References

ACPD

Atmospheric Chemistry and Physics Discussions

ACPD

1680-7375

Copernicus GmbH

Göttingen, Germany

10.5194/acpd-8-781-2008

Utilising shade to optimize UV exposure for vitamin D

Turnbull

D. J.

¹ Parisi

A. V.

Centre for Rural and Remote Area Health, University of Southern Queensland, Toowoomba, Queensland 4350, Australia

16 01 2008

8 1 781 796

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Numerous studies have stated that humans need to utilise full sun radiation, at certain times of the day, to assist the body in synthesising the required levels of vitamin D3. The time needed to be spent in the full sun depends on a number of factors, for example, age, skin type, latitude, solar zenith angle. Current Australian guidelines suggest exposure to approximately 1/6 to 1/3 of a minimum erythemal dose (MED), depending on age, would be appropriate to provide adequate vitamin D3 levels. The aim of the study was to determine the exposure times to diffuse solar UV to receive exposures of 1/6 and 1/3 MED for a changing solar zenith angle in order to assess the possible role that diffuse UV (scattered radiation) may play in vitamin D3 effective UV exposures (UVD3). Diffuse and global erythemal UV measurements were conducted at five minute intervals over a twelve month period for a solar zenith angle range of 4° to 80° at a latitude of 27.6° S. For diffuse UV exposures of 1/6 and 1/3 MED, solar zenith angles smaller than 60° and 50° respectively can be utilised for exposure times of less than 10 min. Spectral measurements showed that, for a solar zenith angle of 40°, the UVA (315–400 nm) in the diffuse component of the solar UV is reduced by approximately 62% compared to the UVA in the global UV, whereas UVD3 wavelengths are only reduced by approximately 43%. At certain latitudes, diffuse UV under shade may play an important role in providing the human body with adequate levels of UVD3 (290–330 nm) radiation without experiencing the high levels of damaging UVA observed in full sun.

References 1

Agar, N. S., Halliday, G. M., Barnetson, R. S., Ananthaswamy, H. N., Wheeler, M., and Jones, A. M.: The basal layer in human squamous tumors harbors more UVA than UVB fingerprint mutations: a role for UVA in human skin carcinogenesis, Proc. Nat. Acad. Sci., 101, 4954–4959, 2004.

Aloia, J. F. and Li-Ng, M.: Correspondence, Epidemiol. Infect., 135, 1095–1098, 2007.

Baron, E. A., Fourtanier, A., Compan, D., Medaisko, C., Cooper, K. D., and Stevens, S. R.: High ultraviolet A protection affords greater immune protection confirming that ultraviolet A contributes to photoimmunosuppression in humans, J. Invest. Dermatol., 121, 869–875, 2003.

CDHAA: Commonwealth Department of Health and Ageing Australia: Ministry of Health New Zealand and National Health and Medical Research Council, Nutrient reference values for Australia and New Zealand including recommended dietary intakes. Draft 2004. Available at: http://www.moh.govt.nz/moh.nsf/0/CC515A13536B3CB4CC256F6D000ABDE0/$File/nutrientreferencevalues.pdf, access: 2 February 2006.

CIE (International Commission on Illumination): Action spectrum for the production of previtamin D3 in human skin, CIE., 174, 2006.

Dawson-Hughes, B., Heaney, R. P., Holick, M. F., Lips, P., Meunier, P. J., and Vieth, R. Estimates of optimal vitamin D status, Osteoporosis. Int., 16, 713–716, 2005.

Diffey, B.: Do we need a revised public health policy on sun exposure?, Brit. J. Dermatol., 154, 1046–1051, 2006.

Garland, C. F., Garland F. C., and Gorham, E. D.: Epidemiologic evidence for different roles of ultraviolet A and B radiation in melanoma mortality rates, Ann. Epidemiol., 13, 395–404, 2003.

Garland, C. F., Gorham, E. D., Mohr, S. B., Grant, W. B., Giovannucci, E. L., Lipkin, M., Newmark, H., Holick, M. F., and Garland, F. C.: Vitamin D and prevention of breast cancer: Pooled analysis, J. Steroid. Biochem., 103, 708–711, 2007.

Gillie, O.: A new government policy is needed for sunlight and vitamin D, Brit. J. Dermatol., 154, 1052–1061, 2006.

Giovannucci, E., Liu, Y., Rimm, E. B., Hollis, B. W., Fuchs, C. S., Stampfer, M. J., and Willett, W. H.: Prospective study of predictors of vitamin D status and cancer incidence and mortality in men, J. Nat. Cancer Inst., 98, 451–459, 2006.

