Cholesterol Levels Appear to Improve Among U.S. Youths

By CnAgri2012-08-10 19:51:13 Print

In a study involving more than 16,000 U.S. children and adolescents, there has been a decrease in average total cholesterol levels over the past 2 decades, although almost 1 in 10 had elevated total cholesterol in 2007-2010, according to a study in JAMA.

"The process of atherosclerosis begins during childhood and is associated with adverse serum lipid concentrations including high concentrations of low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), and triglycerides, and low concentrations of high-density lipoprotein cholesterol (HDL-C). Serum lipid concentrations in childhood are associated with serum lipid concentrations in adulthood," according to background information in the article. "For more than 20 years, primary prevention of coronary heart disease has included strategies intended to improve overall serum lipid concentrations among youths."

Brian K. Kit, M.D., M.P.H., of the Centers for Disease Control and Prevention, Hyattsville, Md., and colleagues conducted a study to examine the trends in serum lipid concentrations among children and adolescents in the U.S. The study included data on 16,116 youths ages 6 to 19 years who participated in the nationally representative National Health and Nutrition Examination Survey (NHANES) during 3 time periods: 1988-1994,1999-2002, and 2007-2010. Among the measures analyzed for all the participants were average serum total cholesterol (TC), non-HDL-C, HDL-C; and among adolescents only (ages 12-19 years), LDL-C and geometric average triglyceride levels. Trends in adverse lipid concentrations were reported for TC levels of 200 mg/dL and greater, non-HDL-C levels of 145 mg/dL and greater, HDL-C levels of less than 40 mg/dL, LDL-C levels of 130 mg/dL and greater, and triglyceride levels of 130 mg/dL and greater.

The researchers found that among youths ages 6 to 19 years between 1988-1994 and 2007-2010, there was a decrease in average serum TC from 165 mg/dL to 160 mg/dL and an increase in average serum HDL-C from 50.5 mg/dL to 52.2 mg/dL. There was also a decrease in the average serum non-HDL-C levels during this time period. "Generally, the sex-, age-, and race/ethnicity-specific trends for TC, HDL-C, and non-HDL-C 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 authors write.

Between 1988-1994 and 2007-2010, there was a decrease in prevalence among youths ages 6 to 19 years of elevated TC from 11.3 percent to 8.1 percent and non-HDL-C from 13.6 percent to 10 percent. Prevalence of low HDL-C was 17.3 percent in 1988-1994 and 14.8 percent in 2007-2010, a nonsignificant decrease. Among adolescents, there was a decrease in prevalence of elevated LDL-C and triglycerides between 1988-1994 and 2007-2010 and a decrease in average serum LDL-C from 95 mg/dL to 90 mg/dL and geometric average serum triglycerides from 82 mg/dL to 73 mg/dL.

In 2007-2010, 22 percent of youths had either a low HDL-C level or high non-HDL-C, which was lower than the 27.2 percent in 1988-1994.

The authors also found that age- and race/ethnicity-adjusted TC was 4.3 mg/dL lower for males and 6.5 mg/dL lower for females in 2007-2010 than in 1988-1994. Males and females who were non-Hispanic black or Mexican American, and also females who were non-Hispanic white had a lower age-adjusted TC in 2007-2010 than in 1988-1994. Age- and race/ethnicity- adjusted HDL-C was higher for males and females in 2007-2010 than in 1988-1994.