Depression is a direct cause of type 2 diabetes, research suggests

Depression can play a direct role in developing type 2 diabetes even if you’re not overweight, researchers have discovered.

Experts have long known that people with diabetes are around twice as likely to suffer depression compared with those without the condition.

It is also well established that people with depression have a higher risk of developing type 2 diabetes.

But new research, funded by the charity Diabetes UK, has found seven genetic variants that contribute to both type 2 diabetes and depression.

Leading experts and charities today labelled the findings ‘hugely important’ and urged health officials to consider depression as a risk factor for type 2 diabetes, alongside obesity, inactivity and a family history of the condition.

Experts have long known that people with the condition are around twice as likely to suffer depression compared with those without diabetes. It is also well established that people with depression have a higher risk of developing type 2. But new research, funded by the charity Diabetes UK, has found seven genetic variants that contribute to both type 2 diabetes and depression

Almost 4.3 million people were living with diabetes in 2021/22, according to the latest figures for the UK. And another 850,000 people have diabetes and are completely unaware of it, which is worrying because untreated type 2 diabetes can lead to complications including heart disease and strokes

Researchers found, for the first time, that depression directly causes an increased risk of developing type 2 diabetes, but not that diabetes causes depression.

The study found that only 36.5 per cent of the effect of depression on type 2 diabetes could be explained by obesity.

Obese people are significantly more likely to have type 2 diabetes than those of normal weight.

The researchers also noted seven genetic variants that contribute to both type 2 diabetes and depression.

These shared genes play a role in insulin secretion or inflammation in the brain, pancreas or fat tissue, with changes in these biological processes potentially explaining how depression increases type 2, they suggested.

WHAT IS TYPE 2 DIABETES?

Type 2 diabetes is a condition which causes a person’s blood sugar to get too high.

More than 4million people in the UK are thought to have some form of diabetes.

Type 2 diabetes is associated with being overweight and you may be more likely to get it if it’s in the family.

The condition means the body does not react properly to insulin – the hormone which controls absorption of sugar into the blood – and cannot properly regulate sugar glucose levels in the blood.

Excess fat in the liver increases the risk of developing type 2 diabetes as the buildup makes it harder to control glucose levels, and also makes the body more resistant to insulin.

Weight loss is the key to reducing liver fat and getting symptoms under control.

Symptoms include tiredness, feeling thirsty, and frequent urination.

It can lead to more serious problems with nerves, vision and the heart.

Treatment usually involves changing your diet and lifestyle, but more serious cases may require medication.

Source: NHS Choices; Diabetes.co.uk

While a direct cause was not found for diabetes causing depression, experts still believe that the burden of living with type 2 diabetes can be a factor in developing depression.

Dr Elizabeth Robertson, director of research at Diabetes UK, said: ‘This hugely important study gives us new insights into the links between genetics, type 2 diabetes and depression, indicating that depression can contribute to the development of type 2 diabetes.

‘Type 2 diabetes is complex, with multiple risk factors – and previous research has shown that the condition is more common in people with depression.

‘This study gives us greater insight into why and indicates that depression should now be considered a risk factor for type 2.

‘This knowledge could help healthcare professionals to improve care and support for people with a history of depression and prevent more cases of type 2 diabetes.

‘We strongly encourage anyone with depression to know their risk of type 2 diabetes by completing Diabetes UK’s free online “know your risk” tool, so they can get the right support to reduce their risk and avoid type 2 diabetes.’

Inga Prokopenko, professor e-One Health and head of statistical multi-omics at the University of Surrey, who led the study, said: ‘Our discovery illuminates depression as a contributing cause of type 2 diabetes and could help to improve prevention efforts.

‘The findings are important for both individuals living with the conditions and healthcare providers, who should consider implementing additional examinations to help prevent type 2 diabetes onset in people suffering from depression.’

The study, published in Diabetes Care, used data from hundreds of thousands of people in the UK and Finland, including 19,344 people with type 2 diabetes, more than 5,000 people diagnosed with depression and 153,079 who self-reported depression.

Writing in the journal, researchers concluded: ‘Our results highlight the importance to prevent type 2 diabetes at the onset of depressive symptoms, and the need to maintain a healthy weight in the context of its effect on depression and type 2 diabetes comorbidity.’

Almost 4.3million people were living with diabetes in 2021/22, according to the latest figures for the UK.

And another 850,000 people have diabetes and are completely unaware of it.

This has concerned health officials as untreated type 2 diabetes can lead to complications including heart disease and strokes.

Approximately 90 per cent of diabetes cases are type 2 diabetes, which is linked with obesity and is typically diagnosed in middle age, rather than type 1 diabetes, a genetic condition usually identified early in life.