Association Between the Korean Healthy Eating Index and High-Sensitivity C-Reactive Protein: A Nationally Representative Study in South Korea, 2022–2024

Background: Maintaining favorable dietary quality may play an important role in disease prevention, and the mitigation of inflammation is considered a key mechanism. Although the association between dietary quality and inflammation has been reported, evidence from South Korea remains limited. Therefore, this study examined the association between the Korean Healthy Eating Index (KHEI) and high-sensitivity C-reactive protein (hs-CRP) levels. Methods: We analyzed a nationally representative sample of 14,050 adults in South Korea. The 14-item KHEI was measured on a scale of 0 to 100, with higher scores indicating better dietary quality, and was categorized into quartiles (Q1–Q4). Serum hs-CRP levels (mg/L) were categorized into low (<1), intermediate (1–<3), and high (≥3) categories. Multinomial logistic regressions were employed to determine the association of KHEI with hs-CRP levels, with the low hs-CRP group as the reference category. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated. Results: In the overall sample, 74.47%, 18.75%, and 6.78% of participants were classified as having low, intermediate, and high hs-CRP levels, respectively. Compared with the lowest KHEI quartile (Q1), participants in Q2, Q3, and Q4 had adjusted ORs (95% CIs) of 0.98 (0.85–1.14), 0.91 (0.78–1.05), and 0.75 (0.64–0.87), respectively, for intermediate hs-CRP levels. For high hs-CRP levels, participants in Q2, Q3, and Q4 had ORs (95% CIs) of 0.81 (0.65–1.01), 0.74 (0.58–0.93), and 0.68 (0.53–0.87), respectively, compared with Q1. Conclusions: Higher KHEI scores was associated with lower odds of having high hs-CRP levels. Prospective studies are needed to analyze the temporal relationship.