Hypercholesterolemia is the presence of excessive cholesterol in the blood. It can be divided in primary and secondary types. Hypercholesterolemia is characterized by elevated serum levels of cholesterol. It is also referred to as dyslipidemia and belongs to the group of hyperlipidemia and hyperlipoproteinemia.
Presentation
In the initials stages, the condition seldom produces any signs and symptoms. However, when the condition remains undiagnosed for a longer duration, then individuals may develop atherosclerosis. Formation of plaques and narrowing of arteries is yet another important marker; and if this goes unnoticed, then individual can also suffer a myocardial infarction or stroke due to diminished blood supply to the heart or brain. These series of events can favor development of tissue ischemia, which is characterized by dizziness, aphasia, paresis, impaired balance and paresthesia.
Familial hypercholesterolemia may present itself with distinct signs and symptoms such as xanthomata, arcus senilis and xanthelasma palpebrarum [6].
Workup
A complete lipid profile to measure the levels of cholesterol helps diagnosing hypercholesterolemia. Total cholesterol greater than 240 mg/dl and LDL cholesterol level between 160 – 189 mg/dl are considered to be high. According to the National Institute of Health, cholesterol level less than 200 mg/dl is considered to be desirable. When the level of total cholesterol exceeds the recommended value of 200mg/dl and HDL cholesterol is below 40 mg/dl then a fasting lipid profile would be indicated.
Treatment
Cholesterol levels should always be normal, and bringing it back to its normal level is the primary goal of treatment. It has been found that with 1% reduction in cholesterol levels, the chance of contracting heart disease decreases by 2%. Several methods are employed to lower the cholesterol levels. These include the following:
- Medications: Statins such as lovastatin, rosuvastatin, pravastatin and atorvastatin are given for lowering the elevated cholesterol. These medications however should not be given to pregnant women. Nicotinic acid is sometimes prescribed for lowering the LDL cholesterol [7] [8]. In addition, cholesterol absorption inhibitors and fibric acid derivatives may also be prescribed.
- Diet therapy: A diet rich in fiber and other nutrients and lower in saturated fats is important for normalizing the cholesterol levels. Along with fiber, β-glucan, soy, omega-3 fatty acids, vitamin C, coenzyme Q10, αclinolenic acid, β sitosterol all help in lowering the cholesterol levels [9].
- Alternative therapy with herbs: Certain herbs such as psyllium, guggul, garlic, hawthorn, extract of olive leaf and red yeast have also shown to have beneficial effects, but for many phytotherapeutic substances further research.
Prognosis
Prognosis of the condition is favorable but greatly depends on the underlying etiology. If hypercholesterolemia remains untreated for long, it can cause several complications such as myocardial infarction, stroke and insulin resistance [5].
Etiology
Interplay of genetic and environmental factors predisposes an individual to develop hypercholesterolemia. Improper dietary habits and obesity are some of the major and common factors that cause the levels of cholesterol to rise beyond normal values. It has been postulated that 50% of non-esterified cholesterol is absorbed by the intestine. However, this varies and it greatly depends on the dietary composition, which is majorly characterized by the percentage of fiber and plant sterols in the food plate. Certain cases of hypercholesterolemia occur due to genetic abnormalities. Familial hypercholesterolemia primarily occurs due to mutations in several genes or a single gene [2].
Hypercholesterolemia can also occur as a secondary accompaniment to various disease conditions such as diabetes mellitus type 2, hypertension, hypothyroidism, nephritic syndrome, Cushing syndrome and anorexia nervosa.
Epidemiology
Familial hypercholesterolemia has a prevalence rate of 1 in 500 individuals. Studies have shown that, middle aged individuals are the most affected by hypercholesterolemia. Several research trials have also pointed towards the fact that with increasing age, the risk of contracting hypercholesterolemia increases. Statistics have revealed that about 34 million Americans suffer from hypercholesterolemia. Men and women are equally affected by this condition.
Pathophysiology
Cholesterol is insoluble in water and therefore requires lipoproteins for the transportation. Lipoproteins are further classified as low density lipoproteins and high density lipoproteins. Both these forms of lipoproteins carry cholesterol, but elevation in the levels of low density lipoproteins carries considerable risk of developing coronary artery disease and atherosclerosis. On the other hand, high levels of high density lipoproteins have a protective effect on the body. Increase in the levels of low density lipoproteins practically occurs due to dietary changes [3].
