Evaluation of vitamin D standardization program protocols for standardizing serum 25-hydroxyvitamin D data: A case study of the program's potential for national nutrition and health surveys

摘要

Background: The Vitamin D Standardization Program (VDSP) has developed protocols for standardizing procedures of 25-hydroxyvitamin D [25(OH)D] measurement in National Health/Nutrition Surveys to promote 25(OH)D measurements that are accurate and comparable over time, location, and laboratory procedure to improve public health practice. Objective: We applied VDSP protocols to existing ELISA-derived serum 25(OH)D data from the Irish National Adult Nutrition Survey (NANS) as a case-study survey and evaluated their effectiveness by comparison of the protocol-projected estimates with those from a reanalysis of survey serums by using liquid chromatography-tandem mass spectrometry (LC-tandem MS). Design: The VDSP reference system and protocols were applied to ELISA-based serum 25(OH)D data from the representative NANS sample (n = 1118). A reanalysis of 99 stored serums by using standardized LC-tandem MS and resulting regression equations yielded predicted standardized serum 25(OH)D values, which were then compared with LC-tandem MS reanalyzed values for all serums. Results: Year-round prevalence rates for serum 25(OH)D concentrations 125 nmol/L were 1.2%, 0.3%, and 0.6% by means of ELISA, VDSP protocols, and LC-tandem MS, respectively. Conclusion: VDSP protocols hold a major potential for national nutrition and health surveys in terms of the standardization of serum 25(OH)D data.