Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Correspondence
  • Published:

Analysis of serum 25-hydroxyvitamin D levels involves taking into account several confounding factors

European Journal of Clinical Nutrition volume 76, pages 1349–1350 (2022)Cite this article

Subjects

With great interest, we read the impressive article entitled “Vitamin D status and obesity in children from Chile” by Pérez-Bravo et al. [1], which analyzed the profiles of vitamin D levels and their relationship with body weight in children (4–14 years) from three regions of Chile (Santiago, Antofagasta, and Concepción). The authors measured serum 25-Hydroxyvitamin D [25(OH)D] levels by enzyme-linked immunosorbent assay to reflect the vitamin D status of children in three regions of Chile. This is a study of great clinical value and we commend the authors for their contribution to the study. However, there are several confounding factors that may affect serum 25(OH)D levels of children in this study that deserve to be presented.

It is well known that sunlight exposure and diet are the two main sources of vitamin D for the body. When human skin is exposed to sunlight or ultraviolet (UV) light, 7-dehydrocholesterol stored in the skin can be generated by photochemical reaction to vitamin D3 [2,3,4]. Therefore, the time that subjects are irradiated to outdoor sunlight and the intensity of UV light outside affected serum 25(OH)D levels and should be regarded as confounding factors. As with anthropometric indicators, the amount of time spent in sunlight should be compared between children in different regions. The UV intensity of sunlight changes seasonally in the same geographical area. Serum 25(OH)D concentrations in humans are different in different seasons, with the lowest concentrations in winter and early spring, when UV intensity is minimal [5]. It is recommended that serum 25(OH)D measurements be standardized by the cosinor model to acquire seasonally corrected serum 25(OH)D concentrations [6, 7]. Vitamin D can be converted to 25(OH)D in human hepatic cells [8]. The conversion of 25(OH)D is diminished if the subject’s liver function is impaired. Therefore, the subject’s liver function status is also an important confounding factor affecting serum 25(OH)D concentration. Biomarkers of liver function in children from different regions should be compared.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

References

  1. Pérez-Bravo F, Duarte L, Arredondo-Olguín M, Iñiguez G, Castillo-Valenzuela O. Vitamin D status and obesity in children from Chile. Eur J Clin Nutr. 2021;10.1038/s41430-021-01043-9. [published online ahead of print, 2021 Nov 12].

  2. Holick MF. The cutaneous photosynthesis of previtamin D3: a unique photoendocrine system. J Invest Dermatol. 1981;77:51–8. https://doi.org/10.1111/1523-1747.ep12479237

    Article  CAS  PubMed  Google Scholar 

  3. Saraff V, Shaw N. Sunshine and vitamin D. Arch Dis Child. 2016;101:190–2. https://doi.org/10.1136/archdischild-2014-307214

    Article  PubMed  Google Scholar 

  4. Carlberg C. Nutrigenomics of Vitamin D. Nutrients. 2019;11:676 https://doi.org/10.3390/nu11030676

    Article  CAS  PubMed Central  Google Scholar 

  5. Farrokhyar F, Tabasinejad R, Dao D, Peterson D, Ayeni OR, Hadioonzadeh R, et al. Prevalence of vitamin D inadequacy in athletes: a systematic-review and meta-analysis. Sports Med. 2015;45:365–78. https://doi.org/10.1007/s40279-014-0267-6

    Article  PubMed  Google Scholar 

  6. Sachs MC, Shoben A, Levin GP, Robinson-Cohen C, Hoofnagle AN, Swords-Jenny N, et al. Estimating mean annual 25-hydroxyvitamin D concentrations from single measurements: the Multi-Ethnic Study of Atherosclerosis. Am J Clin Nutr. 2013;97:1243–51. https://doi.org/10.3945/ajcn.112.054502

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  7. Degerud E, Hoff R, Nygård O, Strand E, Nilsen DW, Nordrehaug JE, et al. Cosinor modelling of seasonal variation in 25-hydroxyvitamin D concentrations in cardiovascular patients in Norway. Eur J Clin Nutr. 2016;70:517–22. https://doi.org/10.1038/ejcn.2015.200

    Article  CAS  PubMed  Google Scholar 

  8. Bikle DD. Vitamin D metabolism, mechanism of action, and clinical applications. Chem Biol. 2014;21:319–29. https://doi.org/10.1016/j.chembiol.2013.12.016

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  9. Azadbakht L, Mirmiran P, Esmaillzadeh A, Azizi F. Dairy consumption is inversely associated with the prevalence of the metabolic syndrome in Tehranian adults. Am J Clin Nutr. 2005;82:523–30. https://doi.org/10.1093/ajcn.82.3.523

    Article  CAS  PubMed  Google Scholar 

Download references

Author information

Author notes

  1. These authors contributed equally: Lu-Lu Zhai, Chun-Xi Chen, Chun-Hua Zhan.

Authors and Affiliations

  1. Department of General Surgery, Renmin Hospital of Wuhan University, Wuhan, China

    Lu-Lu Zhai & Zhi-Gang Tang

  2. Department of Pediatrics, Xishui People’s Hospital, Huanggang, China

    Chun-Xi Chen

  3. Department of Infectious Diseases, Xishui People’s Hospital, Huanggang, China

    Chun-Hua Zhan

  4. Department of Infectious Diseases, Xishui Maternal and Child Health Hospital, Huanggang, China

    Guo-Wen You

  5. Department of Gastroenterology, Xishui Maternal and Child Health Hospital, Huanggang, China

    Qing-lin Chen

Authors
  1. Lu-Lu Zhai
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Chun-Xi Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Chun-Hua Zhan
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Guo-Wen You
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Qing-lin Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Zhi-Gang Tang
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

L-LZ and Z-GT conceived and designed the study. L-LZ, C-XC, C-HZ, G-WY, Q-lC, and Z-GT participated in the drafting and critical revision of the manuscript. All authors read and approved the final version of the manuscript.

Corresponding author

Correspondence to Zhi-Gang Tang.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Zhai, LL., Chen, CX., Zhan, CH. et al. Analysis of serum 25-hydroxyvitamin D levels involves taking into account several confounding factors. Eur J Clin Nutr 76, 1349–1350 (2022). https://doi.org/10.1038/s41430-022-01098-2

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41430-022-01098-2

This article is cited by

Search

Advanced search

Quick links