A new study has suggested that loneliness may be a significant risk factor for the development of type 2 diabetes.
The work, published last week in the journal Diabetologia, examined a large public health data set detailing the physical and mental health of about 24,000 Norwegian adults. Study participants completed a questionnaire in the mid-90’s, and researchers followed their progress until the present day. By the end of 2019, more than a thousand had been diagnosed with type 2 diabetes. An analysis showed that those that reported the highest level of loneliness were twice as likely to develop diabetes as those without feelings of loneliness.
Why would loneliness, of all things, help cause diabetes? Although the study was not designed to answer that question, the authors speculated on possible mechanisms, both chemical and behavioral:
Loneliness is known to trigger a chemical stress response, including excessive secretion of the hormone cortisol, which causes inflammation, heightened glucose levels, and insulin resistance.
Loneliness affects appetite and eating behavior, increasing sugar cravings and other poor dietary choices.
Lonely people may also be less likely to make healthy lifestyle choices. Friends, loved ones, and acquaintances in the community can be a source of positive peer pressure. And you may be more likely to exercise, leave the house, or even just get off the couch if you’ve got friends to see.
The researchers also identified a link between loneliness, diabetes, and insomnia. Lack of sleep, which can be precipitated by the chronic stress associated with loneliness, has been independently linked with diabetes risks and with sugar cravings.
The study is not, by any means, definitive. It wouldn’t be wise to put too much credence into the results of a short questionnaire completed nearly 30 years ago. Nevertheless, it’s not the first such paper to link diabetes and loneliness. A 2017 study found that socially isolated adults are more likely to have type 2 diabetes, while a 2021 study found that loneliness is a stronger predictor of higher A1C levels than depression.
It appears that the causality can proceed in both directions: People with diabetes are more likely to be lonely, and people with loneliness more likely to develop diabetes, a two-way street with the potential to create a vicious cycle. In fact, loneliness is associated with many unfortunate health outcomes, including cardiovascular disease and dementia.
Although the present study doesn’t test the effect of interventions to address loneliness in people that already have type 2 diabetes, other studies have shown that social activity can yield metabolic improvements. It seems probable that behaviors designed to combat loneliness in people with diabetes could deliver health improvements for many.
The authors, a team of experts from Western Norway University of Applied Sciences, believe that their research should help clinicians and diabetes educators to focus more closely on the surprising metabolic impact of loneliness:
We recommend that loneliness should be included in clinical guidelines on consultations and interventions related to type 2 diabetes. It is important that healthcare providers are open to dialogue about an individual’s concerns during clinical consultations, including with regard to loneliness and social interaction.
To read more about loneliness – and find some recommendations on how to get help – we recommend this article by our partners Everyday Health: All About Loneliness: What Causes It, How to Cope With It, and When to Get Help.