Loneliness Compromises the Immune System

Researchers from Ohio State University (Ohio, USA) report that loneliness is linked to a number of dysfunctional immune responses, suggesting that being lonely has the potential to harm overall health. Lisa Jaremka and colleagues studied two populations: a healthy group of overweight middle-aged adults and a group of breast cancer survivors. The researchers measured loneliness in all studies using the UCLA Loneliness Scale, a questionnaire that assesses perceptions of social isolation and loneliness. The researchers first sought to obtain a snapshot of immune system behavior related to loneliness by gauging levels of antibodies in the blood that are produced when herpes viruses are reactivated.  Participants were 200 breast cancer survivors who were between two months and three years past completion of cancer treatment with an average age of 51 years. Their blood was analyzed for the presence of antibodies against Epstein-Barr virus and cytomegalovirus.  Lonelier participants had higher levels of antibodies against cytomegalovirus than did less lonely participants, and those higher antibody levels were related to more pain, depression and fatigue symptoms.  As well, levels of the cytokine interleukin 1-bet were higher in lonelier participants. In an additional set of studies, the researchers sought to determine how loneliness affected the production of proinflammatory proteins, or cytokines, in response to stress. These studies were conducted with 144 women from the same group of breast cancer survivors and a group of 134 overweight middle-aged and older adults with no major health problems.   Baseline blood samples were taken from all participants, who were then subjected to stress – they were asked to deliver an impromptu five-minute speech and perform a mental arithmetic task in front of a video camera and three panelists. Researchers followed by stimulating the participants' immune systems with lipopolysaccharide, a compound found on bacterial cell walls that is known to trigger an immune response. In both populations, those who were lonelier produced significantly higher levels of a cytokine called interleukin-6, or IL-6, in response to acute stress than did participants who were more socially connected.