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Cholesterol linked to stroke

Cholesterol linked to stroke

In study of 165 792 individuals from the lancet May 2009, a decrease of 1mmol/l in LDL cholesterol equates to a reduction in relative risk of stroke by 21.1 per cent.

Despite the inconsistent or weak association between cholesterol and stroke, lowering of cholesterol concentrations with statins reduces the risk of stroke in high-risk populations and in patients with non-cardioembolic stroke or transient ischaemic attack. Statin therapy is the most important advance in stroke prevention since the introduction of aspirin and antihypertensive treatments. Meta-analysis of randomised trials of statins in combination with other preventive strategies, including 165 792 individuals, shows that each 1 mmol/L (39 mg/dL) decrease in LDL cholesterol equates to a reduction in relative risk for stroke of 21·1%.

May 2009 – The Lancet Neurology, Vol. 8 No. 5 pp 453-463

The importance of Blood Glucose Testing

Given that chronic damage to many of the body’s organ systems, including the liver and kidneys, can occur during this time, screening for type 2 diabetes should be an effective way to reduce the burden of this disease in the population.

Laboratory tests for diabetes

Understanding your lab tests

Many of the tests you have done at the laboratory can help you to understand where things are at with your diabetes. They can also help you see changes over time and whether the strategies you are using in your diabetes management are working or not.

What tests can be done to find out if I have diabetes?

There are a number of tests that may be done to find out if you have diabetes.

Fasting blood glucose

A fasting blood glucose level is a measure of how much glucose is in your blood when you have not eaten anything for the past eight to ten hours. The test is normally taken first thing in the morning. Your doctor or nurse will ask you to have nothing to eat after you go to bed at night. When you wake up in the morning you visit the laboratory for the test before you have had anything to eat or drink (except water).

A fasting blood glucose level of either 7mmol/L or greater tells you that you have diabetes. If you have no symptoms of diabetes (thirst, tiredness, repeated infections and needing to pass urine often) the test should be repeated on another day.

Fasting blood glucose level is now the recommended test for finding out if you have diabetes. A fasting blood glucose level can tell you other things as well. If your fasting blood glucose level is between 6.1mmol/L and 6.9mmol/L you may have a condition called “impaired fasting glycaemia” (IFG) or pre-diabetes. This means that the level of glucose in your blood after eating nothing overnight is higher than it is in people without pre-diabetes or IFG, but not as high as it is in people who have diabetes.

Most doctors will ask you to have a test called an “Oral Glucose Tolerance Test” (OGTT) if your fasting blood glucose shows that you have IFG. The oral glucose tolerance test may show that you actually have diabetes or “impaired glucose tolerance” (IGT) instead of IFG. If your tests show that you have either IFG or IGT you need to take action to manage these conditions. Having either of these conditions means you are more likely to go on to develop diabetes. You are also at higher risk of developing cardiovascular disease, that is, disease of your heart and blood vessels.

If you have IFG or IGT you should:

Oral Glucose Tolerance Test (OGTT)

An oral glucose tolerance test is a test where you go to the laboratory before eating anything in the morning. A blood glucose level is taken. Then you will be asked to drink a glass of fluid containing 75 grams of glucose (this is a lot!). You stay in the laboratory and another blood glucose level is taken at one hour and two hours after the drink. These blood glucose levels tell you how well your body uses and stores the glucose you have taken in the drink.

You will normally be asked to do an OGTT if your doctor is unsure whether you have diabetes or not. This is normally if your fasting blood glucose is less than 7mmol/L but more than 6.1mmol/L.

Preparing for an OGTTAn OGTT may not be accurate if you have either eaten a very low carbohydrate diet or been having very strenuous exercise in the three days before taking the test. If you are doing either of these things talk to your doctor before having an OGTT.

The most accurate results of an OGTT will be achieved if it is done after you have had a diet with normal amounts of carbohydrate and moderate exercise only over the previous three days.

What do the results of an OGTT mean?
If you are not pregnant and your blood glucose two hours after an OGTT is 11.1mmol/L or more you have diabetes.

Random blood glucose level

If you have the symptoms of diabetes you may be asked to go to the laboratory for a random blood glucose test. This is a blood glucose level taken at any time of the day after you have eaten at any time (i.e. not in a fasting state). If this level is 11.1mmol/L or more, you have diabetes.

What tests do I have to find out how my diabetes management is going?

Managing your diabetes means managing a number of factors in your life. You can get a good idea of how effective this management is by the results of some of the laboratory tests you have done.

