The effect of a transient immune activation on subjective health perception in two placebo controlled randomised experiments

Altered response to Toll-like receptor 4 activation in fibromyalgia: A low-dose, human experimental endotoxemia pilot study

In this pilot study, a human intravenous injection of low-dose endotoxin (lipopolysaccharide, LPS) model was used to test if fibromyalgia is associated with altered immune responses to Toll-like receptor 4 (TLR4) activation. Eight women with moderately-severe fibromyalgia and eight healthy women were administered LPS at 0.1 ng/kg in session one and 0.4 ng/kg in session two. Blood draws were collected hourly to characterize the immune response. The primary analytes of interest, leptin and fractalkine, were assayed via commercial radioimmunoassay and enzyme-linked immunosorbent assay kits, respectively. Exploratory analyses were performed on 20 secreted cytokine assays by multiplex cytokine panels, collected hourly. Exploratory analyses were also performed on testosterone, estrogen, and cortisol levels, collected hourly. Additionally, standard clinical complete blood counts with differential (CBC-D) were collected before LPS administration and at the end of the session. The fibromyalgia group demonstrated enhanced leptin and suppressed fractalkine responses to LPS administration. In the exploratory analyses, the fibromyalgia group showed a lower release of IFN-γ, CXCL10, IL-17A, and IL-12 and higher release of IL-15, TARC, MDC, and eotaxin than the healthy group. The results of this study suggest that fibromyalgia may involve an altered immune response to TLR4 activation.

Mechanism of the association between sleep quality and mortality in middle-aged and older adults: A prospective study analysis of the UK Biobank

BACKGROUND

Although sleep quality is known to be associated with mortality, how poor sleep quality contributes to an increased risk of mortality is still unknown. We aimed to examine whether lifestyle, psychosocial and biological factors mediate the association.

METHODS

205,654 participants from UK Biobank were used for the analysis. The outcome was all-cause, cardiovascular disease (CVD) and cancer mortality by February 2022. Exposure was assessed by a sleep score consisting of five sleep behaviors at baseline. Lifestyle, psychosocial, and biological factors are regarded as potential mediators. Mediation analysis based on Cox proportional hazards models was performed.

RESULTS

Poor sleep quality was associated with a higher risk of all-cause (Hazard Ratio [HR] = 1.098; 95% CI: 1.058-1.140), CVD (HR = 1.139; 95% CI: 1.045-1.243) and cancer mortality (HR = 1.095; 95% CI: 1.040-1.152). Lifestyle mediators (smoking, physical activity, sedentary, BMI and diet) could explain between 2.6% and 34.0% of the increased risk of all-cause mortality in individuals with poor sleep quality. Self-reported health, frailty, depression, and loneliness were significant psychosocial mediators of this association pathway. About one-fifth of the association can be explained by the biological role of CRP. Similar mediating patterns were observed for CVD and cancer mortality.

LIMITATIONS

Both exposure and mediators were measured at baseline, so the possibility of reverse causality cannot be ruled out.

CONCLUSIONS

Poor sleep quality is associated with an increased risk of death through a combination of lifestyle, psychosocial and biological pathways. Adopting healthy lifestyles and staying psychosocial well-being are cost-effective interventions to lower the risk of death.

Individuals with both higher recent negative affect and physical pain have higher levels of C-reactive protein

Conceptualizing physical pain and negative affect as potentially interactive, we hypothesized that higher levels of peripheral inflammatory markers would be observed consistently only among individuals with both higher negative affect and pain symptomatology. Participants were generally healthy midlife adults from the Bronx, NY (N ​= ​212, M_age ​= ​46.77; 60.8% Black, 25.5% Hispanic/Latina/o) recruited as part of a larger study. Key measures were: reported pain intensity and pain interference at baseline, recent negative affect averaged from self-reports 5x/day for 7 days, and peripheral inflammatory markers (C-reactive protein [CRP] and a composite cytokine measure based on seven cytokines). Controlling for age, BMI, gender, and education, recent negative affect significantly interacted with both pain variables to explain variance in CRP, with higher CRP levels observed only in individuals with both higher negative affect and either higher pain intensity or pain interference. These findings contribute to an emerging literature suggesting that negative affect, pain, and inflammation are related in important and complex ways.

