Objective: We substantiated the conditions of the use of premise insolation to organize a prophylactic irradiation of human skin in order to ensure a synthesis of the required doses of vitamin D.

Materials and methods: Using geometric methods for constructing shadow mask of a light slot of the window according to the State Standard B V.2.2-27: 2010, we calculated a duration of the insolation at 63 points in the conditional model premise with an open half of the window on a horizontal surface at a height of 0.50 m above the floor at different heights of the sun in the warm months of the year (May–September). The dimensions of a conditional bed were 0.84 m width and 1.94 m length. The required exposure time for bedridden patient in the sunspot to receive a prophylactic dose of vitamin D (1000 IU) into organism was calculated by the A.R. Webb, & O. Engelsen model (2020).

Results: The study determined the duration of insolation with the open half of the window of the model premise on a parallel plane in the warm months of the year (May - September) at a height of 0.50 m from the floor at points located on the coordinate grid with a step of 0.50 m and at the average values of the sun standing height which forms a sunspot. At the same time, the duration of the insolation at the points near the window ranged from 1 hour 10 minutes to 3 hours 38 minutes on some above mentioned months.
The results of the analysis on the limitations of the application of the model by A.R. Webb and O. Engelsen (2020) for the determination of the required duration of the human body indoor insolation to achieve the effective ultraviolet B (UVR) doses for vitamin D production equivalent to the oral intake of the recommended prophylactic doses of vitamin D are also presented in the study.

Conclusions: In the insolated premise on a clear day of the warm months of the year (May - September), it is in principle possible to organize the exposure of the part of the skin of a person lying on a bed in a sunspot, formed by an open window, with the required duration and intensity of UVR B that provide a bioeffective dose equivalent to the oral intake of the prophylactic dose of vitamin D (1000 IU).

sunlight, solar charts, insolation of the premise, vitamin D, bioefficiency of ultraviolet radiation of the sun

1. Lips P., Cashman K., Lamberg-Allardt C. et al. Current Vitamin D Status in European and Middle East Countries and Strategies to Prevent Vitamin D Deficiency: a Position Statement of the European Calcified Tissue Society. European Journal of Endocrinology. 2019 ; 180 (4) : 23 - 54. DOI : https://doi.org/10.1530/EJE-18-0736

2. Luxwolda M. F., Kuipers R. S., Kema I. P., Janneke Dijck-Brouwer D. A. and Muskiet F. A. J. Traditionally Living Populations in East Africa Have a Mean Serum 25-hydroxyvitamin D Concentration of 115 nmol/l. British Journal of Nutrition. 2012; 108 (9): 1557 - 1561. DOI : https://doi.org/10.1017/S0007114511007161

3. Parva N. R., Tadepalli S., Singh P. et al. Prevalence of Vitamin D Deficiency and Associated Risk Factors in the US Population (2011-2012). Cureus. 2018 ; 10 (6). DOI : https://doi.org/10.7759/cureus.2741

4. Patwardhan V. G., Mughal Z. M., Chiplonkar S. A. et al. Duration of Casual Sunlight Exposure Necessary for Adequate Vitamin D Status in Indian Men. Indian Journal of Endocrinology Metabolism. 2018 ; 22 (2) ; 249 - 255. DOI : https://doi.org/10.4103/ijem.IJEM_473_17

5. Hoel D. G., Berwick M., Gruijl F. R. and Holick M.F. The Risks and Benefits of Sun Exposure 2016. Dermato-Endocrinology. 2016 ; 8 (1) : e1248325 (17 pages). DOI : https://doi.org/10.1080/19381980.2016.1248325

6. Holick M. F. Sunlight and Vitamin D for Bone Health and Prevention of Autoimmune Diseases, Cancers, and Cardiovascular Disease. The American Journal of Clinical Nutrition. 2004 ; 80 (6) ; 1678S - 1688S.DOI : https://doi.org/10.1093/ajcn/80.6.1678S

7. Lucas R. M., Repacholi M.H. and Mcmichael A. J. Is The Current Public Health Message On UV Exposure Correct? Bulletin of the World Health Organization. 2006 ; 84 : 485 - 491. DOI : https://doi.org/10.2471/BLT.05.026559

8. Holick M.F. and Garabedian M. Vitamin D: Photobiology, Metabolism, Mechanism of Action, and Clinical Applications. Primer on the Metabolic Bone Diseases and Disorders of Mineral Metabolism. Sixth Edition / Ed. M.J. Favus. Washington, DC: American Society for Bone and Mineral Research ; 2006 : 129 - 137.

