Although type 1 diabetes mellitus (T1DM) is traditionally viewed as a youth-onset disorder, the number of older adults being diagnosed with this disease is growing. Improvements in the average life expectancy of people with T1DM have also contributed to the growing number of older people living with this disease. We summarize the evidence regarding the epidemiology (incidence, prevalence and excess mortality) of T1DM in older adults (ages ≥60 years) as well as the genetics, immunology and diagnostic challenges. Several studies report an incidence peak of T1DM in older adults of a similar size to or exceeding that in children, and population prevalence generally increases with increasing age. Glutamic acid decarboxylase antibody positivity is frequently observed in adult-onset T1DM. Guidelines for differentiating T1DM from type 2 diabetes mellitus in older adults recommend measuring levels of C-peptide and autoantibodies, including glutamic acid decarboxylase antibodies. However, there is no gold standard for differentiating T1DM from type 2 diabetes mellitus in people aged 60 years and over. As such, the global variation observed in T1DM epidemiology might be in part explained by misclassification, which increases with increasing age of diabetes mellitus onset. With a growing global population of older adults with T1DM, improved genetic and immunological evidence is needed to differentiate diabetes mellitus type at older ages so that a clear epidemiological picture can emerge.

尽管 1 型糖尿病 （T1DM） 传统上被视为一种青年发病的疾病，但被诊断出患有这种疾病的老年人人数正在增加。T1DM 患者平均预期寿命的延长也导致患有这种疾病的老年人人数增加。我们总结了有关老年人 （≥60 岁） T1DM 流行病学 （发病率、患病率和超额死亡率） 以及遗传学、免疫学和诊断挑战的证据。几项研究报告称，T1DM 在体型相似或超过儿童的老年人中达到峰值，并且人群患病率通常随着年龄的增长而增加。谷氨酸脱羧酶抗体阳性常见于成人发病的 1 型糖尿病患者。老年人区分 1 型糖尿病和 2 型糖尿病的指南建议测量 C 肽和自身抗体（包括谷氨酸脱羧酶抗体）的水平。然而，在 60 岁及以上的人群中，没有区分 1 型糖尿病和 2 型糖尿病的金标准。因此，在 1 型 DM 流行病学中观察到的全球差异可能部分是由错误分类解释的，错误分类随着糖尿病发病年龄的增加而增加。随着全球 1 型糖尿病老年人口的增加，需要改进的遗传和免疫学证据来区分老年人的糖尿病类型，以便出现清晰的流行病学情况。