Dynamic waist circumference change: A superior predictor of incident stroke compared to novel and traditional obesity indices.

BACKGROUND

While obesity is a recognized stroke risk factor, traditional measures like body mass index (BMI) have limitations in assessing body fat distribution. Novel central obesity indices-including waist-to-height ratio (WHtR), body roundness index (BRI), conicity index (CI), a body shape index (ABSI), and weight-adjusted waist index (WWI)-offer accessible alternatives reflecting visceral fat. However, previous studies have often focused on single-time obesity measurements, neglecting how changes over time and their cumulative effects influence stroke risk.

METHODS

This prospective cohort study utilized longitudinal data (2011-2018) from the China Health and Retirement Longitudinal Study (CHARLS). We analyzed 5,896 adults aged ≥45 years without baseline stroke. Seven obesity indices (waist circumference [WC], BMI, WHtR, BRI, CI, ABSI, WWI) were measured at baseline (Wave1, 2011-2012), Wave2 (2013), and Wave 3 (2015). Their longitudinal trajectories from 2012 to 2013 and then to 2015 were modeled using K-means clustering. Their relative change was calculated from 2012 to 2015. Multivariable logistic regression evaluated associations between these obesity measures and incident stroke, adjusting for demographics, lifestyle, and comorbidities.

RESULTS

As of the 2018 survey, 426 participants (7.23 %) experienced incident strokes. Baseline WC was significantly associated with stroke risk: each 1 cm increase corresponded to a 1 % higher risk (OR =1.01, 95 % CI: 1.001-1.02), and participants in the highest WC quartile had a 37 % greater risk compared to those in the lowest quartile (OR = 1.37; 95 % CI: 1.01-1.87). Other baseline obesity measures did not show significant associations. Regarding recent measurements in 2015, only the second quartile of ABSI was significantly associated with stroke risk (OR = 1.36; 95 % CI: 1.01-1.83 versus the first quartile). Crucially, individuals with a consistently high WC trajectory had a 27 % higher risk of stroke compared to those with a low trajectory (OR = 1.27, 95 % CI: 1.02-1.58). In contrast, relative changes in all indices were not associated with stroke risk.

CONCLUSION

Baseline WC and a sustained high WC trajectory are significant predictors of stroke, outperforming other obesity indices. This underscores the critical importance of long-term waist circumference monitoring and management in stroke prevention strategies for middle-aged and older adults.