In 2011, the National Institutes of Health released guidelines for cardiovascular health and risk reduction in children and adolescents. Compiled by an expert panel, these guidelines focused on several well-known risk factors for cardiovascular disease. Perhaps the most eye-opening and controversial of their recommendations is the universal screening of lipids and lipoproteins for children aged 9-11 years.
It is well known that atherosclerosis, the basis for cardiovascular disease (CVD), begins in youth, and that elevated cholesterol levels are a risk factor for the development of atherosclerosis. Children with homozygous hypercholesterolemia have coronary events beginning in the first decade of life. Similarly, roughly 50% of men and 25% of women with heterozygous hypercholesterolemia experience coronary events by age 50 years. These patients commonly have total cholesterol (TC) levels in excess of 250 mg/dL beginning in infancy.
By Dr. Ryan Schroeder and Dr. Neil Skolnik
The rise in obesity has seen an escalation in a new dyslipidemic pattern: one with a moderate to severe increase in triglyceride (TG) level, normal to mild elevation in LDL cholesterol (LDL-C) level, and a reduced HDL cholesterol (HDL-C) level. This pattern has been associated with initiation and progression of atherosclerosis in children and adolescents.
As more data have demonstrated the correlation of abnormal lipid levels in children with development of atherosclerosis, as well as the reduction of CVD risk with early identification and treatment of patients with dyslipidemia, the NIH revised its recommendations on lipid assessment and treatment in children and adolescents.
Lipid Assessment
Studies have shown that pediatric lipid screening based solely on family history of premature CVD or cholesterol disorders misses 30%-60% of children with dyslipidemias. This shortcoming of risk factor assessment supports the need for universal screening in children. Because TC and LDL-C levels decrease as much as 10%-20% during puberty, the ages of 9-11 years are a stable time to initiate screening, as most children will not have begun puberty during this age range.
Screening can be completed by obtaining either a fasting lipid profile (FLP) or non-FLP. Non–HDL-C is more predictive of persistent dyslipidemia than is TC or LDL-C, and can be accurately calculated in a nonfasting state, so is a practical screening tool. When the non–HDL-C level equals 145, then two FLPs should be obtained, at least 2 weeks apart but within 3 months of each other. These results should then be averaged to determine appropriate management.
If an FLP is obtained first, then a second should be obtained only if LDL-C equals 130, non–HDL-C equals 145, HDL-C is less than 40, or TG equals 100. These results should again be averaged. Universal screening should be repeated once again, according to the methods above, between the ages of 17 and 21 years, with age-appropriate cutoffs for lipid levels. There is no role for measuring apolipoprotein B, apolipoprotein A-I, or lipoprotein(a) levels in routine screening.
Routine screening is not recommended for children aged 0-2 years. Screening for children aged 2-8 years and 12-16 years should be based on family history of premature CVD or cholesterol disorders; presence of diabetes mellitus; hypertension; elevated body mass index; smoking history; or presence of certain moderate- or high-risk medical conditions such as chronic kidney disease, Kawasaki disease, or HIV infection.
Dietary Management
As with adult patients, the management of dyslipidemias in children should always include dietary and lifestyle modifications. A diet with total fat at 25%-30% of calories, saturated fat less than 10% of calories, and cholesterol at less than 300 mg/day has been shown to reduce TC and LDL-C levels in healthy children. This diet, named the CHILD-1 (Cardiovascular Health Integrated Lifestyle Diet), should be instituted in all children with a positive family history of early CVD, dyslipidemia, obesity, primary hypertension, diabetes, or exposure to smoking, and should be the initial diet utilized when a childhood lipid disorder is identified.
If after 3 months lipid levels have not reached therapeutic goals (see below), then lipid parameter–specific diet and lifestyle changes should be used, such as those outlined in the CHILD-2-LDL or CHILD-2-TG regimens. These diets should be implemented under the guidance of a registered dietitian.
Medical Therapy
When dietary and lifestyle modifications fail to decrease lipid levels to goal (defined as LDL less than the 95th percentile), or when LDL-C or TG is significantly elevated (equal to 250 or 500 mg/dL, respectively), treatment with a lipid-lowering medication should be considered. Treatment is generally avoided in children younger than age 10 years unless they have a severe primary hyperlipidemia or a high-risk condition.
Studies have documented the safety and efficacy of bile acid sequestrants, as well as HMG CoA (hydroxymethyl glutaryl coenzyme A) reductase inhibitors, or statins, for the treatment of dyslipidemias in children. Statins are commonly used first line, and they have not been shown to have any ill effect on growth, development, or sexual maturation. As with adults, children should be monitored for increases in liver transaminases and development of myopathy.