What is diabetes?
Diabetes is a condition that arises when your body cannot process glucose (a sugar)
entering your bloodstream from the food you eat. This causes a build-up of sugar
in the blood which, untreated, can cause problems. A hormone, insulin, in the pancreas
acts on cells as a key that permits glucose to leave the bloodstream and enter the
body's cells where it is used for energy, growth and storage. People with diabetes
either don't produce enough insulin and cannot meet their requirements with the
insulin they do produce, or their cells do not respond properly to the insulin,
so the glucose that is an end-product of digestion builds up to abnormal levels
in their blood.
Types of diabetes and their symptoms
There are two types of diabetes - insulin-dependent diabetes mellitus or type 1
diabetes, and non-insulin-dependent diabetes mellitus or type II diabetes. There
is also a third form of the disease - gestational diabetes, which is really just
type II diabetes in pregnant women.
Type 1 diabetes
In type 1 diabetes, the pancreas is unable to produce enough insulin.
This disease can strike at any age but is most commonly diagnosed in children and
young adults and tends to be more dramatic in that symptoms come on extremely quickly.
This form is to be treated with a controlled diet and regular exercise and usually
requires one or more injections of insulin a day.
Symptoms include:
- excessive urination as the body tries to rid itself of its glucose load in the urine
- excessive thirst because increased urination causes dehydration
- weakness and fatigue
- irritability
- unexplained weight loss
There appears to be a genetic predisposition to type 1 diabetes, which may then
be triggered by exposure to an environmental trigger, possibly a virus. However,
many people with the disease do not have a family history of it.
Type II diabetes
This is the most common type of diabetes, occurring in around 90% of cases.
People with type II diabetes still produce insulin. However the body can't use it
effectively. To compensate, the pancreas produces more insulin. Glucose levels rise
and diabetes starts to become apparent.
There may be no symptoms at all in type II diabetes, or they may be fairly subtle,
such as a drop in energy levels, cramps, vision disturbance, or passing increased
amounts of urine, says Dr Stephen Twigg, a diabetes specialist at Royal Prince Alfred
Hospital in Sydney and a senior lecturer in medicine at the University of Sydney.
Other symptoms may include:
- a sudden deterioration in eyesight
- recurring infections
- poor wound healing
- itching or numb skin
-
shooting pain in the legs and feet
A simple blood test and/or a two-hour Glucose Tolerance test after drinking a sweet
glucose drink is used to diagnose type II diabetes.
You are more likely to develop type II diabetes if a close relative, such as a parent
or sibling, has the disease. Women who have had gestational diabetes are also at
greater risk of developing type II diabetes, and so are members of certain ethnic
groups, including Aborigines, Torres Strait Islanders, Indians and Pacific Islanders.
You also put yourself at risk if you're overweight or live a sedentary lifestyle.
It doesn't help, either, that many of us have a diet high in sugar, saturated fats
and processed foods, and that it is low in fibre, fruit, vegetables, and complex
carbohydrates such as wholegrain breads or pasta.
Diabetes is also associated with high blood pressure and high cholesterol levels
- if you have either of these conditions, you may be at higher risk of developing
diabetes.
Twenty or 30 years ago, type II diabetes was seen as an older people's disease.
However, that perception has been changing with the increased incidence of type
II diabetes in younger people. "We used to say that the age of onset was around
65 years of age," says Professor Paul Zimmet, director of the International Diabetes
Institute in Melbourne. "Over the past 30 years, that's moved down about 10 years
every decade. It's now not unusual to see 35-year-olds with type II diabetes and
we're also seeing school children with it," he says. "We predict that, in the next
five or 10 years, there will be more children with type II than type 1 diabetes."
Gestational diabetes
Gestational diabetes is type II diabetes that is diagnosed during pregnancy. Unless
it is properly managed it increases the risk of pregnancy complications. After the
birth of the baby, when the woman's size and hormone levels return to normal, her
blood sugar levels usually settle down. However, she is at risk of developing type
II diabetes in later life and should exercise, keep her weight within normal limits
and monitor her blood sugar level.
What are the complications of diabetes?
Long-term complications can include an increased risk of damage to kidneys, eyes
and nerves, says Dr Twigg. As well, heart disease and stroke are approximately three
to four times more common in people with type II diabetes than in the general population,
says Professor Stephen Colagiuri from the Prince of Wales Hospital's Diabetes Centre
in Sydney. Other side effects include poor circulation to the legs and feet. Treatment
for this condition is crucial to prevent complications that can lead to permanent
disabilities and reduced lifespan. The good news is that the risk of developing
any of these complications is enormously reduced if the diabetes is kept under control.
