Lamberg-Allardt, Ramon A Durazo-Arvizu, Christopher T Sempos, Seppo Koskinen, Annamari Lundqvist, Jouko Sundvall, Allan Linneberg, Betina Thuesen, Lise Lotte N Husemoen, Haakon E Meyer, Kristin Holvik, Ida M Grønborg, Inge Tetens, Rikke Andersen