Study finds loneliness linked to diabetes

THE findings of a new study suggest that feelings of loneliness are linked to a significantly higher risk of that person developing Type 2 diabetes.

The research, published in Diabetologia (the journal of the European Association for the Study of Diabetes), was conducted by Associate Professor Roger E Henriksen and his colleagues at Western Norway University of Applied Sciences. As well as examining the association between loneliness and the risk of developing the disease, it looked at whether depression and insomnia played a role.

Loneliness creates a chronic and sometimes long-lasting state of distress which may activate the body’s physiological stress response. While the exact mechanisms are not fully understood, this response is believed to play a central role in the development of Type 2 diabetes through mechanisms such as temporary insulin resistance brought on by elevated levels of the stress hormone cortisol.

It also involves changes in the regulation of eating behaviour by the brain, causing an increased appetite for carbohydrates and subsequently elevated blood-sugar levels. Previous studies found an association between loneliness and unhealthy eating, including the higher consumption of sugary drinks and foods rich in sugars and fats.

The researchers used data from the HUNT study, a collaboration between the HUNT Research Centre (Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology), Trondelag County Council, the Central Norway Regional Health Authority, and the Norwegian Institute of Public Health.

This database contains the health information (from self-reported questionnaires, medical examinations and blood samples) of more than 230000 people, and was obtained via four population surveys.

Baseline information for 24 024 participants was taken from HUNT 2 after excluding individuals with metabolic disorders, Type 1 and Type 2 diabetes, and those for whom bloodtest data were not available. Type-2 diabetes status was the main outcome variable and was based on HbA1c (glycated haemoglobin – a measure of long-term blood-sugar control) being greater than 48mmol/mol when measured in the HUNT 4 survey.

Individuals with insomnia were identified based on their answers to the questions: “How often in the last three months have you”: “had difficulty falling asleep at night”, “woken up repeatedly during the night”, and “woken too early and couldn't get back to sleep” respectively. These were asked as part of HUNT 3, and participants could choose one of three answers: “never/seldom”, “sometimes”, and “several times a week”.

Out of 24024 people, 1179 (4.9%) went on to develop Type 2 diabetes over the course of the study (19952019). These individuals were more likely to be men (59% versus 44%) and had a higher mean age (48 years versus 43 years) than those without Type 2 diabetes. They were also more likely to be married (73% versus 68%) and have the lowest level of education (35% versus 23%). Feelings of loneliness were reported by 13% of participants.

The study found that higher levels of loneliness at baseline were strongly associated with a higher risk of Type 2 diabetes when measured 20 years later. After adjusting for age, sex and education level, they found that participants who responded “very much” when asked whether they had felt lonely were twice as likely to develop Type 2 diabetes than those who did not feel lonely.

Although their study did not examine the exact mechanisms involved, the researchers note that social support, influence and engagement may have positive effects on health-promoting behaviours. For example, advice and support from a friend may influence an individual’s health-related choices and positively affect his or her diet, physical activity level, and overall feelings of stress. Fewer social ties and a lack of these positive influences can make lonely people more vulnerable to behaviour which could increase the risk of developing Type 2 diabetes.

The researchers advise loneliness should be included in clinical guidelines relating to Type 2 diabetes. |