While everyone needs alone time now and again, studies continue to show that social isolation can have a negative impact on health. Just this month, new research linked social isolation with inflammation.
“Social isolation and loneliness have been associated with poor health and increased risk for mortality, and inflammation might explain this link,” said the study authors. Systemic chronic inflammation is associated many major chronic illnesses, including Alzheimer’s disease, cancer and heart disease, according to Franciscan Health.
Specifically, researchers who conducted the new study found that childhood social isolation was “longitudinally associated with elevated levels of soluble urokinase plasminogen activator receptor (suPAR),” a biomarker for chronic inflammation. Other chronic inflammation biomarkers include C-reactive protein and interleukin-6, but suPAR was most closely linked to social isolation, per the study.
“Systemic chronic inflammation might be one biological pathway through which social isolation becomes embedded within people’s physiology,” said the researchers.
They used data from a clinical sample and two nationally-representative birth cohorts: the Danish TRIAGE Study of acutely admitted medical patients, the New Zealand Dunedin Longitudinal Study and the UK Environmental Risk (E-Risk) Longitudinal Twin Study. Across all the cohorts, social isolation was associated with elevated inflammation.
“Our analyses revealed that social isolation and loneliness were associated with inflammation even after controlling for BMI and smoking, supporting the hypothesis of a direct, biological effect of social isolation/loneliness on inflammation, rather than an effect mediated by health-related behaviors,” the study authors revealed.
Social isolation had a stronger link to elevated inflammation than feelings of loneliness. On the other hand, loneliness in mid-adulthood (not early adulthood) was also associated with elevated suPAR, and other research has pointed to health risks associated with loneliness.
Last May, a report from U.S. Surgeon General Dr. Vivek Murthy, said that around half of all U.S. adults have experienced loneliness and it carried the same health risks as smoking 15 cigarettes a day.
“In recent years, about one-in-two adults in America reported experiencing loneliness. And that was before the COVID-19 pandemic cut off so many of us from friends, loved ones, and support systems, exacerbating loneliness and isolation,” Murthy wrote.
This week, The Atlantic also published an article on the increasing trend of social isolation in the U.S. It cited data from the National Restaurant Association that found 74% of all restaurant traffic came from “off premises” customers, up from 61 percent before the COVID-19 pandemic, in 2019. Per the outlet, the share of U.S. adults having dinner or drinks with friends on any given night has declined by more than 30 percent in the past 20 years.
“Self-imposed solitude might just be the most important social fact of the 21st century in America,” The Atlantic noted.
Researchers said a prevailing hypothesis regarding the link between social isolation and inflammation is that social isolation acts as a chronic stressor that contributes to dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis. Cleveland Clinic describes the HPA axis as a communication system of endocrine organs that is integral for stress management in the body through its feedback loop of hormones.
“However, we did not have data with which to explore this mechanism in our cohorts,” said the study authors.
Going forward, the study results “have implications for theory, research, and clinical practice,” they said. Already, the work supports the theory that social isolation in childhood can impact health in adulthood. Further research could focus on using biomarkers such as suPAR and ill health. In clinical settings, these findings could indicate suPAR as a measure to assess the possibility of interventions and prevent disease.
“This is also of importance among clinical populations, where social isolation in addition to medical conditions might increase the patients’ levels of systemic inflammation,” the authors said.