The Association Between Loneliness and Inflammation: Findings From an Older Adult Sample

Identifying leading anti-inflammatory dietary determinants of depression and loneliness in older adults

Objectives

The study aims to explore the association between anti-inflammatory dietary variables and prevalence of depression and loneliness in older adults.

Design

A cross-sectional secondary data analysis was performed using data from the English Longitudinal Study of Ageing (ELSA), targeting adults aged 50 and over.

Method

Data from wave 9 of ELSA were utilised. Binary logistic regression was employed to estimate the Odds ratios (ORs) and 95 % confidence intervals (CIs) for the association between participants' intake of fruits, vegetables, fish, nuts and seeds, legumes, and wholegrains, and the prevalence of depression and loneliness. Two sets of regressions were conducted: the first set examined each dietary component individually, while the second considered all variables simultaneously. Both models were tested with and without adjusting for covariates, including age, gender, ethnicity, self-rated weight, marital status, education, socio-economic status, and activity-limiting long-standing illnesses.

Results

Of 4254 participants included in the analysis, 355 participants (8 %) had depression, and 623 (15 %) reported experiencing loneliness. An association was observed between higher intakes of fruits and lower prevalence of depression (OR = 0.89, 95 % CI: 0.79-1.00, p = 0.05), and between higher intakes of vegetables and lower prevalence of loneliness (OR = 0.91, 95 % CI: 0.83-1.00, p = 0.05). However, these associations lost statistical significance after adjustment for confounders. Similarly, the second model, which included all anti-inflammatory dietary variables, failed to show a significant association with depression and loneliness.

Conclusions

The study does not support the hypothesis that anti-inflammatory variables are associated with prevalence of depression and loneliness in older adults.

Vitamin D Deficiency and IL-6: Risk Factors for Preterm Birth in Black Women: A Retrospective Cross-Sectional Study

BACKGROUND

Non-Hispanic Black women have a 1.5 times greater rate of preterm birth (PTB, any birth occurring at <37 wk of gestation) than non-Hispanic White women. Black women are also more likely to have vitamin D deficiency (VDD; 25[OH]D <20 ng/mL) than White women. Vitamin D has anti-inflammatory effects, which may help explain the association of VDD with PTB in Black women.

OBJECTIVES

To examine associations between inflammatory biomarkers and VDD with PTB as an outcome.

METHODS

We used an exploratory retrospective cross-sectional design utilizing data collected as part of the larger Biosocial Impact on Black Births (BIBB) study. A case-control subsample was selected from the BIBB participants who had stored blood plasma available at 8-25 wk of gestation (n = 172). Fifty-nine PTB cases were included in the current study, with a set of matched controls based on maternal age controls at a 1:2 ratio of PTB to term birth (n = 113, 65.6%). Total 25(OH)D and cytokine levels were measured in the plasma.

RESULTS

Seventy percent of women with PTB had VDD compared with 50% of women with term birth who had VDD. Other inflammatory biomarkers were not associated with PTB except for IL-6. The PTB group had higher IL-6 and lower 25(OH)D levels compared with term birth. In adjusted models controlling for IL-6 and other covariates, odds ratios (OR) for VDD remained significant for predicting PTB (OR: 2.45; 95% confidence interval: 1.18, 5.06; P = 0.016).

CONCLUSIONS

Increased VDD was associated with increased risk of PTB among Black women after controlling for IL-6 and other factors. Achieving adequate vitamin D status in early pregnancy may have an important role in PTB prevention as it is a significant predictor of risk after inflammation and other factors are considered. Further investigation is warranted.

Network analysis of loneliness, mental, and physical health in Czech adolescents

BACKGROUND

The increasing urgency to address rising loneliness among adolescents has become a critical issue, underscoring the need for further studies on its association with mental and physical health. The objective was to examine the changes in loneliness and its relation to mental and physical health issues in three adolescent age groups.

METHODS

A total sample of 14,588 Czech pupils (50.7% boys, mean age 13.6 ± 1.7 years) in grades 5, 7 and 9 was used from a representative dataset of the Health Behaviour in School-aged Children (HBSC) study. The network analysis based on undirected graphical models was used as an exploratory technique to assess and test the structure of the data.

