Due to the rise in obesity rates worldwide, the prevalence of cardiometabolic comorbidities (CMM) is increasing year by year. Body roundness index (BRI) is a new obesity measure of visceral adipose tissueand the risk of BRI and CMM in people with normal body weight has been poorly studied.

To explore the relationship between BRI and high-risk CMM in normal body weight population, and to explore the role of triacylglycerol glucose product (TyG) index in this association.

A total of 42 437 subjects with a body mass index (BMI) of 18.50-23.99 kg/m² who participated in the early screening and comprehensive intervention project of high-risk groups of cardiovascular diseases in Anhui Province in 2017—2021 were selected. According to gender and CMM, the participants were divided into male non-CMM group (n=14 546) , male CMM group (n=2 741) , female non-CMM group (n=20 901) and female CMM group (n=4 249) , and they were divided into four levels according to the BRI quartile of different sexes (Male: M1, M2, M3, M4. Females: F1, F2, F3, F4) . The Bonferroni method was used to compare the differences in the prevalence of CMM among different genders and age groups. Multivariate Logistic regression analysis was used to explore the relationship between BRI quartile level and CMM risk. The mediate function of R (version 4.4.2) software was used to explore the mediating effect of the association between BRI and CMM after adjusting for covariates, and the mediating effect of TyG index was analyzed by medsens function.

The proportion of age, education in high school or above, BMI, total cholesterol (TC) , triglycerides (TG) , low-density lipoprotein cholesterol (LDL-C) , RC, fasting blood glucose (FPG) , TyG index, BRI, SBP, diastolic blood pressure (DBP) , hypertension, diabetes mellitus, dyslipidemia, heart disease, and stroke in the CMM group were higher than those in the non-CMM group, and the proportion of smoking and high-density lipoprotein cholesterol (HDL-C) were lower than those in the non-CMM group (P<0.05) . In the female group, the age, BMI, TC, TG, LDL-C, RC, FPG, TyG index, BRI, SBP, DBP, hypertension, diabetes, dyslipidemia, heart disease, and stroke in the CMM group were higher than those in the non-CMM group, and the proportion of education in high school or above and HDL-C in the female group were lower than those in the non-CMM group (P<0.05) . There were statistically significant differences in the prevalence of CMM, alcohol consumption ratio, TC, TG, LDL-C, RC, FPG, TyG index, SBP and DBP among different genders (P<0.05) , and the prevalence of CMM increased with the increase of BRI level (P_trend<0.001 for males and <0.001 for females) . The prevalence of CMM was different among different genders and age groups (P<0.001) , and the proportion of CMM people over 50 years old (male 89.4%, females 91.2%) is much larger than that under 50 years of age (males 10.6%, female 8.8%) . Multivariate Logistic regression showed that the risk of CMM at M2/F2, M3/F3, and M4/F4 levels was increased compared with BRI M1/F1 levels, regardless of whether confounders were adjusted for confounders (P<0.001) . In the mediating analysis of the association between BRI and CMM, after adjusting for covariates such as gender, age, education, smoking and alcohol consumption, the proportion mediated by TyG index (54.62%, 95%CI=50.19%-60.00%) was much higher than that of RC (22.98%, 95%CI=20.70%-26.00%) and SBP (24.05%, 95%CI=22.05%-27.00%) . The association between BRI and CMM disease was more significantly mediated.

In people with normal body weight, BRI levels were positively correlated with the risk of CMM, and the TyG index played a significant mediating role in this association.

由于全球肥胖率的上升，心血管代谢性共病（CMM）的患病率逐年升高。身体圆度指数（BRI）是一种衡量内脏脂肪组织的新型肥胖指标，目前少有学者研究在体重正常人群中BRI与CMM的患病风险。

探讨在体重正常人群中BRI与CMM高危风险的关系，探究三酰甘油葡萄糖乘积（TyG）指数在这种关联中的作用。

选取2017—2021年参与安徽省心血管疾病高危人群早期筛查与综合干预项目中BMI处于18.5~23.9 kg/m²的42 437名研究对象，经统一培训人员收集人群的一般资料、疾病史和相关生化指标。根据性别和是否患有CMM将研究对象分为男性非CMM组（n=14 546）、男性CMM组（n=2 741）、女性非CMM组（n=20 901）和女性CMM组（n=4 249），分别根据不同性别BRI四分位数将其分为4个水平（男，M1、M2、M3、M4；女，F1、F2、F3、F4）。采用Bonferroni法比较不同性别及年龄段人群CMM患病率差异。采用多因素Logistic回归分析探究BRI四分位水平与CMM患病风险的关系。采用R 4.4.2软件的mediate函数探究在调整协变量后的TyG指数、残余胆固醇（RC）、收缩压在BRI与CMM之间关联的中介效应，并通过medsens函数对TyG指数的中介效应进行敏感性分析。

男性群体中CMM组年龄、学历在高中及以上比例、BMI、总胆固醇（TC）、三酰甘油（TG）、低密度脂蛋白胆固醇（LDL-C）、RC、空腹血糖（FPG）、TyG指数、BRI、收缩压、舒张压及患高血压、糖尿病、血脂异常、心脏病、脑卒中比例高于非CMM组（P<0.05），吸烟比例、高密度脂蛋白胆固醇（HDL-C）低于非CMM组（P<0.05）。女性群体中CMM组年龄、BMI、TC、TG、LDL-C、RC、FPG、TyG指数、BRI、收缩压、舒张压及患高血压、糖尿病、血脂异常、心脏病、脑卒中比例高于非CMM组（P<0.05），学历在高中及以上比例、HDL-C低于非CMM组（P<0.05）。不同性别的BRI四分位水平中CMM患病率、饮酒比例、TC、TG、LDL-C、RC、FPG、TyG指数、收缩压、舒张压比较，差异有统计学意义（P<0.05），且CMM的患病率随BRI水平的升高而增加（男P_趋势<0.001，女P_趋势<0.001）。不同性别和年龄段CMM患病率不同（P<0.001），且CMM人群中≥50岁占比（男89.4%，女91.2%）远高于<50岁（男10.6%，女8.8%）。多因素Logistic回归分析显示，无论是否调整混杂因素，与BRI M1/F1水平相比，M2/F2、M3/F3、M4/F4水平的CMM患病风险均增加（P<0.001）。在BRI与CMM患病之间关联的中介分析中，调整性别、年龄、学历、吸烟及饮酒等协变量后，TyG指数介导占比（54.62%，95%CI=50.19%~60.00%）高于RC（22.98%，95%CI=20.70%~26.00%）和收缩压（24.05%，95%CI=22.05%~27.00%），明显介导了BRI与CMM患病之间的关联。

在体重正常的人群中，BRI水平与CMM的患病风险呈正相关，而TyG指数对这种关联起明显中介作用。