Supplementary Material for: Ethnic Differences in Carotid Intima Media Thickness and Plaque Presence - The HELIUS study

Introduction
In the Netherlands, the prevalence of cardiovascular diseases (CVD) 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 aim to assess ethnic differences in plaque presence and intima media thickness (cIMT) and explore to which 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 3022 participants, 1183, 1051 and 790 individuals were of Dutch, South-Asian Surinamese and Moroccan descent. Mean age was 60.9 years (SD 8.0), 52.8% was 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 µm, 95% CI -27.9; -7.9) and partly explained by ethnic differences in 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.

引言
在荷兰，心血管疾病（CVD）的患病率在南亚苏里南人群体中高于荷兰本土人，而在摩洛哥人群体中则相对较低。传统动脉粥样硬化性心血管疾病的风险因素并不能完全解释这些差异。本研究旨在评估不同民族在斑块存在和内膜中层厚度（cIMT）方面的差异，并探讨这些差异在多大程度上可由传统风险因素解释。
方法
本研究利用来自多民族人群基础健康研究（HELIUS）的横断面数据，该研究招募的参与者接受了颈动脉超声检查。构建了逻辑回归和线性回归模型，以评估民族差异在斑块存在和cIMT方面与荷兰人群的差异，并以荷兰人群为参照。此外，还创建了调整社会经济地位、身高和心血管风险因素的模型。
结果
在3022名参与者中，有1183人、1051人和790人分别属于荷兰、南亚苏里南人和摩洛哥血统。平均年龄为60.9岁（标准差8.0），其中52.8%为女性。与荷兰人群相比，我们发现摩洛哥人群斑块存在的几率较低（0.77，95%置信区间0.62；0.95），而南亚苏里南人与荷兰人群之间没有显著差异（0.91，95%置信区间0.76；1.10）。在调整心血管疾病风险因素后，我们发现南亚苏里南人群斑块存在的几率降低（0.63，95%置信区间0.48；0.82）。在摩洛哥人和南亚苏里南人中，调整社会经济地位并未实质性改变结果。与荷兰人群相比，南亚苏里南人群的cIMT较低（-17.9 µm，95%置信区间-27.9；-7.9），这些差异部分可归因于身高方面的民族差异，因为南亚苏里南人群的平均身高低于荷兰人群。在摩洛哥人和荷兰人群之间没有发现cIMT的差异。
结论
在独立于心血管疾病风险的情况下，不同民族之间的cIMT和斑块患病率存在差异。摩洛哥人群斑块患病率较低的部分原因在于传统心血管疾病风险因素的较低患病率，而身高是南亚人群cIMT差异的重要影响因素。本研究强调了为斑块存在和cIMT设定民族特异性阈值的重要性。