Social Isolation, Loneliness, and Risk of Microvascular Complications Among Individuals With Type 2 Diabetes Mellitus.

Rationale & Objective: Social disconnection has been associated with poor cardiometabolic health. This study sought to investigate the associations of social isolation and loneliness with diabetic microvascular complications (DMCs) among individuals with type 2 diabetes mellitus (T2DM) and compare these associations versus those related to traditional risk factors.

Study Design: Prospective cohort study.

Setting & Participants: A total of 24,297 UK Biobank participants with T2DM and no DMCs at baseline.

Exposure: Social isolation and loneliness were measured using self-reported questionnaires.

Outcome: The incidence of DMCs defined as a composite of diabetic kidney disease, diabetic retinopathy, or diabetic neuropathy.

Analytical Approach: Multivariable cause-specific hazards regression. To compare the relative importance of social disconnection with other established factors, the R values of the Cox models were calculated.

Results: During a median follow-up of 12.6 years, 5,530 patients were documented to experience DMCs (3,458 with diabetic kidney disease, 2,255 with diabetic retinopathy, and 1,146 with diabetic neuropathy). The highest level of social isolation was associated with an increased risk of any DMC component (most vs least: HR, 1.13; 95% CI, 1.05-1.22), especially diabetic kidney disease (HR, 1.14; 95% CI, 1.04-1.25) and neuropathy (HR, 1.31; 95% CI, 1.11-1.53). Any level of loneliness was associated with an increased risk of any DMC component (HR, 1.12; 95% CI, 1.02-1.23) and diabetic kidney disease (HR, 1.16; 95% CI, 1.03-1.30). Social isolation and loneliness exhibited associations with DMCs comparable to those of other conventional risk factors, including smoking, blood pressure, and physical activity.

Limitations: Limited generalizability related to the composition of participants in the UK Biobank Study.

Conclusions: Social isolation and loneliness were independently associated with a higher risk of incident DMCs among individuals with T2DM, with comparable importance to other traditional risk factors. These findings underscore social isolation and loneliness as novel and potentially modifiable risk factors for DMCs.

Plain-language Summary: Social isolation and loneliness are important social determinants that are associated with adverse cardiometabolic health. Individuals with diabetes are particularly vulnerable to social isolation and loneliness. However, the relationship of social isolation or loneliness with diabetic microvascular complications (DMCs) remains unclear. Our study used the UK Biobank study data to investigate the associations of social isolation and loneliness with the development of DMCs. We found that social isolation and loneliness were independently associated with a higher risk of incident DMCs. Remarkably, their association with DMCs was comparable to those of other lifestyle factors such as smoking, blood pressure, and physical activity. These findings collectively imply that social isolation and loneliness are 2 important potentially modifiable risk factors for DMCs among individuals with type 2 diabetes mellitus.