Queensland Children's Medical Research Institute, Royal Children's Hospital, The University of Queensland, Herston, Queensland, 4029, Australia.
Pediatr Diabetes. 2013 Feb;14(1):31-41. doi: 10.1111/j.1399-5448.2012.00890.x. Epub 2012 Aug 23.
Vitamin D is synthesised in the skin through the action of UVB radiation (sunlight), and 25-hydroxy vitamin D (25OHD) measured in serum as a marker of vitamin D status. Several studies, mostly conducted in high latitudes, have shown an association between type 1 diabetes mellitus (T1DM) and low serum 25OHD. We conducted a case-control study to determine whether, in a sub-tropical environment with abundant sunlight (latitude 27.5°S), children with T1DM have lower serum vitamin D than children without diabetes. Fifty-six children with T1DM (14 newly diagnosed) and 46 unrelated control children participated in the study. Serum 25OHD, 1,25-dihydroxy vitamin D (1,25(OH)(2) D) and selected biochemical indices were measured. Vitamin D receptor (VDR) polymorphisms Taq1, Fok1, and Apa1 were genotyped. Fitzpatrick skin classification, self-reported daily hours of outdoor exposure, and mean UV index over the 35 d prior to blood collection were recorded. Serum 25OHD was lower in children with T1DM (n = 56) than in controls (n = 46) [mean (95%CI) = 78.7 (71.8-85.6) nmol/L vs. 91.4 (83.5-98.7) nmol/L, p = 0.02]. T1DM children had lower self-reported outdoor exposure and mean UV exposure, but no significant difference in distribution of VDR polymorphisms. 25OHD remained lower in children with T1DM after covariate adjustment. Children newly diagnosed with T1DM had lower 1,25(OH)(2) D [median (IQR) = 89 (68-122) pmol/L] than controls [121 (108-159) pmol/L, p = 0.03], or children with established diabetes [137 (113-153) pmol/L, p = 0.01]. Children with T1DM have lower 25OHD than controls, even in an environment of abundant sunlight. Whether low vitamin D is a risk factor or consequence of T1DM is unknown.
维生素 D 可通过皮肤在紫外线 B 辐射（阳光）的作用下合成，而血清中的 25-羟基维生素 D（25OHD）则可作为维生素 D 状态的标志物进行测量。多项研究主要在高纬度地区进行，结果表明 1 型糖尿病（T1DM）与血清 25OHD 水平低之间存在关联。我们开展了一项病例对照研究，以确定在阳光充足的亚热带环境（纬度 27.5°S）中，1 型糖尿病患儿的血清维生素 D 是否低于无糖尿病的儿童。56 名 T1DM 患儿（14 名新诊断）和 46 名无血缘关系的对照儿童参与了该研究。测量了血清 25OHD、1,25-二羟基维生素 D（1,25(OH)(2) D）和选定的生化指标。还对维生素 D 受体（VDR）多态性 Taq1、Fok1 和 Apa1 进行了基因分型。记录了 Fitzpatrick 皮肤分类、自我报告的每日户外暴露时间以及采血前 35 天的平均紫外线指数。与对照组（n = 46）相比，T1DM 患儿（n = 56）的血清 25OHD 水平更低[平均值（95%CI）= 78.7（71.8-85.6）nmol/L 比 91.4（83.5-98.7）nmol/L，p = 0.02]。T1DM 患儿的自我报告户外暴露和平均紫外线暴露均较低，但 VDR 多态性的分布无显著差异。在调整了协变量后，T1DM 患儿的 25OHD 仍较低。新诊断为 T1DM 的患儿的 1,25(OH)(2) D 中位数（IQR）[89（68-122）pmol/L]低于对照组[121（108-159）pmol/L，p = 0.03]或确诊糖尿病患儿[137（113-153）pmol/L，p = 0.01]。即使在阳光充足的环境中，T1DM 患儿的 25OHD 水平也低于对照组。维生素 D 水平低是 T1DM 的危险因素还是后果尚不清楚。
