Loneliness Is Now Tied to 10 Diseases and Other Health Risks

“Mind over matter” may be a little more true than you think, and not always for the better.

Research shows that some feelings we experience in our minds can directly affect our physical health. One of those feelings is loneliness. It turns out our social circle influences our bodies, even if we don’t feel it right away.

Various studies have pinpointed specific disease and other health issues tied to loneliness. Let’s get into them.

1. Dementia

Florida State University researchers analyzed data from more than 600,000 people. The university says the study — published in the journal Nature Mental Health — is the biggest of its kind.

The researchers concluded that feelings of loneliness can increase the risk of developing dementia by 31%. Neither age nor sex affected these findings.

2. Stroke

Harvard researchers asked more than 12,000 people older than 50 who had never had a stroke to answer questions on the Revised UCLA Loneliness Scale. Researchers assessed participants twice, with the second time being four years after the first, placing them in groups by their loneliness scores.

Participants classified as baseline lonely had a 25% higher risk of stroke than those not considered lonely. Participants who reported loneliness during each of the two assessments (the “consistently high” group) had a 56% higher risk of stroke than those in the “consistently low” group.

“Loneliness is increasingly considered a major public health issue. Our findings further highlight why that is,” said lead author Yenee Soh, research associate in the Department of Social and Behavioral Sciences, in a press release.

3. Type 2 diabetes

Research from King’s College London found that higher loneliness levels are a “significant predictor” in the onset of type 2 diabetes later in life. Those findings were published in Diabetologia, the journal of the European Association for the Study of Diabetes

The study, which spanned 12 years, looked at 4,112 adults age 50 years and older. It found that the absence of quality human connections and not just a lack of contact predicted the onset of type 2 diabetes.

The association was independent of living alone, depression or social isolation, and remained intact despite such factors as smoking, alcohol, weight, level of blood glucose, high blood pressure and cardiovascular disease.

4. Depression

Research from University College London (UCL) and published in The Lancet Psychiatry journal found that loneliness is the leading cause of depression in adults over age 52 — making up 18% of cases.

Researchers discovered that feelings of loneliness were a greater risk factor than how many social connections a person actually had. They questioned 4,211 participants at regular intervals over 12 years to get these results.

“Building relationships, meaningful connections and a sense of belongingness may be more important than just increasing how much time people spend with others,” senior author Gemma Lewis said in a summary of findings.

5. Death

People who report more periods of feeling lonely have a higher mortality risk than those who report few or no periods of loneliness.

That was the finding of a study from the University of Michigan. Researchers used data from more than 9,000 participants aged 50 and older over eight years.

Researchers note, similar to the UCL study, that living alone or preferring solitude are not the same as feeling lonely.

“Even those who are socially isolated may not feel lonely. It’s the feeling of loneliness, of needing people and purpose and not getting it which appears to be bad for health,” said senior author Lindsay Kobayashi in a summary of the study. “As people age, they transition out of meaningful social roles. They need meaningful replacements. Maintaining integration with families is important, and can be a big source of meaning in life.”

6. Premature death

Research from the University of Chicago concluded that loneliness can increase the risk of premature death by 14% and the answer to “why” lies in our very makeup.

Loneliness is a stress signal to the body that causes it to produce fewer white blood cells. To better understand the cellular mechanism by which loneliness causes illness, researchers specifically looked at leukocytes — cells that are part of the immune system and protect against viruses and bacteria. Leukocytes in lonely participants showed an increase in genes associated with inflammation and a decrease in virus-fighting genes.

Researchers noted that this seems to have a cyclical effect, in which loneliness levels and gene changes seem to propagate each other.

7. Accelerated biological aging

A study from the Mayo Clinic and published by the American College of Cardiology reviewed data from more than 280,000 people.

It found a correlation between social isolation and accelerated biological aging. Biological age is determined by different properties in your cells, rather than chronological age, which is what we traditionally think of as aging.

This study found that a person’s body, especially the heart, ages faster than usual if they have higher levels of loneliness.

8. Cognitive decline

Loneliness affects various parts of your brain — including memory.

Research from Pennsylvania State University found that one or two days of loneliness correlates with decreased cognitive performance. This is a cyclical issue that reinforces itself. As cognitive performance decreases, loneliness increases.

The cognitive tests researchers gave participants to complete at home assessed their visual associative memory, spatial memory and processing speed. Study participants who were lonely during the day had a lower cognitive performance that same day and the next too.

9. Nightmares

Daytime loneliness can lead to nighttime issues.

Research from Oregon State University, published in the Journal of Psychology, studied 1,600 American adults aged 18 to 81.

Researchers found that lonely people are more likely to have bad dreams. Part of the reason seems to be stress, which is associated with loneliness.

10. Falling

A study from the University of Chicago Medicine reviewed data from 2,337 older adults and concluded that resolving issues of loneliness reduced the likelihood of fall-related morbidity and mortality.

The likelihood of having a fall in the span of at least five years increased by 1.11%  for every point increase on the UCLA Loneliness Scale.