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Pre-diabetes nearly DOUBLES the risk of having a heart attack or stroke, study finds

Pre-diabetes nearly DOUBLES the risk of having a heart attack or stroke because high blood sugar damages the arteries, study finds

  • Pre-diabetes is when sugar levels are high but not as high as type 2 diabetes
  • It is common and thought to affect a third of adults in the US and 7million Brits  
  • And now a study suggests sufferers face a higher risk of severe heart problems

Having pre-diabetes can almost double your risk of suffering a heart attack or stroke, research suggests.

The common condition, thought to affect one in three Americans and 7million Brits, develops when blood sugar levels are higher than normal but not elevated enough to be classed as full-blown diabetes. 

If left unchecked it can develop into type 2 diabetes, in which the body becomes unable to control its own blood sugar, and this is often irreversible and causes long-term health problems.

Researchers at Beaumont Hospital in Michigan carried out a study on 25,000 patients, half of whom had pre-diabetes, and revealed they face a heightened risk of serious heart problems such as heart attacks and stroke.

They warned that doctors ‘tend to treat it as no big deal’ but that this research should be a wake-up call to the potential long-term damage it causes. 

High blood sugar levels over a long period of time can cause serious damage to blood vessels and the heart which raises the risk of them failing, the team said.

Pre-diabetes is diagnosed when blood sugar levels are higher than normal, but still too low to be type 2 diabetes. A study suggests the condition can lead to serious cardiovascular events (stock image)


Pre-diabetes is when a patients blood sugar levels are higher than normal, but not high enough for them to be diagnosed with type 2 diabetes.

This means they are at risk of developing diabetes, when the body can no longer control its blood sugar levels. 

What are the symptoms?

Pre-diabetes does not trigger any symptoms. 

Diabetes UK says many people suffering from pre-diabetes never have the condition diagnosed.

How does it develop?

Pre-diabetes is an early alarm that someone is at high risk of developing type 2 diabetes.

Being overweight, having a large waist, a poor diet and not exercising are all factors that increase someone’s risk of suffering from the condition.

Can it be prevented?

Pre-diabetes can be prevented and even reversed by adopting a more healthy lifestyle.

Diabetes UK says managing weight, eating a healthy and balanced diet and being more active can all help.

They add that even shedding five per cent of someone’s body weight can significantly reduce the risks.

How does it differ from type 2 diabetes?

In pre-diabetes someone is at risk of developing type 2 diabetes.

But their insulin still works, allowing the body to keep absorbing sugar from the blood.

This is different to diabetics, because in the condition the body becomes desensitised to insulin and stops taking up sugar from the blood.

Without treatment, diabetes increases the risk of a foot amputation, blurred vision and heart disease among other illnesses.

In the study, scientists followed patients who had either pre-diabetes or normal blood sugar levels between the ages of 18 and 104, and looked at 14 years’ worth of health records.

They found 18 per cent of those with pre-diabetes suffered serious ‘cardiovascular events’ – such as a heart attack – during this time.

But the same only happened to 11 per of those who had normal blood sugar.

They also found people with pre-diabetes were significantly more likely to suffer a stroke.

Even when the pre-diabetes was reversed, past patients still had a higher risk of suffering a heart attack.

Results showed 10.5 per cent of former patients experienced a serious cardiovascular event, compared to six per cent of those who had normal blood sugar levels.  

‘Based on our data, having pre-diabetes nearly doubled the chance of a major adverse cardiovascular event, which accounts for one of four deaths in the US,’ said Dr Adrian Michel, a medicine expert at Beaumont Hospital who led the study.

‘Even if blood sugar levels went back to normal range, it didn’t really change their higher risk of having an event, so preventing prediabetes from the start may be the best approach.’ 

He added: ‘As clinicians, we need to spend more time educating our patients about the risk of elevated blood sugar levels and what it means for their heart health and consider starting medication much earlier or more aggressively.

‘And advising on risk factor modification, including advice on exercise and adopting a healthy diet.’ 

Speaking about the medical view of pre-diabetes he said it tends to be treated as ‘no big deal’. 

‘But we found that pre-diabetes itself can significantly boost someone’s chance of having a major cardiovascular event, even if they never progress to having diabetes.’ 

Pre-diabetes develops when someone has high blood sugar but their body is still able to control it.

This differs from type 2 diabetes, when the pancreas stops working probably meaning the body is unable to regulate its sugar levels.

Without treatment, this can lead to heart disease, foot problems and vision loss or blindness among other factors.

Doctors say pre-diabetes sparks no warning signs, but that when someone starts suffering symptoms of type 2 diabetes – including tiredness, feeling thirsty all the time and blurred vision – they likely already have the condition.

They add the condition can be reversed through managing weight better, eating a healthy and more balanced diet and being more active.