Blood (or plasma) glucose level

This measures how much glucose you have in your blood at the time the test is taken. A person without diabetes would nearly always have a blood glucose level somewhere between 4 and 7.5 mmol (a ‘normal’ blood glucose level).

What are healthy levels for a blood glucose series? Everybody will have different target levels depending on lots of individual factors. You and your doctor need to work out what are realistic and safe target levels for you.

A general guide to target levels for a blood glucose series is:

HBA1c level (also called glycosylated haemaglobin level)

This measures your average blood glucose over the past 4 – 6 weeks. It measures how much glucose is stuck onto your red blood cells. Red blood cells have a life span of about 6 weeks and so the test gives a good indication of what your overall blood glucose levels have been through that time.

Most diabetes specialists and GPs have a lot of confidence in this test and will use it to help show you how you are going with your blood glucose management.

HBA1c levels are measured as a percentage. The HBA1c level is not directly equivalent to blood glucose levels. For example, an HBA1c level of 13% means that your average blood glucose for the past 6 weeks has been around 18 – 19 mmol.

What are healthy HBA1c levels?
Once again, target HBA1c levels will vary from person to person. Work out a safe target HBA1c for you with your doctor.

A general range for HBA1c levels is:

Note: If you are taking insulin and your HBA1c level is less than 6.2% this almost certainly indicates that you are having lots of low blood glucose levels. Having HBA1c levels this low is not safe when you are taking insulin.

Why have it checked?

High blood pressure (hypertension) affects nearly one in five Irish people. It is more common in older age groups but it can affect younger people too. You will likely feel no symptoms even if your pressure is quite high, so by the time you feel unwell some damage may have been done. So it is important to have your blood pressure checked regularly, as part of your “Cardiovascular Risk Assessment”.

Why is high blood pressure a problem?

Persistent high blood pressure can cause the heart to enlarge and weaken. It also damages the blood vessels, especially if you also have raised blood cholesterol or diabetes, or if you smoke. If blood vessels become narrowed or blocked, a heart attack or stroke may occur. High blood pressure is also linked to kidney and eye damage and poor circulation in the arteries of the legs.

How is blood pressure measured?

As the heart pumps, it creates pressure inside the blood vessels and moves the blood forward. This is called the systolic pressure. The heart then relaxes while it fills again and the pressure falls. This is called the diastolic pressure. The pressure is measured in millimetres of mercury (mmHg). An ideal blood pressure is often quoted as being about 130 mmHg (systolic pressure) over 80 mmHg (diastolic pressure), or 130/80, but this should be an upper limit for some (eg, people with diabetes).

What is high blood pressure?

High blood pressure means that the systolic or diastolic pressure, or both, are consistently above the range your doctor thinks is healthy for you.

Blood pressure tends to increase with age, however, so a pressure that may be average for a person of 60 or 70 years would be high for someone in their 20s. Blood pressure also rises at certain times, such as when we exercise or get excited, angry or frightened, but it usually quickly returns to normal.

When deciding whether your blood pressure reading is of concern or not, your doctor will take various factors into account. He or she will also check your pressure on more than one occasion to make sure any rise is persistent.

Should I get my blood pressure checked?

Every adult should have their blood pressure checked regularly. Your doctor will advise you how often – it will depend on your age, whether you are taking any medications and your general health. Regular checks are especially important for:

What causes high blood pressure?

In 95% of people with high blood pressure there is no obvious cause. The remaining 5% generally have a specific cause, such as kidney disease. For those with no obvious cause, it may partly be genetic (it can run in families) or be contributed to by:

What can be done about it?

Achieve and maintain a healthy bodyweight. Being overweight usually means a higher blood pressure. Eat a balanced, low fat diet with grains, eight servings of coloured vegetables and fruit, and two to three servings of low fat milk a day. Choose fish, skinless chicken and lean meat. Avoid fatty, fried food.

Be active regularly. Strive to put a little bit more activity in your day at every opportunity. Aim to accumulate 30 minutes of moderate activity most days of the week. Walking, cycling and swimming are ideal. Find an activity you enjoy so you can keep it up.

Eat less salt. Use herbs, spices, fruit and vinegar for flavouring and dressings and choose low salt preprepared foods, avoid pickled food and avoid excessively salty takeaway foods.

Avoid liquorice – it contains a chemical that can raise blood pressure.

Have no more than two or three alcoholic drinks a day,

Stop smoking quitting reduces your risk of heart attacks or strokes.

Drug treatments

Drugs may help control high blood pressure but they do not cure it. Usually, medication will need to be taken for life. You may need two or more drugs and it may take time to find the right combination and dosage. It is important to let your doctor know about any reactions you have to the drugs, and to follow instructions carefully