A Pilot Study of Vitamin D Inadequacy Among Hospital Staffs at Vachira Phuket Hospital: Prevalence, Risk Factors and Response to Ergocalciferol Supplementation

Piyanat Sakulpipatana

Authors

Piyanat Sakulpipatana Vachira Phuket Hospital, Muang Phuket, Thailand 83000

Keywords:

Vitamin D, , Healthcare workers, , Sun exposure, , Ergocalciferol supplementation

Abstract

Introduction: Vitamin D is vital for bone, immune, and overall health, yet deficiency persists even in tropical countries. Hospital staff are at particular risk due to indoor work and limited sun exposure.

Objective: To preliminarily assess vitamin D status, identify factors associated with vitamin D levels, and evaluate the response to Ergocalciferol (vitamin D₂) supplementation among healthcare personnel at Vachira Phuket Hospital.

Methods: A retrospective pilot cohort study was conducted among 66 healthcare personnel at Vachira Phuket Hospital between June and November 2024, with a 6-month follow-up. Serum 25(OH)D was measured and categorized as deficient (<20 ng/mL), insufficient (20–29 ng/mL), or sufficient (≥30 ng/mL). Participants with vitamin D deficiency or insufficiency received oral ergocalciferol (vitamin D₂) at a dose of 20,000 IU (1- 2 capsules per week).

Results: At baseline, 94.0% of participants had inadequate vitamin D status, with 57.6% classified as insufficient and 36.4% as deficient. Age ≥40 years was significantly associated with lower serum vitamin D levels (p < 0.05), whereas no significant associations were observed with other demographic or behavioral factors. After six months of vitamin D₂ supplementation, serum vitamin D status changed significantly within individuals (p < 0.01). Among participants who were vitamin D deficient at baseline, 45.8% showed improvement in vitamin D status, with 41.7% improving to the insufficient category and 4.1% achieving sufficient levels. However, 54.2% remained vitamin D deficient after supplementation.

Conclusions: Vitamin D insufficiency and deficiency were highly prevalent among hospital personnel, with age ≥40 years identified as a significant factor associated with lower vitamin D levels. Findings from this pilot study suggest that weekly ergocalciferol supplementation of 20,000–40,000 IU may be insufficient to achieve adequate vitamin D status in many individuals. Further studies are warranted to determine the optimal vitamin D supplementation regimen for healthcare personnel.

References

Anjum, I., Jaffery, S. S., Fayyaz, M., Samoo, Z., & Anjum, S. (2018). The role of vitamin D in brain health: A mini literature review. Cureus, 10(7), Article e2960. https://doi.org/10.7759/cureus.2960

Chailurkit, L. O., Aekplakorn, W., & Ongphiphadhanakul, B. (2011). Regional variation and determinants of vitamin D status in sunshine-abundant Thailand. BMC Public Health, 11, Article 853. https://doi.org/10.1186/1471-2458-11-853

Chaiyodsilp, S., Pureekul, T., Srisuk, Y., & Euathanikkanon, C. (2015). A cross-sectional study of vitamin D levels in Thai office workers. The Bangkok Medical Journal, 9(1), 8–11. https://doi.org/10.31524/bkkmedj.2015.02.002

Daniel, W. W., & Cross, C. L. (2018). Biostatistics: A foundation for analysis in the health sciences (11th ed.). Wiley.

Divakar, U., Sathish, T., Soljak, M., Bajpai, R., Dunleavy, G., Visvalingam, N., Nazeha, N., Soh, C. K., Christopoulos, G., & Car, J. (2020). Prevalence of vitamin D deficiency and its associated work-related factors among indoor workers in a multi-ethnic Southeast Asian country. International Journal of Environmental Research and Public Health, 17(1), Article 164. https://doi.org/10.3390/ijerph17010164

Hattapornsawan, Y., Pangsuwan, S., Ongphiphadhanakul, B., & Udomsubpayakun, U. (2012). Prevalence of vitamin D deficiency in nurses at the Royal Irrigation Hospital. Journal of the Medical Association of Thailand, 95(12), 1569–1574.

Johanson, G. A., & Brooks, G. P. (2010). Initial scale development: Sample size for pilot studies. Educational and Psychological Measurement, 70(3), 394–400. https://doi.org/10.1177/0013164409355692

Martineau, A. R., Jolliffe, D. A., Hooper, R. L., Greenberg, L., Aloia, J. F., Bergman, P., Dubnov-Raz, G., Esposito, S., Ganmaa, D., Ginde, A. A., Goodall, E. C., Grant, C. C., Griffiths, C. J., Janssens, W., Laaksi, I., Manaseki-Holland, S., Mauger, D., Murdoch, D. R., Neale, R., . . . Camargo, C. A., Jr. (2017). Vitamin D supplementation to prevent acute respiratory tract infections: Systematic review and meta-analysis of individual participant data. BMJ, 356, Article i6583. https://doi.org/10.1136/bmj.i6583

Nowak, A., Boesch, L., Andres, E., Battegay, E., Hornemann, T., Schmid, C., Bischoff-Ferrari, H. A., Suter, P. M., & Krayenbuehl, P. A. (2016). Effect of vitamin D3 on self-perceived fatigue: A double-blind randomized placebo-controlled trial. Medicine, 95(52), Article e5353. https://doi.org/10.1097/MD.0000000000005353

