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Solar ultraviolet B radiation and photoproduction of vitamin D3 in central and southern areas of Argentina.
J Bone Miner Res. 1995 Apr; 10(4):545-9.JB

Abstract

The incidence of nutritional rickets in the southern part of Argentina is 8-12 times higher than in the rest of the country. Winter 25(OH)D serum levels in normal population of southern areas are lower than in central and northern areas. To elucidate these differences, we compared the photoconversion of provitamin D3 (7-DHC) to previtamin D3 in two cities: Ushuaia (latitude 55 degrees S) and Buenos Aires (34 degrees S). Ampules containing 7-DHC were exposed to sunlight one day in the middle of each month either from 10:30 a.m. to 2:30 p.m. or from 8:00 a.m. to 5:00 p.m. The percentages of photoproducts formed were determined by high performance liquid chromatography (HPLC). Previous studies have proved that this is a valid model to assess "in vitro" the photoproduction of vitamin D3 in human skin. Previtamin D3 + vitamin D3 formed in Ushuaia were less (p < 0.02) than those found in Buenos Aires during all seasons: summer, (X +/- SEM) 6.4 +/- 0.8% vs. 13.2 +/- 1.8%; autumn, 1.2 +/- 0.7% vs. 6.3 +/- 1.3%; winter, 0.8 +/- 0.7% vs. 3.6 +/- 0.7%; spring, 3.4 +/- 0.5% vs. 9.1 +/- 1.1%. The photoproducts produced from 10:30 a.m. to 2:30 p.m. were similar for each month and latitude to those formed when the ampules were exposed from 8:00 a.m. to 5:00 p.m. We conclude that in Ushuaia there is a prolonged "vitamin D winter" during which cutaneous synthesis of vitamin D is absent, leading to lower serum values of 25(OH)D and contributing to the higher incidence of rickets.

Authors+Show Affiliations

Sección Osteopatías Médicas, Hospital de Clínicas, Facultad de Medicina, Universidad de Buenos Aires, Argentina.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

7610924

Citation

Ladizesky, M, et al. "Solar Ultraviolet B Radiation and Photoproduction of Vitamin D3 in Central and Southern Areas of Argentina." Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, vol. 10, no. 4, 1995, pp. 545-9.
Ladizesky M, Lu Z, Oliveri B, et al. Solar ultraviolet B radiation and photoproduction of vitamin D3 in central and southern areas of Argentina. J Bone Miner Res. 1995;10(4):545-9.
Ladizesky, M., Lu, Z., Oliveri, B., San Roman, N., Diaz, S., Holick, M. F., & Mautalen, C. (1995). Solar ultraviolet B radiation and photoproduction of vitamin D3 in central and southern areas of Argentina. Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, 10(4), 545-9.
Ladizesky M, et al. Solar Ultraviolet B Radiation and Photoproduction of Vitamin D3 in Central and Southern Areas of Argentina. J Bone Miner Res. 1995;10(4):545-9. PubMed PMID: 7610924.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Solar ultraviolet B radiation and photoproduction of vitamin D3 in central and southern areas of Argentina. AU - Ladizesky,M, AU - Lu,Z, AU - Oliveri,B, AU - San Roman,N, AU - Diaz,S, AU - Holick,M F, AU - Mautalen,C, PY - 1995/4/1/pubmed PY - 1995/4/1/medline PY - 1995/4/1/entrez SP - 545 EP - 9 JF - Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research JO - J Bone Miner Res VL - 10 IS - 4 N2 - The incidence of nutritional rickets in the southern part of Argentina is 8-12 times higher than in the rest of the country. Winter 25(OH)D serum levels in normal population of southern areas are lower than in central and northern areas. To elucidate these differences, we compared the photoconversion of provitamin D3 (7-DHC) to previtamin D3 in two cities: Ushuaia (latitude 55 degrees S) and Buenos Aires (34 degrees S). Ampules containing 7-DHC were exposed to sunlight one day in the middle of each month either from 10:30 a.m. to 2:30 p.m. or from 8:00 a.m. to 5:00 p.m. The percentages of photoproducts formed were determined by high performance liquid chromatography (HPLC). Previous studies have proved that this is a valid model to assess "in vitro" the photoproduction of vitamin D3 in human skin. Previtamin D3 + vitamin D3 formed in Ushuaia were less (p < 0.02) than those found in Buenos Aires during all seasons: summer, (X +/- SEM) 6.4 +/- 0.8% vs. 13.2 +/- 1.8%; autumn, 1.2 +/- 0.7% vs. 6.3 +/- 1.3%; winter, 0.8 +/- 0.7% vs. 3.6 +/- 0.7%; spring, 3.4 +/- 0.5% vs. 9.1 +/- 1.1%. The photoproducts produced from 10:30 a.m. to 2:30 p.m. were similar for each month and latitude to those formed when the ampules were exposed from 8:00 a.m. to 5:00 p.m. We conclude that in Ushuaia there is a prolonged "vitamin D winter" during which cutaneous synthesis of vitamin D is absent, leading to lower serum values of 25(OH)D and contributing to the higher incidence of rickets. SN - 0884-0431 UR - https://www.unboundmedicine.com/medline/citation/7610924/Solar_ultraviolet_B_radiation_and_photoproduction_of_vitamin_D3_in_central_and_southern_areas_of_Argentina_ DB - PRIME DP - Unbound Medicine ER -