Study on the mediating effect of triglyceride-glucose index on the association between body mass index and the risk of early neurological deterioration in large artery atherosclerosis-type minor stroke

Yang Ling; Peng Xiaoyan; Chen Fangfang; Yan Jingjing; Li Jun

doi:10.3969/j.issn.1672-5921.2026.02.002

Abstract：Objective To investigate the associations of body mass index(BMI)and triglyceride-glucose(TyG)index with early neurological deterioration(END)in patients with large artery atherosclerosis(LAA)-type minor ischemic stroke,and to analyze the mediating effect of TyG index on the relationship between BMI and the risk of END in LAA-type minor ischemic stroke.Methods A retrospective consecutive cohort study was conducted on patients with LAA-type minor ischemic stroke(National Institutes of Health stroke scale[NIHSS]score≤5 on admission)diagnosed and treated in the Department of Neurology of Suqian First Hospital,from January 2023 to July 2025.Clinical data of the patients,including gender,age,BMI,admission blood pressure(systolic and diastolic blood pressure),risk factors for cerebrovascular diseases(hypertension,diabetes mellitus,coronary heart disease,history of stroke,smoking history[smoking was defined as smoking at least 1 cigarette per day for≥1 year],heavy alcohol consumption[alcohol intake≥24 g/d]),and NIHSS score on admission were collected.Fasting blood samples were collected within 24 hours after admission for complete laboratory examinations,including platelet count,neutrophil count,lymphocyte count,fasting blood glucose,creatinine,total cholesterol,triglycerides,high-density lipoprotein cholesterol,and low-density lipoprotein cholesterol.The treatment regimens within 72 hours after admission included monotherapy antiplatelet therapy,dual antiplatelet therapy,statins,antihypertensive drugs,and hypoglycemic drugs.The TyG index was calculated as ln(fasting triglycerides[mg/dl]×fasting blood glucose[mg/dl]/2),where triglycerides(mg/dl)=triglycerides(mmol/L)×88.57 and fasting blood glucose(mg/dl)=fasting blood glucose(mmol/L)×18.02.END was defined as an increase of≥2 points in the NIHSS score or an increase of≥1 point in the motor subscore within 72 hours after the onset of acute ischemic stroke compared with the scores at admission.All patients were divided into the END group and non-END group according to the occurrence of END.Clinical data were compared between the two groups,and variables with statistically significant differences in univariate analysis were included in multivariate Logistic regression analysis to explore the independent risk factors for END in LAA-type minor ischemic stroke.Spearman correlation analysis was used to investigate the correlations of BMI and TyG index with the occurrence of END in patients with LAA-type minor ischemic stroke,as well as the correlation between BMI and TyG index,with the correlation intensity classified as:extremely strong correlation(0.8≤|r|＜1.0),strong correlation(0.6≤|r|＜0.8),moderate correlation(0.4≤|r|＜0.6),weak correlation(0.2≤|r|＜0.4),and extremely weak correlation(0＜|r|＜0.2).The Bootstrap method was adopted to analyze whether the TyG index mediated the association between BMI and END in LAA-type minor ischemic stroke;the mediating effect was considered to be established if the total effect(c),the effect of the independent variable(BMI)on the mediating variable(TyG index)(a),the effect of the mediating variable(TyG index)on the dependent variable(END in LAA-type minor ischemic stroke)(b),and the indirect effect(95%CI excluding 0)were all statistically significant.If the 95%CI of the indirect effect included 0,there was no mediating effect.Based on the established mediating effect,the partial mediating effect was confirmed if the direct effect coefficient c' of BMI on END in LAA-type minor ischemic stroke was statistically significant(P＜0.05)after controlling for the mediating variable(TyG index).Results A total of 381 patients with LAA-type minor ischemic stroke were enrolled,including 227 males and 154 females,aged 34 to 94 years,with a mean age of(66±11)years.Among them,120 patients were in the END group and 261 in the non-END group.(1)Statistically significant differences were observed between the END group and non-END group in the proportion of patients with diabetes mellitus(33.3%[40/120]vs.21.8%[57/261]),admission systolic blood pressure([167±21]mmHg vs.[158±21]mmHg),admission diastolic blood pressure([93±15]mmHg vs.[86±16]mmHg),fasting blood glucose(6.36[5.34,8.85]mmol/L vs.5.51[4.95,6.57]mmol/L),total cholesterol([4.74±1.18]mmol/L vs.[4.31±1.05]mmol/L),triglycerides(1.25[0.84,1.91]mmol/L vs.1.09[0.73,1.43]mmol/L),low-density lipoprotein cholesterol([3.08±0.88]mmol/L vs.[2.75±0.90]mmol/L),BMI([26.20±3.85]kg/m2 vs.[24.35±2.84]kg/m2),and TyG index(8.84±0.83 vs.8.42±0.78,all P＜0.05).(2)Multivariate Logistic regression analysis(excluding fasting blood glucose and triglycerides)showed that BMI(OR,1.136,95%CI 1.051-1.228)and TyG index(OR,1.631,95%CI 1.160-2.295)were independent risk factors for END in patients with LAA-type minor ischemic stroke(both P＜0.05).(3)Spearman correlation analysis revealed that TyG index(r=0.222)and BMI(r=0.216)were positively correlated with the occurrence of END in LAA-type minor ischemic stroke(both P＜0.01),and TyG index was also positively correlated with BMI(r=0.214,P＜0.01).(4)Mediation effect analysis using the Bootstrap method with TyG index as the mediating variable showed that BMI had a direct effect on END in patients with LAA-type minor ischemic stroke(c'=0.155,95%CI 0.081-0.230,P＜0.01),and TyG index exerted a partial mediating effect on the association between BMI and END(β=0.032,95%CI 0.012-0.060,P＜0.01).The total effect value c was 0.187,and the mediating effect accounted for 17.11%of the total effect.Conclusions Both BMI and TyG index are associated with the occurrence of END in patients with LAA-type minor ischemic stroke,and TyG index exerts a mediating effect on the relationship between BMI and the risk of END in these patients.Therefore,in clinical practice,the TyG index may serve as a simple and valuable auxiliary metabolic marker for assessing the risk of END in patients with LAA-type minor ischemic stroke.