Cross-sectional analysis of universal vitamin D supplementation in former East Germany during the first year of life.

Background: Universal vitamin D supplementation is controversial. Preventative examinations and public health initiatives in former East Germany that included vitamin D prophylaxis for children were regulated by official recommendations and guidelines. The aim of this study is to analyse the impact of a standardised nationwide guideline for universal supplementation with 400 International Units (IU) vitamin D3/day during the first year of life on clinical and biochemical parameters and the influence of surrounding factors.