Premature cardiac ageing in South Asian compared to Afro-Caribbean subjects in a community based screening study: cardiac ageing in South Asians

People of South Asian (SAs) and African Caribbean (AC) origin have increased cardiovascular morbidity, but underlying mechanisms are poorly understood. Ageing is the key predictor of deterioration in diastolic function, which can be assessed by echocardiography using E/e’ ratio as a surrogate of left ventricular (LV) filling pressure. The study aimed to assess a possibility of premature cardiac ageing in SA and AC subjects. We studied 4540 subjects: 2880 SA and 1660 AC subjects. All participants underwent detailed echocardiography, including LV ejection fraction (LVEF), average septal-lateral E/e’, LV mass index (LVMI). When compared to ACs, SAs were younger, with lower mean LVMI, systolic BP, diastolic BP and BMI, as well as a lower prevalence of hypertension and smoking (p ≤0.001 for all). In a multivariate linear regression model including age, gender, ethnicity, BP, heart rate, BMI, waist circumference, LVMI, history of smoking, hypertension, coronary artery disease, diabetes, medications, SA origin was independently associated with higher E/e’ (regression coefficient ± standard error -0.66±0.10, p<0.001, adjusted R-squared for the model 0.21, p<0.001). Furthermore, SAs had significantly accelerated age-dependent increase in E/e’ compared to ACs. On multivariable Cox regression analysis without adjustment for E/e’ SA ethnicity was independently predictive of mortality (p=0.04). After additional adjustment for E/e’ the ethnicity lost its significance value, whilst E/e’ was independently predictive of higher risk of death (p=0.008). Premature cardiac ageing is evident in SAs and may contribute to high cardiovascular morbidity in this ethnic group, compared to ACs.