Respiratory Sinus Arrhythmia as a Physiological Resilience Marker for Children's Health

OBJECTIVE

The current study aimed to test parasympathetic nervous system activity, indexed through resting respiratory sinus arrhythmia (RSA) as a resilience factor that moderates the associations between socioeconomic status (SES), circulating cytokines, and somatic health in children.

METHODS

The sample included 181 parent-child dyads (mean [standard deviation] child age = 9.91 [0.57] years; 50.3% boys). Parents reported on family income, parental education, and subjective social status, to index SES. Children provided serum samples for assaying circulating inflammatory cytokines and had RSA measured during a 5-minute seated resting period. We used a composite measure of inflammation that combined standardized measures of interleukin 6, interleukin 10, and tumor necrosis factor α. Parents reported on their child's global health impairment and number of chronic health conditions.

RESULTS

Lower SES was associated with poorer global health, and higher levels of inflammation were associated with poorer global health, but these associations were not significant among children with high resting RSA. Specifically, resting RSA moderated the association between SES and global health impairment (B = 0.09, standard error [SE] = 0.02, p < .001). Preliminary evidence suggests that resting RSA may also moderate the association between inflammation and global health impairment (B = -0.12, SE = 0.03, p < .001), although this effect was no longer significant after Winsorizing an outlier value of a child with high global health impairment (B = -0.06, SE = 0.03, p = .04).

CONCLUSIONS

High resting RSA may represent a physiological profile of resilience in children, weakening the associations between low SES and poor somatic health, and between greater inflammation and poor somatic health.

Poor sleep quality is associated with worse self-rated health in long sleep duration but not short sleep duration

Unhealthy sleep duration, either short or long, is associated with worse health and central subjective dimensions of sleep and health such as fatigue. It has been argued that the link between sleep duration and health may depend on the quality of the slept hours, and on its functional impact (ie, fatigue). The present study therefore assessed whether the relationship between last night's sleep duration and general self-rated health (SRH) differs as a function of sleep quality, and secondly, whether current fatigue and sleep quality are factors linking sleep duration and SRH. The present cross-sectional dataset involved 1304 individuals (57% female, M_age = 28.8, range 18-79). Participants completed surveys for general SRH, previous night's sleep duration and sleep quality, and current fatigue. Results showed the expected inverted U-shaped (ie, quadratic) relation between last night's sleep duration and SRH and a linear relation between last night's sleep quality and SRH. However, long sleep duration was only associated with poorer SRH in individuals who also reported poor sleep quality. Further, the quadratic relationship between sleep duration and SRH was partially mediated by fatigue and sleep quality. The results of this multi-study analysis suggest that SRH is particularly poor in those who slept both long and with poor quality the night before, while good sleep quality may protect those with a long sleep duration from poor SRH. Thus, last night's long sleep does not seem to be associated with poor subjective health unless it is coupled with poor sleep quality. Furthermore, fatigue and sleep quality are potential pathways linking short and long sleep duration with SRH. Different dimensions of sleep interact in their association with health, and future research will benefit from an integrative approach.

[Association of self-rated health with inflammatory markers among nursing home employees]

OBJECTIVES

Although self-rated health (SRH), the self-evaluation of one's own health status, has been reported to be associated with the immune status, the relationship between three different SRH measures (global, self-comparative, and age-comparative) with inflammatory markers as well as the relative strength of these associations by age are not well understood. The current study investigated the associations between SRH measures and inflammatory markers among nursing home employees.

METHODS

A sample of 120 Japanese employees at a nursing home (90 women and 30 men), aged 21-68 years (mean, 40.9 years), underwent a blood test for the measurement of inflammatory markers (interferon-γ, interleukin [IL]-4, IL-6, and tumor necrosis factor [TNF]-α, white blood cell count) and SRH during the annual health checkup. Multiple regression analysis adjusted for covariates was performed to analyze the relationship between inflammatory markers and SRH measures stratified by age, that is, aged < 40 years (younger age group) and 40 years and over (older age group).

