The “Journal of the American Medical Association” has issued an impressive report card the children of the U.S.A. Recent researchers reveals that cholesterol levels have improved among children and teens over the past two decades, despite rising obesity rates during the same period according to the “Center for Disease Control and Prevention.”
The study, which analyzed blood samples collected from more than 16,000 young people from 1988 to 2010, found that about 8 percent of participants aged 6 to 19 had high total cholesterol levels in 2010 compared with more than 11 percent who had elevated cholesterol at the beginning of the study. Researchers also found a corresponding rise in “good” HDL cholesterol levels and a decrease in levels of harmful triglycerides, another component of cholesterol that’s often tied to excess sugar consumption.
Scientists said they weren’t sure what had led to the encouraging changes reported Tuesday in the Journal of the American Medical Assn. Use of cholesterol-lowering drugs remains rare among children, they noted. Their best guess is that some environmental factor — perhaps lifestyle changes — may be driving down cholesterol, and several surmised that the improvements were rooted in reduced rates of smoking and the success of campaigns to lower fat and cholesterol in the diet.
The findings “cannot be interpreted as anything but good news,” said Dr. Rae-Ellen Kavey, a specialist in children and cholesterol at the University of Rochester in New York. Kavey acknowledged that she found some of the changes inexplicable, but said she did not question their significance, since improvements were seen in kids of all ages, ethnic backgrounds and even among children who were already obese.
“It’s important to remember that cholesterol levels are impacted by a variety of factors, besides physical activity and obesity,” added Kit.
While cholesterol-lowering medications such as statins have probably contributed to improvements in adult cholesterol levels, very few children are taking these drugs.
Some factors that may be contributing to improved cholesterol levels? Parents and teens are smoking less than they were two decades ago, and this may have led to an overall rise in HDL, said Dr. Sarah de Ferranti, director of preventive cardiology at Boston Children’s Hospital who wrote an editorial that accompanied the study.
Still, the findings may temper a tide of gloom over the prognosis for the nation’s youths, whose obesity rate has tripled over the last three decades. A recent projection by the American Heart Assn.estimated that the increase would translate into a 16.6% rise in heart attacks by 2030.
Given the high rates of obesity and diabetes among children and their well-chronicled sedentary behavior, it is unlikely that children are adopting heart-healthy habits, De Ferranti added. More plausibly, she said, what has improved is the nutritional profile of foods that children are offered at school and home or that they can easily buy for themselves.
And starting in 2003, a public health campaign ultimately led to the removal of most trans-fatty acids — which raise heart risk even more than saturated fats — from packaged foods sold in the United States. From 2000 to 2009, the level of trans-fatty acids in the average middle-aged American’s bloodstream had plummeted 58%, according to a February report in the Journal of the American Medical Assn.
But De Ferranti cautioned that the changes in foods on the American market could have a dark side: In reducing saturated fat and removing trans fats, many manufacturers have pumped up the sugar and carbohydrate content. That may help explain why obesity among children and adults continued to grow through much of the study period, even as cholesterol readings improved.
Though complex, cholesterol measures have become one of medicine’s strongest predictors of a person’s risk of cardiovascular disease. Researchers have long linked obesity to rising levels of dangerous cholesterol and an increased likelihood of heart attacks and strokes.
“We need to dig down to better understand the reasons for the decline,” said de Ferranti. “It doesn’t mean we’ve solved the cholesterol problem in kids, but we need to think of other ways to shift their eating patterns and physical activity levels to improve cholesterol even more.”
De Ferranti suggested that by understanding the caused for decline it might help guide health policymakers in the future.
She also said that studies like these help researchers understand which kind of interventions have the greatest impact.
D. Chandler Contributed to this article