What's your cholesterol number?
Widespread measurement of cholesterol levels has provided a major breakthrough in the prevention of coronary heart disease (heart attacks) and strokes. It is well known that lowering elevated cholesterol levels prevents disability and death.
Data from the Framingham Heart Study in the USA showed that people with total cholesterol levels greater than 7.8 mmol/l had a three to five times greater risk of death from heart attack than people with levels less than 5.2 mmol/l. However, people with the same total cholesterol levels can be at very different risks depending on the balance among the different types of cholesterol present.
Screening for cholesterol levels
The total cholesterol in the blood should be tested in all adults older than 20 years at least twice yearly. Total cholesterol can be measured whether you have fasted or not. People with diabetes or diseases of the blood vessels should do a cholesterol profile after a 12-hour fast. This profile provides information on the various types of cholesterol. These include HDL cholesterol (which is called 'good cholesterol' because it scavenges cholesterol in the blood and returns it to the liver) and LDL cholesterol, known as 'bad cholesterol', because it accumulates in the blood vessels, causing blockage.
Signs of high cholesterol
Most people are unaware of their cholesterol status as this is a 'silent disease'. Unfortunately, high cholesterol levels are often not detected until too late, after a stroke or a heart attack. Men who have family members who died at an early age from heart attack should be screened early for total and LDL cholesterol. Men with other risk factors such as hypertension, diabetes, underactive thyroid gland and central obesity ('big belly') are likely to have high cholesterol levels too.
Causes of high cholesterol
High cholesterol levels are more common in men under 55 years than in women of the same age. However, women and men have the same risk after age 55. High levels of cholesterol occur because of genetic factors superimposed on diets high in fats. Elevated LDL cholesterol is caused by greater production of LDL or decreased breakdown of LDL by the liver. Men who eat high levels of saturated fats, trans fats and cholesterol retard the breakdown of LDL. Cholesterol levels generally increase with advancing age. High HDL levels are protective and are promoted by sustained aerobic exercise.
Prevention and treatment
The goals are to lower LDL cholesterol, which blocks heart vessels, and to raise HDL cholesterol, which removes cholesterol, from the blood. This is accomplished by lifestyle measures and taking medication. Lifestyle actions include improved eating patterns with reduction of saturated fat and dietary cholesterol, weight loss where needed, increased physical activity and cessation of smoking. Medications called statins are considered first-line treatment if lifestyle changes are inadequate to lower LDL cholesterol.
Dr Pauline Williams-Green is a family physician and president of the Caribbean College of Family Physicians; email: firstname.lastname@example.org.