RESULTS

Among the participants aged 40 years and over, poor global SRH was significantly associated with an increase in IL-6, while poor age-comparative SRH was significantly associated with an increase in TNF-α among participants aged < 40 years in the fully adjusted model controlling for potential confounders. Age-comparative SRH was also significantly associated with an increase in IL-6 among all participants. Self-comparative SRH was not significantly associated with inflammatory markers.

CONCLUSIONS

Our results suggest that three SRH measures are not equivalently associated with inflammatory markers, especially when the analyses were performed separately for the younger and older populations. This implies that not only differences in forms of SRH but also in age modify the relationship between SRH and inflammatory markers.

The association between subjective health perception and lifestyle factors in Shiga prefecture, Japan: a cross-sectional study

Background

The Ministry of Health has reported that in Japan, the Shiga prefecture has the highest life expectancy. Subjective health perception is a predictive indicator of mortality. For this study, we examined the association between subjective health perception and multiple lifestyle factors.

Methods

Data were obtained from the 2015 Health and Nutrition Survey in Shiga prefecture. The analytic sample comprised 6057 adults aged 20 or older. Information on subjective health perception and lifestyle behaviors was obtained from a self-administered questionnaire. As for subjective health perception, participants were divided into 2 groups: (1) Excellent or Good and (2) Average, Poor, or Very Poor. A 1-day dietary survey was also administered. The health behaviors score (HBS) was calculated based on 5 factors: consuming a healthy diet, never smoking, low-risk alcohol drinking, regular exercise, and moderate sleep duration. HBS scores ranged from 0 to 5. Multiple logistic regression was used to calculate the sex-, age- BMI- and energy intake-adjusted odds ratios (ORs) of poor subjective health across HBS, with 0 points as the reference.

Results

Among all participants, 2397 (39.6%) individuals were classified into the good subjective health group. Participants with an HBS of 3 (OR 0.59, 95% CI 0.37–0.96), 4 (OR 0.40, 95% CI 0.24–0.65) or 5 (OR 0.33, 95% CI 0.19–0.59) had a lower OR of rating themselves as being average/poor health compared with those having zero. The association with a higher HBS was remarkable (p for trend: < 0.001). Additional analyses revealed that the combinations including regular exercise were particularly associated with a lower risk of subjective average/poor health.

Conclusions

This study showed that the higher the number of healthy lifestyle factors, the lower risk of subjective average/poor health. Combinations of healthy lifestyle factors, especially those involving exercise, suggest good subjective health for individuals living in the Shiga prefecture.

The role of inflammation in the relationship of self-rated health with mortality and implications for public health: Data from the English Longitudinal Study of Aging (ELSA)

Self-rated health (SRH) predicts mortality after adjustment for potential confounders, including measures of health status. Prodromal disease might lead to worsened SRH and higher mortality. But no study of SRH and mortality has focussed on inflammation. The objective of this study is to investigate the influence of inflammation upon the association between SRH and mortality in a British cohort. The English Longitudinal Study of Ageing (ELSA) involves interviewing participants aged over 50 every two years. We analysed data for 3405 men and 4139 women. Mortality for consenting members was detected by linkage with UK National Health Care registry up to March 2012. Demographic, clinical, and health behaviours at wave 2 were treated as confounders, as well as inflammation-related disease and C-reactive protein (CRP). A five-step hierarchical multivariable logistic regression was estimated. An association was observed between SRH and mortality after adjusting for all variables. In men, compared to those with excellent health, CRP only, and CRP and inflammation-related disease combined, could explain 7.03% and 24.35% of increased risk of dying associated with poor health, respectively. For women, the corresponding figures were 8.95% and 24.28%, respectively. Inflammation is associated with increased risk of death, and may help to explain approximately a quarter of the association between SRH and mortality. Individuals with relatively poor SRH may be aware of underlying inflammation that increases the risk of illness and death, and this may lead to increased use of services, for example. Identifying the cause and treating inflammation in those without a diagnosis may help to increase survival and life quality among those who perceive their health to be relatively poor.