Diet plays a very important role in maintaining the blood cholesterol levels. A diet that is rich in saturated fats and low in fiber can cause an increase in the cholesterol content. Studies have shown that if about 2 grams of plant sterol is included in our diet on a daily basis, it can significantly reduce the absorption of dietary cholesterol [4].
Prevention
Regular exercise and a healthy diet rich in fibers and other essential nutrients helps in maintaining normal levels of cholesterol. Adopting a healthy lifestyle that demands limiting alcohol consumption and smoking, along with regular exercising can go a long way in prevention of hypercholesterolemia. In addition, men above the age of 35 years and women above 45 years should regularly get their lipid profile checked [10].
Summary
Hypercholesterolemia can pose risk of developing cardiovascular diseases. In instances when high levels of cholesterol circulate in the system, it can get deposited along the arterial walls and form plaques. Development and gradual deposition of plaques can narrow down the arteries, which would eventually prevent sufficient blood flow to the heart, brain and other organs. A secondary phenomenon that accompanies this event is formation of a clot which develops when plaques rupture, obstructing the blood flow giving rise to stroke or myocardial infarction [1].
Patient Information
- Definition: Elevated level of cholesterol beyond 240 mg/dl is defined as hypercholesterolemia. Such a type of condition increases the risk of developing various other conditions.
- Cause: Unhealthy dietary habits, sedentary lifestyle and genetic factors all have a pivotal role in development of hypercholesterolemia. In addition, other secondary disease conditions such as hypertension, diabetes, Cushing syndrome, hypothyroidism, anorexia nervosa and obesity also significantly increase the risk of developing hypercholesterolemia.
- Symptoms: The condition is asymptomatic during the initial stages. As the disease progresses, the signs and symptoms experienced are that of the secondary disease that has set in as a result of untreated elevated levels of cholesterol.
- Diagnosis: Conducting a complete lipid profile is important in determining the lipid levels. When the level of cholesterol is beyond 200 mg/dl, then a fasting lipid profile is suggested.
- Treatment: Modifications in dietary habits and lifestyle factors are important for lowering the cholesterol level. If these do not work, then statins are given for lowering the levels. In addition, nicotinic acid has also been found to be helpful in normalizing the LDL cholesterol.
References
- The Lipid Research Clinics Coronary Primary Prevention Trial results. II. The relationship of reduction in incidence of coronary heart disease to cholesterol lowering. JAMA 1984; 251:365.
- Ueda M. Familial hypercholesterolemia. Mol Genet Metab. Dec 2005;86(4):423-6.
- NICE clinical guideline 67.
- Henkin Y, Shai I, Zuk R, et al. Dietary treatment of hypercholesterolemia: do dietitians do it better? A randomized, controlled trial. Am J Med 2000; 109:549.
- Ford I, Murray H, Packard CJ, et al. Long-term follow-up of the West of Scotland Coronary Prevention Study. N Engl J Med 2007; 357:1477.
- Sibley C, Stone NJ. Familial hypercholesterolemia: a challenge of diagnosis and therapy. Cleve Clin J Med. Jan 2006;73(1):57-64
- Effects of pravastatin in patients with serum total cholesterol levels from 5.2 to 7.8 mmol/liter (200 to 300 mg/dl) plus two additional atherosclerotic risk factors. The Pravastatin Multinational Study Group for Cardiac Risk Patients. Am J Cardiol 1993; 72:1031.
- Ridker PM, Cook NR. Statins: new American guidelines for prevention of cardiovascular disease. Lancet 2013.
- Henkin Y, Shai I, Zuk R, et al. Dietary treatment of hypercholesterolemia: do dietitians do it better? A randomized, controlled trial. Am J Med 2000; 109:549.
- Stefanick ML, Mackey S, Sheehan M, et al. Effects of diet and exercise in men and postmenopausal women with low levels of HDL cholesterol and high levels of LDL cholesterol. N Engl J Med 1998; 339:12.