Aims — We conducted an international population-based study comparing the incidence of young- (age 20-39 years) and usual- (age≥40 years) onset diabetes among Chinese-Canadian immigrants; their source populations (mainland China, Hong Kong, Taiwan); and other Canadians.
Methods — Using population-based data (2000-17; n=3.4 million cases), we calculated incidence rates and incidence rate ratios comparing the average incidence for each cohort.
Results — The average incidence of young-onset diabetes (YOD) among immigrants from China, Hong Kong, and Taiwan was 165.5, 121.0, and 78.4 per 100,000 person-years respectively. Immigrants from China and Hong Kong had higher YOD incidence than their source populations (RR China: 2.59, 2.44-2.74; Hong Kong: 1.64, 1.49-1.81), while immigrants from Taiwan had lower rates versus Taiwan (RR 0.63, 0.45-0.86). YOD incidence among immigrants from China increased sharply by 8.3% (3.3-13.6%) per year from 2011 onward-over twice the annual increase among non-Chinese Canadians. The average incidence rates of usual-onset diabetes among immigrants from China, Hong Kong, and Taiwan were higher than (RR 1.77, 1.73-1.81), similar to (0.98, 0.96-1.01), and lower than (0.36, 0.32-0.40) those in each source population respectively.
Conclusions — Diabetes incidence among Chinese migrants is unexpectedly heterogeneous, varying according age at migration, territory of origin, and the occurrence of diabetes in the source population.