Abstract
IMPORTANCE: Epidemiologic studies suggest that people who were exposed to famine during early life but now live in nutrient-abundant environments have an elevated risk of type 2 diabetes (T2D) and other cardiometabolic conditions. Although many individuals who were exposed to famine in early life have now immigrated to high-income countries, the association between early life famine exposure and cardiometabolic outcomes among immigrants is unknown. OBJECTIVE: To investigate the associations of early life exposure to the Great Chinese Famine with the incidence of T2D, hypertension, and cardiovascular hospitalization among immigrants. DESIGN, SETTING, AND PARTICIPANTS: This population-based cohort study in Ontario, Canada, used 3 cohorts (1 for each coprimary outcome of T2D, hypertension, and cardiovascular hospitalization) of adult Chinese immigrants aged 20 to 85 years living in Ontario from April 1, 1992, to March 31, 2019. Participants were followed up until 85 years of age, relocation from Ontario, or March 31, 2023 (whichever occurred first). Data were analyzed from April 22, 2024, to September 30, 2025. EXPOSURE: Prenatal, childhood, and adolescent exposure to famine, classified by year of birth (1941-1952). Those born before 1941 or after 1962 served as the comparison group. MAIN OUTCOMES AND MEASURES: Incident T2D, hypertension, and cardiovascular hospitalization were the coprimary outcomes. RESULTS: The T2D cohort included 188 292 individuals (exposed: mean [SD] age, 52.6 [10.8] years; 53.3% female; unexposed: mean [SD] age, 37.4 [12.5] years; 54.9% female), the hypertension cohort included 180 510 individuals (exposed: mean [SD] age, 51.8 [10.6] years; 52.3% female; unexposed: mean [SD] age, 36.6 [11.5] years; 55.0% female), and the cardiovascular hospitalization cohort included 208 921 individuals (exposed: mean [SD] age, 50.5 [12.0] years; 51.5% female; comparison: mean [SD] age, 37.8 [13.1] years; 54.6% female). Event rates among the famine-exposed group were 13.6% for T2D, 29.8% for hypertension, and 1.6% for cardiovascular hospitalization. Early life famine exposure was associated with increased hazards of T2D (prenatal: hazard ratio [HR], 1.58 [95% CI, 1.49-1.68]; childhood: HR, 1.45 [95% CI, 1.38-1.54]; adolescent: HR, 1.37 [95% CI, 1.28-1.46]) and hypertension (prenatal: HR, 1.22 [95% CI, 1.17-1.27]; childhood: HR, 1.25 [95% CI, 1.21-1.30]; adolescent: HR, 1.25 [95% CI, 1.20-1.31]). Prenatal and childhood exposure to famine were not associated with risk of cardiovascular hospitalization (prenatal: HR, 0.92 [95% CI, 0.76-1.12]; childhood: HR, 0.98 [95% CI, 0.86-1.11]), but adolescent exposure to famine was associated with a 14% decrease in risk of cardiovascular hospitalization (HR, 0.86 [95% CI, 0.75-0.98]). CONCLUSIONS AND RELEVANCE: In this cohort study of Chinese immigrants, early life famine exposure was strongly associated with increased risks of incident T2D and hypertension, but not cardiovascular hospitalization. Early life undernutrition is a novel cardiometabolic risk factor among immigrants associated with the burden of T2D and hypertension in high-income countries.