RESULTS

The association between loneliness and health decreased with age. There was a significant positive association between loneliness, feeling low, and irritability. No significant direct association between loneliness and physical health complaints was found.

CONCLUSION

Further studies, preferably of longitudinal character, are needed to confirm the changes in associations between loneliness and mental and physical health outcomes.

Psychological Stress and Cognitive Brain Health: Policies to Reduce Dementia Risk

Alzheimer's disease and related dementias (ADRD) pose a massive public health challenge, affecting over 6.7 million Americans aged 65 and older-a number projected to double by 2050. Despite advances in pharmacological treatments, there remains no cure or method to reverse the disease. This paper highlights the role of psychological stress as a critical yet underappreciated risk factor for cognitive decline and reviews its complex interplay with behavioral, social, and biological mechanisms. Chronic psychological stress drives physiological and behavioral changes that are linked to accelerated cognitive deterioration, particularly in older adults. Early interventions can target stress management and behavioral prevention strategies, which include physical activity, healthy diet, and social engagement. Further, key barriers to meaningful policy change to prevent and slow ADRD include lack of public awareness, stigma around mental health and aging, and misaligned funding incentives. Policy initiatives can improve brain health literacy, increase equitable access to services, and enhance community-level and environmental factors to promote healthy aging. Prioritizing stress reduction and promoting early detection and prevention can meaningfully reduce ADRD risk and progression, improving public health broadly.

The Legal and Ethical Dimensions of Hospital Visitation Bans in the COVID-19 Era

Background/Objectives: The COVID-19 pandemic compelled countries worldwide to implement stringent visitation restrictions across hospitals, nursing homes, and long-term care facilities to mitigate viral transmission. While initially justified by the uncertainty surrounding the virus, these restrictions often lasted well beyond the acute stage of the pandemic, leading to substantial psychological and physical harm, particularly for older adults. This study assesses the effects of these controls and offers strategies to balance public health priorities with patients' rights and psychological well-being during public health crises. Methods: An integrative review and comparative analysis of legislative measures and the psychological effects of visitation restrictions was undertaken. International and national visitation regulations and case studies were reviewed, and ethical frameworks were considered. Results: Our findings indicate that prolonged isolation due to extended visitation restrictions led to higher rates of anxiety, depression, and delirium among patients, creating ethical dilemmas for healthcare providers. Legal responses to this challenge varied globally. International human rights organizations called for policies bridging public health priorities with patients' rights to family and caregiver support. Some U.S. states enacted proactive legislation to strengthen family visitation rights, while other jurisdictions lack these visitation protections. Conclusions: Prolonged visitation restrictions during the pandemic show the need for legislation integrating public health protections with in-person family and caregiver support. The ethical imperatives of limiting the psychological harm caused by healthcare isolation and the legislative solutions to protect public health and the psychological well-being of patients during health crises are discussed.

Loneliness Gets Under the Skin: A Scoping Review Exploring the Link Between Loneliness and Biological Measures of Inflammation

BACKGROUND

Research suggests that systemic inflammation may link loneliness to adverse health outcomes, yet there is a gap in comprehensively reviewing recent evidence on the relationship between loneliness and biological measures of inflammation in adults. This scoping review synthesizes current research to address the question: Is there a definitive link between loneliness and biological markers of inflammation in adults?

METHODS

Following the methods outlined by Arksey and O'Malley, we developed a protocol, defined our research question, and systematically searched PubMed, CINAHL, Embase, and Scopus for English-language studies conducted from 2018 to 2023 exploring the relationship between loneliness and biomarkers of inflammation in adults.

RESULTS

Twelve studies meeting the inclusion criteria displayed heterogeneity in terms of sample characteristics, loneliness scales, and inflammatory biomarkers. The UCLA Loneliness Scale, in various forms, emerged as the predominant tool for measuring loneliness, while C-reactive protein and interleukin-6 were the most frequently evaluated inflammatory biomarkers. Notably, all 12 studies reported an association between loneliness and at least 1 biological marker of inflammation.

