Abstract
OBJECTIVE: Individuals who are obesity or abdominal obesity (AO) often develop insulin resistance. This study aims to explore the separate and combined effects of body mass index (BMI), AO [assessed by waist circumference (WC)], and triglyceride-glucose (TyG) index on the incidence risk of stroke. METHODS: We analyzed 8746 participants aged 45 years or older from the China Health and Retirement Longitudinal Study (CHARLS). The primary study outcome was stroke incidence. Cox proportional hazard models were applied to explore the association between the combination of BMI, AO, and TyG index with the risk of stroke. RESULTS: During a median follow-up of 9 years, 812 (9.28%) participants had occurred strokes. Restricted cubic splines curves revealed a significant linear relationship between BMI, WC, and TyG index with the risk of stroke, the HRs were 1.24 (95% CI: 1.02, 1.51) for BMI, 1.38 (95% CI: 1.16, 1.64) for AO, and 1.25 (95% CI: 1.04, 1.49) for TyG index. Cox regression analysis revealed that participants with BMI ≥ 28 or AO and higher levels of TyG have higher risk of stroke, the HRs were 1.48 (95% CI: 1.13, 1.93) for BMI ≥ 28 and TyG ≥ median group, 1.75 (95% CI: 1.36, 2.25) for AO and TyG ≥ median group. Compared with individuals with no biomarker elevations, the HRs for incident stroke were 1.51 (95% CI: 1.21, 1.89), 1.72 (95% CI: 1.34, 2.21), and 1.99 (95% CI: 1.45, 2.72) for those with one, two, or three biomarkers in the high-value group, respectively. Kaplan Meier curve demonstrates that individuals with three risk factors have the highest risk of stroke. The TyG index partially mediated the effects of BMI and AO on stroke events by 6.6% and 6.9%, respectively. CONCLUSIONS: The separate and combined effects of BMI, AO, and TyG index were significantly associated with the risk of stroke, with TyG index partially mediating the impact of BMI and AO on stroke events. The findings highlighted the importance of joint evaluation of BMI, AO, and TyG index for primary prevention of stroke.