BACKGROUND: For correct interpretation of the high-density lipoprotein cholesterol (HDL-C) data from the Korea National Health and Nutrition Examination Survey (KNHANES), the values should be comparable to reference values. We aimed to suggest a way to calibrate KNHANES HDL-C data from 2008 to 2015 to the Centers for Disease Control and Prevention (CDC) reference method values. METHODS: We derived three calibration equations based on comparisons between the HDL-C values of the KNHANES laboratory and the CDC reference method values in 2009, 2012, and 2015 using commutable frozen serum samples. The selection of calibration equation for correcting KNHANES HDL-C in each year was determined by the accuracy-based external quality assurance results of the KNHANES laboratory. RESULTS: Significant positive biases of HDL-C values were observed in all years (2.85-9.40%). We created the following calibration equations: standard HDL-C=0.872×[original KNHANES HDL-C]+2.460 for 2008, 2009, and 2010; standard HDL-C=0.952×[original KNHANES HDL-C]+1.096 for 2012, 2013, and 2014; and standard HDL-C=1.01×[original KNHANES HDL-C]-3.172 for 2011 and 2015. We calibrated the biases of KNHANES HDL-C data using the calibration equations. CONCLUSIONS: Since the KNHANES HDL-C values (2008-2015) showed substantial positive biases compared with the CDC reference method values, we suggested using calibration equations to correct KNHANES data from these years. Since the necessity for correcting the biases depends on the characteristics of research topics, each researcher should determine whether to calibrate KNHANES HDL-C data or not for each study.
Algorithms ; Calibration ; Cholesterol, HDL/*blood/standards ; Humans ; *Nutrition Surveys ; Reference Values ; Republic of Korea

OBJECTIVETo assess the relationship between overweight, obesity and blood lipid profiles of children and adolescents and to validate body mass index (BMI) cutoff points for overweight and obesity screening to Chinese children and adolescents, recommended by Working Group of Obesity, China (WGOC), International Life Science Association.

METHODS2293 children and adolescents (1124 males and 1169 females), aged between 10 and 18 years, were randomly selected as samples from 6 schools in Beijing area. Fasting serum lipids including total cholesterol (TC), total triglycerides (TG), high density lipoprotein cholesterol (HDLC), thropometrical index as weight and height were measured. BMI equals to weight in kilograms were then divided by the square of height in meters.

RESULTSAccording to BMI cutoff points recommended by WGOC, samples fell into 3 groups including normal group (BMI < 85 percentiles), overweight group (BMI >or= 85 and < 95 percentiles) and obesity group (BMI >or= 95 percentiles). Results clearly showed an increase of both serum TC and TG and a decrease of HDLC when BMI was increasing, among most age groups regardless of sex difference and the difference among BMI groups was statistically significant (P < 0.05 or P < 0.01).

CONCLUSIONSResults of this study indicated that there was an obvious dose-effect relationship between BMI and lipid profiles which accounted for some rationality of the BMI cutoff points recommended by WGOC. The authors reckoned the findings important to managing relevant adult diseases during childhood, in China.

Adolescent ; Biomarkers ; blood ; Body Mass Index ; Child ; China ; Cholesterol ; blood ; Cholesterol, HDL ; blood ; Female ; Guidelines as Topic ; standards ; Humans ; Lipids ; blood ; Male ; Obesity ; diagnosis ; Reproducibility of Results ; Triglycerides ; blood