From raising your risk of diabetes to ageing you quicker than SMOKING: All the dangers of loneliness

In the digital age where working means never leaving your home for many, loneliness is an ever-growing problem that leaves people feeling isolated and scared.

But experts have shown the anxiety-inducing issue is not just having an impact on mental well-being — it damages people’s physical health too.

Everyone feels lonely from time to time, but chronic loneliness is not the same as having no friends or little social contact.

Many people live happy, solitary lives, while others can feel isolated even if they are in a loving relationship or have a big family.

The condition is about feeling misunderstood or uncared for and is particularly prevalent in older people who have retired or are bereaved.

Here MailOnline breaks down six of the biggest dangers of loneliness:

Ageing you quicker than smoking

Being lonely and unhappy can age you quicker than smoking, a study suggested this week.

A collaboration of researchers from Stanford University and the Chinese University of Hong Kong claimed the negative emotional effects of social isolation sped up people’s biological clocks more than cigarettes.

Feeling lonely, unhappy and hopeless was found to add up to an extra year and eight months onto someone’s age — five months more than smoking.

Experts believe the chronic inflammation, caused by being unhappy, damages cells and vital organs.

The study, published on Tuesday in the journal Aging-US, drew on data from 12,000 Chinese adults. 

Everyone has a chronological age — the amount of time they’ve physically been alive for.

Researchers, including scientists at Stanford University, in California, estimated how many years were added to someone’s life by the above. They used biological years, or how old a person ‘seems’ based on factors including blood, kidney status and BMI. This differs from the chronological age, or how long someone has been alive. Rural areas likely raised someone’s age because of a lack of access to hospitals, while never getting married has long been thought to raise someone’s risk of an earlier death

But people also have a biological age, which estimates the body’s decline based on factors including bodily functions and lifestyle.

Using blood samples, surveys and medical data, experts generated an aging model to predict participants’ biological age.

Participants were then matched by their chronological age and gender and had their results compared, to establish which were aging fastest.

Researchers did not specify how they defined loneliness. 

Laurie Theeke, an expert from George Washington University who was not involved in the study, told DailyMail.com that it was ‘no surprise’ that loneliness led to faster aging than smoking.

‘I have been studying this since 2002, and there are many national datasets that show loneliness leads to a shorter lifespan, higher mortality and more co-morbidities — so this doesn’t surprise me at all.’

She said lonely people tended to have higher inflammation and anxiety levels than others, and also be less active, both contributing to worse health.

Increasing the risk of dementia by up to 40 per cent

Loneliness has also been linked to dementia.

A study by Florida State University suggested it might increase the chances of getting dementia by around 40 per cent.

They believe the greater risk of depression, worse cardiovascular health and physical inactivity could be behind the relationship.

All three have been proven to increase the chances of the memory-robbing disease, with the latter two potentially starving the brain of oxygen by narrowing arteries. 

But the researchers also claimed the increased levels of stress caused by loneliness could also be boosting the risk.

High levels of the stress hormone cortisol has been linked to impaired memory and the wearing away of the part of the brain associated with remembering.

The research, published in the Journal of Gerontlogy in 2020, tracked nearly 12,000 people of 10 years.

Loneliness was defined based on whether participants said they had felt lonely in the last two weeks at the start of the study. 

Writing in the journal, Dr Angelina Sutin and colleagues said: ‘Loneliness has recently been identified as a significant public health problem but one that can be addressed with financial and institutional support. 

‘The research highlights one poor outcome associated with loneliness: Individuals with loneliness are more likely to develop dementia than less lonely individuals. 

‘Addressing this psychosocial risk factor will likely have a broad range of positive outcomes, including lowering risk and prevalence of dementia.’

Doubles the risk of type 2 diabetes 

Loneliness could double a person’s risk of developing type two diabetes because it can create a ‘long-lasting state of distress’, experts say.

Scientists believe that such distress can activate the body’s stress response.

While experts are not clear exactly how stress causes diabetes, high levels of cortisol have been shown to bring on temporary insulin resistance. 

When people eat carbohydrates, the food is broken down into blood sugar. This tells the pancreas to release insulin, which allows glucose to enter the body’s cells.

But over time, high blood sugar levels can cause insulin resistance. 

Because the insulin isn’t as effective at breaking down the sugars, it causes the body to produce more and more of it.

