Study on the reference values of serum lipids in children aged 3-18 years old in Beijing, China.

Background: The present study was designed to explore the reference values of serum lipids in children in Beijing.
Methods: A total of 1071 healthy children from Beijing between 3 and 18 years of age were enrolled and divided into four groups: A, 3-5-year-old group; B, 6-9-year-old group; C, 10-14-year-old group; and D, 15-18-year-old group. Blood samples were obtained from the cubital veins of the participants under a fasting condition. A Hitachi 7600 Automatic Biochemistry Analyzer was used to determine the serum levels. The cut-off points of reference values were the 75th and 95th percentiles for total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) while the 25th and 5th percentiles were used for high-density lipoprotein cholesterol (HDL-C) concentrations.
Results: The highest 95th percentiles of TC among the four groups were 5.34 mmol/L for boys and 5.11 mmol/L for girls. Compared with those of boys, female TG levels were obviously higher in the 10-14-year-old group (P < 0.05) and HDL-C levels were significantly higher in the 15-18-year-old group (P < 0.05). The serum TC, HDL-C, and LDL-C all peaked during the 6-9-year-old period and then declined during the adolescent stage. Also, the serum TG continuously increased with a relative plateau during the 6-14-year-old period. Obese and overweight children had higher TG and LDL-C levels but lower HDL-C levels.
Conclusion: This study showed a picture of the serum lipids distribution in Chinese children and found that their TC levels were lower than those of children in Japan, Iran, and France, but were higher than those of Italian children.