CONCLUSION

Research consistently associates loneliness with poor health outcomes in aging adults, but the underlying mechanisms remain unclear. This scoping review suggests that inflammation may serve as a pathway linking loneliness to adverse health outcomes. However, the variability across studies highlights the need for standardized measurement methods and a consideration of both the duration and extent of loneliness. Enhancing our understanding of how loneliness affects systemic inflammation may help clarify why loneliness is associated with negative health outcomes.

Inflammation and olfactory loss are associated with at least 139 medical conditions

Olfactory loss accompanies at least 139 neurological, somatic, and congenital/hereditary conditions. This observation leads to the question of whether these associations are correlations or whether they are ever causal. Temporal precedence and prospective predictive power suggest that olfactory loss is causally implicated in many medical conditions. The causal relationship between olfaction with memory dysfunction deserves particular attention because this sensory system has the only direct projection to memory centers. Mechanisms that may underlie the connections between medical conditions and olfactory loss include inflammation as well as neuroanatomical and environmental factors, and all 139 of the medical conditions listed here are also associated with inflammation. Olfactory enrichment shows efficacy for both prevention and treatment, potentially mediated by decreasing inflammation.

Loneliness and sleep in everyday life: Using ecological momentary assessment to characterize the shape of daily loneliness experience

BACKGROUND

Loneliness has been linked to an increased risk of sleep problems. Past research has largely relied on trait loneliness or daily recall loneliness when evaluating associations with sleep.

OBJECTIVE

The present study extended this work by evaluating the patterns of loneliness throughout the day, including a daily average of all reports, a maximum value, and daily variation. These loneliness patterns predicted daily subjective and objective sleep measures to evaluate whether they provide unique insight to this relationship.

METHODS

Undergraduate students (n = 71; 77% female; age 18-28) completed 2weeks of electronic surveys 4 times a day to assess loneliness. Each morning participants completed a diary of their prior night's sleep quality, as well as wore actigraphy devices to objectively assess sleep parameters. A total of 778 momentary surveys and 565days of actigraphy-assessed sleep data were collected. Multilevel models tested whether within-person daily aggregates of loneliness were associated with within-person daily sleep outcome variables.

RESULTS

Subjective sleep duration, quality, and fatigue were significantly predicted by daily average loneliness. Subjective sleep latency, quality, and fatigue were significantly predicted by daily max loneliness. Only fatigue was significantly predicted by daily loneliness variability. No objective sleep measures were significantly predicted by daily loneliness measures.

CONCLUSIONS

Patterns of daily loneliness focusing on central tendency (average) or intensity (max) were more consistently associated with subjective (but not objective) assessments of sleep than variability.

Association between Marital Status and Cognitive Impairment in a Multi-Ethnic Asian Population

OBJECTIVE

This study aimed to examine the potential factors associated with marital status and determine the association between marital status and cognitive impairment in a multi-ethnic Asian population.

METHOD

This study included 2,321 participants from Singapore Multi-Ethnic Cohort revisit study (aged 40-89). Participants were classified into married and unmarried group at baseline and follow-up according to self-reported marital status. Mini-Mental Status Examination (MMSE) was administered, and cognitive impairment was defined as a MMSE <26. We conducted both cross-sectional and longitudinal analyses to examine the association of marital status at 1 timepoint as well as marital transition with cognitive impairment.

RESULTS

Of the 2,321 participants, a total of 1,914 (82.5%) were married. The factors associated with marital status included younger age, male sex, higher household income, higher education, and higher physical activity levels. Additionally, married participants also had higher alternative healthy eating index (AHEI-2010) scores and a lower burden of hypertension and diabetes. Among those who were married, the median (Q1, Q3) MMSE score was 29 (28, 30) while among those who were unmarried it was 29 (27, 30) (p < 0.01). Participants who had never been married had the highest odds of cognitive impairment compared to their married counterparts (model III: OR = 1.48, 95% CI: 1.03, 2.14). Older age (p interaction value = 0.003) and Indian ethnicity (p interaction value = 0.028) further strengthened these associations.

CONCLUSION

Marriage was associated with lower odds of cognitive impairment. Marriage provides social support, companionship, and engagement in mentally stimulating activities contributing to better cognitive health. By identifying risk factors such as marital status, interventions and support systems can be developed to promote healthy cognitive aging.

