Associations of the unhealthy plant-based diet index with hsCRP and BMI in Korean adults.

BACKGROUND: This study investigated the associations of the unhealthy Plant-based Diet Index (uPDI) with high-sensitivity C-reactive protein (hsCRP) and body mass index (BMI) using data from the 2022-2023 Korea National Health and Nutrition Examination Survey. METHODS: The study included adults aged 19-64 years, excluding individuals with implausible energy intake (<500 or >5,000 kcal/day), underweight status, or missing data, resulting in a final sample of 5,610 participants. The uPDI was calculated by summing energy-adjusted, quintile-based scores across 19 predefined food groups. Elevated hsCRP was defined as ≥3 mg/L, and obesity as BMI ≥ 25 kg/m2. Survey-weighted regression analyses were performed after adjustment for demographic and lifestyle covariates. RESULTS: Among women, higher uPDI scores were positively associated with both hsCRP (p < 0.001) and BMI (p < 0.001) in multivariable-adjusted linear regression models. Logistic regression analyses revealed that higher uPDI scores correlated with elevated hsCRP (odds ratio [OR]: 2.043; 95% confidence interval [CI], 1.298-3.217; P-trend = 0.006) and obesity (OR: 1.876; 95% CI, 1.440-2.444; P-trend < 0.001). In contrast, no significant associations were identified in men across any model. CONCLUSION: Greater adherence to an unhealthy plant-based dietary pattern was associated with increased inflammation and adiposity among Korean women. While sensitivity analyses consistently supported these findings, the cross-sectional design means these results indicate associations, not causal relationships.