Association between weight-adjusted waist index and cardiometabolic multimorbidity in older adults: Findings from the English Longitudinal Study of Ageing

Abstract

The weight-adjusted waist index (WWI) is a novel anthropometric measure designed to better reflect central obesity than traditional indices such as body mass index and waist circumference (WC). This study examined the prospective association between WWI and cardiometabolic multimorbidity (CMM) and evaluated its predictive utility. We included 3,348 participants (mean age 63 years; 45.1% male) from the English Longitudinal Study of Ageing who were free from hypertension, coronary heart disease, diabetes, and stroke at baseline (wave 4: 2008-2009). WWI was calculated as WC (cm) divided by the square root of body weight (kg). CMM was defined as the presence of ≥ 2 of the following conditions at wave 10 (2021-2023): hypertension, cardiovascular disease, diabetes, or stroke. Multivariable logistic regression and measures of discrimination were used to assess associations and predictive value. Over 15 years, 197 participants developed CMM. Restricted cubic spline analysis indicated a linear dose-response relationship between WWI and CMM risk (p for nonlinearity = .44). Each 1 SD increase in WWI was associated with higher odds of CMM (odds ratio, OR = 1.30; 95% CI: 1.12-1.51), persisting after adjustment for physical activity (OR = 1.28; 95% CI: 1.10-1.49). Similar associations were observed across WWI tertiles. Adding WWI to conventional risk models slightly improved discrimination (ΔC-index = 0.0065; p = .29), with a significant improvement in model fit (-2 log likelihood, p = .001). Higher WWI levels were independently and linearly associated with increased CMM risk in older adults. WWI also improved CMM risk prediction beyond conventional risk factors.

Keywords: Cardiometabolic multimorbidity; Cohort study; Visceral adiposity; Weight-adjusted waist index.

Fig. 1

Restricted cubic spline curve of the association between WWI and risk of cardiometabolic multimorbidity. WWI, weight-adjusted waist index. Reference value for WWI is 9.6; dashed lines represent the 95% confidence intervals for the spline model (solid line). The model was adjusted for age, sex, smoking status, alcohol consumption, systolic blood pressure, total cholesterol, high density lipoprotein cholesterol, handgrip strength, and physical activity

Fig. 2

Associations of WWI with cardiometabolic multimorbidity. CI, confidence interval, OR, odds ratio; SD, standard deviation; WWI, weight-adjusted waist index. Model 1: Adjusted for age and sex. Model 2: Model 1 plus smoking status, alcohol consumption, systolic blood pressure, total cholesterol, high density lipoprotein cholesterol, and handgrip strength. Model 3: Model 2 plus physical activity