Phruetthiphat, O., Kusuwannakul, N., Khuangsirikul, S., Tutaworn, T., Songpatanasilp, T., & Chotanaphuti, T. (2021). Prevalence of vitamin D inadequacy among orthopedic surgeons. Journal of Southeast Asian Medical Research, 5(1), 35–41. https://www.jseamed.org/index.php/jseamed/article/view/85

Płudowski, P. (2023). Supplementing vitamin D in different patient groups to reduce deficiency. Nutrients, 15(17), Article 3725. https://doi.org/10.3390/nu15173725

Rajatanavin, N., Kanokrungsee, S., & Aekplakorn, W. (2019). Vitamin D status in Thai dermatologists and working-age Thai population. The Journal of Dermatology, 46(3), 206–212. https://doi.org/10.1111/1346-8138.14742

Rothen, J. P., Rutishauser, J., Walter, P. N., Hersberger, K. E., & Arnet, I. (2020). Oral intermittent vitamin D substitution: Influence of pharmaceutical form and dosage frequency on medication adherence: A randomized clinical trial. BMC Pharmacology and Toxicology, 21, Article 51. https://doi.org/10.1186/s40360-020-00430-5

Sangkaew, B., Nuinoon, M., & Jeenduang, N. (2018). Association of vitamin D receptor gene polymorphisms with serum 25(OH)D levels and metabolic syndrome in Thai population. Gene, 659, 59–66. https://doi.org/10.1016/j.gene.2018.03.047

Siwamogsatham, O., Ongphiphadhanakul, B., & Tangpricha, V. (2015). Vitamin D deficiency in Thailand. Journal of Clinical & Translational Endocrinology, 2(1), 48–49. https://doi.org/10.1016/j.jcte.2014.10.004

Sowah, D., Fan, X., Dennett, L., Hagtvedt, R., & Straube, S. (2017). Vitamin D levels and deficiency with different occupations: A systematic review. BMC Public Health, 17, Article 519. https://doi.org/10.1186/s12889-017-4436-z

Suntrapa, S., & Orthopedics Association of Thailand. (2012). Vitamin D status, calcium intake, and bone health markers among indoor working individuals in Thailand. Journal of Bone and Mineral Metabolism, 30(4), 456–462.

Suntrapa, S., & Suntrapa, S. (2018). Response of serum 25-hydroxyvitamin D to vitamin D2 supplementation in healthy Thai adults: A real-world clinical evaluation. Thai Journal of Orthopaedic Surgery, 42(3), 17–24.

Suntrapa, S., Chailurkit, L. O., & Ongphiphadhanakul, B. (2015). Prevalence of vitamin D insufficiency and its relationship with bone mineral density in Thai populations. Journal of the Medical Association of Thailand, 98(Suppl. 2), S105–S111.

Thai Endocrine Society. (n.d.). Clinical practice guideline for the prevention and treatment of vitamin D deficiency. Retrieved December 6, 2025, from https://www.thaiendocrine.org/ข้อแนะนำเกี่ยวกับ-ภาวะข/?download=1433

Tobias, D. K., Luttmann-Gibson, H., Mora, S., Danik, J., Bubes, V., Copeland, T., LeBoff, M. S., Cook, N. R., Lee, I. M., Buring, J. E., & Manson, J. E. (2023). Association of body weight with response to vitamin D supplementation and metabolism. JAMA Network Open, 6(1), Article e2250681. https://doi.org/10.1001/jamanetworkopen.2022.50681

Tran, V., Duarte Romero, B. L., Andersen, H., Clarke, M., Collins, L. G., Dawson, T., Hartel, G., Lefevre, J. G., Lucas, R. M., McLeod, D. S. A., Milne, R. L., Sinclair, C., Whiteman, D. C., Waterhouse, M., & Neale, R. E. (2025). Effect of daily sunscreen application on vitamin D: Findings from the open-label randomized controlled Sun-D Trial. British Journal of Dermatology, 193(6), 1128–1137. https://doi.org/10.1093/bjd/ljaf310

Usategui-Martín, R., De Luis-Román, D. A., Fernández-Gómez, J. M., Ruiz-Mambrilla, M., & Pérez-Castrillón, J. L. (2022). Vitamin D receptor (VDR) gene polymorphisms modify the response to vitamin D supplementation: A systematic review and meta-analysis. Nutrients, 14(2), Article 360. https://doi.org/10.3390/nu14020360

van den Heuvel, E. G. H. M., Lips, P., Schoonmade, L. J., Lanham-New, S. A., & van Schoor, N. M. (2024). Comparison of the effect of daily vitamin D2 and vitamin D3 supplementation on serum 25-hydroxyvitamin D concentration (total 25(OH)D, 25(OH)D2, and 25(OH)D3) and importance of body mass index: A systematic review and meta-analysis. Advances in Nutrition, 15(1), Article 100119. https://doi.org/10.1016/j.advnut.2023.09.016

Walsh, J. S., Bowles, S., & Evans, A. L. (2017). Vitamin D in obesity. Current Opinion in Endocrinology, Diabetes and Obesity, 24(6), 389–394. https://doi.org/10.1097/MED.0000000000000371