Ethnic differences in subclinical vascular function in South Asians, Whites, and African Americans in the United States

Abstract

Background South Asians are a high-risk ethnic group for cardiovascular disease despite having lower levels of conventional cardiovascular risk factors such as obesity and smoking. Ethnic differences in pulse wave reflections, arterial stiffness, and subclinical atherosclerosis as measured using augmentation index (AIX), pulse wave velocity (PWV), and carotid intima-media thickness (CIMT) may reflect some of this excess risk. Methods We conducted a cross-sectional analysis of pooled data from three community-based sources in Atlanta, Georgia, USA. Data on 530 South Asians collected from local health fairs was compared with data on 507 White and 192 African Americans from the Emory Predictive Health Initiative and 351 White and 382 African Americans from the Morehouse and Emory Team up to Eliminate Health Disparities Study. Results Linear regression models adjusted for age, sex, smoking, MAP, fasting glucose, TC, HDL-C, creatinine, and body mass index were used to assess the relationship between ethnicity and vascular function measures. In fully adjusted models, South Asians had higher heart rate corrected AIX as compared with Whites and African Americans (by 5.47%, p < 0.01 and 3.50%, p < 0.01; respectively), but lower PWV (by 0.51 m/s, p < 0.01 and 0.72 m/s, p < 0.01; respectively) and lower CIMT (by 0.02 mm p = 0.03 and 0.04 mm p < 0.01; respectively). Conclusions Systemic pulse wave reflections, independent of other risk factors, are higher in South Asians as compared with Whites and African Americans. Future research is needed to determine whether higher AIX explains the increased cardiovascular risk among South Asians.

Central and local arterial stiffness in White Europeans compared to age-, sex-, and BMI-matched South Asians

“…Notably, this review also reported that other CVD risk factors are not or only modestly related to cf-PWV, an observation that matches our findings. We add the insight that the association between age and central stiffness was not ethnicity-dependent, which agrees with the American study [ 3 ] but disagrees with the Dutch study [ 26 ]. In the latter study, the positive relation between age and cf-PWV was significantly greater for the South Asian group than for the Dutch group, resulting in a greater cf-PWV difference between ethnicities at higher age.…”

The effects of experimental, meteorological, and physiological factors on short-term repeated pulse wave velocity measurements, and measurement difficulties: A randomized crossover study with two devices

“…Other studies utilizing the SphygmoCor CvMS device reported comparable effects of age on cfPWV measurements ranging from: 0.2 m/s per 10 years ( 58 ), to 0.3–0.4 m/s ( 59 ), to somewhat larger effects of around 0.7–0.9 m/s reported by the same group of authors ( 16 , 60 ). While age was identified as the strongest determinant of PWVao too ( 61 ), studies that investigated factors influencing Arteriograph’s PWVao measurements did not reported comparable, unstandardized regression metrics.…”

“…Sex, with higher values of PWVao in women compared to men, was also identified as significant factor in another study investigating Arteriographs’ PWVao measurements ( 61 ). However, while reports on the relationship between sex and central PWV measurements that were taken by devices other than Arteriograph were varied, all studies including those utilizing oscillometric devices reported either greater values of central PWV in men ( 16 , 59 , 60 , 62 , 76 – 78 ) or no association with sex ( 69 , 79 – 82 ). Thus, it appears that higher values of PWVao measurements in women may be specific to Arteriograph device.…”

“…Similarly, sex was not identified as significant predictor of cfPWV in the multivariable linear regression models controlling for age, MAP, HR in the study by Mitchell et al (83) which is based on apparently healthy Framingham Heart Study offspring cohort (83). Focusing solely on SphygmoCor's cfPWV measurements, the results are contradictory, with more studies reporting that in multivariate linear regression models, cfPWV increases with age similarly for both sexes (31,(80)(81)(82), others revealed that men have higher cfPWV values ranging from 0.27 to 0.72 m/s (16,59,60). We discovered no significant interaction between sex and age for either device.…”

Risk Amplifiers for Vascular Disease and CKD in South Asians

“…44,45 Ethnic differences between South Asians, White patients, and Black patients living in the United States showed higher pulse wave reflections in South Asians, a marker of arterial stiffness. 46 Further investigation is needed to determine the optimal medical management in patients with subclinical atherosclerotic disease and its effect on long-term cardiovascular outcomes.…”