D-tecting Disease - From Exposure to Vitamin D During Critical Periods of Life

"1. This study is based on a unique Danish social experiment that took place during a well-defined period between 1937 and December 1985, when it was mandatory to fortify all margarine with vitamin D (1.25 μg/100 g). This well-defined vitamin D fortification period makes it possible to investigate the impact of fetal exposure to extra vitamin D from food fortification on the risk of developing diseases later on. This study is possible due not only to the well-defined adjacent time window but also to the complete registration of every citizen via a civil registration number. This number can be linked, on an individual level, to Danish birth, patient and medical registries; social and ethnic registries; and clinical and other large databases~2. Case-cohort study: vitamin D measurements from dried blood spots and the risk of diseases later on"