UPDATED 10/21/2023

Loneliness is more than an emotion. It is an experience. That experience can affect your mental well-being but it can also play a role in your physical health. Here is research to show how it can impact you and what you can do about it.

Loneliness is far more than just a bad feeling—it harms both individual and societal health. It is associated with a greater risk of cardiovascular disease, dementia, stroke, depression, anxiety, and premature death. The mortality impact of being socially disconnected is similar to that caused by smoking up to 15 cigarettes a day, and even greater than that associated with obesity and physical inactivity. And the harmful consequences of a society that lacks social connection can be felt in our schools, workplaces, and civic organizations, where performance, productivity, and engagement are diminished.

Dr. Vivek H. Murthy, The 2023 U.S. Surgeon General’s Advisory on the
Healing Effects of Social Connection and Community

One is the Loneliest Number

Living alone may increase the risk for cancer death.

Diagnosis Life summary:
A study published in Cancer (https://doi.org/10.1002/cncr.35042) looked at more than 473,000 people between the ages of 18 and 64 over a period of 22 years. Of those people, 114,772 adults lived alone and 358,876 lived with someone else. Over that time, 2.5% of those living alone died from cancer compared to only 1.6% living with others. That is a 32% increased risk! That risk was even higher for men, 38% for men vs. 30% for women. It goes to show that there are health benefits to being around other people that goes far beyond having friends and family around.

Dogs really are man’s best friend.

Diagnosis Life summary:
A study published in Nature (https://doi.org/10.1038/s41598-017-16118-6) reveals what all dog owners already know — dogs really are man’s best friend. Researchers reviewed the health records of 3.4 million people in Sweden. People who owned a dog were less likely to have heart disease or die from any cause during the 12 years covered by the study. The protective effect was particularly prominent for people living alone, who usually have a higher risk of early death than those who live with other people.

Mental health disorders may be more common in people who live alone.

Diagnosis Life summary:
Do you live alone? A study in PLOS One (https://doi.org/10.1371/journal.pone.0215182) used Britain’s National Psychiatric Morbidity Surveys from 1993, 2000, and 2007 to look for the prevalence of common mental health conditions (e.g., depression and anxiety disorders) in people who lived alone. Mental health issues were more 63-88% more likely in people living alone but the researchers attributed 84% of that to loneliness. Living alone makes you independent not lonely. You can choose to make meaningful social connections and engage with others. Whether’s its a Zoom chat or a phone call, stay in touch with the people you care about. It’s good for your health.

Middle-aged men may be at increased for cancer if they are lonely.

Diagnosis Life summary:
A study in Psychiatry Research (https://doi.org/10.1016/j.psychres.2021.113868) screened for loneliness and/or social isolation in 2,570 middle-aged men. Over the study period, 649 participants (25.3%) developed cancer. Men who were lonely or isolated had an increased incidence for cancer. However, only loneliness remained a factor when lifestyle and health factors were taken into consideration. Interestingly, loneliness was associated with lung cancer but not colon or prostate cancer.

One out of five people suffers from loneliness.

Diagnosis Life summary:
In this age of social media, you would think that it would be easier for people to connect with one another. After all, you are only a click away from anyone anywhere in the world. It turns out that is far from true. A prevalence study in the Annals of Family Medicine (https://doi.org/10.1370/afm.2358) found that on average 20% of people reported feelings of loneliness or isolation. That number increased to 33% when looking at people between 18 and 24 years old but decreased to 11% for those over 65. It seems that those more likely to use social media may be furthest removed from making meaningful connections. Unfortunately, that has real-life consequences. Researchers, in this study and others, find that loneliness correlates with lower ratings for physical and mental health.

People who are hospitalized for heart disease may be at higher risk for complications if they are lonely.

Diagnosis Life summary:
Feeling lonely is bad for your health. A study in Heart (https://doi.org/10.1136/heartjnl-2019-315460) looked at more than 13,000 adults who had been hospitalized because of heart disease (cardiac arrhythmias, heart attacks, heart failure, and “bad” heart valves). Each study participant completed a survey during their initial hospital stay. After one year, the researchers then used registries to see how the participants fared. They found that people hospitalized with heart disease were at higher risk for dying after one year if they lived alone or if they were feeling lonely. Lonely women had a near 3-fold higher risk and men a more than 2-fold risk than their non-lonely counterparts. This is why it is so important that we try to connect with people, whether it is with people in our personal life or even in a rehab setting. Our health depends on it.

Social isolation may increase the risk for dementia in older adults.

Diagnosis Life summary:
A study in Neurology (https://doi.org/10.1212/WNL.0000000000200583) looked at the effect of social isolation on more than 462,000 adults without dementia who lived in the U.K. (average age 57). Approximately 5,000 of them developed dementia within 12 years. Social isolation, regardless of whether someone felt lonely or had depressive symptoms, increased that risk by 25%. Loneliness, especially if there were depressive symptoms attached, increased the risk by 4%.

Social isolation may increase the risk for heart attack and stroke.

Diagnosis Life summary:
A study in Lancet (https://doi.org/10.1016/S2468-2667(20)30291-7) looked at social isolation in nearly 940,000 adults in the U.K (14% designated as most isolated, 46% moderately isolated, 40% least isolated = control group). Over 7 years, 42,402 had a first-time cardiac events and 19,999 had a first-time stroke. People living alone and who had less contact with friends/family/groups were more than twice as likely to have an event (60% vs. 27%). Social isolation also increased the risk for dying from that event but only if the person did not go the hospital. Those who did not seek hospital care had fatalities as high as 86% for cardiac events and 91% for stroke. People in the most isolated group were also more likely to be in poor health, physically inactive, obese, or smokers, which could have also impacted the outcomes.