Diabetes is a condition characterised by high glucose levels. Glucose comes from our food and is also produced in the liver. Glucose is the main source of energy for the body's cells and is transported through the blood stream. Glucose needs to enter cells to be used. 

“Insulin is the hormone that acts like a 'key' to allow glucose to enter cells. This uptake of glucose usually takes place in the liver and muscles. If the pancreas does not produce insulin, glucose is not able to enter the cells. Glucose levels in the blood stream rise, resulting in diabetes,” says Dr Teh ​Ming Min​g​, Senior Consultant from the Depar​tment of Endocrinology, Singapore General Hospital​ (SGH), a member of the SingHealth​ group.

Singapore has the second-highest proportion of diabetes patients among developed nations.¹ Around 1 in 9 (or 11.3%) people in Singapore aged 18-69 have diabetes.² 

1 in 3 Singaporeans have a lifetime risk of developing diabetes.³

1. Type 1 diabetes

Type 1 diabetes occurs when the body is unable to produce insulin. It usually presents in children and young adults, but may also present in older adults.

2. Type 2 diabetes

Type 2 diabetes occurs when the body does not produce enough insulin or when the insulin produced does not work properly.

3. Gestational diabetes

Gestational diabetes occurs when hormones produced during pregnancy result in the body cells being more resistant to the action of insulin.

Type 2 diabetes is caused by the body not producing enough insulin, or the insulin is there but it is not working properly. Hence, the blood glucose level is high.

Researchers do not fully understand why some people develop type 2 diabetes and others do not. However, it is important to take note of some of the risk factors:

1. Being overweight

The more fatty tissue you have, the more resistant your body is to the action of insulin.

2. Inactivity

The less active you are, the greater your risk of developing diabetes. Physical activity helps you to control your weight, uses up sugar as energy and make your cells much more sensitive to the insulin. Hence, it is important to have a healthy lifestyle to reduce the risk of developing type 2 diabetes.

3. Family history

Your risk increases if a parent or sibling has type 2 diabetes.

4. High blood pressure

High blood pressure of greater than 140/90 millilitres mercury (mmHg) is recognised as a risk factor for developing type 2 diabetes.

5. Abnormal cholesterol and triglyceride levels

If you have low levels of high-density lipoprotein (HDL) or good cholesterol, your risk of developing type 2 diabetes is higher. Triglyceride is another type of fat carried in the blood. People with high triglyceride level are at increased risk of developing type 2 diabetes. You can discuss with your doctor about checking your cholesterol and triglyceride levels.

6. Gestational diabetes

Your risk of developing diabetes is greater if you have had gestational diabetes. You are also at risk of developing diabetes if you have given birth to a baby weighing more than 4 kg.

7. Polycystic ovary syndrome   

This is a condition associated with irregular menstrual periods, excessive hair growth and being overweight.

Early symptoms of diabetes may not be obvious, or there may not be any symptoms at all. Some of the symptoms of diabetes are listed below. You may want to consider seeing your doctor to find out whether you have diabetes if you have some of the following symptoms.

1. Excessive thirst and urination

These are classic symptoms of diabetes. “When you have diabetes, there is too much glucose in your blood. Your kidneys usually filter glucose, but most of the glucose is reabsorbed, so that in those without diabetes, no glucose appears in the urine. But if the blood glucose levels are too high, the kidneys are unable to keep up and excess glucose will appear in the urine,” explains Dr Teh Ming Ming.

Glucose excretion into the urine will also draw out water into the urine. This increases urination and leads to dehydration, with more thirst to compensate for this fluid loss.

2. Fatigue

This can be due to many factors. Dehydration as a result of increased urination can cause fatigue. Moreover, the body’s inability to use sugar for energy needs can cause fatigue.

3. Weight loss

Uncontrolled diabetes with high blood glucose levels can lead to weight loss. This is because you lose glucose (and therefore calories) through your urine.

4. Blurred vision

High levels of blood glucose pulls the fluid from the lenses of your eyes. This can affect the ability to focus.

In addition, uncontrolled diabetes for prolonged periods of time can cause significant damage to the retina. This in turn can also affect your vision    

5. Slow-healing sores and frequent infections

High glucose levels can lead to frequent infections and slow-healing wounds.

You can discuss with your doctor about having blood tests done to find out whether you have diabetes. The blood tests are:

Random blood glucose

A random blood glucose sample that is taken without fasting. A random blood glucose of greater than 11.1 mmol/L is suggestive of diabetes.

Fasting blood glucose

A fasting blood sugar is normally measured after an overnight fast. A fasting blood sugar of 7.0 mmol/L or higher on separate occasions indicates that you have diabetes. Fasting blood glucose measured in an accredited laboratory is the preferred test for the diagnosis of diabetes. This test is easy to perform and is supported by strong evidence.

Oral glucose tolerance test (OGTT)

In this test, you will have a fasting blood glucose level taken, and asked to drink a standard amount (75 g) of a sugary drink. A fasting reading of 7.0 mmol/L or a glucose reading of > 11.1 mmol/L two hours after this drink indicates that you have diabetes.     

Glucose is a type of sugar that our body uses for energy required to perform body functions. Glucose is present in our body at all times, even while sleeping, since all cells need glucose for energy.

Without diabetes, glucose levels are kept very tightly between 4.0-6.0 mmol/L. However, once diabetes develops, it becomes challenging to keep glucose levels within this range whilst avoiding frequent hypoglycaemia (low blood glucose).

Glucose comes largely from carbohydrates (simple sugar and starches). Upon absorption from the digestive tract into the blood stream, it moves into the tissue fluid and eventually into the cells. Glucose that is not used immediately for energy is stored in the liver. Importantly, for glucose to move into the cells, insulin is required.

Insulin is a hormone produced by our pancreas. In those without diabetes, there is a constant supply of insulin produced so that glucose may enter into the cells. When insulin is not available, glucose stays in the blood and tissue fluid.

In those without diabetes, the pancreas produces insulin almost continuously, and in response to the amount of glucose in the blood. This is so precise that exactly the right amount of insulin is produced to keep blood glucose levels in a tight range.

1  International Diabetes Federation (IDF), 2015
2 The Ministry of Health Singapore, 2010
3  The Ministry of Health Singapore, 2017

Ref: K21

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