Serum vitamin D levels among children aged 0-12 years in the First Affiliated Hospital of Harbin Medical University, China

Background Vitamin D deficiency (VDD) and vitamin D insufficiency (VDI) are highly prevalent in the world, but the vitamin D status of children in northeast China is seldom investigated. The aim of this study was to clarify the prevalence of VDD and VDI among children in the First Affiliated Hospital of Harbin Medical University in Heilongjiang province in China. Methods We collected data from 9795 children who were outpatients aged 0-12 years who visited the First Affiliated Hospital of Harbin Medical University from September 2014 to August 2016. Serum 25-hydroxy vitamin D [25(OH) D] levels were determined by chemiluminescent immunoassay and categorized as <20, 20-30 and> 30 ng/mL. Results The highest mean level of serum 25(OH) D was found at the 1-3 years stage (31.14 ng/mL) and the lowest at 6-12 years stage (18.58 ng/mL). The mean serum 25(OH) D level among school girls (17.86 ng/mL) was lower than that of boys (19.12 ng/mL). The prevalence of vitamin D sufficiency during 2014 was only 17.2%, but increased to similar to 45% in 2016. Conclusions The prevalence of VDD and insufficiency among children in the First Affiliated Hospital of Harbin Medical University is high, especially among children aged 6-12 years.