9. Holick M. F. High Prevalence of Vitamin D Inadequacy and Implications for Health. Mayo Clinic Proceedings. 2006 ; 81 (3) : 353 - 373. DOI : http://dx.doi.org/10.4065/81.3.353

10. Jones G. and Dwyer T. Bone Mass in Prepubertal Children: Gender Differences and the Role of Physical Activity and Sunlight Exposure. Journal of Clinical Endocrinology and Metabolism. 1998 ; 83 (12) : 4274 - 4279. DOI : https://doi.org/10.1210/jcem.83.12.5353

11. Reid I. R., Gallagher D. J. A. and Bosworth J. Prophylaxis Against Vitamin D Deficiency in the Elderly by Regular Sunlight Exposure. Age and Ageing. 1986 ; 15 (1) : 35 - 40. DOI : https://doi.org/10.1093/ageing/15.1.35

12. Sato Y., Iwamoto J., Kanoko T. and Satoh K. Amelioration of Osteoporosis and Hypovitaminosis D by Sunlight Exposure in Hospitalized, Elderly Women with Alzheimer's Disease: A Randomized Controlled Trial. Journal of Bone and Mineral Research. 2005 ; 20 (8) : 1327 - 1333. DOI : http://dx.doi.org/10.1359/JBMR.050402

13. Webb A. R., and Engelsen O. Ultraviolet Exposure Scenarios: Balancing Risks of Erythema and Benefits of Cutaneous Vitamin D Synthesis. Advances in Experimental Medicine and Biology. 2020 ; 1268 : 387 - 405. DOI : http://dx.doi.org/10.1007/978-3-030-46227-7_20

14. Nastanova z rozrakhunku insoliatsii obiektiv tsyvilnoho pryznachennia : DSTU-N B V.2.2-27:2010. Chynnyi vid 2011-01-01 [Guidelines for the Calculation of the Insolation for Civilian Objects: State Standard B V.2.2-27: 2010. Valid from 2011-01-01. Kiev: KNUBA, 2010.81 p.]. Kyiv : KNUBA ; 2010 : 81 p. (in Ukrainian).

15. Webb A. R. and Engelsen O. Calculated Ultraviolet Exposure Levels for a Healthy Vitamin D Status. Photochemistry and Photobiology. 2006 ; 82 (6) : 1697-1703. DOI : https://doi.org/10.1111/j.1751-1097.2006.tb09833.x

16. Engelsen O. The Relationship between ultraviolet radiation exposure and vitamin D status. Nutrients. 2010. Vol. 2 (5). P. 482 - 495 DOI : https://doi.org/10.3390/nu2050482

17. TayemY., Alotaibi R., Hozayen R. and Hassan A. Therapeutic Regimens for Vitamin D Deficiency in Postmenopausal Women: a Systematic Review. Menopause Review. 2019 ; 18 (1) : 57 - 62. DOI : https://doi.org/10.5114/pm.2019.84159

18. Weaver C. M., Bischoff-Ferrari H. A. and Shanahan C. J. Cost-Benefit Analysis of Calcium and Vitamin D Supplements. Archives of Osteoporosis. 2019 ; 14 (1) : 50 (12 p.) DOI : https://doi.org/10.1007/s11657-019-0589-y

19. Masters G. M. Renewable and Efficient Electric Power Systems. New Jersey : John Wiley & Sons, Inc.; 2004. 676 p. (P. 385 - 413). DOI : https://doi.org/10.1002/0471668826

20. Holick M. F. Ultraviolet B Radiation. The Vitamin D Connection. Advances in Experimental Medicine and Biology. 2017 ; 996 : 137 - 154. DOI : http://dx.doi.org/10.1007/978-3-319-56017-5_12

21. Bouillon R., Eisman J., Garabedian M., Holick M., Kleinschmidt J. et al. Action Spectrum for the Production of Previtamin D3 in Human Skin : CIE 174. Vienna : CIE; 2006.