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Poor self-rated health (SRH) is associated with increased risk of death.

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In a prospective study, inflammation explained 1/4 of the association.

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Identifying inflammation early may improve survival and life quality.

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SRH can assist management, inform policy and guide research.

Self-rated health in adolescence as a predictor of 'multi-illness' in early adulthood: A prospective registry-based Norwegian HUNT study

Self-rated health (SRH) is a marker of future health and a possible predictor of future multimorbidity, which is a major challenge for population health and health care. There is a lack of studies on adolescent SRH and patterns of health problems across the transitional period from adolescence to early adulthood. Therefore, this study aimed to identify groups of people with similar health problems in early adulthood and explore the predictive value of adolescent SRH on the group classification after a period of 10–19 years. Data from 8828 adolescents participating in the Young HUNT-1 survey (1995–1997) were linked to the Norwegian registry of general practitioner (GP) claims, which includes diagnoses recorded in GP consultations in 2006–2014. We used latent class analysis (LCA) to identify groups of patients with similar health problems in early adulthood and explored SRH as a predictor of class membership using latent class regression, adjusting for baseline chronic disease, frequency of health care attendance, sex and age. The mean age at baseline was 16 years, and 50% of the participants were female. SRH was reported as very good by 28%, good by 61% and not good by 11%. We identified five groups of patient classification (classes): Healthy (35%), Infections and general problems (26%), Musculoskeletal problems (21%), Psychological problems (6%) and Multi-illness (13%). We found a gradual increase in the probability of belonging to the Healthy class with better SRH, and an inverse pattern for the Psychological and Multi-illness classes. This pattern remained after adjusting for baseline variables. In conclusion, there is a clear association between adolescent SRH and the risk of having multi-illness in early adulthood, seen as a proxy for later multimorbidity. This finding warrants greater attention to SRH in adolescence as a possible indicator in targeted prevention of future health problems.

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Adolescent self-rated health (SRH) predicted health problems 10–19 years later.

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Patients were classified into five groups with similar patterns of health problems.

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Better SRH increased the probability of adults belonging to the healthiest group.

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Not good SRH tripled the risk for multi-illness compared to very good SRH.

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Low SRH in adolescence is a possible predictor of multimorbidity in adulthood.

Comparison of bacterial lipopolysaccharide-induced sickness behavior in rodents and humans: Relevance for symptoms of anxiety and depression

Increasing evidence from animal and human studies suggests that inflammation may be involved in mood disorders. Sickness behavior and emotional changes induced by experimental inflammatory stimuli have been extensively studied in humans and rodents to better understand the mechanisms underlying inflammation-driven mood alterations. However, research in animals and humans have remained compartmentalized and a comprehensive comparison of inflammation-induced sickness and depressive-like behavior between rodents and humans is lacking. Thus, here, we highlight similarities and differences in the effects of bacterial lipopolysaccharide administration on the physiological (fever and cytokines), behavioral and emotional components of the sickness response in rodents and humans, and discuss the translational challenges involved. We also emphasize the differences between observable sickness behavior and subjective sickness reports, and advocate for the need to obtain both subjective reports and objective measurements of sickness behavior in humans. We aim to provide complementary insights for translational clinical and experimental research on inflammation-induced behavioral and emotional changes, and their relevance for mood disorders such as depression.

