People who feel lonely are more likely to develop type 2 diabetes, according to a new Norwegian study that analyzed data collected from more than 24,000 people over more than 20 years. Diabetes has become one of the top 10 causes of death worldwide, according to the World Health Organization (WHO), with the number of people living with the disease increasing significantly over the past twenty years. The WHO also reported a 70 percent increase since 2000, stating that the disease was behind the largest rise in male mortality among the top 10 global health-related causes.

Also, the latest peer-reviewed study on diabetes, published in the European Association for the Study of Diabetes journal, relies on recent research suggesting that feelings of loneliness and psychological stress may be risk factors for type 2 diabetes, as it is one of the first population studies to analyze this link. While researchers are still trying to understand the relationship between stress and type 2 diabetes, high levels of cortisol, a stress hormone, are believed to cause temporary insulin resistance. This, in turn, can affect how the brain regulates eating behaviors, such as cravings for more carbohydrates, which can raise blood sugar levels.

In the same context, researchers at the Western Norway University of Applied Sciences examined this association and whether it could also be a result of depression and insomnia, both of which have been linked to loneliness and diabetes. The data collected from the Hunt study, a collaboration between the Norwegian Centre for Science and Technology Research and several Norwegian organizations and authorities, was used by the researchers for the analysis. The Hunt study collected information from self-reported questionnaires, medical examinations, and blood samples in four population surveys conducted between 1984 and 2019 from more than 230,000 people. The researchers focused on data collected from 24,024 individuals between 1995 and 1997 as a baseline and whether these individuals eventually developed type 2 diabetes over more than two decades. Scientists found that those who expressed feelings of loneliness at baseline from 1995 to 1997 "were strongly associated with an increased risk of developing type 2 diabetes." The study found that 4.9 percent of people in the group, or 1,179, developed type 2 diabetes. Nearly 13 percent of study participants also reported experiencing varying degrees of loneliness. The results showed that men were more likely to develop type 2 diabetes at 59.3 percent compared to 44 percent of women and were older, averaging 47.9 years. Type 2 diabetes patients were more likely to be married, at 73.1 percent, compared to 67.5 percent, and had lower levels of education, at 34.8 percent compared to 23.3 percent.

The latest research supports findings from two prospective studies that finally examined loneliness and the risk of type 2 diabetes and found loneliness to be a "significant indicator" of the disease after adjusting for various factors such as gender, education, alcohol consumption, physical activity, and body mass index. The researchers expressed some caution when interpreting their results, although they were consistent with previous studies. Some follow-up data from the most recent population survey conducted between 2017 and 2019 were incomplete, and a large number of participants were excluded from the latest survey due to missing information on blood test results. The authors also noted that both factors were potential sources.