Stroke Incidence Evolution in People With Newly Diagnosed Diabetes and Impaired Glucose Tolerance: A 34-Year Follow-up of the Da Qing Diabetes Study

OBJECTIVE To examine the incidence of stroke in Chinese adults with newly diagnosed type 2 diabetes (NDD), impaired glucose tolerance (IGT), and normal glucose tolerance (NGT) over a 34-year follow-up period. RESEARCH DESIGN AND METHODS This cohort study included participants with NDD, IGT, and NGT initially identified in 1986 in the Da Qing Diabetes Prevention Study who were followed up for 34 years. Patients with IGT were randomized into a 6-year lifestyle intervention or control group. The stroke incidence and hazard ratios (HRs) were determined across the three glucose-level groups. RESULTS Over 34 years, the cumulative stroke incidence in the NDD, IGT nonintervention, and IGT intervention groups were 65.4%, 62.8%, and 49.8%, respectively. The annual incidence in the NDD group was significantly higher than that in the NGT group (24.3 vs. 18.5 per 1,000 person-years), after adjusting for age and sex. After adjusting for risk factors, the risk of stroke was significantly higher in the NDD (HR 1.80, 95% CI 1.46–2.21, P < 0.001), IGT nonintervention (HR 1.52, 95% CI 1.11–2.07, P = 0.008), and IGT intervention (HR 1.33, 95% CI 1.17–1.63, P = 0.01) groups than in the NGT group. A reduced stroke risk was observed in the overall IGT intervention group compared with the NDD group (HR 0.77, 95% CI 0.64–0.94, P = 0.009), especially in women (HR 0.64, 95% CI 0.47–0.88, P = 0.006). CONCLUSIONS Over 34 years, ∼50% of Chinese adults with NDD and IGT experienced stroke. Further efforts in diabetes management and intervention are required.