Solar ultraviolet B radiation and photoproduction of vitamin D3 in central and southern areas of argentina
- 1 April 1995
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Bone and Mineral Research
- Vol. 10 (4), 545-549
- https://doi.org/10.1002/jbmr.5650100406
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°S) and Buenos Aires (34°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. 63 ± 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.Keywords
This publication has 17 references indexed in Scilit:
- Seasonal variations of 25 hydroxyvitamin D and parathyroid hormone in Ushuaia (Argentina), the southernmost city of the worldBone and Mineral, 1993
- Influence of Season and Latitude on the Cutaneous Synthesis of Vitamin D3: Exposure to Winter Sunlight in Boston and Edmonton Will Not Promote Vitamin D3Synthesis in Human Skin*Journal of Clinical Endocrinology & Metabolism, 1988
- Serum Vitamin D2and Vitamin D3Metabolite Concentrations and Absorption of Vitamin D2in Elderly Subjects*Journal of Clinical Endocrinology & Metabolism, 1986
- Circulating vitamin D metabolite concentrations in children with nutritional ricketsThe Journal of Pediatrics, 1983
- Calciferols: Actions and Deficiencies in ActionVitamins & Hormones, 1983
- Spectral Character of Sunlight Modulates Photosynthesis of Previtamin D 3 and Its Photoisomers in Human SkinScience, 1982
- Photosynthesis of Previtamin D 3 in Human Skin and the Physiologic ConsequencesScience, 1980
- Assessment of Plasma 25-Hydroxyvitamin D Response to Ultraviolet Irradiation over a Controlled Area in Young and Elderly SubjectsClinical Science, 1980
- Vitamin D Deficiency in Welfare Institutions for the AgedActa Medica Scandinavica, 1980
- Seasonal Changes in Human Plasma Levels of 25-Hydroxyvitamin DNature, 1974