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Diabetes - Type 2
If you have just been diagnosed with Type 2 diabetes, or know someone who has, you understandably want to find out more information. Click through the subheadings below to learn about Type 2 diabetes.
Type 2 diabetes is a metabolic disorder. People with Type 2 diabetes
have an impaired ability to convert sugar in their blood into energy in
their bodies.
After eating, we need insulin, a hormone made in the pancreas, to
channel sugar from our blood into our cells. In Type 2 diabetes, the
pancreas makes some insulin but it is not produced in the amount your
body needs (unlike Type 1 diabetes where the body does not make any
insulin).
Insulin inhibits the production of glucose from the liver. When we
do not produce enough insulin, glucose is overproduced by the
liver and stays in the blood.
At the same time, muscles become less responsive to insulin, a
condition known as 'insulin-resistance'. The combined result is high
blood sugar levels, which can be very damaging to blood vessels and
organs.
Type 2 diabetes has no cure but can be managed, it:
- accounts for 85-90% of all cases of diabetes
- can be triggered by unhealthy eating and lack of physical
activity
- usually occurs in people over 45 years of age.
Both genetic and environmental factors cause Type 2 diabetes.
Some genes are associated with an increased risk in type 2 diabetes
and seem to predominantly cause impaired insulin production. You are
more likely to develop diabetes if there is a family history of the
disease.
Type 2 diabetes is often referred to as a 'lifestyle disease' and
is promoted by a poor diet, obesity, lack of physical
exercise and an 'apple shape' body. This is where extra weight is
carried around the waist. There is also increased risk associated with
high blood pressure or cardiovascular disease
Obesity is driving a worldwide epidemic in Type 2 diabetes.
Type 2 diabetes is a complex disease that we do not yet fully
understand. Read some of the media releases below to understand some of
our more recent breakthroughs.
Insulin
Insulin regulates the entry of glucose into muscle and fat cells and
also the production of glucose from the liver. This regulation becomes
defective in Type 2 diabetes and causes abnormalities in carbohydrate
and fat metabolism.
Our cells have small channels that allow entry of glucose into the
cell. These channels are not permanently open and require a trigger to
open them. Insulin is this trigger. In healthy cells, when insulin
binds to the insulin receptor, the glucose channels will open and
glucose flows into the cell from the bloodstream. When glucose enters
the cell, the glucose is converted into useable energy for the
cell.
Beta cells
Beta cell failure is fundamental to the development of diabetes.
Type 1 diabetes is caused by the destruction of beta cells by the cells
of the immune system. In contrast, in Type 2 diabetes, beta cell
function declines gradually over time. This decline seems to have a
strong genetic determination.
When beta cells are affected, they often are no longer able to
produce enough insulin to satisfy the body’s needs. This is known as
relative insulin deficiency and results in insulin levels insufficient
to clear glucose from the blood.
Insulin resistance
In Type 2 diabetes, the decline in beta cells usually occurs in
conjunction with insulin resistance. Insulin resistance is when cells
become less sensitive to the hormone insulin, caused by the cells not
recognising the insulin signal. When this occurs, normal levels of
insulin in the blood become inadequate to keep blood glucose levels
within a normal range. The major cells affected are fat, muscle and
liver cells.
Abdominal fat
Excess fat, especially in the abdominal area is also important.
Insulin resistance is strongly correlated with waist measurements and
abdominal fat levels, which are also under some degree of genetic
control. Garvan’s research shows that fat directly around organs in the
stomach, rather than fat under the skin, is a major risk factor.
The incidence of diabetes is rising globally. In 2005, over 700,000
(3.6%) Australians had diabetes (Reference 1). By 2008, the reported
incidence of diabetes increased to 800,000 (4.0%). This number is
continuing to rise.
Almost 300 Australians are developing Type 2 diabetes every day.
Many more have diabetes but do not know it. About 50% of people who
have diabetes are not yet diagnosed. In addition, more have
pre-diabetes.
Reasons for an increase in Type 2 diabetes:
- an increase in the rates of obesity and physical inactivity
- an ageing population
- better detection of diabetes
- longer survival of affected individuals
Pre-diabetes is a condition in which blood glucose levels are higher
than normal but not high enough for a diagnosis of diabetes (Reference
2). It:
- is also known as Impaired Glucose Tolerance (IGT) and Impaired
Fasting Glucose (IFG)
- is caused by the same mechanisms mentioned for diabetes
- usually has no symptoms
- has a 1 in 3 chance of developing Type 2 diabetes within 10
years
- can be reversed.
