Associations between IL-1ß, IL-6, and TNFα polymorphisms and longitudinal trajectories of cognitive function in non-demented older adults.

Inflammation is implicated in Alzheimer's disease (AD), and specific single nucleotide polymorphisms (SNPs) in inflammatory cytokine genes are associated with increased AD risk. Whether the same polymorphisms also predict domain-specific cognitive change in cognitively healthy older adults is unclear. Specific SNPs in three cytokine genes, IL-1ß (rs16944), IL-6 (rs1800795), and TNFα (rs1800629) were assessed for association with longitudinal trajectories spanning up to 16 years of global cognitive function, episodic memory, attention and working memory, and executive function in a sample of 324 non-demented older adults. Only rs1800629 (TNFα) was associated with significant change in global cognitive function over time [γ = 5.22; 95% CI: 0.61, 9.83; p = 0.027]. Despite an association with AD risk, rs16944 and rs1800795 may not predict cognitive decline in cognitively healthy older adults. The presence of an A at rs1800629 (TNFα) may have broad, protective effects on cognitive function, over time. More validation studies are needed to determine whether specific cytokine SNPs are associated with respective serum levels to further understanding of AD biomarkers that may also serve as markers of cognitive decline.

The role of late-differentiated T cells, a proxy for IFN-γ-production, in older adults' social networks.

Interferon-γ (IFN-γ), an inflammatory biomarker that promotes antiviral immunity, may be a prerequisite for sociability. IFN-γ production in older adulthood is driven by late-differentiated CD8+ T cells, particularly CD28-and CD57+ subsets, which increase with age, reduce immune response, and increase chronic disease risk. The present study investigated the relationship between late-differentiated T cells (LDTC) and sociability in a longitudinal study of healthy aging. 139 older adults (Mage = 77.95, range 65-93; 58% female, 57% college educated, and 94% Caucasian) provided data at up to 10 occasions (M = 7). Social network size and diversity and cytomegalovirus (CMV) status were collected at every wave. Percentage of LDTC was measured at up to 4 waves and averaged for each participant. There were no significant main effects of LDTC or interactions between LDTC and time on social network size or diversity. Adjustment for baseline age, gender, and sensitivity analyses including CMV and imputed data did not change results. IFN-γ may not play a role in dictating social behavior in older adults. Alternately, LDTC may not have accurately represented circulating levels of IFN-γ. Future work should continue exploring IFN-γ and social behavior, particularly as it relates to age-related changes. The role of IFN-γ-producing, late-differentiated T cells in older adults' social networks.

Sleep Variability and Inflammation in Midlife and Older Women.

OBJECTIVE: Shorter sleep duration and more sleep disturbances, in addition to greater night-to-night fluctuations in sleep (intraindividual variability; IIV), have been associated with elevated inflammation. However, these associations were only at the between-person level. The current study examined the within-person relationship between mean levels and IIV of sleep duration and sleep disturbances and C-reactive protein (CRP) in healthy, aging women. METHODS: Participants ( N = 179) from a longitudinal study of activity and well-being in middle-aged and older women (mean age = 62 years; range = 50-75 years) completed a 7-day daily diary, every 3 months, for 2 years (up to nine bursts). Sleep was assessed each day asking participants how many hours of sleep they got the night before and with the four-item PROMIS Sleep Disturbance Short Form. Finger-stick dried blood spot samples were collected after each 7-day daily diary. RESULTS: In bursts when women experienced greater than average variability in sleep duration, they had higher CRP ( γ = 0.06, p = .004). Within-person changes in mean sleep duration were not associated with CRP. In addition, neither mean sleep disturbances nor sleep disturbance IIV were associated with CRP. CONCLUSIONS: This study is the first to show that within-person changes in variable sleep duration are related to changes in inflammation. Findings from the current study suggest that greater variability in sleep duration is related to higher CRP, which may increase risk for early morbidity and mortality. Future studies should investigate inflammation as a pathway linking sleep variability and health.

Repetitive thought, cognition, and systemic inflammation in the midlife in the United States study.

OBJECTIVE: Poor cognition increases risk for negative health outcomes, and this may be explained by associations with systemic inflammation. Previously, amount of repetitive thought (Total RT) interacted with IQ to predict interleukin-6 (IL-6) in older adults. This study continued the investigation of repetitive thought (RT) as an element involved in the effect of cognition on inflammation. DESIGN: Participants (N = 164) came from the Midlife in the United States Refresher project (Mage = 45.33, SD = 11.51, ranges = 25-74; 48.2% female; 85% Caucasian). Cognition was assessed via telephone, inflammatory biomarkers (IL-6, C-reactive protein (CRP), and tumour-necrosis factor-alpha (TNF- α)) analysed after blood draw, and RT derived from daily diary data. RESULTS: Cognition significantly interacted with RT valence (p = .009) to explain CRP after covariate adjustment. Better cognition and more negative RT valence was associated with lower CRP (ß = -0.190 [-.387, .008]). Worse cognition and more negative RT valence was associated with higher CRP (ß = 0.133 [-.031, .297]). No significant effects were found for IL-6 or TNF-α. CONCLUSION: RT may interact with cognition to affect different inflammatory biomarkers. Those with worse cognition may benefit more from skills related to regulating thought than those with better cognition.

