A scientific statement from the American Heart Association about objective and perceived social isolation and its effects of cardiovascular health was published in the Journal of the American Heart Association.
It is well established in the literature that loneliness, isolation, and other social determinants are important for shaping cardiovascular health. Nearly a quarter of Americans aged 65 years or older are socially isolated, and a consequence of the COVID-19 pandemic has been an increase in social isolation, especially among young and older adults, women, and individuals with low-income.
The relationship between social isolation, loneliness, and incident coronary heart disease (CHD) remains unclear. A meta-analysis of 11 CHD and 8 stroke studies found evidence of increased risk for CHD associated with social isolation or loneliness (relative risk [RR], 1.29; 95% CI, 1.04-1.59). However, another study that pooled data from the Million Women study and UK Biobank found no relationship between social isolation incident CHD (RR, 1.01; 95% CI, 0.98-1.04).
After developing CHD, evidence supported a relationship between CHD death before reaching the hospital and social isolation (RR, 1.86; 95% CI, 1.64-2.12). Similarly, an all-women study and an all-men study found evidence that social isolation was associated with increased risk for fatal CHD and all-cause mortality, respectively.
A systematic review found that among patients with existing CHD, social isolation increased morbidity and mortality by 2- to 3-fold for up to 6 years, after correcting for cardiac risk factors. Conversely, another systematic review found no evidence that poor structural support increased risk for cardiac mortality (RR, 1.56; 95% CI, 0.94-2.58) or the composite outcomes of cardiac and all-cause mortality (RR, 1.12; 95% CI, 0.98-1.29).
For heart failure (HF), there was limited data supporting a causal relationship between social isolation and incident HF.
The statement authors sought to understand potential mediators of the relationship between cardiovascular health and isolation. They found 3 potential domains: behavioral, psychological, and physiological.
There was evidence that known behavioral risk factors for cardiovascular disease (CVD) may be affected by social isolation and loneliness. For example, several studies have found positive relationships between smoking behaviors and loneliness and greater isolation has been associated with more sedentary time and consumption of fewer fruits and vegetables.
Both the psychological factors of depression and psychological distress have been related with loneliness.
For physiological factors, there is a potential relationship between loneliness and social isolation with inflammation, sleep, and allostatic load, however, the studies explicitly testing the mediation between isolation and CVD are sparse.
No studies about potential interventions for mitigating the adverse effects of social isolation or loneliness on cardiovascular health were found in the literature.
The statement authors wrote, “Social isolation and loneliness are common, yet underrecognized determinants of cardiovascular health and brain health. Overall, findings suggest an increased risk of worse outcomes among individuals with prevalent CHD and stroke in those who are also socially isolated or lonely; however, these studies do not suggest causality, and associations may be mediated by other factors that need to be further tested in intervention trials.”
Cené CW, Beckie TM, Sims M, et al. Effects of objective and perceived social isolation on cardiovascular and brain health: a scientific statement from the American Heart Association. J Am Heart Assoc. Published online August 14, 2022. doi:10.1161/JAHA.122.026493