Ethnic Differences in Carotid Intima-Media Thickness and Plaque Presence: The HELIUS Study

Introduction: In the Netherlands, the prevalence of cardiovascular diseases (CVDs) is higher among South-Asian Surinamese and lower among Moroccans compared to the Dutch. Traditional risk factors for atherosclerotic CVD do not fully explain these disparities. We aimed to assess ethnic differences in plaque presence and carotid intima-media thickness (cIMT) and explore to what extent these differences are explained by traditional risk factors. Methods: We used cross-sectional data from a subgroup of participants enrolled in the multi-ethnic population-based Healthy Life in an Urban Setting (HELIUS) study who underwent carotid ultrasonography. Logistic and linear regression models were built to assess ethnic differences in plaque presence and cIMT with the Dutch population as reference. Additional models were created to adjust for socioeconomic status, body height, and cardiovascular risk factors. Results: Of the 3,022 participants, 1,183, 1,051, and 790 individuals were of Dutch, South-Asian Surinamese, and Moroccan descent, respectively. Mean age was 60.9 years (SD: 8.0), and 52.8% were female. Compared to the Dutch, we found lower odds for plaque presence in Moroccans (0.77, 95% CI: 0.62; 0.95) and no significant differences between the South-Asian Surinamese and Dutch population (0.91, 95% CI: 0.76; 1.10). After adjustment for CVD risk factors, we found a lower plaque presence in South-Asian Surinamese (0.63, 95% CI: 0.48; 0.82). In both Moroccan and South-Asian Surinamese individuals, adjustment for socioeconomic status did not materially change the results. cIMT was lower in South-Asian Surinamese compared to the Dutch (-17.9 μ m, 95% CI: -27.9; -7.9) and partly explained by ethnic differences in the body height as South-Asian Surinamese individuals were, on average, shorter than the Dutch population. No differences in cIMT between Moroccans and Dutch were found. Conclusions: cIMT and plaque prevalence differ between ethnic groups independent of CVD risk. Lower plaque prevalence in Moroccans was partly attributable to a lower prevalence of traditional CVD risk factors, while body height was an important contributor to differences in cIMT in South Asians. This study emphasizes the need for ethnic-specific cut-off values for plaque presence and cIMT.