Introduction: YOD (age at diagnosis [AAD]<40 years) is associated with greater cardiovascular disease (CVD) risk than usual-onset diabetes (UOD, AAD≥40 years). It is unknown whether this pattern varies by ethnicity.

Methods: We included adults in Ontario, Canada with incident diabetes (2002-12, followed to 2018). We matched each case with ≤5 diabetes-free controls by age, sex, and ethnicity. The outcome was CVD (coronary artery disease, congestive heart failure, stroke, peripheral revascularization, lower extremity amputation). We constructed Cox proportional hazards models to estimate the association between AAD and CVD relative to controls.

Results: We included 411,030 cases (3.5% South Asian; 4.3% Chinese) and 2,000,035 controls. The hazard ratios (HR) for CVD in UOD versus controls were higher in Chinese (2.38, 2.2-2.5) and South Asian (2.5, 2.4-2.7) people than White people (1.9, 1.9-1.9; pinteraction<0.0001). The HR for CVD in YOD versus controls were similar across ethnicities (Chinese: 5.2, 3.6-7.3; South Asian: 4.4, 3.7-5.3; White: 4.6, 4.4-4.8). In YOD and controls, Chinese and South Asian people had lower hazard of CVD than White people. In UOD, CVD hazard was lowest in Chinese people, and similar in South Asian and White people.

Discussion: Although Chinese and South Asian people have a lower hazard of CVD compared to White people, YOD is associated with a 4- to 5-fold greater hazard of CVD across ethnicities.


C. Ke: None. T. Stukel: None. A. Luk: Research Support; Self; Bayer Healthcare Pharmaceuticals Inc., Roche Pharma. Other Relationship; Self; Merck Sharp & Dohme Corp. J.C. Chan: None. B.R. Shah: None.


Canadian Institutes of Health Research; South Asian Network Supporting Awareness and Research

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at