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Abstract(s)
Introdução: Durante a exposição à luz solar, a 7-deidrocolesterol na pele absorve
radiação UV-B, sendo convertida numa variedade de produtos com propriedades
biológicas únicas. A Vitamina D é metabolizada sequencialmente no fígado e rins em 25-
hidroxi-colecalciferol, a forma circulante maioritária, e em 1,25-dihidroxi-colecalciferol, a
forma biologicamente ativa. Esta desempenha um importante papel na regulação do
metabolismo do cálcio e fosfatos, sendo relevante para a manutenção de funções
metabólicas e saúde óssea. A produção de vitamina D induzida pela luz solar pode ser
influenciada por vários fatores, entre os quais o uso de protetores solares. Estes poderão
ser químicos, exercendo a sua ação através da absorção dos raios UV que neutralizam, ou
físicos, que atuam refletindo a radiação UV necessária à síntese de Vitamina D. Com esta
revisão bibliográfica pretende-se relacionar o uso de protetores solares com a sua possível
influência na produção de Vitamina D e, consequentemente, na remodelação óssea.
Métodos: Pesquisa de artigos no motor de busca Pubmed, em língua inglesa e
portuguesa, com preferência a artigos publicados nos últimos 10 anos, mas sem restrições
de data de publicação, utilizando múltiplas associações entre os termos ‘’sunscreen’’,
‘’vitamin D’’, ‘’bone remodelling’’, ‘’sunlight’’, ‘’photoprotection’’, ‘’physiology’’,
‘’metabolism’’, ‘’SPF’’, ‘’UV’’.
Resultados: A interpretação da bibliografia demonstrou que, de acordo com a maioria
dos estudos, a utilização de protetor solar leva a uma menor síntese de Vitamina D
cutânea acompanhado de uma atenuação do possível aumento de 25(OH)D obtido na
ausência de proteção, no entanto esta revelou-se insuficiente para a colocar fora dos
limites de referência sendo, por vezes, desprezível na clínica. Já na remodelação óssea, as
alterações no status de Vitamina D consequentes da proteção solar, também não se
mostraram capazes de induzir alterações na função tiroideia nem nos marcadores do
metabolismo ósseo, não tendo, por fim, sido associados a alterações na massa óssea.
Conclusão: Perante os resultados obtidos, evidencia-se que os benefícios advenientes da
proteção solar superam os eventuais riscos que esta poderá trazer ao status de Vitamina D
e ao metabolismo ósseo associado. No entanto, poucos estudos procuraram investigar a
influência da utilização crónica dos novos protetores solares recomendados que possuem
um SPF superior a 50. A investigação da influência dos protetores solares na remodelação
óssea ainda é escassa, sendo possível que no futuro se chegue a diferentes conclusões.
Introduction: During solar exposure, 7-dehydrocholesterol in the skin absorbs UV-B radiation, being converted in a variety of products in which some have unique biological properties. Vitamin D is then further metabolized in the liver and kidneys in 25- hydroxycholecalciferol, its major circulating form, and in 1,25-dihydroxyvitamin D, its active biological form, which has an important role in the regulation of calcium and phosphate metabolism, being relevant for the maintenance of metabolic functions and bone health. The production of Vitamin D induced by solar exposure is influenced by a variety of factors, including the use of sunscreen. These can be chemical, acting by neutralizing the absorbed UV rays, or physical, which act by reflecting the incident UV radiation needed to produce Vitamin D. This review aims to establish the relation of sunscreen use with their possible influence on the production of Vitamin D and, consequently, on bone remodeling. Material and methods: Search and analysis of English and portuguese articles through Pubmed search engine, with preference given to articles published in the last 10 years without excluding others, using multiple associations of the terms ‘’sunscreen’’, ‘’vitamin D’’, ‘’bone remodeling’’, ‘’sunlight’’, ‘’photoprotection’’, ‘’physiology’’, ‘’metabolism’’, ‘’SPF’’, ‘’UV’’. Results: The interpretation of the bibliography demonstrated that, according to majority of studies, the usage of sunscreen diminishes the synthesis of cutaneous Vitamin D and attenuates the increase of 25(OH)D observed in the absence of sunscreen, however, these effects were revealed insufficient to push it out of its reference range, often considered despicable. As to bone remodeling, the consequent Vitamin D status due to sunscreen usage was not found to induce any changes in the thyroid function or bone metabolism markers and, lastly, it was not associated with changes in bone mass. Conclusions: According to the obtained results, evidence suggests that the benefits of sunscreen usage outweigh the potential risks it might bring to vitamin D status and its associated bone metabolism. However, only a few studies investigated the influence of chronic usage of newly recommended sunscreens with SPF higher than 50. In the same way, sunscreen usage influence on bone remodeling is still an understudied topic and new studies in the future might lead us to different conclusions.
Introduction: During solar exposure, 7-dehydrocholesterol in the skin absorbs UV-B radiation, being converted in a variety of products in which some have unique biological properties. Vitamin D is then further metabolized in the liver and kidneys in 25- hydroxycholecalciferol, its major circulating form, and in 1,25-dihydroxyvitamin D, its active biological form, which has an important role in the regulation of calcium and phosphate metabolism, being relevant for the maintenance of metabolic functions and bone health. The production of Vitamin D induced by solar exposure is influenced by a variety of factors, including the use of sunscreen. These can be chemical, acting by neutralizing the absorbed UV rays, or physical, which act by reflecting the incident UV radiation needed to produce Vitamin D. This review aims to establish the relation of sunscreen use with their possible influence on the production of Vitamin D and, consequently, on bone remodeling. Material and methods: Search and analysis of English and portuguese articles through Pubmed search engine, with preference given to articles published in the last 10 years without excluding others, using multiple associations of the terms ‘’sunscreen’’, ‘’vitamin D’’, ‘’bone remodeling’’, ‘’sunlight’’, ‘’photoprotection’’, ‘’physiology’’, ‘’metabolism’’, ‘’SPF’’, ‘’UV’’. Results: The interpretation of the bibliography demonstrated that, according to majority of studies, the usage of sunscreen diminishes the synthesis of cutaneous Vitamin D and attenuates the increase of 25(OH)D observed in the absence of sunscreen, however, these effects were revealed insufficient to push it out of its reference range, often considered despicable. As to bone remodeling, the consequent Vitamin D status due to sunscreen usage was not found to induce any changes in the thyroid function or bone metabolism markers and, lastly, it was not associated with changes in bone mass. Conclusions: According to the obtained results, evidence suggests that the benefits of sunscreen usage outweigh the potential risks it might bring to vitamin D status and its associated bone metabolism. However, only a few studies investigated the influence of chronic usage of newly recommended sunscreens with SPF higher than 50. In the same way, sunscreen usage influence on bone remodeling is still an understudied topic and new studies in the future might lead us to different conclusions.
Description
Keywords
Protetor Solar Remodelação Óssea Vitamina D