Psychological and neurobiological mechanisms involved in the relationship between loneliness and cognitive decline in older adults

Loneliness, among older adults, is one of the risk factors for developing dementia. Still, little is known about the neurobiological and psychological conditions that link loneliness to cognitive decline. The current study investigated several research aims: First, it sought to identify neurobiological and psychological pathways that may account for the relationship between loneliness and decline across several cognitive domains. These pathways included depressive symptoms, total gray matter volume, and conditional analyses of pro-inflammatory cytokines and brain-derived neurotrophic factor (BDNF) expression. Second, it examined loneliness as a predictor of mild cognitive impairment (MCI) and Alzheimer's disease (AD). Third, it sought to determine whether the relationship between loneliness and cognitive decline is sex-specific in older adults. Longitudinal data were collected from 2130 Rush Memory and Aging Project participants. Participants underwent annual cognitive and psychological assessments and neuroimaging procedures every year. BDNF gene expression was measured in the dorsolateral prefrontal cortex, cytokines were measured in serum, and the final consensus clinical diagnosis was identified at the time of death. All linear mixed and multinomial logistic regression models controlled for age at baseline, education, sex, and APOE genotype. Participants were largely women (73 %), and Caucasian (93 %). The average education was 14.93 (SD = 3.34). The average age at baseline was 80.05 (SD = 7.57). Results showed that gray matter volume and depressive symptoms partially mediated the relationship between loneliness and cognitive decline. There was a significant interaction between loneliness and BDNF expression in relation to cognitive decline. Higher levels of BDNF expression was associated with slower decline in semantic memory and visuospatial ability. Finally, the current study also established that higher levels of loneliness was positively associated with the incidence of AD and other dementias. The present findings support the growing literature, which tends to show that the consequence of loneliness goes beyond the feeling of being isolated. Loneliness may induce physiological changes in our brains, leading to cognitive decline. Future research can explore a wide range of biological and psychological expressions of loneliness to clarify how loneliness relates to dementia.

Remotely-administered resilience and self-compassion intervention targeting loneliness and stress in older adults: a single-case experimental design

OBJECTIVES

Loneliness and chronic stress are prevalent issues for older adults that have been linked to adverse health outcomes. We conducted a remote resilience and self-compassion intervention targeting loneliness and chronic stress.

METHODS

This study utilized a multiple-phase-change single-case experimental design with three consecutive 6-week phases: control, intervention, follow-up. Assessments and biomarker collection (blood pressure, inflammation, sleep actigraphy) were conducted at each phase. Participants completed a 6-week remotely-administered resilience and self-compassion intervention using techniques from cognitive behavioral therapy and resilience training. Repeated measures ANOVAs were conducted over the 12-week period from control (week 0) to intervention completion (week 12) and over the 18-week period from control (week 0) to follow-up (week 18) in supplemental analyses.

RESULTS

Participants reported a reduction in stress (p < 0.001; ηp2 = 0.15), depression (p =  0.02; ηp2 = 0.08), and loneliness (p = 0.003; ηp2 = 0.18), and an increase in self-compassion (p  =  0.01; ηp2 = 0.13) from control to intervention completion (weeks 0-12). Post-hoc tests revealed that stress reduced significantly during the intervention phase (weeks 6-12) and loneliness reduced significantly during the control phase (weeks 0-6). Some improvements in blood pressure, inflammation, and sleep quality were noted in a subsample of participants.

CONCLUSION

Findings indicate that our remote resilience and self-compassion intervention for older adults targeting loneliness and chronic stress was efficacious.

