References
- Sempos CT, Vesper HW, Phinney KW, Thienpont LM, Coates PM. Vitamin D status as an international issue: national surveys and the problem of standardization. Scand J Clin Lab Invest Suppl. 2012;72:32–40.
- Cashman KD, Kiely M. Towards prevention of vitamin D deficiency and beyond – knowledge gaps and research needs in vitamin D nutrition and public health. Brit J Nutr 2011;106:1617–27.
- Hilger J, Friedel A, Herr R, Rausch T, Roos F, Wahl DA, Pierroz DD, Weber P, Hoffmann K. A systematic review of vitamin D status in populations worldwide. Br J Nutr 2014;111:23–45.
- Binkley N, Krueger D, Cowgill CS, Plum L, Lake E, Hansen KE, DeLuca HF, Drezner MK. Assay variation confounds the diagnosis of hypovitaminosis D: a call for standardization. J Clin Endocrinol Metab 2004;89:3152–7.
- Carter GD. Accuracy of 25-hydroxyvitamin D assays: confronting the issues. Curr Drug Targets 2011;12:19–28.
- Carter GD, Carter R, Jones J, Berry J. How accurate are assays for 25-hydroxyvitamin D? Data from the international vitamin D external quality assessment scheme. Clin Chem 2004;50:2195–7.
- Carter GD. 25-Hydroxyvitamin D: a difficult analyte. Clin Chem 2012;58:486–8.
- Lai JK, Lucas RM, Banks E, Posonby AL, Ausimmune Investigator Group. Variability in vitamin D assays impairs clinical assessment of vitamin D status. Intern Med J 2012; 42:43–50.
- Wallace AM, Gibson S, de la Hunty A, Lamberg-Allardt, Ashwell M. Measurement of 25-hydroxyvitamin D in the clinical laboratory: current procedures, performance characteristics and limitations. Steroids 2010;75:477–88.
- Binkley N, Sempos CT; for the Vitamin D Standardization Program (VDSP). Standardizing vitamin D assays: the way forward. J Bone Miner Res 2014;29:1709–14.
- Institute of Medicine Food and Nutrition Board. Dietary reference intakes for calcium and vitamin D. Washington, DC: National Academy Press; 2011
- Cashman KD, Kiely M, Kinsella M, Durazo-Arvizu RA, Tian L, Zhang Y, Lucey A, Flynn A, Gibney MJ, Vesper HW, Phinney KW, Coates PM, Picciano MF, Sempos CT. 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. Am J Clin Nutr 2013;97:1235–42.
- NORDEN (2013). Nordic Nutrition Recommendations 5th Edition (NNR5) – Vitamin D. Available at: http://www.slv.se/en-gb/Startpage-NNR/Public-consultation11/ (accessed August 2013).
- Heistaro S, Methodology report – Health 2000 survey. Publications of the National Public Health Institute. Available at: http://www.terveys2000.fi/doc/methodologyrep.pdf; accessed 12 November 2014.
- Meyer HE, Falch JA, Søgaard AJ, Haug E. Vitamin D deficiency and secondary hyperparathyroidism and the association with bone mineral density in persons with Pakistani and Norwegian background living in Oslo, Norway, The Oslo Health Study. Bone 2004;35:412–7.
- Thuesen BH, Cerqueira C, Aadahl M, Ebstrup JF, Toft U, Thyssen JP, Fenger RV, Hersoug LG, Elberling J, Pedersen O, Hansen T, Johansen JD, Jørgensen T, Linneberg A. Cohort profile: the Health2006 cohort, research centre for prevention and health. Int J Epidemiol 2014;3:568–75.
- Madsen KH, Rasmussen LB, Andersen R, Mølgaard C, Jakobsen J, Bjerrum PJ, Andersen EW, Mejborn H, Tetens I. Randomized controlled trial of the effects of vitamin D-fortified milk and bread on serum 25-hydroxyvitamin D concentrations in families in Denmark during winter: the VitmaD study. Am J Clin Nutr 2013;98:374–82.
- Met Eireann (2014). Available at: http://www.met.ie/climate-ireland/climate-of-ireland.asp
- Cashman KD, Muldowney S, McNulty B, Nugent A, FitzGerald AP, Kiely M, Walton J, Gibney MJ & Flynn A. Vitamin D status of Irish adults: findings from the National Adult Nutrition Survey. Br J Nutr 2013;109:1248–56.
- Cashman KD, Kinsella M, McNulty BA, Walton J, Gibney MJ, Flynn A, Kiely M. Dietary vitamin D2 – a potentially underestimated contributor to vitamin D nutritional status of adults? Br J Nutr 2014;112:193–202.
- Rahmani YE, Botelho JC, Vesper HW. CDC Vitamin D Standardization Certification Program. Endocr Rev 2013;34(03_MeetingAbstracts): SUN-277.
- Tian L, Durazo-Arvizu RA, Myers G, Brooks S, Sarafin K, Sempos CT. The estimation of calibration equations for variables with heteroscedastic measurement errors. Stat Med 2014;33:4420–36.
- Department of Health. Dietary reference values for food energy and nutrients for the United Kingdom. London: Her Majesty's Stationery Office (Report on Health and Social Subjects, 41; 1991.
- Commission of the European Communities. Vitamin D. In Nutrient and Energy Intakes of the European Community. Report of the Scientific Committee for Food (31st series), Brussels, Luxembourg, 1993. pp 132–139,
- Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, Murad MH, Weaver CM; Endocrine Society. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2011;96:1911–30.
- Enko D, Fridrich L, Rezanka E, Stolba R, Ernst J, Wendler I, Fabian D, Hauptlorenz S, Halwachs-Baumann G. 25-hydroxy-Vitamin D status: limitations in comparison and clinical interpretation of serum-levels across different assay methods. Clin Lab 2014;60:1541–50.
- Webb AR, Kline L, Holick MF. Influence of season and latitude on the cutaneous synthesis of vitamin D3: exposure to winter sunlight in Boston and Edmonton will not promote vitamin D3 synthesis in human skin. J Clin Endocrinol Metab 1988;67:373–8.
- Andersen R, Mølgaard C, Skovgaard LT, Trolle E, Tetens I, Ovesen L. Teenage girls and elderly women living in northern Europe have low winter vitamin D status. Eur J Clin Nutr 2005;59:533–41.
- Andersen R, Brot C, Jakobsen J, Mejborn H, Mølgaard C, Skovgaard LT, Trolle E, Tetens I, Ovesen L. Seasonal changes in vitamin D status among Danish adolescent girls and elderly women: the influence of sun exposure and vitamin D intake. Eur J Clin Nutr 2013;67:270–4.
- Andersen R, Mølgaard C, Skovgaard LT, Brot C, Cashman KD, Jakobsen J, Lamberg-Allardt C, Ovesen L. Pakistani immigrant children and adults in Denmark have severely low vitamin D status. Eur J Clin Nutr 2008;62: 625–34.
- Cashman KD, Kinsella M, Walton J, Flynn A, Hayes A, Lucey AJ, Seamans KM, Kiely M. The 3 epimer of 25-hydroxycholecalciferol is present in the circulation of the majority of adults in a nationally representative sample and has endogenous origins. J Nutr 2014;144:1050–7