Abstract: Background Cardiometabolic multimorbidity（CMM） represents one of the most prevalent and stable multimorbidity patterns. Relative fat mass（RFM），as a novel anthropometric indicator for assessing adiposity，has shown promise as a predictor of individual cardiometabolic diseases. However，evidence regarding its association with the risk of CMM remains limited. Objective To investigate the association between RFM and the risk of CMM across different genders，and to evaluate the potential role of RFM in the prevention and management of CMM. Methods A total of 116 321 permanent residents from 12 urban communities（including Suzhou） were selected as study participants from March 2017 to July 2021. Based on gender and CMM status，participants were stratified into CMM and non-CMM groups. Baseline characteristics were compared between these groups separately for each gender. Multivariable logistic regression analysis was employed to examine the association between RFM and the risk of CMM stratified by sex. Restricted cubic spline（RCS） curves were applied to explore potential non-linear relationships. Subgroup analyses and interaction tests were conducted to investigate variations in the association across different populations. Results A total of 116，321 participants were included in this study. Among them，46 637（40.1%） were male，with 11 969 cases（25.7%） in the CMM group and 34 668 cases（74.3 %） in the non-CMM group；while 69 684（59.9%） were female，with 16，668 cases（23.9%） in the CMM group and 53 016 cases（76.1%） in the non-CMM group. RFM levels were significantly higher in the CMM group than in the non-CMM group for both sexes. Multivariable logistic regression indicated that higher RFM levels were positively associated with a higher prevalence of CMM，both before and after adjustment for confounders，and this association was consistent across genders. After adjusting for confounding factors including age，smoking，alcohol consumption，education level，body mass index，low-density lipoprotein cholesterol，remnant cholesterol，blood glucose，systolic blood pressure，and diastolic blood pressure，the RCS model revealed a nonlinear relationship between RFM and CMM risk in both males and females（inflection point at OR=1：25.26 for males，P for non-linearity<0.001；38.41 for females，P for non-linearity=0.001）. Subgroup analysis showed that the interactions between RFM and gender，age，education level，BMI，smoking，and alcohol consumption were all statistically significant（P for interaction<0.05）. Conclusion Higher RFM is significantly associated with an increased risk of CMM，and this association is more pronounced in males，individuals aged ≥ 45 years，those with a high school education or below，smokers，drinkers，and individuals with a BMI<24 kg/m2 .

Key words: Relative fat mass, Cardiovascular metabolic comorbidity, Obesity, Disease risk, Cross-sectional study

摘要： 背景 心血管代谢性共病（CMM）是目前最为常见且稳定的共病模式之一。相对脂肪量（RFM）作为新型体脂评估工具，其在单一心脏代谢性疾病中表现出预测风险的潜力，目前关于 RFM 与 CMM 患病风险之间的研究较少。目的 探讨不同性别人群 RFM 与 CMM 患病风险之间的关系，并评估 RFM 在 CMM 防治中的作用。方法 选取2017 年 3 月—2021 年 7 月居住在宿州等 12 个城市社区 116 321 名常住居民为研究对象。根据性别以及是否患 CMM，将男性和女性患者分别分为 CMM 组和非 CMM 组，比较不同性别 CMM 组和非 CMM 组基线特征。以不同性别 RFM 四分位间距分组，采用多因素 Logistic 回归分析探讨不同性别人群中 RFM 与 CMM 患病风险的关系。通过限制性立方样条（RCS）曲线探讨不同性别间 RFM 与 CMM 之间的非线性关系。采用进行亚组分析和交互作用检验，探讨不同亚组人群中 RFM 与 CMM 关联的差异。结果 本研究共纳入 116 321 名受试者，男性 46 637 例（40.1%），其中 CMM 组共11969 例（25.7 %），非 CMM 组 34 668 例（74.3%）；女性 69 684 例（59.9%），其中患 CMM 组 16 668 例（23.9%），非 CMM 组 53 016 例（76.1%）。男性和女性中，CMM 组的 RFM 水平均高于非 CMM 组（P<0.001）。多因素 Logistic回归分析结果显示，调整了年龄、学历、吸烟、饮酒、BMI、低密度脂蛋白胆固醇、残余胆固醇、血糖、收缩压及舒张压等混杂因素后，男性 T2（T4 组 CMM 患病风险分别为 T1 组的 1.530、2.086、2.945 倍（P<0.001），女性 F2（F4组 CMM 患病分别为 F1 组的 1.205、1.532、1.760 倍（P<0.001）；且男性 RFM 每升高一个单位，CMM 患病风险增加 1.109倍（OR=1.109，95%CI=1.101~1.116，P<0.001），女性 RFM 每升高一个单位，CMM 患病风险增加 1.054 倍（OR=1.054，95%CI=1.049~1.060，P<0.001）。RCS 曲线分析结果显示，男性和女性中 RFM 与 CMM 患病风险均呈非线性关系（男性：OR=1 的拐点为 25.26，P 非线性 <0.001；女性：OR=1 的拐点为 38.41，P 非线性 =0.001）。亚组分析结果显示，RFM与 CMM 发病风险在男性（OR=1.108，95%CI=1.101~1.115）、年龄≥ 45 岁（OR=1.011，95%CI=1.008~1.013）、高中以下学历（OR=1.013，95%CI=1.011~1.015）、现在吸烟（OR=1.062，95%CI=1.054~1.069）、现在饮酒（OR=1.021，95%CI=1.015~1.028）及 BMI<24 kg/m2 （OR=1.010，95%CI=1.007~1.014）人群中具有更强的关联作用；交互作用分析结果显示，RFM 与 CMM 发病风险的关联受性别、年龄、学历、吸烟、饮酒、BMI 之间的交互作用影响（P 交互<0.05）。结论 较高的 RFM 可能与 CMM 患病风险密切相关，且这种关联在男性、年龄≥ 45 岁、高中以下学历、吸烟、饮酒及 BMI<24 kg/m2 人群中更为显著。

关键词: 相对脂肪量, 心血管代谢性共病, 肥胖, 患病风险, 横断面研究