Trends in HDL Cholesterol and Their Association with Dietary Carbohydrate Reduction Among Korean Adults: A Serial Cross-Sectional Trend Analysis Using KNHANES 2014–2023

Purpose: Low HDL cholesterol (HDL-C) is a common lipid abnormality among East Asian populations, including Koreans, and is closely associated with increased cardiovascular disease risk. This has traditionally been linked to high-carbohydrate dietary patterns. Therefore, it is essential to assess how recent changes in dietary and lifestyle habits in Korea have influenced HDL-C levels. Methods: This study utilized data from the Korea National Health and Nutrition Examination Survey (KNHANES), conducted from 2014 to 2023. Using a complex sampling method, we analyzed annual trends in carbohydrate intake and HDL-C levels in Korean adults (aged 20–59 years), stratified by gender (male and female) and age (20–39 and 40–59 years), and identified determinants such as demographic factors, health behaviors, and dietary intake. Results: The primary factor in the increase in HDL-C levels was a reduction in carbohydrate intake. When analyzed by age and gender, this significant upward trend in HDL-C levels was consistently observed across all four groups: young men, middle-aged men, young women, and middle-aged women. However, the increase in obesity, indicated by increased BMI and waist circumference, had a negative impact on the improvement in HDL-C levels. The recent improvement in HDL-C levels in Korean adults can be attributed to the successful national dietary policy (reducing carbohydrate intake and increasing healthy fat intake). Conclusions: Public health policies should thus continue emphasizing healthy dietary practices, strengthening smoking cessation initiatives, and managing obesity. These findings suggest similar dietary and lifestyle interventions could effectively reduce cardiovascular disease risk in other Asian populations undergoing comparable dietary transitions.