Association of dietary lipid intake with low-density lipoprotein cholesterol levels: analysis of two independent population-based studies.

PURPOSE: Serum low-density lipoprotein cholesterol (LDL-C) concentration is associated with the risk of cardiovascular disease. However, whether cholesterol and fat intake independently affect serum LDL-C levels remains controversial. We aimed to explore the differential effects of dietary cholesterol and fats on blood lipid profiles according to the presence of dyslipidemia. METHODS: A cross-sectional study was conducted based on data from the sixth Korean National Health and Nutrition Examination Survey (2013-2015), and a prospective cohort study was conducted using data from the Korean Genome Epidemiology Study. The analyses used data from 10,068 adults and from 9652 adults, respectively. Adjusted mean values of blood lipids were calculated according to cholesterol and fat intake using analysis of covariance. A repeated-measures covariance pattern linear mixed model with unstructured covariance within participants was used to examine longitudinal associations between cholesterol intake and serum concentrations of total cholesterol and LDL-C. Substitutional analysis was conducted to estimate carbohydrate substitution with saturated fat or unsaturated fat. RESULTS: Serum LDL-C level was significantly higher in dyslipidemic subjects who consumed more than 300 mg cholesterol per day than in those who consumed less than 300 mg cholesterol per day. At a mean 9-year follow-up, levels of total cholesterol and LDL-C were significantly higher in dyslipidemic individuals with higher baseline cholesterol intake after adjustment for potential confounders. In regard to dietary fats, replacing carbohydrate with unsaturated fat was associated with lower level of LDL-C in subjects with dyslipidemia. CONCLUSIONS: Serum LDL-C is associated with the intake of dietary cholesterol, especially in individuals with dyslipidemia.