Trends in Serum Lipid Profiles and Lifestyle Factors Among Korean Adolescents, 2007–2018

Objectives: Trends in serum lipids among teenagers would be crucial predictors of potential cardiovascular disease in adults. We aimed to investigate the trends in lipid profiles and related factors, including obesity, smoking, exercise, alcohol use, and total fat intakes in Korean adolescents from 2007 to 2018. Methods: We analyzed 5,967 participants aged 12–19 yrs from the Korea NHANES 2007–2018. Fasting total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) levels were measured. Results: All kinds of lipid profiles, except TG, showed increasing trends from 2007 to 2018 (P<0.01). Nevertheless, the prevalence of dyslipidemia showed a trend of decreasing in boys (from 33.3 to 26.6%; P=0.002) and maintained in girls (from 28.4 to 30.2%; P=0.465), mainly due to a substantial decrease in hypo-HDL-cholesterolemia (9% reduction in boys, 5% reduction in girls). This occurred amid an increasing trend of central obesity in boys (P<0.001). In lifestyle factors, there were no significant changes in alcohol use and muscle-strengthening exercise, while a substantial decrease in smoking rate was observed. A favorable effect of muscle-strengthening exercise on both TG and HDL-C and an unfavorable impact of smoking on HDL-C were observed. Alcohol use was associated with higher HDL-C in both genders, but it showed opposite associations with TG between boys (unfavorable) and girls (favorable). Regarding dietary factors, there were increasing trends in total fat intakes and the percentage of energy supply from total dietary fat (〔total fat (%E)〕 in both genders. In boys, an increase in total fat (%E) was related to the higher HDL-C in normal-weight subjects (P<0.01 in both genders); however, it was associated with higher LDL-C in overweight girls (P=0.001). Conclusions: Increases in fat intakes and a decline in smoking rates appeared to have positively impacted HDL-C in Korean adolescents over the past 12 years. We confirmed a rise in fat intakes was linked with the increase in LDL-C among overweight adolescents. Therefore, close monitoring for the dyslipidemia prevalence is essential in Korean adolescents whose obesity prevalence is on the rise.