ビタミンＤと代謝性疾患

Update on recent progress in vitamin D research. Vitamin D and metabolic disease.

　ビタミンＤ不足・欠乏が１型糖尿病や２型糖尿病，メタボリックシンドロームなどの代謝性疾患と関連することが，様々な疫学研究やメタ解析で示されている。しかし，いずれの疾患もビタミンＤ補充による糖代謝異常や肥満，脂質代謝異常などの改善効果は明らかにされておらず，因果関係の詳細は不明である。25-hydroxyvitamin D［25（OH）D］値が20 ng/mL未満のビタミンＤ欠乏例のみでの検討では，天然型ビタミンＤ補充による糖代謝改善効果を示す報告もあり，治療介入すべき25（OH）D値や必要補充量，補充期間などについて今後の検討が待たれる。

　Numerous epidemiological studies and meta-analyses have indicated that there is a link between Vitamin D insufficiency/deficiency and metabolic disorders such as type 1 and type 2 diabetes mellitus as well as metabolic syndrome. However, vitamin D supplementation has not demonstrated improvement effects in obesity, disorders of glucose and lipid metabolism in any of these illnesses；therefore, the details of the causal relationship remain unclear. Improvement in glucose metabolism was observed in a study in which only vitamin D deficient patients with 25-hydroxyvitamin D［25（OH）D］levels of less than 20 ng/mL were given native vitamin D supplementation. Further studies are needed to determine the 25（OH）D level at which intervention is needed along with the required amount and duration of such supplementation.