Almost everyone knows that the build-up of cholesterol in the arteries is harmful for the heart. But what many don’t know is that this build-up can occur anywhere in the body and might lead to lower limb gangrene and kidney damage in addition to heart attack and stroke, collectively referred to as CVD (cardiovascular disease) by doctors. CVD has a number of risk factors, most important of which are diabetes, high blood pressure (BP), smoking and abnormal lipid levels or ‘dyslipidemia’.
Lipids are types of fats in the body. The two main forms are cholesterol and triglycerides. Both travel in the blood in the form of lipoproteins, which are of three types: low-density lipoprotein (LDL) which carries 60-70 per cent of the total blood cholesterol; high-density lipoprotein (HDL) which carries 20-30 per cent of the total blood cholesterol and very low-density lipoprotein (VLDL), which is rich in triglyceride and carries 10-15 per cent of the blood cholesterol. Any imbalance or abnormality in their levels is known as dyslipidemia.
Although dyslipidemia can occur because of genetic causes, it is more often due to lifestyle factors such as diabetes, smoking, a sedentary lifestyle and obesity. Certain medicines (steroids and some hormones) and disease conditions (thyroid problems) can also cause dyslipidemia.
LDL, better known as the ‘bad cholesterol’, is the most important lipid element responsible for cholesterol build up. At any given LDL level, every 1 mg/dl increase leads to a one per cent increase in heart attack risk. Although, there is no ‘normal’ range of LDL, the risk of heart attacks increases particularly rapidly when the LDL levels increase above 100 mg/dl. However, more recent data suggests that among those with a heightened risk of heart attacks and strokes (such as those already having heart disease), it is good to have even lower levels i.e. less than 70 mg/dl of LDL.
It is better to start lowering LDL levels at a younger age. For example, a 10 mg/dl reduction in LDL level at the age of 40 is likely to reduce the life-time risk of heart attacks by 50 per cent whereas the same reduction achieved at 70 years will lead to only 20 per cent reduction. LDL levels as low as less than 40 mg/dl have been shown to be safe, and even beneficial to some patients with a history of heart attacks.
HDL, better known as ‘good cholesterol’, removes cholesterol from blood vessels and returns it to liver where it is broken down. Thus, HDL appears to protect against the development of atherosclerosis. A low level of HDL has been consistently shown to be associated with an increased risk of CVD and seems to be a stronger reason for heart attacks than increased LDL. Ideally, the HDL levels should be maintained above 40 mg/dl in men and above 50 mg/dl in women.
Increased triglyceride levels point only towards coming cardiovascular risk, rather than being the cause of CVD itself. However, newer evidence has clearly shown that raised triglyceride levels on their own also increase the risk of heart attacks. A triglyceride level of less than 150 mg/dl is considered ideal.
Dyslipidemia can be managed in simple ways, like being active, balancing your calorie intake and expenditure. Manage your weight, stop smoking and take precautions if you are a diabetic. As always, your doctor is the best judge to monitor your condition.