We ask the experts to settle
common questions we have
all wondered about.
In U.S. publications, cholesterol readings are measured in milligrams/decilitre, but in Canada the readings are in numbers. For example, in the U.S. high cholesterol is defined as a total reading of 240 mg/dl, but in Canada we talk about high cholesterol as a total reading of 7 or 8. How does one compare these readings? And what is a healthy level of cholesterol?
That's correct - American and Canadian health-care systems use different units to measure cholesterol. In Canada, the number is actually in millimoles/litre, which is from the International System of Units. The American units can easily be translated into the Canadian measurement using online conversion tables available on websites such as http://www.onlineconversion.com/cholesterol.htm. To avoid confusion, I recommend, when possible, to refer to only Canadian websites about cholesterol.
It is also important, especially if you surf the Internet for health information, to understand that there is not just one desirable level of cholesterol for everyone. In other words, it depends on your own circumstances.
Cholesterol is one of the major risk factors of heart disease. Your family physician will assess all the factors that may affect your risk to determine your individual cholesterol targets. In addition to one's cholesterol readings, doctors will also consider blood pressure and smoking status. The doctor will plug these risk factors into the Framingham calculator - a risk stratification tool commonly used by physicians and recommended by the Canadian Cardiovascular Society based on research evidence. This calculation, in conjunction with other factors such as diabetes diagnosis and family history, determines whether an individual's 10-year risk of heart disease is low, intermediate or high.
Based on this assessment, your physician will help to reduce your risk of heart disease by setting your ideal target cholesterol readings - bad cholesterol as well as the ratio of total cholesterol to HDL (high-density lipoprotein, also referred to as good cholesterol).
Low-density lipoprotein (LDL) is the bad cholesterol and too much can build up plaque in the walls of the arteries that feed the heart and brain. This increases the risk of a heart attack or stroke.
HDL, the good cholesterol, works to clear the arteries of LDL. Exercise is the most efficient and reliable means to build up your HDL. My general heart-health advice is to aim for a low level of LDL and an increased level of HDL.
Now, for the specifics: If you are at high risk of heart disease, the target LDL is less than 2 and the target ratio of total cholesterol to HDL is less than 4. For an individual at intermediate risk, it is recommended to have a LDL reading of less than 3.5 and a ratio of less than 5. And if you are at low risk, aim for a LDL reading below 5 and a ratio of less than 6.
Your cholesterol level, unlike your family history, is a heart-disease-risk factor you can control through lifestyle changes. You don't have to do it alone. Your family doctor can help to tailor a plan to meet your cholesterol targets. Plans differ from patient to patient, but the common theme is a healthy diet and regular exercise. A good rule of thumb is to incorporate foods into your diet that are low in fat and high in fibre, with a focus on fruits, vegetables and omega-3 fatty acids.
As well, make 150 minutes of cardiovascular exercise part of your routine each week.
In certain cases, doctors will also recommend medications to help bring cholesterol levels to the desirable targets.
The Canadian Cardiovascular Society suggests that men over 40 and women over 50 have their cholesterol profile measured every one to three years.
Nayana Suchak is a family physician at the Granovsky Gluskin Family Medicine Centre at Mount Sinai Hospital in Toronto.