SOME QUESTIONS AND ANSWERS

Why is a high blood sugar level harmful?

Too high a level of glucose in the blood has several harmful effects. Glucose is involved in many chemical processes in tissues. Because it is widely distributed as fuel through the blood, excessive glucose levels also affect many organs in the body. This can damage some of these organs, causing the complications often seen in the later stages of diabetes.

Raised blood glucose levels, resulting from insulin resistance in type 2 diabetes or from a lack of insulin in type 1, directly damage the insulin producing beta cells in the pancreas and certain other sensitive cells e.g. in the retina of the eyes, in the kidneys and in nerves. Damage occurs via several pathways, through a mechanism termed oxidative stress, but the end result is a decline in function and eventual death of cells.

Only about 2 per cent of the tissue in the pancreas contains beta cells, which make up around 80 per cent of the islets of Langerhans, named after the German scientist Paul Langerhans, who first described them in 1869. The average adult has about 1,000,000 such islets. On prolonged exposure to high glucose levels, these relatively few beta cells may be completely destroyed. For this reason, people with type 2 diabetes can eventually become dependent on insulin injections for survival, in the same way as those with type 1 diabetes.

Glucose can also react chemically with proteins, cross-linking them and damaging their function. One of them, haemoglobin A1C, is measured for diagnostic purposes and gives an indication of the long-term average blood glucose level.

Is diabetes a serious condition?

Before the development of insulin therapy, type 1 diabetes was usually fatal. But since then, many of those with the disease have been able to lead normal lives. Advances in treatment also mean that complications can be avoided or minimised through close attention to lifestyle and medication.

Although lifestyle changes and oral medications are used initially to treat type 2 diabetes, and symptoms are generally less pronounced than in type 1 disease, type 2 diabetes is not any less serious and also requires commitment on the part of both the healthcare team and the patient for its successful management. Here too, much can be done to safeguard long-term health.

Gestational diabetes is also serious, because it carries significant risks to the health of both mother and baby, and close attention to monitoring and managing blood glucose levels through diet, exercise and insulin self-treatment is essential.

Does diabetes follow the same course in all people?

No. In type 1 diabetes, for example, some people enjoy a long and satisfying life with their diabetes well controlled with insulin. Others, who do not manage to keep close control of their blood glucose level and other risk factors, may experience complications or a more rapid worsening of their condition.

The rate of progression of type 2 diabetes may depend on how long it remained undiagnosed, as well as on how tight a control of blood glucose and blood pressure is achieved, since clinically significant organ damage (e.g. retinopathy or nephropathy) may already have occurred before treatment is begun. So early diagnosis is highly desirable.

Pregnancy in a woman who already has diabetes does not seem to worsen permanently any pre-existing retinopathy, or accelerate the course of kidney disease, although it is associated with a higher risk of pre-eclampsia and stroke, and may carry a higher risk of miscarriage if blood sugar control was poor before pregnancy.