The Association of Loneliness with Diabetes Is Mediated by Physical Activity and BMI but Not Diet Quality

Loneliness is considered a predictor of poor health through numerous pathways. Mediators of this association has not been extensively explored. The study objective was to determine if diet quality and physical activity are parallel mediators with body mass index (BMI) as the third mediator in the association of loneliness with diabetes. The sample, middle-aged and older African American and White adults, 36-77 years, participated in the second follow-up wave of the prospective Healthy Aging in Neighborhoods of Diversity across the Life Span study, 2013-2017. Loneliness was measured by the UCLA 3-item loneliness scale. Participants were categorized as not diabetic, pre-diabetic, or diabetic based on fasting blood glucose, self-reports, or taking medication for diabetes. The Mean Healthy Eating Index-2010 score was calculated from two 24 h dietary recalls collected using the USDA automated multiple pass method. Physical activity was derived from the Baecke questionnaire. The Hayes PROCESS macro, model #80, was used to perform the mediational analysis. Covariates were age, sex at birth, race, income, alcohol intake, and education. Loneliness was inversely and significantly associated with diet quality and physical activity. The only significant indirect path was loneliness > physical activity > BMI > diabetes. Better understanding of modifiable lifestyle behaviors when developing interventions may improve mental health, thereby improving health.

Older adults' self-reported prospective memory lapses in everyday life: Connections to inflammation and gender

OBJECTIVE

Limited research has focused on the association between inflammatory markers and features of subjective cognitive functioning among older adults. The present work examined links between inflammation and a specific subjective cognitive report: prospective memory (PM), or our memory for future intentions, such as attending an appointment or taking medication.

METHOD

We assessed self-reported PM lapses using a two-week ecological momentary assessment (EMA) diary protocol via smartphone as well as levels of blood-based inflammation among 231 dementia-free older adults (70-90 years, 66% women) enrolled in the Einstein Aging Study.

RESULTS

Overall, PM lapses were largely unrelated to inflammatory markers. However, a significant gender difference was observed in the link between basal levels of interleukin (IL)-8 and PM lapses: higher levels of basal IL-8 were associated with more PM lapses among men (estimate = 0.98, 95%CI: [0.43, 1.53], p < .001) but not women (estimate = -0.03, 95%CI: [-0.45, 0.39], p = .826). No other significant relationships between PM lapses and basal or stimulated (ex vivo) cytokine levels (IL-1β, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor-alpha [TNF-α]) or C-reactive protein (CRP) emerged.

CONCLUSION

Elevated levels of IL-8 in older men may possibly be an early indicator of neurodegeneration that relates to PM performance. Future studies should continue to examine PM and inflammation across genders to identify possible mechanisms through which these constructs may indicate neurodegeneration and dementia risk.

Sex-specific impacts of social isolation on loneliness, depressive symptoms, cognitive impairment, and biomarkers: Results from the social environment and biomarker of aging study

OBJECTIVES

To investigate sex-specific associations between social isolation and psychological outcomes and biomarkers among community-dwelling middle-aged and older adults using a nationally representative population-based cohort study.

METHODS

Data from 757 participants from the Social Environment and Biomarkers of Aging Study (SEBAS) were retrieved for analysis, and all participants were stratified by sex. The associations between social isolation and psychological outcomes (loneliness, depressive symptoms, and cognitive impairment) at the 4-year follow-up were examined by multivariate logistic regression models, and associations between social isolation and biomarkers at the 4-year follow-up were examined by multivariate generalized linear models (GLMs).

RESULTS

For men, social isolation was not associated with the development of loneliness. However, being married (adjusted odds ratio (aOR) 0.32 [95% confidence interval (CI) 0.13-0.74], p<0.001) was associated with a lower risk of loneliness, indicating potential protective effects of marriage for men. On the other hand, social isolation was associated with a 2-fold higher risk of loneliness in women (aOR 2.26 [1.01-5.09], p<0.001). Social isolation was not associated with depressive symptoms after adjusting for other demographics. For men, being married (aOR 0.51 [0.26-0.99], p<0.05) or having good self-reported health (aOR 0.44 [0.21-0.92], p<0.05) was protective against depressive symptoms. For women, only good self-reported health (aOR 0.30 [0.13-0.70], p<0.01) provided protective effects against depressive symptoms. Similarly, other demographic factors (being married and having a higher educational level) but not social isolation were associated with lower risks of cognitive impairment. No significant associations were noted between social isolation and selected biomarkers.

CONCLUSIONS

Sex-different associations between social isolation and loneliness were noted; the effects of demographic factors, such as being married, self-reported health status, and high education levels, on subsequent loneliness, depression, and cognitive function were also sex-different. Further intervention studies are needed to explore sex-specific approaches to deal with the interplay of social isolation, loneliness, psychological outcomes and other demographic factors.

