Social Isolation and Adult Mortality

Abstract

The health and survival benefits of social embeddedness have been widely documented across social species, but the underlying biophysiological mechanisms have not been elucidated in the general population. We assessed the process by which social isolation increases the risk for all-cause and chronic disease mortality through proinflammatory mechanisms. Using the 18-year mortality follow-up data (n = 6,729) from the National Health and Nutrition Examination Survey (1988–2006) on Social Network Index and multiple markers of chronic inflammation, we conducted survival analyses and found evidence that supports the mediation role of chronic inflammation in the link between social isolation and mortality. A high-risk fibrinogen level and cumulative inflammation burden may be particularly important in this link. There are notable sex differences in the mortality effects of social isolation in that they are greater for men and can be attributed in part to their heightened inflammatory responses.

Social Network Ties and Inflammation in U.S. Adults with Cancer

“…In addition, positive links between social isolation and impaired immunity have been found in both animal and human studies. For instance, social isolation promotes immune dysfunction by slowing wound healing in rats (Hermes et al 2006); enhancing the peripheral production of pro-inflammatory cytokines (Dowd et al 2007); and increasing levels of several inflammatory markers, including C-reactive protein (CRP), fibrinogen, and serum albumin (Yang et al 2013). …”

“…Although a wide variety of illnesses and conditions have been linked to social network ties (see, e.g., the review by Yang et al [2013]), cancer has been less studied at the population level. However, this area of study deserves more attention, because cancer is the second-leading cause of death in the United States, and there is increasing evidence that social disconnectedness is consequential for cancer-related outcomes (see, e.g., the review by Penwell and Larkin [2010]).…”

“…In humans, higher levels of social embeddedness and support have been found to be associated with better survival from breast (Kroenke et al2013), colorectal (Ikeda et al 2013), and lung cancer (Kemeny and Schedlowski 2007). Social isolation, on the other hand, appears to increase the risks of mortality from breast (Kroenke et al 2006), lung, and other cancers (Yang et al 2013). Although social disconnectedness has been related to poor immunocompetence in general, how it is related to inflammation for individuals afflicted with cancer is not clear.…”

“…Higher CRP concentrations have been found among individuals living with colorectal (Erlinger et al 2004), kidney, and all-cause cancers (Johnson and Master 2010). In patients diagnosed with cancer, increasing levels of inflammation marked by CRP concentration and low serum albumin have predicted poor cancer prognosis across multiple sites, independent of stage (McMillan 2009; Hickman et al 1980); increased metastasis; and decreased cancer-specific survival (Canna et al 2004, Jabs et al 2005; Pierce et al 2009; Yang et al 2013). An elevated plasma fibrinogen level has also been shown to increase cancer mortality in men (Yano et al 2001; Yang et al 2013).…”

Prestroke Living Situation and Depression Contribute to Initial Stroke Severity and Stroke Recovery

“…Patients with poor social support were found to have a decreased protective immune response against viral infection [41] and enhanced inflammation has been suggested as a possible mechanism mediating the detrimental effects of isolation[42]. An association has been described between social isolation and concomitant depression with increased levels of inflammatory markers such as IL-6 and CRP [43].…”