Causes Of Type 2 Diabetes: What To Look Out For

Causes Of Type 2 Diabetes: What To Look Out For

Type 2 diabetes is the most common form of the disease, affecting 90% of the 3.9 million Britons living with diabetes.  Several things can combine to cause type 2 diabetes, including your genes and your lifestyle. 


What is type 2 diabetes?


Type 2 diabetes is a chronic condition in which your blood sugar levels are too high. 

When you eat carbohydrates, your body breaks them down into glucose, which is absorbed into the bloodstream for distribution around your body. Glucose provides your body’s cells with the fuel they need to work and live.  

An essential hormone called insulin acts like a key, unlocking cells so that glucose can enter. It allows the cells to burn glucose for energy, regulates glucose levels in the blood, and ensures excess glucose is stored. 

When you have type 2 diabetes, your cells can’t respond effectively to insulin, or your body can’t produce enough of the hormone for its needs. The cells in your tissues and organs are starved of energy, and glucose builds up in your blood. 


What is insulin resistance?


Type 2 diabetes often starts with insulin resistance, which means that the body produces lots of insulin but can’t use it effectively. Your body needs more insulin to allow glucose to enter the cells and control blood sugar levels. Initially, the pancreas makes more insulin to keep up with the body’s needs, but eventually, it can tire, progressively making less insulin and leading to higher blood glucose levels.


What causes type 2 diabetes?


Type 2 diabetes is caused by several factors, including your family history, ethnicity, and how you live your life.


Overweight, obesity and type 2 diabetes


Type 2 diabetes is strongly linked to being overweight or obese. According to a UK Government report:

Being overweight or obese is the main modifiable risk factor for type 2 diabetes. In England, obese adults are five times more likely to be diagnosed with diabetes than adults of a healthy weight. Currently 90% of adults with type 2 diabetes are overweight or obese. People with severe obesity are at greater risk of type 2 diabetes than obese people with a lower BMI‘. 

If you’re obese, a diet plan can help put diabetes into remission and return blood sugar to normal levels.

However, not all people who are obese get type 2 diabetes and not all people with type 2 diabetes are overweight. So, weight is not the only factor to consider when identifying the causes of type 2 diabetes. 


Body fat distribution

All fat is not the same. Body fat distribution is also a significant risk factor for type 2 diabetes. Weight on the belly or around your waistline is a particular problem. 

If you have a large waist measurement, you’re more likely to develop type 2 diabetes. Men have a higher risk if their waist is between 94 and 102cm and are at very high risk if it is over 102cm. Women are at increased risk if their waist is 80 to 88cm and at very high risk if it is over 88cm. 

The cause of this is thought to be because fat can build up around your organs, affecting the function of the liver and pancreas. Abdominal fat cells may release inflammatory chemicals, which can cause the body to be more resistant to insulin. 


Physical inactivity

People who are not physically active are more likely to develop type 2 diabetes. People with type 2 diabetes tend to be more sedentary than non-diabetic individuals. Sedentary behaviour is also linked to obesity. The WHO estimates that lack of exercise accounts for around 7% of the burden of diabetes in Europe.

Living an active life improves blood glucose control in type 2 diabetes, reduces cardiovascular risk, helps you lose weight, and improves wellbeing.


Genetics and ethnicity

Some genes can increase your risk of developing type 2 diabetes. The condition runs in some families- but there isn’t a clear pattern of inheritance. You’re more likely to develop the disease if you have a close family member with type 2 diabetes, and the risk increases with the number of members affected. 

You’re between two and six times more likely to develop diabetes if you have a parent, brother, sister or child with the condition. But not everyone with the same genetic heritage will develop type 2 diabetes. Lifestyle factors like diet and exercise also have an impact. However, lifestyle habits and choices can often be learned from your family members.

Some races and ethnic groups are at increased risk of type 2 diabetes. You are at increased risk if you’re of African-Caribbean, Black African, Hispanic, Pacific Island or South Asian heritage.



Certain medications can increase your risk of diabetes. Corticosteroids are used to reduce inflammation in asthma and auto-immune conditions. However, they can lead to a type of diabetes called steroid diabetes. This is more common in people already at risk of diabetes because of their family history, ethnicity, obesity or history of gestational diabetes.

You are more likely to develop type 2 diabetes if you take steroids for a longer time, especially for more than three months.


Type 1 diabetes and COVID-19

During the COVID-19 pandemic, doctors noticed that more people were developing. Scientists believe that the coronavirus might trigger diabetes or make the condition worse. One study showed that 5% of people admitted to hospital with COVID-19 developed diabetes. 

Doctors picked up new cases of type 1 diabetes and type 2 diabetes. However, with the type 2 cases, it is difficult to be sure that the disease was triggered by the virus and not by lifestyle changes caused by the lockdown. Doctors are also querying whether Covid-19 causes a new type of diabetes because of the stress of infection and medical treatment, including steroids. 

With a new virus, research is at an early stage. Scientists have theorised that the coronavirus causes inflammation in the body leading to insulin resistance. Also, coronavirus infects ACE-2 receptors on the cells, which are found in the pancreas. Studies have shown coronavirus in the insulin-producing beta cells in the pancreas. The infection may kill the cells or change the way they work and reduce insulin production. 

The extensive PHOSP-COVID study is following 10,000 people who were in hospital with COVID-19 to monitor the long-term effects of the virus. This will include looking at people with new or existing type 2 diabetes to understand how their condition has been affected.

To find out more about effective diabetes medications, or to speak to one of our specialists at the London Diabetes Clinic about prospective treatment options, contact us today.


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Carol Willis

Carol Willis - Diabetes Clinic Facilitator

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