Loneliness and social isolation pose a greater health risk than obesity, researchers say.

Obesity is considered to be one of the main health problems internationally. Worldwide, more than two billion people are overweight or even obese. In the United States, more than 40% of the population is obese. But new research reveals an even greater health threat: loneliness and social isolation.

Social connection is a basic need

“Being socially connected to others is generally seen as a basic need for a person, crucial to both well-being and survival,” explains psychologist and co-author of the study, Prof. Julianne Holt-Lunstad of Brigham Young University in Provo, Utah. But the number of adults living alone is increasing. The trend of being less socially connected and experiencing more loneliness is constantly increasing.

Two meta-analyses reveal that loneliness and social isolation increase the risk of premature death by up to 50 percent. Prof. Julianne Holt-Lunstad and her colleagues presented the results at the 125th Annual Congress of the American Psychological Association (APA) in Washington.

Loneliness and social isolation are not the same

Although the terms loneliness and social isolation are used interchangeably, there are notable differences between the two. Social isolation is defined as a lack of contact with other people, while loneliness embodies the feeling of not being emotionally connected to others. Essentially, this means that a person can also feel lonely in the presence of other people.

According to a 2016 survey of more than 2,000 American adults, 72 percent have felt lonely at some point in their lives, and 31 percent of respondents even felt loneliness at least once a week. Both loneliness and social isolation are associated with poor health. A study last year described a possible link to Alzheimer’s disease, and another study found a link between social isolation and a lower survival rate in breast cancer patients.

For the her study, Prof. Holt-Lunstad and her team tried to determine how loneliness and social isolation affect the risk of early death.

Reliable evidence that loneliness kills

The research is based on two meta-analyses of studies that have investigated a link between loneliness, social isolation and mortality. The first meta-analysis involved more than 300,000 adults in 148 studies, and the second meta-analysis consisted of 70 studies involving more than 3.4 million adults.

Data from the first meta-analysis revealed that the risk of premature death in adults is 50 percent lower if they have more connections to other individuals.

Using the second meta-analysis, the scientists found that loneliness, social isolation, and living alone were all associated with an increased risk of early death. The risk was even similar to or even greater than premature death from obesity or other known risk factors.

A “loneliness epidemic”

Prof. Holt-Lunstad finds these results particularly worrying, given that the ageing population is increasing. “Indeed, many nations around the world now suggest we are facing a ‘loneliness epidemic. The challenge we face now is what can be done about it.”” she adds. “The challenge now is what we can do about it.”

Prof. Holt-Lunstad believes that more resources need to be channelled into the fight against loneliness among individuals and within society. For example, she suggests that more attention should be paid to the practice of social skills in school children, and that doctors also keep an eye on the presence of social contacts with their patients by default.

Furthermore, Prof. Holt-Lunstad says that older adults should not only prepare for the financial changes in retirement, but also for the changes in the social environment, because often many of the social contacts are related to the workplace. Urban planners should think of places and spaces that are shared and inviting to meetings and communication, such as leisure centers or city parks.

How loneliness affects the brain

Loneliness activates the regions in the brain that monitor threats, a study reports. This makes people who are socially isolated harder and more dismissive: as a form of self-preservation. It can push lonely people to the margins of society.

Professor John Cacioppo, an expert in the field of loneliness, reports on this in an earlier study and says: “We discovered an extraordinary pattern of spread that takes people to the edge of the social network when they become lonely. There, people have fewer friends, and loneliness means that they lose the few connections they had.

These mutually reinforcing effects mean that our social structure frays at the edges, like yarn that detaches at the end of a crochet sweater.”

Loneliness makes you more sensitive to social threats

The study by Prof. Cacioppo and his team compared the brains of lonely and non-lonely people with the help of an electrocardiogram. Participants were shown a series of words that differed in how social and positive they were. The brains of lonely people quickly discovered words associated with social threats – such as “hostile” – than those who did not suffer from loneliness.

However, the lonely people were also more generally looking for words with negative associations. But this could be an ancient defense mechanism for survival, the study authors argue: “Fish on the edge of a group are more likely to be attacked by enemies; not because they are the slowest or weakest, but because they are easier to isolate and hunt. This has led to the behavior of fish swimming into the center of the swarm when predators attack. Behind this lies an evolutionary theory,” the researchers say. “Standing on the edge of a social group is not only sad, but downright dangerous. Our evolutionary model of perceived social isolation (loneliness) on the brain, as well as a growing number of behavioral research, suggest that loneliness promotes self-preservation in the short term, including increased indirect vigilance against social threats.”