[Survey on the levels of lipids in school-aged children of Beijing, Tianjin, Hangzhou, Shanghai, Chongqing and Nanning cities].

OBJECTIVE

To investigate the lipid levels of Han ethnicity Chinese children at school-age, to provide objective data for the formulation of prevention and management strategy regarding dyslipidemia among children and adolescents.

METHODS

20 191 children (with 10 669 boys and 9522 girls) aged 7 to 16 years old from 6 representative geographical areas, including Beijing, Tianjin, Hangzhou, Shanghai, Chongqing and Nanning, were surveyed in a randomly selected clustered sample in China. Data on fasting blood triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) levels were measured. Non-high-density lipoprotein cholesterol (non-HDL-C) levels were calculated with data collection, entry, and collation were under the same criteria.

RESULTS

(1) In the 7 - 16 year-old group, TG (P(95)) fluctuated between 1.26 mmol/L and 1.88 mmol/L, while TC (P(95)) was between 4.80 mmol/L and 5.46 mmol/L. LDL-C (P(95)) was between 2.67 mmol/L and 3.27 mmol/L while non-HDL-C (P(95)) was between 3.36 mmol/L and 3.91 mmol/L, suggesting that age did not seem to be an affecting factor for the lipid level (P > 0.05). The level of HDL-C (P(5)) fluctuated between 1.08 mmol/L and 0.83 mmol/L, and the dependability analysis on HDL-C and age showed statistically significant difference (P < 0.01, r = -0.274). (2) In the 7 - 9 year-old group, the levels of TG, TC, LDL-C and non-HDL-C of boys were lower but the HDL-C level was higher than in girls. However, in the 10-16 year-old group, the levels of five lipids of boys were all lower than in girls, with all the differences statistically significant (P < 0.05). (3) The levels of TG, TC, LDL-C and non-HDL-C in the obese group were significantly higher than those in non-obesity group, as HDL-C was significantly lower than in non-obese group (P < 0.01). Incidence rates of single and multiple dyslipidemia in obese group were significantly higher than in non-obese group (P < 0.01). (4) Grouped by region, the abnormal rates of TG were descending, with the ranking as North (10.4%), Midwest (9.7%) and East (8.3%), while the abnormal rates of TC were descending with the ranking as Midwest (6.0%), North (5.2%) and East (4.8%). The abnormal rates of LDL-C were descending as the ranking of North (3.1%), East (2.6%) and Midwest (0.9%), with the abnormal rates of non-HDL-C were descending as Midwest (6.5%), North (4.2%) and East (3.6%). The abnormal rates of HDL-C were descending as Midwess (14.2%), North (5.7%) and East (5.5%). All the differences in the above-said items were statistically significant (P < 0.05). (5) According to the standards of hyperlipidemia formulated by the American Academy of Pediatrics, the incidence rates of abnormal TG, TC, LDL-C, non-HDL-C, HDL-C were 9.4%, 5.4%, 2.2%, 4.8%, 8.6% respectively.

CONCLUSION

(1) Levels of lipids were affected by many factors, but age was not one of them in children and adolescents. However, HDL-C was declining along with the increase of age, to some extent. (2) Girls had a relatively protective tendency through the increasing HDL-C level when they entered the puberty years. (3) Lipids levels in non-obese group were significantly better than the obese group. (4) The lipids levels of children and adolescents in the Eastern region of the country were better than that in the northern and mid-western areas.