Loneliness increases the risk of type 2 diabetes: a 20 year follow-up – results from the HUNT study

• Published in: Diabetologia Vol. 66; no. 1; pp. 82 - 92
• Main Authors: Henriksen, Roger E., Nilsen, Roy M., Strandberg, Ragnhild B.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.01.2023; Springer Nature B.V
• Subjects: Clinical practice guidelines; Diabetes; Diabetes mellitus (non-insulin dependent); Diabetes Mellitus, Type 2 - epidemiology; Follow-Up Studies; Human Physiology; Humans; Insomnia; Internal Medicine; Loneliness; Medicine; Medicine & Public Health; Mental depression; Metabolic Diseases; Norway - epidemiology; Population studies; Risk factors; Sleep disorders; Surveys; Norway; Type 2 diabetes; Loneliness; HUNT study; Depression; Insomnia
• ISSN: 0012-186X; 1432-0428
• DOI: 10.1007/s00125-022-05791-6

Aims/hypothesis Type 2 diabetes is one of the leading causes of death globally and its incidence has increased dramatically over the last two decades. Recent research suggests that loneliness is a possible risk factor for type 2 diabetes. This 20 year follow-up study examined whether loneliness is associated with an increased risk of type 2 diabetes. As both loneliness and type 2 diabetes have been linked to depression and sleep problems, we also investigated whether any association between loneliness and type 2 diabetes is mediated by symptoms of depression and insomnia. Methods We used data from the Trøndelag Health Study (HUNT study), a large longitudinal health study based on a population from central Norway ( n =24,024). Self-reports of loneliness (HUNT2 survey, 1995–1997) and data on HbA 1c levels (HUNT4 survey, 2017–2019) were analysed to evaluate the associations between loneliness and incidence of type 2 diabetes. Associations were reported as ORs with 95% CIs, adjusted for sex, age and education. We further investigated the role of depression and insomnia as potential mediating factors. Results During the 20 year follow-up period, 4.9% of the study participants developed type 2 diabetes. Various degrees of feeling lonely were reported by 12.6% of the participants. Individuals who felt most lonely had a twofold higher risk of developing type 2 diabetes relative to those who did not feel lonely (adjusted OR 2.19 [95% CI 1.16, 4.15]). The effect of loneliness on type 2 diabetes was weakly mediated by one subtype of insomnia but not by symptoms of depression. Conclusions/interpretation This study suggests that loneliness may be one factor that increases the risk of type 2 diabetes; however, there is no strong support that the effect of loneliness on type 2 diabetes is mediated by depression or insomnia. We recommend that loneliness should be included in clinical guidelines on consultations and interventions related to type 2 diabetes. Graphical abstract