Discrimination and health: The mediating role of daily stress processes.

OBJECTIVE: Exposure to discrimination is consistently linked with worse physical and mental health outcomes. One potential reason is that discriminatory experiences shape the way people interpret and affectively react to daily stressful events which in turn impacts health. The current study examined the role of these two daily psychological stress processes as a pathway linking the longitudinal association between perceived discrimination and health outcomes. METHOD: Participants in the National Study of Daily Experiences (NSDE), a subset of the Midlife in the United States (MIDUS) study, were followed over three waves spanning 20 years (N = 1,315). Perceptions of lifetime and everyday discrimination were measured by questionnaire at Wave 1; daily assessments of stress, threat appraisals, and negative affect were assessed through 8 days of daily dairies at Wave 2; measures of physical health (chronic conditions, functional limitations, and self-rated physical health) and mental health (depression, anxiety, and self-rated mental health) were assessed at Wave 3. Each wave of data was collected 9-10 years apart. RESULTS: Lifetime and everyday discrimination were associated with worse physical and mental health outcomes 20 years later. Daily threat appraisals and negative affective reactivity to daily stressors mediated the effect of discrimination on physical and mental health. CONCLUSION: Daily psychological stress processes are a potential mechanism by which exposure to unfair treatment relates to health. Findings underscore the insidious nature of unfair treatment and demonstrate how such experiences may be particularly consequential for daily stress processes and later physical and mental health outcomes. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

A Multisite Preregistered Paradigmatic Test of the Ego-Depletion Effect.

We conducted a preregistered multilaboratory project (k = 36; N = 3,531) to assess the size and robustness of ego-depletion effects using a novel replication method, termed the paradigmatic replication approach. Each laboratory implemented one of two procedures that was intended to manipulate self-control and tested performance on a subsequent measure of self-control. Confirmatory tests found a nonsignificant result (d = 0.06). Confirmatory Bayesian meta-analyses using an informed-prior hypothesis (δ = 0.30, SD = 0.15) found that the data were 4 times more likely under the null than the alternative hypothesis. Hence, preregistered analyses did not find evidence for a depletion effect. Exploratory analyses on the full sample (i.e., ignoring exclusion criteria) found a statistically significant effect (d = 0.08); Bayesian analyses showed that the data were about equally likely under the null and informed-prior hypotheses. Exploratory moderator tests suggested that the depletion effect was larger for participants who reported more fatigue but was not moderated by trait self-control, willpower beliefs, or action orientation.

Correlates of Poor Sleep and Subsequent Risk of Misdiagnosis in College Students Presenting with Cognitive Complaints.

OBJECTIVES: To examine the relationships of poor sleep to both subjective and objective cognitive functioning, attention deficit hyperactivity disorder (ADHD) and sluggish cognitive tempo (SCT) symptoms, and mental health variables in college students, controlling for noncredible symptom reporting and noncredible performance. METHODS: 99 undergraduate students (Mage = 19.9, SD = 1.1), 60% female and 72% first-year students, completed a neuropsychological battery and self-report questionnaires at a single lab visit. 56% of the sample identified as "poor sleepers" (>5 on the Pittsburgh Sleep Quality Index [PSQI]). RESULTS: Poor sleepers reported worse current (college grade point average [GPA]) but not past (high school GPA, American college test [ACT] score) academic performance. Additionally, they reported more mental health concerns, including depression and stress, but not anxiety. Poor sleepers reported more functional impairment and subjective cognitive concerns, including more Diagnostic and Statistical Manual of Mental Disorders (DSM) inattentive and hyperactive/impulsive symptoms, more SCT symptoms, and more executive dysfunction, even when controlling for depressive symptoms. However, poor sleepers did not differ from good sleepers on measures of objective cognition. CONCLUSIONS: ADHD and SCT symptoms and concerns in college students may be related to poor sleep, which can lead to misdiagnosis for individuals presenting with ADHD-like complaints for the first time in college. Sleep difficulties may be modifiable with empirically supported sleep interventions; thus, in assessment for either of these presentations, a careful sleep history should be taken.

Exposure and reactivity to repetitive thought in the neuroticism-distress relationship.

INTRODUCTION: Distress has been assumed to result from exposure to repetitive thought (RT). However, if RT is viewed as internally generated stressors, both exposure and affective reactivity to RT could play roles in generating distress. METHODS: Three studies (young adults, N=99; midlife women, N=111; older adults, N=159) assessed exposure and reactivity to daily RT and tested whether neuroticism was related to individual differences in both exposure and affective reactivity. RESULTS: Across all 3 studies, reactivity effects on depressive symptoms exceeded those of exposure to RT, and neuroticism was associated with more exposure and greater affective reactivity. Furthermore, RT exposure and reactivity accounted for most when not all of the relationship between neuroticism and depressive symptoms. DISCUSSION AND CONCLUSIONS: Further consideration of both exposure and affective reactivity to RT can not only increase the explanatory power of this construct but also suggest effective targets for intervention.