Hyperlipidemia

Descriptive text is not available for this imageBASICS

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.

  • There are five major lipoprotein families:
    • Chylomicrons
    • Very-low-density lipoproteins (VLDLs)
    • Low-density lipoproteins (LDLs)
    • Intermediate-density lipoproteins (IDLs)
    • 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 cholesterol: <120 mg/dL (borderline, 120 to 144 mg/dL)
      • Non-HDL cholesterol significantly predicts pediatric atherosclerosis and is as powerful as any other lipoprotein cholesterol measure. It can be measured nonfasting and is a good screening tool for dyslipidemia.
    • More detailed age- and gender-specific values are available (refer to Table 2 of 2008 Clinical Report: Lipid Screening and Cardiovascular Health in Childhood).
  • Primary hypercholesterolemia or hypertriglyceridemia: elevation in serum cholesterol or triglyceride from an inherited disorder of lipid metabolism (i.e., familial hypercholesterolemia [FH])
  • Secondary hypercholesterolemia or hypertriglyceridemia: elevation in serum cholesterol or triglyceride from another disease process (e.g., diabetes mellitus)

EPIDEMIOLOGY

Incidence

  • The incidence of FH is increasing worldwide.
  • Small subpopulations around the world have higher incidence rates. In 2018, the incidence in Lebanese Christians was 1/85; in Afrikaners in South Africa, 1/72 to 1/100; in French Canadians, 1/270; and in Ashkenazi Jews originating from Lithuania, 1/67 due to a founder effect.

Prevalence

The prevalence rate of the homozygous state of familial hypertriglyceridemia (FHTG) is 1 in 250,000 and that of the heterozygous state is 1 in 250. Unknown causes result in hypercholesterolemia and/or hypertriglyceridemia in 2% of the population.

RISK FACTORS

Genetics

  • FH: dominantly inherited LDL receptor defect
  • Familial combined hyperlipidemia (FCHL): dominantly inherited polygenic lipid disorder
  • FHTG: autosomal recessive disorder due to lipoprotein lipase defects

GENERAL PREVENTION

  • Universal cholesterol screening is recommended between ages 9 and 11 years and then again between 17 and 21 years via a lipid panel (nonfasting is acceptable) according to the National Heart, Lung, and Blood Institute (NHLBI)/American Academy of Pediatrics (AAP) guidelines.
  • In selective populations with high-risk factors (children with conditions that increase the risk of cardiovascular disease (CVD) +/− family history of premature heart disease), screening should begin as early as 2 years of age.
  • 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 (normal body mass index [BMI] for age)
  • 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, age-appropriate blood pressure (BP)
  • Normal blood glucose (fasting blood glucose ≤100 mg/dL)
  • Being physically active
  • Avoiding the use of and exposure to tobacco products

There's more to see -- the rest of this topic is available only to subscribers.