High Cholesterol in a Child - An Overview

Introduction:

Cholesterol (a fatty substance) is a crucial structural component of the cell membrane. It is essential for steroid hormones, bile acids, and vitamin synthesis. Cholesterol is absorbed from the diet with triglycerides (TGs) or synthesized in the liver. It is transported by lipoproteins (made of fats and proteins) such as chylomicrons, very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL). Abnormal cholesterol, TGs, or lipoprotein levels are called dyslipidemia.

In adults, dyslipidemia increases the risk of heart diseases (also called cardiovascular diseases, CVDs), diabetes mellitus (DM), hypertension, and obesity. Increasing evidence shows that dyslipidemia in children and adolescents is associated with atherosclerosis (narrowing arteries due to cholesterol buildup), premature CVDs, and many other health conditions.

What Is the Normal Level of Cholesterol in Children?

To define dyslipidemia, the normal distribution of lipids and lipoproteins in children must be determined. It is because lipid levels change with growth and maturation. Hence, the average values in children differ from those in adults and vary by age, gender, and ethnicity. For anyone aged 19 or younger, the average cholesterol levels are total cholesterol< 170 milligrams per deciliter (mg/dL), LDL cholesterol< 100mg/dL, and HDL cholesterol> 45 mg/dL.

What Are the Causes of High Cholesterol Levels in a Child?

The following are the two primary causes of dyslipidemia in children and adolescents.

1. Primary Dyslipidemia: Primary dyslipidemia can be caused by a genetic mutation in lipoprotein metabolism. Patients with inherited disorders of dyslipidemia have a family history of premature CVDs. The monogenic conditions (interaction of a single gene with the environment) include familial hypercholesterolemia (FH), familial defective apolipoprotein B, and familial hypertriglyceridemia. In adults, FH is the most frequent monogenic disease associated with CVDs. A polygenic disease is caused by an interaction between multiple genes and the environment. Polygenic conditions include familial combined hyperlipidemia (FCHL) and polygenic hypercholesterolemia. FCHL is the most common primary lipid disorder, occurring in one to two percent of adults. In children, this condition is linked to obesity.

2. Secondary Dyslipidemia: Secondary dyslipidemia can be due to certain conditions, including obesity, type 2 DM, nephrotic syndrome (a kidney disease), hypothyroidism (low thyroid hormone level), liver disease, and medications (corticosteroids, beta-blockers, anti-cancer drugs, and anti-HIV drugs). Increased dietary intake of saturated fats is another pertinent cause of dyslipidemia. One must note that most cases in children are considered secondary dyslipidemia.

What Are the Health Conditions Associated With High Cholesterol Levels in a Child?

1. Vitamin D Metabolism and High Cholesterol: Vitamin D mediates calcium metabolism and bone health. In addition, it is involved in immunity, anti-inflammatory activities, and endocrine function. Vitamin D also mediates calcium absorption in the intestines. Increased intestinal calcium levels inhibit the synthesis and secretion of TGs and reduce the intestinal absorption of fatty acids (FAs). Then, the absorbed calcium decreases cholesterol levels by converting cholesterol into bile acids.

Several mechanisms suggest how vitamin D can affect lipid profiles (a test that measures blood cholesterol). Vitamin D deficiency may affect lipoprotein metabolism, leading to increased TGs and decreased HDL cholesterol levels (also known as good cholesterol). It is well-documented that vitamin D is linked to risk factors such as obesity, high blood pressure, and CVDs.

Studies indicate higher vitamin D levels are linked to a favorable lipid profile in children. Hence, clinicians must advise vitamin D replacement in obese patients with dyslipidemia to improve their lipid profiles. Also, instead of lifestyle modifications such as weight reduction, exercise, or diet changes, clinicians should be cautious about using vitamin D supplementation when dealing with obese children.

2. Respiratory Diseases and High Cholesterol: Cholesterol has an intricate effect at the cell level, favoring inflammation. The dysregulation of cholesterol in airway smooth muscle cells can aid in the disease mechanism of asthma. Dyslipidemia may activate immunity that amplifies inflammation in the respiratory tract and subsequently increase muscle tone, airway inflammation, and hyperreactivity (mechanisms in asthma).

Several studies have detailed the positive association between obesity and asthma in children. In the obesity–asthma link, dyslipidemia is a possible contributing factor to the development of “obese asthma.” In other words, obesity is linked with dyslipidemia, compromising respiratory function. However, more research regarding dietary intake, glucose metabolism, infection, and body fat is required linking respiratory inflammation and dyslipidemia.

3. Behavioral Health Problems and High Cholesterol: Increasing evidence supports the association between behavioral health problems and lipid levels. Cholesterol is essential to myelin formation and nerve cell function in the central nervous system (CNS). As a result, high cholesterol levels can cause serotonin (a hormone that regulates mood, sleep, and digestion) transmission dysfunction. It is also implicated in the disease mechanisms of psychiatric illnesses such as mood disorders. Several studies have reported the association between lipid profiles and depression and suicide attempts in children.

How Is High Cholesterol in a Child Managed?

Treatment of high cholesterol levels in children is similar to those in adults as it involves lifestyle interventions and pharmacologic therapy (medications). However, lifestyle modification is the primary intervention for high cholesterol in children and adolescents. These include:

1. Increased Physical Activity: It includes regular exercise and reducing stationary time (in front of a television, computer, or phone).

2. Healthy Eating: A diet to decrease cholesterol levels includes limiting foods high in saturated fat, sugar, and trans fat. A child must also eat plenty of fresh fruits, vegetables, and whole grains.

3. Weight Loss: Losing weight is of utmost importance if the child is overweight or has obesity.

However, these lifestyle changes are sometimes not enough to lower the child’s cholesterol level. The clinician may provide medication in some cases, such as:

1. When the child is ten years old.

2. Has an LDL (bad) cholesterol level> 190 mg/dL (after six months of diet modification and exercise).

3. Has an LDL cholesterol level> 160 mg/dL and is at high risk for CVD.

4. Has primary dyslipidemia.

The American Heart Association (AHA) recommends the use of Statins (Lovastatin, Simvastatin, Fluvastatin, Atorvastatin, and Rosuvastatin) in children less than ten years. Statins are also effective at reducing disease and death rates in CVD patients. These medications result in beneficial cholesterol reductions of about 20 to 50 percent. Due to their efficacy in adults, statins are one of the first-line medications in children with dyslipidemia.

Conclusion:

A high cholesterol level in a child might be associated with low vitamin D levels, asthma, and behavioral health problems such as depression and suicidal thoughts. Various studies provide evidence to increase the understanding of the impact of childhood lipid profiles. However, further large-scale studies are required for effective screening, treatment, and preventive strategies for related health problems among children and adolescents.