Hyperglycaemia: Protect Your Heart By Lowering Your Blood Sugar Levels

Chicken or egg - which came first? Even though it's an intriguing question, whatever the answer may be, it doesn't really matter. I don't expect that even chickens spend much time mulling it over.

But a similar sort of question - one that matters considerably - is posed by type 2 diabetes: Is heart health compromised by the high blood sugar levels of diabetes, or by other conditions such as hypertension that can be triggered by diabetes? In short: Which comes first and which matters most?

Two studies published this month in the Annals of Internal Medicine indicate that hyperglycaemia (high blood sugar) may be more of a culprit in the development of heart disease than previously expected.

Getting a little hyper
In a previous e-alert I told you about the groundbreaking INTERHEART study that revealed a list of health factors that put the heart at greatest risk. I'm sure that most HSI members were not surprised to see diabetes high on that list. For many years now, researchers have been examining the ways diabetes is associated with heart disease.

One of the most recent of those studies comes from Johns Hopkins University in Baltimore, in the US. The Hopkins researchers reviewed the results of 13 studies to analyse the association between heart disease in diabetic subjects and the severity of hyperglycaemia (which is measured by the percentage of glycosylated haemoglobin (HbA1c) in blood).

Daily fluctuations of blood glucose do not affect HbA1c, so this marker provides a more accurate overall indicator of hyperglycaemia. In a nutshell: An HbA1c level of five percent is considered quite safe, and seven percent or less is considered normal. A level higher than seven is a red flag, signalling the possibility of type 2 diabetes.

After reviewing the 13 studies, the Hopkins team concluded that hyperglycaemia may be directly associated with an increased risk of heart disease in people with diabetes. And more specifically, every time HbA1c increases by one percentage point, the risk of heart disease or stroke raises by nearly 20 percent. Likewise, when HbA1c percentage drops, heart disease risk drops as well.

The danger zone
I've told you before about the A1c test, which gives an average measurement of HbA1c percentage in the blood over the 60 to 90 days prior to the test date. And it was this test that was used by a UK research team to monitor hyperglycaemia in more than 10,200 subjects (both diabetic and non-diabetic) over a three-year period, with an additional three-year follow-up period.

The UK researchers found that for every HbA1c percentage point that rose above five percent, risk of problems associated with heart disease rose more than 20 percent. And this elevated risk remained consistent, even when other factors such as smoking, high blood pressure and a previous history of heart problems were taken into account.

This study produced two striking results: 1) Moderate-to-high blood sugar levels were apparently directly responsible for heart disease risk, and 2) Subjects whose HbA1c percentages were well below the conventional danger level were still at risk.

One of the authors of the study told the New York Times that the commonly accepted 'average' blood sugar readings may need to be reassessed.

Way to go
The next time you have a blood test, talk to your doctor about these two studies and ask him to make a point of including an A1c test to determine your HbA1c level.

If your HbA1c reading is in the pre-diabetic or diabetic range, your doctor may suggest taking a drug to manage blood sugar levels. The most common drug for type 2 diabetes is Glucophage, the brand name for metformin. But most people will probably find the tried and true method of diet modification and daily exercise to be more effective.

I've told you before about a New England Journal of Medicine study that enlisted more than 3,200 adults (the average age was 51) who were diagnosed with pre-diabetic elevated glucose levels.

Subjects were divided into three groups: one group received a daily dose of Glucophage; one group received a daily placebo; and one group participated in an intensive programme with a goal of at least 7 percent weight loss through diet adjustment, two and a half hours of moderate exercise each week, and educational sessions to reinforce behaviour modification.

After following these subjects for an average of almost 3 years, the researchers found that Glucophage reduced the incidence of diabetes by about 30 percent versus placebo, but lifestyle changes slashed the incidence rate by more than HALF - a full 58 percent. Plus, patients in the Glucophage group had six times more gastrointestinal side effects than those in the exercise and diet group.

Changing key lifestyle factors such as diet and physical activity is easier said than done. But in the case of controlling blood sugar, a little effort goes a long way.