Relationships between Interpersonal Goals and Loneliness in Older Adults: A Cross-Sectional Study

Loneliness is linked to many physiological and psychological issues and disproportionately affects older adults. Interpersonal goals (compassion and self-image) are essential to interpersonal relationships; however, how they relate to loneliness in older adults is unknown. We investigated the impact of interpersonal goals on loneliness using the Ecosystem-Egosystem Theory of Social Motivation. This study, adopting a descriptive cross-sectional correlational design, used data from the 2016 Health and Retirement Study. Participants (n = 3212) included people aged >65 years (mean age: 75; female: 60.1%). We performed exploratory factor analysis with principal axis factoring and varimax rotation to examine the suitability of compassionate and self-image goals as separate factors. The complex samples general linear model was used to assess the relationship between loneliness and interpersonal goals. Interpersonal goals were significantly negatively associated with loneliness. Respondents with higher compassion and self-image goals reported lower loneliness levels. Our results contribute to understanding how interpersonal goals relate to loneliness in older adults. These initial findings warrant further investigation.

Palmatine ameliorates LPS-induced HT-22 cells and mouse models of depression by regulating apoptosis and oxidative stress

Depression is one of the most common neuropsychiatric disorders that is characterized by low mood, lack of motivation, slow thinking, and recurrent suicidal thoughts. The mechanism of action of palmatine in depression has been rarely reported and remains unclear. The present study examined the neuroprotective effects of palmatine on lipopolysaccharide (LPS)-induced oxidative stress, apoptosis, and depression-like behavior. In this study, cell apoptosis was evaluated by CCK-8, flow cytometry, and Hoechst 33258 staining in LPS-induced HT-22 cells. Meanwhile, reactive oxygen species (ROS) and mitochondrial membrane potential were detected in vitro. In vivo, we investigated depressive-like behaviors in mice by an open field test (OFT) and elevated plus-maze test (EPM). Additionally, the levels of superoxide dismutases (SOD), TNF-α, IL-1β, and IL-6 were detected by enzyme-linked immunosorbent assay. The hematoxylin-eosin staining and TUNEL staining were used to evaluate the pathology of the hippocampus. The expression of Nrf2/HO-1 and BAX/Bcl-2 pathways in the hippocampus were assessed by Western blot analysis. Palmatine could significantly reduce apoptosis and ROS levels, and improve mitochondrial damage. Moreover, palmatine significantly improves movement time and central square crossing time in OFT, and improves open arms and movement time in EMP. And the levels of SOD, TNF-α, IL-1β, and IL-6 were significantly decreased after palmatine treatment. More importantly, palmatine improved neuronal apoptosis in the hippocampus, and depression through BAX/Bcl-2 and Nrf2/HO-1 signaling pathways. We provide evidence that palmatine further alleviates the depressive-like behavior of LPS-induced by improving apoptosis and oxidative stress.

Affective Neuroscience of Loneliness: Potential Mechanisms underlying the Association between Perceived Social Isolation, Health, and Well-Being

Loneliness, or the subjective feeling of social isolation, is an important social determinant of health. Loneliness is associated with poor physical health, including higher rates of cardiovascular disease and dementia, faster cognitive decline, and increased risk of mortality, as well as disruptions in mental health, including higher levels of depression, anxiety, and negative affect. Theoretical accounts suggest loneliness is a complex cognitive and emotional state characterized by increased levels of inflammation and affective disruptions. This review examines affective neuroscience research on social isolation in animals and loneliness in humans to better understand the relationship between perceptions of social isolation and the brain. Loneliness associated increases in inflammation and neural changes consistent with increased sensitivity to social threat and disrupted emotion regulation suggest interventions targeting maladaptive social cognitions may be especially effective. Work in animal models suggests the neural changes associated with social isolation may be reversible. Therefore, ameliorating loneliness may be an actionable social determinant of health target. However, more research is needed to understand how loneliness impacts healthy aging, explore the role of inflammation as a potential mechanism in humans, and determine the best time to deliver interventions to improve physical health, mental health, and well-being across a diverse array of populations.