How is diabetes treated?
The main aim of treatment for both type 1 and type II diabetes is to keep blood
glucose levels as close as possible to normal to minimise the risk of developing
complications.
Whereas part of the treatment for type 1 diabetes involves regular insulin injections,
treatment for type II diabetes is generally achieved with the use of tablets as
well as changes to lifestyle.
The tablets given to type II diabetics to lower blood sugar levels include the sulphonylurea
drugs that stimulate the pancreas to produce more insulin and make the insulin work
better once it gets to the cells; and the biguanide drug, metformin, that boosts
the effectiveness of insulin in the body.
Lifestyle changes include a healthier diet, high in fibre, low in refined carbohydrates
and low in saturated fats, as well as taking more exercise.
Gestational diabetes is often controlled by diet. If this fails, women are put on
injected insulin for the duration of their pregnancy. Even though they have a form
of type II diabetes, they cannot take the biguanide or sulphonylurea tablets as
these drugs cross the placenta and have been associated with birth defects. Women
with type II diabetes on tablets before their pregnancy must transfer to insulin
while pregnant.
It is important for women with diabetes to achieve best possible blood sugar control
before becoming pregnant, to minimise problems for themselves and their baby.
Can you be cured of diabetes?
Unfortunately, at present, the answer to this question is no. However, serious complications
can be reduced or prevented.
For people with type 1 diabetes, lifelong daily insulin injections, regular blood
glucose tests using a finger-pricking device, and a disciplined eating plan and
regular exercise are usually required. Fortunately research continues on pancreas
transplantation as well as the transplant of the specific insulin-producing cells.
Those with type II diabetes may go back to normal levels of blood sugar as they
get back to normal weight and start to exercise regularly.
What's the best way to avoid developing diabetes?
Finnish and US studies in the last 18 months both clearly show that those who are
susceptible to developing diabetes can dramatically reduce their risk with aggressive
lifestyle intervention, aiming for 7% of body weight loss and 150 minutes of exercise
per week, according to Dr Twigg.
Recently, a very common condition known as pre-diabetes, which affects around 16%
of Australians, has been identified. The blood glucose level in this group is higher
than normal, but has not yet reached the level considered to be within the diabetic
range. The 2 hour Glucose Tolerance test is normal, but cells in the body do not
respond adequately to the insulin produced. Blood cholesterol and triglycerides
may be abnormal.
"If you have pre-diabetes, your risk of developing diabetes is roughly five to 10%
per year," explains Dr Twigg. "Without aggressive intervention, after five years,
up to half of the group will have developed diabetes. We know we can reduce the
risk by more than half in this group with significant weight loss and regular exercise."
How's the future looking for diabetes?
The focus is on prevention rather than cure, says Dr Twigg. "The earlier diabetes
is diagnosed the better. We're also trying to detect tissue damage as early as possible
to prevent complications."
As far as treatment goes, there are new types of medication being developed, including
a drug that tries to stop the adverse effect of glucose on cells. "There's also
a new drug being trialled in Australia based on the saliva from the gila monster,
a lizard found in the Arizona desert," says Dr Zimmet. The saliva, it turns out,
lowers blood sugar levels. Safer, more reliable forms of insulin are also being
trialled, including inhaled insulin; while companies are trying to produce insulin
in tablet form.
Trials are underway at Sydney's Westmead Hospital to transplant insulin-producing
cells into people with type 1 diabetes. "It's early days with this one, but the
results are looking quite hopeful," says Dr Twigg. "Down the track, it may be possible
to infuse insulin producing cells into people with type II diabetes as well."
The International Diabetes Institute and Deakin University have discovered a gene
that may have enormous implications for not only diabetes, but also ageing, cancer
and a number of chronic diseases. "That's very exciting," says Professor Zimmet.
"We're the only group in the world working on that." The group is also looking at
the role of potato toxin and other food toxins in causing type 1 diabetes.
All in all, the outlook for anyone with diabetes is much brighter than it was 15
or 20 years ago. "We used to be pretty negative about diabetes because there weren't
good studies to show that good control reduced the risk of complications, and we
didn't have the ways of treating diabetes that we do now," says Professor Zimmet.
But rather than viewing it as purely a chronic condition, type II diabetes can be
seen as a wake-up call, as an opportunity to ditch or improve your bad habits, so
leading to a much better quality of life as well as a longer life.
