Hyperlipidemia

Description

Hyperlipidemia is an elevation of serum lipids. These lipids include cholesterol, cholesterol esters (compounds), phospholipids, and triglycerides. Lipids are transported as part of large molecules called lipoproteins.

• Five major families of lipoproteins:
  • Chylomicrons
  • Very-low-density lipoproteins (VLDLs)
  • Intermediate-density lipoproteins (IDLs)
  • Low-density lipoproteins (LDLs)
  • High-density lipoproteins (HDLs)
• Normal serum lipid concentrations:
  • Total cholesterol: 170 mg/dL (borderline, 170 to 199 mg/dL)
  • LDL cholesterol: <110 mg/dL (borderline, 110 to 129 mg/dL)
  • HDL cholesterol: ≥45 mg/dL (low <40 mg/dL)
  • Total triglycerides: 100 mg/dL (borderline, 100 to 140 mg/dL)
  • Non-HDL: <120 mg/dL (borderline, 120 to 144 mg/dL)
    • Non-HDL cholesterol is a significant predictor of the presence of atherosclerosis in children and as powerful as any other lipoprotein cholesterol measure. It can be measured nonfasting and should be added as a screening tool for dyslipidemia.
  • More detailed age- and gender-specific values are available (refer to Table 2 of Lipid Screening and Cardiovascular Health in Childhood).
• Primary hypercholesterolemia or hypertriglyceridemia: elevation in serum cholesterol or triglyceride as a result of an inherited disorder of lipid metabolism (i.e., familial hypercholesterolemia [FH])
• Secondary hypercholesterolemia or hypertriglyceridemia: elevation in serum cholesterol or triglyceride as a result of another disease process (e.g., diabetes mellitus)

Epidemiology

• The prevalence of homozygous FH is 1 in 1,000,000; the prevalence of the heterozygous state is 1 in 500.
• Overall, hypercholesterolemia and/or hypertriglyceridemia of unknown causes occur in 2% of the pediatric population.
• National Health and Nutrition Exam Surveys (NHANES I to III) provide information about normal pediatric serum cholesterol concentrations.
  • For all children 4 to 17 years, the 95th percentile for serum total cholesterol is 216 mg/dL and the 75th percentile is 181 mg/dL.
  • The average total and LDL cholesterol levels before puberty are significantly higher in girls than they are in boys.
  • The mean total cholesterol level for all children from 4 to 11 years old peaks at age 9 to 11 years and then gradually decreases until mid to late adolescence.

Risk Factors

General Prevention

• Fat intake is generally unrestricted prior to 2 years of age. After age 2 years, two complementary approaches are recommended:
  • Diet and lifestyle guidelines to promote:
    • Consumption of an overall healthy diet
    • A healthy body weight (BMI between the 5% and 85% for age and sex, in adults 18.5 to 24.9 kg/m²)
• Recommended lipid levels:
  • LDL cholesterol <110 mg/dL
  • HDL cholesterol >50 mg/dL in women, >40 mg/dL in men
  • Triglycerides <150 mg/dL
• Normal BP (age appropriate)
• Normal blood glucose (fasting blood glucose ≤100 mg/dL)
• Being physically active
• Avoiding use of and exposure to tobacco products