22. Grant R. H. and Gao W. Diffuse Fraction of UV Radiation under Partly Cloudy Skies as Defined by the Automated Surface Observation System (ASOS). Journal of Geophysical Research Atmospheres. 2003 ; 108 (D2) : 4046. DOI : https://doi.org/10.1029/2002JD002201

23. Daylight in Buildings : EN 17037:2018. 72 p. URL : https://standards.iteh.ai/catalog/standards/sist/6fd9e65f-c3ba-4cda-a69c-dcbd8b7dce8d/sist-en-17037-2019

24. Salum G. M., García Molleja J., Regalado Díaz B. A., Guerrero León L. A. and Berrezueta C. Calculation of the Sun Exposure Time for the Synthesis of Vitamin D in Urcuquí, Ecuador. 5th International Work-Conference on Bioinformatics and Biomedical Engineering : Proceedings of Abstracs. Granada, Spain; 2017 : 27. URL : https://arxiv.org/abs/1706.01541

25. Terushkin V., Bender A., Psaty E.L., Engelsen O., Wang S.Q. and Halpern A.C. Estimated Equivalency of Vitamin D Production from Natural Sun Exposure Versus Oral Vitamin D Supplementation Across Seasons at Two US Latitudes. Journal of the American Academy of Dermatology. 2010 ; 62 (6) : 929.e1 - 929.e9. DOI : http://dx.doi.org/10.1016/j.jaad.2009.07.028

26. Akimenko V. Ya. and Steblii N. M. Eritemna doza yak odyn iz kryteriiv hihiienichnoi rehlamentatsii insoliatsii [Erythema Dose as One of the Criteria for the Hygienic Regulation of Insolation]. Dovkillia i zdorovia (Environment&Health). 2018 ; 1 (85) : 26 - 31. DOI : https://doi.org/10.32402/dovkil2018.01.026

27. Duarte I., Rotter A., Malvestiti A. and Silva M. The Role of Glass as a Barrier Against the Transmission of Ultraviolet Radiation: an Experimental Study. Photodermatology, Photoimmunology and Photomedicine. 2009 ; 25 (4) : 181 - 184. DOI : http://dx.doi.org/10.1111/j.1600-0781.2009.00434.x

28. Bugner D., LaBarca J., Kopperl D. et. al. Survey of Environmental Conditions Relative to Display of Photographs in Consumer Homes. 13th International Symposium on Photofinishing Technology Proceedings. Las Vegas, Nevada; 2004 : 31 - 36.

29. Holick M. F. Vitamin D: Importance in the Prevention of Cancers, Type 1 Diabetes, Heart Disease, and Osteoporosis. The American Journal of Clinical Nurition. 2004 ; 79 (3) : 362 - 371. DOI : https://doi.org/10.1093/ajcn/79.3.362

30. Holick M. F. The Vitamin D Advantage. New York : iBooks, Inc.; 2004. DOI : https://doi.org/10.1007/978-1-59259-740-6_25

31. Webb A. R., Kift R., Berry J. L. and Rhodes L. E. The Vitamin D Debate: Translating Controlled Experiments into Reality for Human Sun Exposure Times. Photochemistry and Photobiology. 2011 ; 87 (3) : 741 - 745. https://doi.org/10.1111/j.1751-1097.2011.00898.x

32. Fitzpatrick T. B. The Validity and Practicality of Sun-Reactive Skin Types I through VI. Archives of Dermatology. 1988 ; 124 (6) : 869 - 871. http://doi.org/10.1001/archderm.124.6.869

