Vitamin D deficiency: a global perspective

Abstract

Vitamin D is essential for the maintenance of good health. Its sources can be skin production and diet intake. Most humans depend on sunlight exposure (UVB 290-315 nm) to satisfy their requirements for vitamin D. Solar ultraviolet B photons are absorbed by the skin, leading to transformation of 7-dehydrocholesterol into vitamin D3 (cholecalciferol). Season, latitude, time of day, skin pigmentation, aging, sunscreen use, all influence the cutaneous production of vitamin D3. Vitamin D deficiency not only causes rickets among children but also precipitates and exacerbates osteoporosis among adults and causes the painful bone disease osteomalacia. Vitamin D deficiency has been associated with increased risk for other morbidities such as cardiovascular disease, type 1 and type 2 diabetes mellitus and cancer, especially of the colon and prostate. The prevalence of hypovitaminosis D is considerable even in low latitudes and should be taken into account in the evaluation of postmenopausal and male osteoporosis. Although severe vitamin D deficiency leading to rickets or osteomalacia is rare in Brazil, there is accumulating evidence of the frequent occurrence of subclinical vitamin D deficiency, especially in elderly people. RESUMO Deficiência de Vitamina D: Uma Perspectiva Global.A vitamina D é essencial para a manutenção da saúde. A sua fonte principal é a pele ou pode ser ingerida com a dieta. A maioria dos seres humanos depende da exposição solar para adquirir quantidades suficientes de vitamina D. A radiação ultravioleta tipo B transforma o 7-dehidrocolesterol em vitamina D3 (colecalciferol). A época do ano, latitude, pigmentação da pele, idade e uso de filtros solares são fatores que influenciam a produção cutânea. Deficiência de vitamina D pode causar raquitismo e osteomalacia, exacerbar a perda óssea na osteoporose, como também pode associar-se a várias morbidades como doenças cardiovasculares, diabetes mellitus tipo 1 e 2, câncer de prós-tata e de intestino grosso. A prevalência de hipovitaminose D tem sido relatada com grande freqüência mesmo em regiões de baixa latitude e deve ser considerada na avaliação da osteoporose. Embora a deficiência severa levando a osteomalacia possa ser vista raramente no Brasil, evidências se acumulam da freqüente ocorrência de deficiência subclínica, especialmente em idosos.

Predictors of vitamin D deficiency and insufficiency in adult Bahrainis: a cross-sectional study

“…Results from the present study are consistent with published studies suggesting that female sex is one of the most common risk factors associated with vitamin D deficiency and insufficiency in developing countries (7,8,17,(19)(20)(21) . This could be due to the fact that women tend to spend more time indoors than men, in addition to their style of clothing and sun protection and sun avoidance attitude, which could all attribute to the vitamin D deficiency in Bahraini women.…”

Vitamin D deficiency in HIV-infected individuals: one more risk factor for bone loss and cardiovascular disease?

“…There is no consensus on the ideal serum concentration of 25(OH)D and there are many suggested values for setting the lower limit of normality from 20 to as much 37 ng/mL (14,15,22,23). Therefore the level of vitamin D should be the one that does not induce a rise in parathyroid hormone (PTH), and the optimal serum 25(OH)D concentrations have yet to be established (14,15,22,23).…”

“…Therefore the level of vitamin D should be the one that does not induce a rise in parathyroid hormone (PTH), and the optimal serum 25(OH)D concentrations have yet to be established (14,15,22,23). It is not surprising that discordant results are obtained because these laboratories use substantially different methodology for measurement of 25(OH)D, which, to this time, has not been standardized (14,15,22,23).…”

“…In healthy adults, vitamin D deficiency sets in in a subtle manner, with mild hypocalcemia, and secondary hyperparathyroidism, causing trabecular bone loss and a thinning of the cortical bone, leading to an increased risk of osteoporosis and fractures (15,22). Before antiretroviral treatment was introduced, few studies had indicated that bone metabolism was affected in HIVpositive patients, although it has recently been confirmed that infected patients present a higher risk of low bone mass and osteoporosis.…”

Nutrición infantil y salud ósea

“…Es evidente que la dieta no cubre los requerimientos en vitamina D; sin embargo, la fuente más importante de ésta debe proceder de la transformación de la provitamina de la piel en colecalciferol, por la acción de las radiaciones solares. La creciente preocupación por el riesgo de cáncer de piel ligado a la exposición solar ha propiciado una verdadera pandemia de déficit en vitamina D, que sin duda influirá en la obtención de un adecuado PMO 44,45 . Por esto, la AAP duplicó recientemente las recomendaciones de vitamina D dadas en 2003 46 .…”