Waist-to-height ratio time in target range and incident cardiovascular disease across glycemic status in middle-aged and older Chinese adults: A longitudinal cohort study.

BACKGROUND: Waist-to-height ratio (WHtR) is a simple marker of central obesity, but whether long-term target attainment is associated with incident cardiovascular disease (CVD) independent of baseline WHtR remains unclear. This study examined the association of WHtR time in target range (WHtR-TTR) with incident CVD and evaluated its consistency across glycemic status. METHODS: We included 5550 CVD-free participants from the China Health and Retirement Longitudinal Study (CHARLS). WHtR-TTR was defined as the percentage of visits with WHtR <0.5 across three waves and was categorized as 0%, 33.3%, 66.7%, and 100% of visits within the target range. Multivariable Cox proportional hazards models assessed the association with incident CVD. Stratified analyses were performed across normal glucose regulation (NGR), prediabetes (Pre-DM), and diabetes mellitus (DM) groups. RESULTS: During follow-up, 1375 incident CVD events occurred. CVD incidence decreased from 28.14% in the 0% WHtR-TTR group to 17.88% in the 100% group (P < 0.001). In Model 3, hazard ratios (HRs) for 33.3%, 66.7%, and 100% WHtR-TTR versus 0% were 0.88 (95% CI 0.74-0.96), 0.83 (95% CI 0.71-0.94), and 0.76 (95% CI 0.63-0.92), respectively. After additional adjustment for baseline WHtR, the corresponding HRs were 0.89, 0.84, and 0.79. Each 33.3-percentage-point increase in WHtR-TTR was associated with lower incident CVD risk (HR 0.92; 95% CI 0.87-0.98). No significant interaction with glycemic status was observed. CONCLUSIONS: A higher percentage of visits within the WHtR target range was associated with a lower risk of incident CVD independent of baseline WHtR and traditional cardiometabolic risk factors.