The relationship between social isolation, social support, and loneliness with cardiovascular disease and shared risk factors: A narrative review

•Social health is an established risk factor for cardiovascular disease, however, the potential causal pathway between cardiovascular disease (and shared risk factors) is yet to be clearly established.•As social health is modifiable, intervention may be a potential avenue for reducing the burden of poor health outcomes such as CVD.•There is also a higher likelihood of reverse causation; poor social health could result from CVD and CVD risk factors. Cardiovascular disease (CVD) is the greatest contributor to global morbidity and mortality. Poor social health plays a critical role in CVD incidence. Additionally, the relationship between social health and CVD may be mediated through CVD risk factors. However, the underlying mechanisms between social health and CVD are poorly understood. Certain social health constructs (social isolation, low social support and loneliness) have complicated the characterisation of a causal relationship between social health and CVD. To provide an overview of the relationship between social health and CVD (and its shared risk factors). In this narrative review, we examined published literature on the relationship between three social health constructs (social isolation, social support, and loneliness) and CVD. Evidence was synthesised in a narrative format, focusing on the potential ways in which social health affects CVD, including shared risk factors. The current literature highlights an established relationship between social health and CVD with a likelihood for bi-directionality. However, there is speculation and varied evidence regarding how these relationships may be mediated through CVD risk factors. Social health can be considered an established risk factor for CVD. However, the potential bi-directional pathways of social health with CVD risk factors are less established. Further research is needed to understand whether targeting certain constructs of social health may directly improve the management of CVD risk factors. Given the health and economic burdens of poor social health and CVD, improvements to addressing or preventing these interrelated health conditions would have societal benefits.