Eventually, this leads to the pancreas becoming worn out, sending the system out of whack and causing blood sugar levels to stay high.

The Norwegian team analysed health information of more than 24,000 people, 1,179 of whom went on to develop type two diabetes, via population surveys between 1995 and 2019.

Loneliness was gauged using a survey that asked respondents whether they had felt lonely over the past two weeks on a four-point scale of ‘no’, ‘a little’, ‘a good amount’ and ‘very much’.

The findings, published in the European Association for the Study of Diabetes’s journal Diabetologia this week, showed that higher levels of loneliness were strongly associated with a higher risk of type two diabetes when measured 20 years later.

After adjusting for age, sex and education level the team found that participants who responded ‘very much’ were twice as likely to develop type two diabetes than those who did not feel lonely.

Writing in the study, the team at Western Norway University of Applied Sciences in Bergen, said: ‘This study suggests that loneliness may be one factor that increases the risk of type 2 diabetes.

‘We recommend that loneliness should be included in clinical guidelines on consultations and interventions related to type 2 diabetes.’

Boosts the chances of heart disease and stroke by up to a third

Ensuring people are less lonely could also help reduce their risk of heart problems, such as stroke.

British researchers found having poor social relationships increased the chance of coronary heart disease (CHD) by 29 per cent.

And it boosted the risk of stroke by 32 per cent. 

The team from the University of York said their observational study could only prove loneliness was linked to the two conditions, not behind them.

But previous research has also linked heart disease to stress and inflammation — a collateral effect of loneliness.

The team behind the latest research said public health policy should aim to address social isolation to prevent the two deadly diseases. 

Their review, published in the journal Heart in 2016, looked at 23 studies, 11 of which focused on heart disease and eight on stroke.

The studies measured social isolation and loneliness in participants. 

The researchers said: ‘The main finding of our review, that isolated individuals are at increased risk of developing CHD and stroke, supports public health concerns over the implications of social relationships for health and well-being. 

‘Our work suggests that addressing loneliness and social isolation may have an important role in the prevention of two of the leading causes of morbidity in high-income countries.’

Associated with higher levels of obesity 

Because of some of the problems mentioned already, research has shown loneliness can be as great a health risk as obesity.

But some studies have also shown it is associated with people putting on too much weight, as well.

Understandably, people can resort to ditching exercise or comfort eating when feeling sad and alone.

This can lead to them putting on weight and becoming obese, increasing the risk of the knock-on effects of being fat.

However, the relationship can also work the other way. Some research has suggested that obese people are more likely to become isolated.

Extremely obese people can often feel stigmatised, increasing how lonely they feel or causing them to be less social. 

A review of six papers looking into obesity and loneliness or self-isolation found an association between the two in some — but not all — studies.  

The review was published in the journal Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy last year. 

The team from the University Medical Center Hamburg-Eppendorf in Germany said the studies presented a mixed picture.

They said: ‘While some studies point to an association between obesity and increased loneliness levels, it should be acknowledged that findings are mixed.

‘Further research is required to shed further light on these associations.’ 

‘Moderately significant effect’ on depression 

Loneliness has consistently been linked to depression, too.

Being on your own and feeling uncared for produces immediate feelings of sadness and low mood.

If this feeling persists for weeks or months, it could be a sign of clinical depression, which can also be accompanied by hopelessness, poor concentration and suicidal thoughts.

But much like with obesity, the link to loneliness is murky and could actually be caused the other way round.

When someone is depressed, they are more likely to stay inside and stop seeing their friends, increasing their chances of loneliness.

It means the two issues can result in a never-ending cycle without treatment. 

A large-scale review by Turkish researchers found loneliness has a ‘moderately significant effect on depression’. 

The review, published in the International Journal of Social Psychiatry in 2018, looked at 88 studies.

In total, around 40,000 participants were analysed. 

Results showed loneliness impacted depression in everyone studied, but especially carers, hospital patients, students and the elderly. 

Dr Evren Erzen, of Artvin Coruh University, and colleagues said a sense of not belonging may indirectly lead to depression.

Writing in the journal, they said: ‘Society leaves patients, carers and elderly alone with their problems and they distance from daily life, experiencing depression. 

‘In addition, problems experienced in the period of puberty leads teenagers who believe that no one understands them to experience feelings of loneliness which may cause depression. 

‘The need to feel a sense of belonging may be seen as the common characteristic between these two groups with very different age profiles and social environments.’