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Validation of summer and winter ELISA measurements of serum 25-hydroxyvitamin D concentrations in Mongolia.
Asia Pac J Clin Nutr. 2017; 26(6):987-993.AP

Abstract

BACKGROUND AND OBJECTIVES

Assay cost, quality, and availability pose challenges for vitamin D surveys in limited resource settings. This study aimed to validate an inexpensive vitamin D assay (ELISA) under real-world conditions in Mongolia, the northernmost developing country, to characterize the assay's usefulness and inform the design of epidemiologic studies in similar regions.

METHODS AND STUDY DESIGN

We collected paired summer and winter serum samples from 120 men and women (aged 20-57 years) in urban and rural Mongolia, analyzed each sample for 25(OH)D concentration using both Immunodiagnostic Systems ELISA and DiaSorin LIAISON 25(OH)D TOTAL, and compared the assays using multiple statistics. LIAISON was itself validated by participation in the DEQAS program.

RESULTS

Correlation and agreement between assays were higher in summer (Pearson's correlation=0.60, Spearman's rank correlation=0.67, Lin's concordance correlation=0.56) than winter (rP=0.37, rS=0.43, rC=0.33), although ELISA less accurately assigned subjects to sufficiency categories in summer (percent agreement=44%) than winter (58%), during the latter of which most subjects were deficient ([25(OH)D] categories used: >75 nmol/L (optimal), 50-75 nmol/L (adequate), 25-50 nmol/L (inadequate), <25 nmol/L (deficient)). Compared with LIAISON, ELISA tended to indicate higher vitamin D status in both seasons (mean paired difference: 7.0 nmol/L (95% CI: 3.5-10.5) in summer, 5.2 nmol/L (95% CI: 2.9-7.5) in winter).

CONCLUSIONS

ELISA proved useful for measuring and ranking subjects' vitamin D status in Mongolia during summer, but levels were too low in winter to sensitively discriminate between subjects, and ELISA overestimated status in both seasons. These findings have implications for the timing and interpretation, respectively, of vitamin D surveys in highly deficient populations.

Authors+Show Affiliations

Harvard T.H. Chan School of Public Health, United States. Email: sbromage@mail.harvard.edu.National Institute of Medical Sciences, Mongolia.Boston Children's Hospital, United States. Harvard Medical School, United States.Boston University Medical Center, United States.Harvard T.H. Chan School of Public Health, United States. Harvard Medical School, United States. Brigham and Women's Hospital, United States.

Pub Type(s)

Journal Article
Validation Study

Language

eng

PubMed ID

28917222

Citation

Bromage, Sabri, et al. "Validation of Summer and Winter ELISA Measurements of Serum 25-hydroxyvitamin D Concentrations in Mongolia." Asia Pacific Journal of Clinical Nutrition, vol. 26, no. 6, 2017, pp. 987-993.
Bromage S, Tselmen D, Bradwin G, et al. Validation of summer and winter ELISA measurements of serum 25-hydroxyvitamin D concentrations in Mongolia. Asia Pac J Clin Nutr. 2017;26(6):987-993.
Bromage, S., Tselmen, D., Bradwin, G., Holick, M. F., & Ganmaa, D. (2017). Validation of summer and winter ELISA measurements of serum 25-hydroxyvitamin D concentrations in Mongolia. Asia Pacific Journal of Clinical Nutrition, 26(6), 987-993. https://doi.org/10.6133/apjcn.122016.02
Bromage S, et al. Validation of Summer and Winter ELISA Measurements of Serum 25-hydroxyvitamin D Concentrations in Mongolia. Asia Pac J Clin Nutr. 2017;26(6):987-993. PubMed PMID: 28917222.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Validation of summer and winter ELISA measurements of serum 25-hydroxyvitamin D concentrations in Mongolia. AU - Bromage,Sabri, AU - Tselmen,Daria, AU - Bradwin,Gary, AU - Holick,Michael F, AU - Ganmaa,Davaasaambuu, PY - 2017/9/18/entrez PY - 2017/9/18/pubmed PY - 2019/8/7/medline SP - 987 EP - 993 JF - Asia Pacific journal of clinical nutrition JO - Asia Pac J Clin Nutr VL - 26 IS - 6 N2 - BACKGROUND AND OBJECTIVES: Assay cost, quality, and availability pose challenges for vitamin D surveys in limited resource settings. This study aimed to validate an inexpensive vitamin D assay (ELISA) under real-world conditions in Mongolia, the northernmost developing country, to characterize the assay's usefulness and inform the design of epidemiologic studies in similar regions. METHODS AND STUDY DESIGN: We collected paired summer and winter serum samples from 120 men and women (aged 20-57 years) in urban and rural Mongolia, analyzed each sample for 25(OH)D concentration using both Immunodiagnostic Systems ELISA and DiaSorin LIAISON 25(OH)D TOTAL, and compared the assays using multiple statistics. LIAISON was itself validated by participation in the DEQAS program. RESULTS: Correlation and agreement between assays were higher in summer (Pearson's correlation=0.60, Spearman's rank correlation=0.67, Lin's concordance correlation=0.56) than winter (rP=0.37, rS=0.43, rC=0.33), although ELISA less accurately assigned subjects to sufficiency categories in summer (percent agreement=44%) than winter (58%), during the latter of which most subjects were deficient ([25(OH)D] categories used: >75 nmol/L (optimal), 50-75 nmol/L (adequate), 25-50 nmol/L (inadequate), <25 nmol/L (deficient)). Compared with LIAISON, ELISA tended to indicate higher vitamin D status in both seasons (mean paired difference: 7.0 nmol/L (95% CI: 3.5-10.5) in summer, 5.2 nmol/L (95% CI: 2.9-7.5) in winter). CONCLUSIONS: ELISA proved useful for measuring and ranking subjects' vitamin D status in Mongolia during summer, but levels were too low in winter to sensitively discriminate between subjects, and ELISA overestimated status in both seasons. These findings have implications for the timing and interpretation, respectively, of vitamin D surveys in highly deficient populations. SN - 0964-7058 UR - https://www.unboundmedicine.com/medline/citation/28917222/Validation_of_summer_and_winter_ELISA_measurements_of_serum_25_hydroxyvitamin_D_concentrations_in_Mongolia_ L2 - http://apjcn.nhri.org.tw/server/APJCN/26/6/987.pdf DB - PRIME DP - Unbound Medicine ER -