Incidence of Type 1 Diabetes May Be Underestimated in the Chinese Population: Evidence From 21.7 Million People Between 2007 and 2017

OBJECTIVE─ Previous reports of the annual incidence of type 1 diabetes (T1D) in China were conducted using retrospective hospital cases, which may not reflect the reality. This longitudinal study estimated T1D incidence in a 21.7-million Chinese population during 2007-2017. <p>RESEARCH DESIGN AND METHODS─ A population-based registry of T1D was performed by the Beijing Municipal Health Commission Information Center. Annual incidence and 95% confidence intervals (CI) were calculated by age group and gender. The association of gender with T1D incidence and predicted new T1D cases were assessed using Poisson regression models. Annual percentage change and average annual percentage of change were assessed using Joinpoint regression. </p> <p>RESULTS─ Overall, there were 6,875 individuals who developed T1D from 2007 to 2017 in this population. T1D incidence [95% CI] (/100,000 persons) significantly increased from 2.72 [2.51, 2.93] in 2007 to 3.60 [3.38, 3.78] in 2017 (p<0.001). The T1D onset peak was in the 10-14 age group. While no significant trend was found in the 0-14 and 15-29 age groups, T1D incidence markedly increased from 1.87 to 3.52 in ≥30 age group (p<0.05). The prevalence of diabetic ketoacidosis at diagnosis was highest in 0-4 age group. We predicted T1D new cases will increase to 1.57-fold over the next decade. </p> CONCLUSIONS─ T1D incidence in this large Chinese population is higher than has been reported previously. During 2007-2017, although the incidence peak was in the 10-14 age group, the T1D incidence increased sharply in adults but not in youth.