Getting under the skin: Social isolation and biological markers in the National Health and Aging Trends Study

• Published in: Journal of the American Geriatrics Society (JAGS) Vol. 70; no. 2; pp. 408 - 414
• Main Authors: Cudjoe, Thomas K M, Selvakumar, Sruthi, Chung, Shang-En, Latkin, Carl A, Roth, David L, Thorpe, Jr, Roland J, Boyd, Cynthia M
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.02.2022
• Subjects: Aged; Aged, 80 and over; Aging; Biomarkers; Biomarkers - blood; Body mass index; C-Reactive Protein - analysis; Chronic illnesses; Female; Healthy Aging; Healthy Volunteers - statistics & numerical data; Humans; Inflammation - blood; Interleukin-6 - blood; Male; Medicare; Morbidity; Mortality; Older people; Residence Characteristics; Risk factors; Social interactions; Social Isolation; Social organization; Spirituality; Surveys and Questionnaires; Trends; Typology; United States; United States; biological markers; interleukin-6; C-reactive protein
• ISSN: 0002-8614; 1532-5415
• DOI: 10.1111/jgs.17518

Social isolation is a risk factor for morbidity and mortality comparable to well-established risk factors including smoking, hypertension, and a sedentary lifestyle. The specific biological mechanisms that connect social isolation to morbidity and mortality remain unclear. Interleukin-6 (IL-6) and C-reactive protein (CRP) are biological markers that are upregulated during inflammation and can have long-term negative consequences for the health of individuals as they age. Utilizing Round 7 (2017) data from the National Health and Aging Trends Study (NHATS), we examine the relationship between social isolation and two biological markers: IL-6 and high-sensitivity CRP. This study included a nationally representative sample of 4648 Medicare beneficiaries 65 years and older who provided samples using dried blood spot (DBS) techniques. We defined social isolation utilizing a multi-domained typology that considers living arrangement, core discussion network, religious attendance, and social participation. IL-6 and CRP were obtained via DBS that were collected in Round 7 of the NHATS. We performed linear regression to examine the association between social isolation and biological markers IL-6 and CRP. After adjusting for age, gender, race/ethnicity, income, tobacco use, body mass index, and chronic conditions, we found that severe social isolation and social isolation were significantly associated with higher levels of IL-6 and CRP values among older adults. Social isolation is associated with higher levels of biological markers (IL-6 and CRP). Our findings inform the pathway between social isolation and morbidity and mortality among older adults. IL-6 or CRP could be a proximal outcome measures for future clinical and social interventions that seek to alter the trajectory of social isolation and its associated health outcomes.