Summary: Blood tests from older adults who experienced social isolation showed elevated levels of interleukin‑6 and C‑reactive protein, two inflammatory biomarkers linked to poorer long‑term health.
Source: Wiley
New research published in the Journal of the American Geriatrics Society indicates that older adults in the United States who experienced social isolation had higher circulating levels of interleukin‑6 (IL‑6) and C‑reactive protein (CRP), markers of systemic inflammation that are associated with increased risk of chronic disease and functional decline.
The analysis used a nationally representative sample of 4,648 Medicare beneficiaries aged 65 and older, drawn from Round 7 (2017) of the National Health and Aging Trends Study (NHATS).
The authors suggest that clinical and social interventions aimed at reducing social isolation could influence biological pathways such as inflammation, potentially altering trajectories of health and longevity in older adults.
“Our findings show a clear association between social isolation and biological measures of inflammation,” said lead author Thomas K. M. Cudjoe, MD, MPH, of Johns Hopkins School of Medicine. “This study advances efforts to identify the mechanisms through which social isolation contributes to higher rates of illness and premature death among older adults.”
Dr. Cudjoe added that future longitudinal studies should combine objective social isolation measures with biological markers to deepen understanding of these complex biopsychosocial interactions and to inform targeted interventions.
About this aging and inflammation research news
Author: Katherine Falzon
Source: Wiley
Contact: Katherine Falzon – Wiley
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Original Research: Open access. “Getting under the skin: Social isolation and biological markers in the National Health and Aging Trends Study” by Thomas K.M. Cudjoe et al., Journal of the American Geriatrics Society
Abstract
Getting under the skin: Social isolation and biological markers in the National Health and Aging Trends Study
Background
Social isolation is increasingly recognized as a major risk factor for poor health in older adults, with effects on morbidity and mortality on par with traditional risks such as smoking, high blood pressure, and physical inactivity. However, the biological mechanisms that link social isolation to adverse health outcomes are not fully understood. IL‑6 and high‑sensitivity CRP are well‑established biomarkers that rise during inflammatory processes; chronically elevated levels of these proteins are implicated in the development and progression of cardiovascular disease, metabolic disorders, and other age‑related conditions.
Methods
The study used data from Round 7 (2017) of NHATS and focused on 4,648 community‑dwelling Medicare beneficiaries aged 65 and older who provided dried blood spot (DBS) samples. Social isolation was measured using a multi‑domain typology that incorporated living arrangement, size of the core discussion network, frequency of religious attendance, and participation in social activities. IL‑6 and CRP concentrations were quantified from DBS samples. The researchers applied linear regression models to assess the association between social isolation categories and biomarker levels, adjusting for demographic and health covariates.
Results
After controlling for age, sex, race/ethnicity, income, tobacco use, body mass index, and existing chronic conditions, the analysis found that both social isolation and severe social isolation were significantly associated with higher IL‑6 and CRP values. These associations persisted in adjusted models, suggesting that the relationship between social isolation and inflammation is not explained solely by common demographic or health differences.
Conclusions
The study concludes that social isolation is linked to elevated inflammatory markers among older adults. These findings provide biological evidence that helps explain how social isolation contributes to poorer health outcomes and increased mortality risk. Measuring IL‑6 or CRP could serve as a proximal outcome for evaluating the effectiveness of clinical and social interventions designed to reduce isolation and improve health trajectories in aging populations. Incorporating both objective social measures and biological markers in future studies could help guide more effective policies and programs to support the health of older adults.