Vitamin D deficiency in Thailand

摘要

Vitamin D deficiency has received increased attention over thepast several years since vitamin D may play an important role notonly inbonemetabolismbut alsoinavarietyofnon-skeletaldiseasessuch as diabetes mellitus, autoimmune diseases, infectious diseases,cardiovascular diseases and cancer [1–3]. Vitamin D is primarily syn-thesized in the skin and is partly derived from dietary sources [4].During exposure to sunlight, ultraviolet B (UVB) (wavelength 290–305 nm) penetrates the skin and converts 7-dehydrocholesterol toprevitamin D 3 . Previtamin D 3 is then rapidly converted by a heatdependent process to vitamin D 3 (cholecalciferol) [5,6]. Vitamin D 2(ergocalciferol), from dietary sources or supplements, and vitaminD 3 are metabolized in the liver to 25-hydroxyvitamin D (25(OH)D),which is the major circulating formof vitamin D and isused to deter-mine an individual’s vitamin D status [1]. The circulating 25(OH)D isthen metabolized in the kidneys to its biologically more active form,1,25-dihydroxyvitamin D [1].