33. Halliday G. M., Byrne S. N. and Damian D. L. Ultraviolet A Radiation: its Role in Immunosuppression and Carcinogenesis. Seminars in Cutaneous Medicine and Surgery. 2011 ; 30 : 214 - 221. DOI : http://dx.doi.org/10.1016/j.sder.2011.08.002

34. Ullrich S. E. Mechanisms Underlying UV-Induced Immune Suppression. Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis. 2005 ; 571 (1-2); 185 - 205. DOI : https://doi.org/10.1016/j.mrfmmm.2004.06.059

35. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Solar and Ultraviolet Radiation. Lyon: WHO, International Agency for Research on Cancer ; 1990 ; 55 : 325 p.

36. Sola Y. and Lorente J. Contribution of UVA Irradiance to the Erythema and Photoaging Effects in Solar and Sunbed Exposures. Journal of Photochemistry and Photobiology B: Biology. 2015 ; 143 : 5 - 11. DOI : https://doi.org/10.1016/j.jphotobiol.2014.10.024

37. Kligman L. H. and Sayre R. M. An Action Spectrum for Ultraviolet Induced Elastosis in Hairless Mice: Quantification of Elastosis by Image Analysis. Photochemistry and Photobiology. 1991 ; 53 (2) : 237 - 242. DOI : https://doi.org/10.1111/j.1751-1097.1991.tb03928.x

38. Bisset D.P. and Hannon T. Orr. Wavelength Dependence of Histological, Physical and Visible Changes in Chronically UV-Irradiated Hairless Mouse Skin. Photochemistry and Photobiology. 1989 ; 50 : 763 - 769. DOI : https://doi.org/10.1111/j.1751-1097.1989.tb02907.x

39. McKenzie R., Smale D. and Kotkamp M. Relationship between UVB and Erythemally Weighted Radiation. Photochemical and Photobiological Sciences. 2004 ; 3 (3) : 252 - 256. DOI : https://doi.org/10.1039/b312985c

40. Sergeychuk O.V. Analysis of Ukrainian Standard of Calculating Insolation: DSTU-N B V.2.2-27: 2010. Vestnik MGSU. 2011 ; 6 : 449 - 458. URL : http://vestnikmgsu.ru/index.php/en/component/sjarchive. 41. Lund C. C. and Browder N. C. Estimation of Areas of Burns. Surgery Gynecology and Obstetrics. 1944 ; 79 : 352 - 358. 42. UV Station Data Based on Operational TEMIS Satellite Ozone Data. URL : https://www.temis.nl/uvradiation /UVarchive/stations_uv.php. 43. Gies P., Deventer E., Green A. C. et. al. Review of the Global Solar UV Index 2015 Workshop Report. Health Physics. 2018 ; 114 (1) : 84 - 90. DOI : https://doi.org/10.1097/HP.0000000000000742 44. UF-indeks [UV-Index]. URL : https://www.who.int/uv/intersunprogramme/activities/uv_index/ru/ (in Russian). 45. Trang M. H., Cole D.E., Rubin L.A. et. al. Evidence That Vitamin D3 Increases Serum 25-Hydroxyvitamin D More Effectively Than Does Vitamin D2. American Journal of Clinical Nutrition. 1998 ; 68 : 854 - 858. DOI : https://doi.org/10.1093/ajcn/68.4.854 46. Armas L. A.G., Hollis B. W. and Heaney R. P. Vitamin D2 is Much Less Effective Than Vitamin D3 in Humans. The Journal of Clinical Endocrinology and Metabolism. 2004 ; 89 (11) : 5387 - 5391. DOI : https://doi.org/10.1210/jc.2004-0360 47. Rapuri P., Gallagher J. C. and Haynatzki G. Effect of Vitamin D2 and D3 Supplement Use on Serum 25OHD Concentration in Elderly Women in Summer and Winter. Calcified Tissue International. 2004 ; 74 : 150 - 156. DOI : https://doi.org/10.1007/s00223-003-0083-8