Overall lipid profiles have improved among children and adolescents in the United States since the late 1980s, although they still fall well short of public health goals, according to a report in the Aug. 8 issue of JAMA.
In what researchers described as the first study to track serum lipid concentrations in a nationally representative sample over more than 2 decades, youths aged 6-19 years showed significant declines in total cholesterol and non-HDL cholesterol accompanied by rises in HDL cholesterol; adolescents also showed decreases in triglycerides, said Dr. Brian K. Kit of the National Center for Health Statistics, Hyattsville, Md., and his associates.
These changes "are comparable to those reported among U.S. adults during a similar time frame," they noted.
Dr. Kit and his colleagues assessed time trends in serum lipid concentrations, comparing data from the National Health and Nutrition Examination Surveys (NHANES) for 1988-1994 with data from the 2007-2010 NHANES of 16,116 youths. For these surveys, cholesterol levels were measured in subjects aged 6-19 years and triglycerides were measured in those aged 12-19 years.
The overall study population showed a 5-mg/dL decrease in mean serum total cholesterol over time, from 165 mg/dL to 160 mg/dL, and a concomitant rise in mean serum HDL cholesterol from 50.5 mg/dL to 52.2 mg/dL. Mean serum non-HDL cholesterol dropped 8 mg/dL, from 115 mg/dL to 107 mg/dL.
"Generally, the sex-, age-, and race/ethnicity-specific trends ... were similar in direction to the overall trends and consistent with a favorable trend, although for each group the magnitude was not the same and the trend was not always significant," the investigators said (JAMA 2012;308:591-600).
For example, Mexican-American children of both sexes and black girls and adolescents did not show significant increases in HDL cholesterol.
Adolescents as a whole also showed a 9-mg/dL decline in mean serum triglycerides over time, from 82 mg/dL to 73 mg/dL. But again, there were some exceptions in specific age, gender, and race/ethnicity subgroups. For example, Mexican-American boys and adolescents showed no increase or decrease in triglyceride concentration between the late 1980s and 2010.
The subgroup of obese children and adolescents showed similar significant declines in total cholesterol and non-HDL cholesterol, compared with the overall study population, but their increases in HDL cholesterol did not reach significance. Their overall improvement was encouraging, given the marked increase in childhood obesity that occurred in the United States during the study period, Dr. Kit and his associates said.
In accordance with the main finding of this study, the prevalence of elevated total cholesterol decreased from 11.3% to 8.1% and that of non-HDL cholesterol dropped from 13.6% to 10% during the study period.
This study was funded by the Heart, Lung, and Blood Institute. No financial conflicts of interest were reported.