Standardizing 25-Hydroxyvitamin D values from the Canadian Health Measures Survey

Published

September 30, 2015

Author(s)

Kurtis Sarafin, Ramon Durazo-Arvizu, Lu Tian, Karen W. Phinney, Susan Tai, Johanna Camara, Hubert W. Vesper, Joyce M. Merkel, Evan Green, Christopher T. Sempos, Stephen P. Brooks

Abstract

Background: The Canadian Health Measures survey (CHMS) is an ongoing cross sectional national survey that includes a measure of 25-hydroxyvitamin D (25(OH)D) by Diasorin LIAISON immunoassay. The survey repeats approximately every two years with a new sample of about 5600 individuals (termed a cycle). The LIAISON instrument was changed after Cycle 1 and the assay was changed by the manufacturer after Cycle 2. Objective: To standardize the original CHMS 25(OH)D values from Cycle 1 and 2 to values based on the internationally recognized reference measurement procedures developed by the US National Institute for Standards and Technology (NIST) and Ghent University, Belgium. Design: Standardization was accomplished using a two-step procedure. First, serum samples corresponding to original plasma samples were re-measured using the current LIAISON method. Second, 50 serum samples with known 25(OH)D values assigned by the NIST and Ghent reference laboratories were measured using the current LIAISON method. Weighted Deming regression analysis was used to estimate mathematical models for each step, i.e. (1) YCurrent = XOriginal; (2) YNIST-Ghent = XCurrent. The two models were then solved to calculate the mathematical model used to convert the ‘original' values to NIST-Ghent reference procedure values. Results: Using the combined Cycle 1 and 2 data, the percentage of all Canadians with 25(OH)D values <40 nmol/L increased from 16.4% (original) to 19.4% (standardized) and values <50 nmol/L increased from 29.0% (original) to 36.8% (standardized). The 25(OH)D standardized distributions for Cycles 1 and 2 were similar across age/sex groups with slightly higher values associated with Cycle 2 in the young and old. This is in contrast to the original data that indicated lower Cycle 2 values for all age groups.

Citation

American Journal of Clinical Nutrition

Pub Type

Journals

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Keywords

Canadian Health Measures Survey, 25-hydroxyvitamin D, reference measurement procedure, Vitamin D Standardization Program

Citation

Sarafin, K. , Durazo-Arvizu, R. , Tian, L. , Phinney, K. , Tai, S. , Camara, J. , Vesper, H. , Merkel, J. , Green, E. , Sempos, C. and Brooks, S. (2015), Standardizing 25-Hydroxyvitamin D values from the Canadian Health Measures Survey, American Journal of Clinical Nutrition, [online], https://doi.org/10.3945/ajcn.114.103689 (Accessed April 23, 2024)