Cardiovascular Risk Associated With General and Abdominal Obesity in Young Adults Without Traditional Risk Factors: A Korean Nationwide Cohort Study.

Abstract

Objective: Body mass index (BMI) is widely used to classify obesity but does not adequately characterize central adiposity. Waist-to-height ratio (WHtR) is a simple anthropometric marker of central obesity that may detect cardiovascular risk not captured by BMI. This study examined whether WHtR provides prognostic information beyond BMI for cardiovascular risk stratification in young adults.

Methods: We analyzed 1,743,968 adults aged 30-39 years who underwent health screening through the 2009 Korean National Health Insurance Service program. Participants were classified into four groups according to BMI and WHtR: BMI <25 kg/m² and WHtR <0.5; BMI ≥25 kg/m² and WHtR <0.5; BMI <25 kg/m² and WHtR ≥0.5; and BMI ≥25 kg/m² and WHtR ≥0.5. The primary endpoint was a composite of myocardial infarction (MI), stroke, and cardiovascular death. Multivariable Cox proportional hazards models were used to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs).

Results: During a median follow-up of 14.2 years, 37,120 participants (2.12%) experienced the composite outcome. After multivariable adjustment, participants with normal BMI but elevated WHtR (Group 3) had an increased risk compared with Group 1 (aHR, 1.171; 95% CI, 1.118-1.226), with a slightly higher point estimate than Group 2. A similar pattern was observed for MI, whereas stroke risk was more strongly associated with elevated BMI.

Conclusion: Elevated WHtR was associated with increased risk of MI and the composite outcome among young adults with normal BMI. WHtR may provide information complementary to BMI for early cardiovascular risk stratification.