Genetics, diet, and lifestyle are well-known factors that contribute to type 2 diabetes risk. But there may be a social component that strongly affects your chances of developing the disease, too, suggests a study published in September 2020 in Diabetologia.
Specifically, feeling lonely — even if you don’t live alone and you do have social interactions in your daily life — is associated with a higher risk for type 2 diabetes, the authors found.
For the study, researchers assessed loneliness by asking more than 4,000 adults without type 2 diabetes how often they felt they lacked companionship, felt left out, or felt isolated from others. Responses were averaged on a scale from 1 to 3 points, with higher scores indicating more frequent feelings of loneliness.
After about a decade of follow-up, a total of 264, or 6.4 percent, of participants developed type 2 diabetes. People with type 2 diabetes by the end of the study started out with average loneliness scores of 1.42, compared with 1.33 for individuals who didn’t develop type 2 diabetes.
Loneliness was associated with 46 percent greater odds of developing type 2 diabetes, the study found.
“The study shows a strong relationship between loneliness and the later onset of type 2 diabetes,” says the lead study author, Ruth Hackett, PhD, of the Institute of Psychiatry, Psychology, and Neuroscience at King’s College London in the United Kingdom.
“What is particularly striking is that this relationship is robust even when factors that are important in diabetes development are taken into account, such as smoking, alcohol intake, and blood glucose, as well as mental health factors such as depression,” Hackett says. “There was an independent effect of loneliness on the development of diabetes, above and beyond health behavior.”
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What the Research Says About Loneliness and Type 2 Diabetes
This is the first study to demonstrate that loneliness is linked to an increased risk of developing type 2 diabetes, says Andrew Steptoe, a doctor of science and doctor of philosophy and the head of the department of behavioral science and health at University College London in the United Kingdom.
Previous research has tied social isolation to a risk of type 2 diabetes, but this isn’t the same thing as loneliness, says Dr. Steptoe, who wasn’t involved in the current study. Loneliness is a subjective experience of dissatisfaction with social and personal relationships, and may not necessarily be linked objectively with how many close friends or social activities people have, Steptoe says.
Fewer close friends and social contacts are, however, associated with an increased risk of developing type 2 diabetes, according to a study published in December 2017 in BMC Public Health. This study looked at how many close friends and family members people had regular contact with in their daily lives and found that each one-person reduction in the size of these social networks was associated with a 12 percent higher chance of developing type 2 diabetes for men and 10 percent greater chance for women.
Isolation has also been tied to a greater risk of premature death in previous research, including a study published in December 2019 in Heart. For one year, this study followed individuals who had been hospitalized for heart problems. Women in the study who reported high levels of loneliness were three times more likely to die during the study, and lonely men were about twice as likely to die.
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Limitations of the Diabetes and Loneliness Study
One limitation of the current study is that researchers assessed loneliness only at a single point in time. Another is that the three-question loneliness evaluation used in the study didn’t enable researchers to examine nuanced variations in how people experience loneliness, social isolation, or living alone.
The study wasn’t designed to show how loneliness might cause type 2 diabetes. But it’s possible that so-called psychosocial stress that develops as a result of feeling lonely might lead people to have persistently elevated levels of the stress hormones epinephrine and cortisol, both of which can play a role in the development of type 2 diabetes, says Yacob Pinchevsky, PhD, of the faculty of health sciences at the University of the Witwatersrand in Johannesburg, South Africa.
“Put simply, the regular activation of stress-related biological systems due to chronic loneliness may lead to further wear and tear on the body, which could result in increased risk for the development of type 2 diabetes,” says Dr. Pinchevsky, who wasn’t involved in the latest study.
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Reducing Stress May Help Combat the Effects of Loneliness
It’s not clear from the study whether managing stress or making an effort to make more friends or to create a more active social life might reduce the risk of developing type 2 diabetes, says Sabine Rohrmann, PhD, MPH, of the Epidemiology, Biostatistics, and Prevention Institute at the University of Zurich in Switzerland.
Because loneliness can be subjective, more friends or social contacts don’t necessarily mean people will feel less lonely, says Dr. Rohrmann, who wasn’t involved in the study. Some people who push outside their comfort zone to socialize more may also feel stress as a result that triggers a surge in the cortisol and inflammation that contribute to the development of type 2 diabetes, Rohrmann adds.
This means people who worry about loneliness leading to type 2 diabetes may want to focus their prevention efforts on things that don’t cause stress for them, like eating healthier foods or exercising more.
“A walk in the park — even by oneself — is a good start,” Rohrmann suggests.