Properties of the Sickness Questionnaire in an Australian sample with chronic medically unexplained symptoms

Sickness behavior including malaise, fatigue and increased pain sensitivity is thought to be adaptive and facilitate recovery from disease. However, it may also reduce functioning and health if symptoms persists, which is why validated instruments for its assessment are needed. We evaluated the English translation of the Sickness Questionnaire (SicknessQ) in an Australian population of 156 participants with high level of persistent musculoskeletal pain and/or gastrointestinal symptoms without an organic explanation. The SicknessQ total score had an adequate model fit and no other models were found to fit data better. The SicknessQ correlated most strongly with fatigue, stress, anxiety and depression, which explained 62% of the variance in SicknessQ, but not with physical functioning. The mean score (8.9; 95 %CI: 8.0-9.8) was in between those previously reported in a general population sample and in primary care patients. In conclusion, the evaluation of the English version of the SicknessQ in an Australian sample with significant, chronic unexplained medical symptoms supports the use of the English version of the total SicknessQ score as an overall measure of sickness behavior.

Patients with ME/CFS (Myalgic Encephalomyelitis/Chronic Fatigue Syndrome) and chronic pain report similar level of sickness behavior as individuals injected with bacterial endotoxin at peak inflammation

Background

Chronic sickness behavior is implicated in ME/CFS (Myalgic Encephalomyelitis/Chronic Fatigue Syndrome) and chronic pain but the level of subjective sickness behavior in these conditions has not been investigated or compared to other clinical and non-clinical samples, or to the level in experimental inflammation. Furthermore, the relationship between sickness behavior and self-rated health and functioning is not known in patients with ME/CFS and chronic pain. The aim of the present study was to investigate how sickness behavior in patients with chronic conditions differs from that in individuals with experimental acute sickness, primary care patients, the general population and healthy subjects. In addition, we wanted to explore how sickness behavior is related to self-rated health and health-related functioning.

Methods

Sickness behavior was quantified using the sickness questionnaire (SicknessQ). Self-ratings were collected at one time-point in 6 different samples. Levels of sickness behavior in patients with ME/CFS (n ​= ​38) and patients with chronic pain (n ​= ​190) were compared to healthy subjects with lipopolysaccharide(LPS)-induced inflammation (n ​= ​29), primary care patients (n ​= ​163), individuals from the general population (n ​= ​155) and healthy subjects (n ​= ​48), using linear regression. Correlations and moderated regression analyses were used to investigate associations between sickness behavior and self-rated health and health-related functioning in ME/CFS, chronic pain and the general population.

Results

LPS-injected individuals (M ​= ​16.3), patients with ME/CFS (M ​= ​16.1), chronic pain (M ​= ​16.1) and primary care patients (M ​= ​10.7) reported significantly higher SicknessQ scores than individuals from the general population (M ​= ​5.4) and healthy subjects (M ​= ​3.6) all p's ​< ​0.001). In turn, LPS-injected individuals, patients with ME/CFS and chronic pain reported significantly higher SicknessQ scores than primary care patients (p's ​< ​0.01). Higher levels of sickness behavior were associated with poorer self-rated health and health-related functioning (p's ​< ​0.01), but less so in patients with ME/CFS and chronic pain than in individuals from the general population.

Conclusions

Patients with ME/CFS and chronic pain report similar high levels of sickness behavior; higher than primary care patients, and comparable to levels in experimental inflammation. Further study of sickness behavior in ME/CFS and chronic pain populations is warranted as immune-to-brain interactions and sickness behavior may be of importance for functioning as well as in core pathophysiological processes in subsets of patients.

Cross-sectional associations between inflammation, sickness behaviour, health anxiety and self-rated health in a Swedish primary care population

This study investigated associations between inflammatory markers, sickness behaviour, health anxiety and self-rated health in 311 consecutive primary care patients. Poor self-rated health was associated with high sickness behaviour ( ρ = 0.28, P < 0.001; ρ = 0.42, P = 0.003) and high health anxiety ( ρ = 0.31, P < 0.001; ρ = –0.32, P = 0.003). High levels of interleukin 6 were associated with poor self-rated health in men ( ρ = 0.26, P = 0.009). Low levels of interleukin-6 were associated with poor self-rated health in women ( ρ = –0.15, P = 0.04), but this association was non-significant when adjusted for health anxiety ( ρ = –0.08, P = 0.31). These results are consistent with the theory that interoceptive processes draw on both inflammatory mediators and the state of sickness behaviour in inferring health state.