Loneliness was found to be a greater risk factor for cardiovascular disease (CVD) among adults with diabetes than a wide range of traditional lifestyle factors including diet, exercise, smoking, and alcohol consumption, according to study findings just published in the European Journal of Cardiology.1
Specifically, compared with study participants with the lowest score (0) on a validated scale of loneliness, the risk of developing CVD over a period of approximately 10 years was 11% and 26% higher among those with scores of 1 or 2, respectively, according to the published results. Investigators from the Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, reported similar findings for coronary heart disease (CHD) but a nonsignificant association of loneliness with stroke.1
When they evaluated the relationship between participants’ social isolation scores and CVD outcomes, the results were not significant.
“The quality of social contact appears to be more important for heart health in people with diabetes than the number of engagements,” said study author Lu Qi, MD, PhD, HCA Regents distinguished chair and professor at Tulane University, in an ESC statement. “We should not downplay the importance of loneliness on physical and emotional health.”2
Qi and colleagues cite findings from studies in the general population to suggest that both loneliness and social isolation are related to a greater likelihood of CVD. Their interest in this study was to better understand these associations specifically in a population with diabetes and to examine their relative importance compared to traditional risk factors. The research team also evaluated the interactions of loneliness or social isolation with the degree of risk factor control in relation to CVD risk.1
Investigators tapped the UK Biobank, retrieving data for 18 509 adults aged 37 to 73 years who had diabetes but did not have CVD at baseline. Mean age was 60 years; 40.2% were women; and the majority (91%) were White. Loneliness and isolation were assessed with a 2-item and 3-item scale, respectively. “High-risk” features were assigned 1 point each (Right). Qi et al assessed level of risk factor control based on HbA1c, blood pressure (BP), LDL-C, and renal function values within guideline-recommended target range, and smoking status.
The team reported the proportions of participants with loneliness and social isolation scores as follows:
During the mean follow-up period of 10.7 years Qi and team recorded 3247 CVD incidents, including 2771 CHD incidents and 701 strokes. In the fully adjusted model (controlled for sex, age, deprivation, BMI, medications, physical activity, diet, ETOH, tobacco use, and HbA1c, BP, and LDL-C control) compared with participants with scores of 0 on the loneliness scale, hazard ratios for CVD were 1.11 (95% CI, 1.02 to 1.20) and 1.26 (95% CI, 1.11 to 1.42) for participants with loneliness scale scores of 1 and 2, respectively (Ptrend<.001). As noted, the investigators observed no significant association between scores on the social isolation scale and CVD.1
When they assessed relative strength to predict CVD in individuals with diabetes, the investigators found that loneliness ranked higher than typical lifestyle factors utilized in current CV risk models. They also reported an additive interaction between loneliness and degree of risk factor control on CVD (Padditive interaction =.005).
“Specifically, if both loneliness and a low degree of risk factor control were present, this would result in an additional 8.5% of cases of CVD,” the researchers wrote.1 They add that despite the relatively modest effect size of the additive interaction, when multiplied by the growing numbers of people with diabetes worldwide, even a small increase is “considerable regarding the number of patients affected by CVD complications and therefore has important public health implications.”1
“Loneliness ranked higher as a predisposing factor for cardiovascular disease than several lifestyle habits. We also found that for patients with diabetes, the consequence of physical risk factors…was greater in those who were lonely compared to those who were not,” Qi said in the ESC statement.2
Writing in an accompanying editorial,3 Kai G. Kahl, PhD, professor in the department of psychiatry, social psychiatry and psychotherapy at Hannover Medical School, Hanover, Germany, and colleagues agreed with a statement by Qi that questions about loneliness and social isolation should become standard in clinical care for patients with diabetes and with CVD or at risk for the latter. They point to the simplicity of the 2- and 3-question assessments that might at least provide a window on what are very “complex constructs.”3
“We urge all health care professionals to treat social isolation and loneliness as the important biomarkers of CVD that they have been shown to be and refer respective patients to appropriate health care professionals,” they concluded.3