Glerup, H., Mikkelsen, L., Hass, E., Overbeck, S., Thomsen, J., Charles, P., and Eriksen, E. F.: Commonly recommended daily intake of vitamin D is not sufficient if sunlight exposure is limited, J. Intern. Med., 247, 260–268, 2000.

Gorham, E. D., Garland, C. F., Garland, F. C., Grant, W. B., Mohr, S. B., Lipkin, M., Newmark, H. L., Giovannucci, E., Wei, M., and Holick, M. F.: Optimal vitamin d status for colorectal cancer prevention a quantitative meta analysis, Am. J. Prev. Med., 32, 210–216, 2007.

Grant, W. B., Garland, C. F., and Gorham, E. D.: An estimate of cancer mortality rate reductions in Europe and the U.S. with 1000 I.U. of oral vitamin D per day, Rec. Results. Cancer. Res., 174, 225–234, 2007.

Holick, M. F., Matsuoka, L. Y., and Wortsman, J.: Age, vitamin D, and solar ultraviolet, Lancet, 2, 1104–1105, 1989.

Holick, M. F.: Evolution, biologic functions, and recommended dietary allowances for vitamin D, in: Vitamin D: Physiology, Molecular Biology and Clinical Applications, Humana Press, New Jersey, 1–16, 1998.

Holick, M. F.: Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease, Am. J. Clin. Nutr., 80, 1678S–1688S, 2004.

Lappe, J. M., Travers-Gustafson, D., Davies, K. M., Recker, R. R., and Heaney, R. P.: Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial, Am. J. Clin. Nutr., 85, 1586–1591, 2007.

Lucas, R., McMichael, T., Smith, W., and Armstrong, B.: Solar ultraviolet radiation: global burden of disease from solar ultraviolet radiation, World Health Organization, Switzerland, 250 pp., 2006.

Moan, J., Dahlback, A., and Setlow, R. B.: Epidemiological support for an hypothesis for melanoma induction indicating a role for UVA radiation, Photochem. Photobiol., 70, 243–247, 1999.

Parisi, A. V., Kimlin, M. G., and Turnbull, D.: Spectral shade ratios on horizontal and sun normal surfaces for single trees and relatively cloud free sky, J. Photoch. Photobio. B., 65, 151–156, 2001.

Pathak, M. A., Nghiem, P., and Fitzpatrick, T. B.: Acute and chronic effects of the sun, in: Fitzpatrick's dermatology in general medicine, McGraw-Hill, New York, 1598–1607, 1999.

PS (Position Statement): Estimates of beneficial and harmful sun exposure times during the year for major Australian population centres, Med. J. Australia, 184, 338–341, 2006.

Sabburg, J. and Long, C. N.: Improved sky imaging for studies of enhanced UV irradiance, Atmos. Chem. Phys., 4, 2543–2552, 2004.

Samanek, A. J., Croager, E. J., Gies, P., Milne, E., Prince, R., McMichael, A. J., Lucas, R. M., and Slevin, T.: Estimates of beneficial and harmful sun exposure times during the year for major Australian population cities, Med. J. Australia, 184, 338–341, 2006.

Setlow, R. B., Grist, E., Thompson, K., and Woodhead, A. V.: Wavelengths in the induction of malignant melanoma, Proc. Nat. Acad. Sci., 90, 6666–6670, 1993.

Sliney, D. H.: Epidemiological studies of sunlight and cataract: the critical factor of ultraviolet exposure geometry, Ophthal. Epidemiol., 1, 107–119, 1994.

Terenetskaya, I.: Spectral monitoring of biologically active solar UVB radiation using an in vitro model of vitamin D synthesis, Talanta, 53, 195–203, 2000.

Turnbull, D. J. and Parisi, A. V.: Spectral UV in Public Shade Settings, J. Photoch. Photobio. B., 69, 13–19, 2003.

Turnbull, D. J., Parisi, A. V., and Kimlin, M. G.: Vitamin D effective wavelengths due to scattered UV in the shade, J. Ster. Biochem. Mol. Biol., 96, 431–436, 2005.

Turnbull, D. J., Parisi, A. V., and Sabburg, J.: Scattered UV beneath public shade structures during winter, Photochem. Photobiol., 78, 180–183, 2003.

Vieth, R., Bischoff-Ferrari, H., Boucher, B. J., Dawson-Hughes, B., Garland, C. F., Heaney, R. P., Holick, M. F., Hollis, B. W., Lamberg-Allardt, C., McGrath, J. J., Norman, A. W., Scragg, R., Whiting, S. J., Willett, W. C., and Zittermann, A.: The urgent need to recommend an intake of vitamin D that is effective, Am. J. Clin. Nutr., 85, 649–650, 2007.

Webb, A. R.: Vitamin D synthesis under changing UV spectra, Environmental UV Photobiology, Plenum Press, New York, 185–202, 1993.