What causes type 2 diabetes?

What causes type 2 diabetes?

Knowing the causes of type 2 diabetes can go a long way in diabetes prevention.1 By learning what increases diabetes risk, you can take proactive steps to protect your health.

In this article, we explain the causes and risk factors of type 2 diabetes in adults and children, review the symptoms of this condition and discuss the steps you can take to prevent it.  

What are the causes of type 2 diabetes?

Type 2 diabetes occurs as a result of insulin resistance – a condition in which the body’s cells no longer respond effectively to insulin.2,3 When cells become resistant to insulin, they don’t take up glucose from the blood and use it for energy as well as they should.2 

This causes the body to produce more insulin to make up for it and to ‘persuade’ cells to take up glucose.2 Over time, this wears out the body’s insulin ‘factory’ – the pancreatic beta cells.2 Eventually, the cells no longer produce enough insulin.2,3

Exactly why some people develop insulin resistance and then type 2 diabetes, while others don’t, isn’t entirely clear.2 But, there are risk factors that can make developing the condition more likely.2 

By avoiding or reducing these risk factors, it’s possible to prevent type 2 diabetes (unlike type 1 diabetes).1

What causes type 2 diabetes in adults?

The main factors that raise the risk of type 2 diabetes in adults include:1,3,4

• Age. Being 45 or older (although diabetes can be diagnosed at any age) 
• Family history. Inheriting certain genes from a close family member with diabetes
• Lifestyle. Things like smoking, not exercising and having an unbalanced diet
• Body mass index (BMI). Having obesity or being overweight (in particular, a higher waist circumference  – fat around the waist)4
• Race or ethnicity. Some populations, including Southeast Asians, are more likely to develop type 2 diabetes than Europeans.4

Race/ethnicity and type 2 diabetes risk

People from certain racial or ethnic backgrounds are more likely to develop type 2 diabetes, but this may vary from country to country. Globally, for example, Southeast Asian populations develop type 2 diabetes at a higher rate than Europeans, even when they have a lower BMI.4 

In the UK, Asian and Black British populations are more prone to type 2 diabetes.5 In the US, American Indian/Alaskan Native, non-Hispanic Black and Hispanic populations are most at risk.6 

Finally, in Australia, type 2 diabetes is particularly prevalent in Aboriginal and Torres Strait Islander people, while in Canada, Canadian First Nation people are more likely to develop the condition.3

What causes type 2 diabetes in children?

The risk factors for type 2 diabetes in children include:4

• Obesity
• Having a family history of type 2 diabetes or gestational diabetes in the mother
• Eating a diet high in fat and added sugars and insufficient in fibre
• Being of Hispanic, Black, Asian or Indigenous descent3,5,6

Other factors, like poor nutrition early in childhood and weight at birth, may also affect risk.4

What are the symptoms of type 2 diabetes?

The symptoms of type 2 diabetes are largely similar to those of type 1 diabetes and include:1,3,5

• Being constantly thirsty
• Being constantly hungry
• Peeing more often or peeing more at night
• Blurred vision or other vision problems
• Losing weight without meaning to
• Lack of energy or fatigue
• Ulcers that are slow to heal
• Tingling or numbness in the hands or feet
• Recurrent infections

However, the main difference between type 1 and type 2 diabetes symptoms is that the latter may come on more gradually and can be less dramatic and harder to detect.3 In many cases, type 2 diabetes is entirely symptomless, which is why early detection and screening are especially important.3 

If you’re experiencing diabetes symptoms or have questions about the differences between type 1 and type 2 diabetes, speak to your healthcare professional.1

Is type 2 diabetes preventable?

Is type 2 diabetes preventable?

Type 2 diabetes can potentially be prevented.1,3 Some key steps you can take to avoid this condition include:7

• Eating a balanced diet that’s rich in whole grains, vegetables and fruits and less processed foods and added sugars
• Exercising regularly
• Maintaining a healthy weight or losing weight if you’re overweight or obese 
• Quitting smoking or not taking up cigarettes 
• Avoiding excessive drinking of alcohol

If you’ve been diagnosed with type 2 diabetes, the above lifestyle interventions, regular check-ups and diabetes medication can all help prevent complications.3 Learn more about the available treatments for type 2 diabetes in our dedicated article.

Although the precise cause of type 2 diabetes is not known, some factors can make it significantly more likely for you to develop the condition.2,3 Some of these risk factors can be prevented. 

By making lifestyle changes that are within your grasp, like maintaining a healthy weight and eating a balanced diet, you can help keep type 2 diabetes at bay.7