Division of Rheumatology, Allergy and Clinical Immunology, University of California at Davis School of Medicine, 451 Health Sciences Drive, Suite 6510, Davis, CA 95616, USA.
Autoimmun Rev. 2010 Mar;9(5):A355-65. doi: 10.1016/j.autrev.2009.12.003. Epub 2009 Dec 5.
Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by absolute insulin deficiency resulting from the progressive immune-mediated destruction of pancreatic islet beta cells. It is thought to be triggered by as yet unidentified environmental factors in genetically susceptible individuals, the major genetic contribution coming from loci within the HLA complex, in particular HLA class II. The worldwide incidence of T1D varies by at least 100-fold, being highest in Finland and Sardinia (Italy) and lowest in Venezuela and China. The incidence has been increasing worldwide at an annual rate of approximately 3%. While genetic factors are thought to explain some of the geographic variability in T1D occurrence, they cannot account for its rapidly increasing frequency. Instead, the declining proportion of newly diagnosed children with high-risk genotypes suggests that environmental pressures are now able to trigger T1D in genotypes that previously would not have developed the disease during childhood. Although comparisons between countries and regions with low and high-incidence rates have suggested that higher socioeconomic status and degree of urbanization are among the environmental factors that play a role in the rising incidence of T1D, the findings are too inconsistent to allow firm conclusions. Morbidity and mortality as well as causes of death also show considerable geographic variation. While glycemic control has been identified as a major predictor of the micro- and macrovascular complications of T1D and shows considerable geographical variability, it does not appear to be the only factor involved in the regional differences in complication rates. The role of genetics in susceptibility to nephropathy, retinopathy and other diabetic complications largely remains to be explored.
1 型糖尿病（T1D）是一种慢性自身免疫性疾病，其特征是由于胰腺胰岛β细胞的进行性免疫介导破坏导致绝对胰岛素缺乏。据认为，它是由尚未确定的环境因素在遗传易感个体中引发的，主要的遗传贡献来自 HLA 复合物内的基因座，特别是 HLA 类 II 类。T1D 的全球发病率至少相差 100 倍，在芬兰和撒丁岛（意大利）最高，在委内瑞拉和中国最低。全球发病率以每年约 3%的速度增长。虽然遗传因素被认为可以解释 T1D 发生的一些地理变异，但它们不能解释其发病率的迅速增加。相反，具有高风险基因型的新诊断儿童的比例下降表明，环境压力现在能够在以前不会在儿童时期发生疾病的基因型中引发 T1D。尽管比较发病率低和高的国家和地区表明，较高的社会经济地位和城市化程度是导致 T1D 发病率上升的环境因素之一，但这些发现太不一致，无法得出确凿的结论。发病率和死亡率以及死亡原因也显示出相当大的地理差异。虽然血糖控制已被确定为 T1D 微血管和大血管并发症的主要预测因素，并且显示出相当大的地理变异性，但它似乎不是导致并发症发生率区域差异的唯一因素。遗传在易患肾病、视网膜病变和其他糖尿病并发症中的作用在很大程度上仍有待探索。