You can help your body respond better to insulin through weight loss
and physical activity, and thus reduce the chance of progression to
diabetes.
Pre-diabetes has similar risk factors as Type 2 diabetes.
There are many risk factors for Type 2 diabetes. You are at higher
risk of developing type 2 diabetes if you fit any of the following
criteria:
• You are overweight, do not get enough exercise and/or
have high blood pressure
• You have a family member with diabetes
• You are over 55 years of age
• You have heart disease or have suffered a heart attack or a
stroke
• You had/have gestational (pregnancy) diabetes
• You have Polycystic Ovarian Syndrome and are overweight
• You are over 35 years of age and are of Aboriginal, Torres
Strait Islander, Pacific Islander, Asian or Indian heritage
• You have pre-diabetes (impaired fasting glucose or glucose
tolerance).
Calculate your risk by using the Australian Type 2 diabetes Risk
Assessment Tool developed by the Baker IDI Heart and Diabetes
Institute:
Calculate your risk
Type 2 diabetes develops gradually, so sometimes symptoms can go
unnoticed. This means that a sufferer can go undiagnosed, and therefore
untreated, for a long time.
Common symptoms can include:
• frequent urination
• thirst
• blurred vision
• skin infections
• slow healing
• tingling and numbness in the feet.
Diabetes is diagnosed on the basis of a person’s blood glucose level
under certain conditions – either by a Fasting Blood Glucose (FBG) or
Oral Glucose Tolerance Test (OGTT). These tests are ordered by the
Doctor.
A healthy lifestyle is your best defence against Type 2
diabetes.
The risk of Type 2 diabetes can be greatly reduced by eliminating
the risk factors that cause the disease.
Some risk factors are not modifiable, such as age, sex and genetics.
But most risk factors can be modified.
Major modifiable risk factors include (Reference 1):
• overweight and obesity
• physical inactivity
• poor diet
• tobacco smoking.
The incidence of some risk factors is increasing, including obesity.
Obesity rose from 11% of adults in 1995 to 24% of adults in 2008
(Reference 3). Indigenous Australians and people from lower
socioeconomic groups are affected more than others.
Further help to prevent diabetes consult with your GP and other
health provider services (e.g. Diabetes Australia,
Diabetes Centres) for:
• health advice and education
• referrals to diabetes specialists
• risk assessments
• screening/monitoring
You can also join community-based programs (such as quit smoking and
exercise groups).
In the early stages of type 2 diabetes, you are likely to feel fine.
Long-term effects develop gradually but these can become disabling or
life-threatening. People who have had diabetes for many years are
likely to develop long-term complications.
The major organs affected by this disease include your heart, eyes,
kidneys and nerves.
Complications may be minimised by good blood sugar control and other
measures.
There are several long-term effects of type 2 diabetes:
• Heart Disease
Diabetes is a well-established risk factor for heart disease.
If you have diabetes you are more than twice as likely to have a
heart attack as non-diabetics (reference 3). Almost 10% of diabetic
Australians (25 years and over) have coronary heart disease compared
with 6% of Australians without diabetes (reference 4).
Most people with diabetes have abnormal cholesterol or lipid levels
(reference 4), which increases the risk of heart attack and stroke.
Blood pressure and cholesterol levels should be monitored as closely
as blood sugar.
• Nerve Damage
Nerve damage, or neuropathy, begins as tingling, burning and
numbness in the toes and feet. If the nerves continue to be damaged,
these problems will gradually spread upward.
In uncontrolled diabetes, nerve damage may eventually lead to loss
of feeling in the affected limb. Nerve damage to the feet or poor blood
flow are dangerous long-term effects of Type 2 diabetes.
• Eye Damage
People with diabetes are at an increased risk of developing diabetic
retinopathy (retinal disease), cataracts and glaucoma. This can lead to
a loss of vision or blindness.
Diabetic retinopathy is the leading cause of blindness in adults
(aged 20–74) years with more than 12,000 new cases of blindness each
year (reference 4).
