目的: 探讨炎症反应是否参与体质量指数（body mass index, BMI）与动脉硬化的相关性。方法: 从江苏省高邮地区采用电脑随机抽样的方法抽取自然人群，最终4 508名纳入研究。采集人口学特征信息、身体测量指标、血常规、生化、病史及臂踝脉搏波传导速度（brachial-ankle pulse wave velocity, baPWV）等信息。根据BMI将人群分为低体重组（BMI<18.5 kg/m²）、正常体重组（18.5 kg/m²≤BMI<24 kg/m²）、超重组（24 kg/m²≤BMI<28 kg/m²）和肥胖组（BMI≥28 kg/m²）。多因素线性回归分析BMI和baPWV的相关性。中介效应分析探究白细胞计数是否参与BMI与baPWV相关性。结果: 多因素调整年龄、性别、收缩压、血糖、总胆固醇、低密度脂蛋白胆固醇、谷丙转氨酶、谷草转氨酶、肌酐、吸烟、饮酒、糖尿病和降压治疗后，与正常体重组相比，低体重组、超重组、肥胖组与baPWV的回归系数（β）和95%置信区间分别为1.01（0.51~1.51）、-0.12（-0.27~0.02）和-0.28（-0.49~-0.08）。中介效应分析显示白细胞计数在BMI和baPWV之间的关联中起中介作用，低体重组、超重组和肥胖组中介百分比分别为3.3%、11.4%、9.8%（均P<0.05）。结论: 低体重人群动脉硬化患病风险可能更高，炎症反应介导BMI与动脉硬化的相关性。

Objective To investigate if the inflammation mediated the association of body mass index(BMI) and the atherosclerosis. Methods A total of 4 508 subjects were randomly recruited from Gaoyou, and the indexes including the demographic characteristics, BMI, blood routine, biochemical test, disease history and brachial-ankle pulse wave velocity (baPWV) were measured. According to BMI, they were divided into low body weight group(BMI<18.5 kg/m²), normal weight group (18.5 kg/m²≤BMI<24 kg/m²), overweight group (24 kg/m²≤BMI<28 kg/m²) and obesity group (BMI≥28 kg/m²). The univariate and multivariate linear regression analysis was used to analyze the correlation between BMI and baPWV. The mediation analysis was used to evaluate whether white blood cell count was involved in the correlation between BMI and baPWV. Results After adjustment of age, gender, systolic blood pressure, fasting blood glucose, total cholesterol, low density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, creatinine, smoking, drinking, diabetes and antihypertensive treatment, compared with normal weight group, the regression coefficient and 95% confidence interval of low body weight group, overweight, obesity group with baPWV were 1.01(0.51-1.51), -0.12(-0.27-0.02) and -0.28(-0.49- -0.08), respectively. The mediation analysis showed that white blood cell count mediated the correlation of BMI and baPWV, the mediation percentage of low body weight, overweight and obesity groups were 3.3%, 11.4% and 9.8%, respectively(all P<0.05). Conclusions The people of low weight could have a higher risk of atherosclerosis, and the inflammation might mediate the correlation between BMI and arterial stiffness.