If identified early, diabetic retinopathy can be treated by laser
surgery. Although it cannot be cured completely, early detection and
treatment can prevent nearly all cases of severe vision loss and
blindness. Despite this, the disease is estimated to account for 17% of
all blindness and vision impairment in Australia (reference 4).
• Kidney Disease
Diabetes is the leading cause of kidney failure (reference 3). High
blood glucose, especially if blood pressure is also high, can lead to
kidney damage, known as ‘diabetic nephropathy’, which can progress to
kidney failure, requiring treatment with dialysis or a transplant.
• Other complications
• digestive diseases (pancreatic cancer, constipation,
diarrhoea, liver disease and gallstones)
• infections
• oral diseases
• problems in pregnancy.
Prevention/Solution
If you have Type 2 diabetes, you need to make a lifelong commitment
to blood sugar monitoring, exercise and healthy diet. These measures
plus blood pressure control, lowering of cholesterol and smoking
cessation can dramatically reduce the likelihood of complications.
Careful management of your diabetes, particularly by keeping your
blood sugar under control will help to prevent long-term
complications.
See our media releases below for all the latest Type 2
diabetes research from the Garvan.
Research in this program is focused on how we regulate body weight
and energy, and on obtaining a better understanding of Type 2 diabetes
at multiple levels. There is a particular emphasis on the release of
insulin and its mode of action in normal and disease states.
Research strengths include live cell microscopy, the use of mass
spectrometry for the discovery of new molecules affected by this
disease, gene manipulation and studies of our metabolism.
Our studies have begun to identify factors that may be released
from our immune cells or blood vessels early in the disease and we are
examining key differences in fat (adipose tissue) from different parts
of the body.
Our recent highlights include:
• We have shown that insulin activates a 'motor protein', known
as myo1c, that drives glucose transport molecules to the cell
surface.
• In close collaboration with the Shanghai Institute of Materia
Medica, scientists have uncovered the therapeutic properties of bitter
melon, a vegetable that is used in traditional Chinese medicine. We
have found that four compounds isolated in bitter melon help to mediate
the movement of glucose transporters to the cell surface, a very
important step in the uptake of glucose from the blood into cells in
the body.
• We have found that over-eating generates the production of
toxic oxygen scavenging molecules, or 'free radicals', which
trigger insulin resistance.
• There are proteins in our cells that receive and transmit
messages to and from other cells. We have shown that one of these
proteins "PKCepsilon" (PKCε) is a key player in regulating removal of
glucose from the blood. When PKC is blocked, the body is protected
against the development of a pre-diabetic condition, despite a poor
diet and physical inactivity.
• We have found that fats disrupt movement of protein out of
the cellular protein-folding compartment in pancreatic
insulin-producing cells, triggering cell death.
• Our neuroscience researchers have shown that a hormone
released naturally from the gut after a meal could be used to treat
obesity and Type 2 diabetes. The hormone peptide YY (PYY) acts on the
brain, contributing to a feeling of satiety, suggesting the use of this
hormone as a weight loss medication.
• Our researchers have concluded that low levels of PYY could
be used as a predictor for the development of Type 2 diabetes. Clinical
studies showed that people with a family history of Type 2 diabetes,
but not yet showing signs of insulin resistance themselves, produce
lower levels of PYY after eating, a very early sign of
pre-diabetes.
News
Understanding why some obese people stay sensitive to insulin
MEDIA RELEASE:
01 Feb 2012
Obesity, especially central obesity, is associated with insulin resistance, which precedes diabetes, sometimes by more than a decade. However, it’s not only a question of body weight or fat distribution, because some obese people remain insulin-sensitive, with insulin working as well in their bodies as in someone lean.
Deconstructing diabetes – why one size does not fit all
MEDIA RELEASE:
30 Nov 2011
Professor David James, Head of the Diabetes and Obesity Program at Garvan, believes it’s time to draw attention to the many things we don’t yet know about the complex metabolic disease we call ‘Type 2 diabetes’, and to the oversimplifications that abound in discussion of future treatments.
Exploring the amazing little world of the fat cell
MEDIA RELEASE:
28 Sep 2011
For the first time, Australian scientists have detailed the proteins, or functional molecules, inside and around the ‘plasma membrane’ of a fat cell, the permeable barrier between the cell’s inner workings and the rest of the body. Understanding the way that proteins function at the surface of these cells will help us unravel some of the complexities underlying Type 2 diabetes.
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