Meredith A. Pung

Racial differences in sleep architecture: the role of ethnic discrimination.

African Americans have been consistently shown to have less deep (slow wave sleep; SWS) and more light (Stages 1 and 2) sleep than Caucasian Americans. This paper explored whether discrimination, a stressor that uniquely impacts certain ethnic groups, contributes to differences in sleep architecture. The sleep of 164 African and Caucasian Americans was examined with laboratory based polysomnography (PSG). Experiences of perceived discrimination (The Scale of Ethnic Experience) and sociodemographic factors were also assessed. After adjusting for age, body mass index (BMI), socioeconomic status (SES) and smoking status, African Americans slept approximately 4.5% more total sleep time (TST) in Stage 2 sleep and 4.7% less TST in SWS than Caucasian Americans (ps<.05). Perceived discrimination was a partial mediator of ethnic differences in sleep architecture. Individuals who reported experiencing more discrimination slept more time in Stage 2 and less time in SWS (ps<.05). Results suggest that the impact of stress related to ethnic group membership plays a part in explaining differences in sleep architecture.

Overnight changes of immune parameters and catecholamines are associated with mood and stress.

Objectives: To test the hypothesis that a nocturnal decrease of secretion of inflammation markers and catecholamines would be associated with mood and stress variables even after controlling for objective sleep variables. Methods: A total of 130 healthy volunteers participated in this study, spending 2 nights in the Gillin Laboratory of Sleep and Chronobiology at the University of California, San Diego, General Clinical Research Center. Blood samples were obtained before sleep (10:30 PM) and after awakening (6:30 AM) on the first day, and these samples were assayed for inflammatory biomarkers and catecholamines. On the second night, polysomnographic records were scored for objective sleep variables, e.g., total sleep time and wake after sleep onset. Self-rating scales for mood, stress, depression, and daily hassles were administered the second day. Results: The nocturnal decrease in interleukin-6 was smaller in people who reported more negative mood or fatigue and greater in those who reported more uplift events (e.g., with Profile of Mood States fatigue rp = −.25 to −.30). People with high stress or high depression levels had smaller nocturnal decreases of epinephrine. That relationship was even stronger when partial correlations were used to control for morning level and sleep variables. The associations between nocturnal changes of C-reactive protein, soluble tumor necrosis factor-receptor I, and norepinephrine with psychological states were nonremarkable. Conclusions: The analyses of nocturnal change scores (difference scores) add substantial information compared with the traditional analyses of morning levels of immune variables and catecholamines alone. Subjective well-being is significantly associated with a greater nocturnal decrease of interleukin-6 and epinephrine. More research on nocturnal adaptation processes is warranted. &Dgr; = delta, difference score; AHI = Apnea-Hypopnea Index; CRP = C-reactive protein; IL = interleukin; MFSI = Multidimensional Fatigue Symptom Inventory; POMS = Profile of Mood States; PSG = polysomnography; PSQI = Pittsburgh Sleep Quality Index; PSS-10 = Perceived Stress Scale; sTNF-RI = soluble tumor necrosis factor-receptor I; TNF = tumor necrosis factor; TST = total sleep time; WASO = wake after sleep onset.

Physicians' immunization knowledge, attitudes, and practices: a valid and internally consistent measurement tool.

Because physicians play a crucial role in immunizations,1–3 there is a need for reliable and valid assessments of physician-related determinants of immunizations. As part of a project aimed at improving immunization rates by targeting physicians,4 we developed measures of factors, which, according to theories of planned behavior5 and cognitive social learning,6 influence physicians’ immunization practices. Our measures include knowledge (understanding of the schedule, efficacy, and side effects of vaccines); attitudes (evaluative reactions toward immunizations); vested interest (perceptions of personal professional consequences of immunizations); self-efficacy (beliefs in personal capability to properly immunize); and perceived barriers (factors hindering proper immunizations). With few exceptions,7–9 studies measuring these variables either do not examine or do not report reliability and validity of their measures. Interventions based on potentially unreliable or invalid measures of needs may result in wasted resources or may not detect real improvements in immunization practices. Our measures should be of interest to those who plan interventions to improve physicians’ immunization practices or evaluate the effects of such interventions.

Pilot Randomized Study of a Gratitude Journaling Intervention on Heart Rate Variability and Inflammatory Biomarkers in Patients With Stage B Heart Failure.

Objective Stage B, asymptomatic heart failure (HF) presents a therapeutic window for attenuating disease progression and development of HF symptoms, and improving quality of life. Gratitude, the practice of appreciating positive life features, is highly related to quality of life, leading to development of promising clinical interventions. However, few gratitude studies have investigated objective measures of physical health; most relied on self-report measures. We conducted a pilot study in Stage B HF patients to examine whether gratitude journaling improved biomarkers related to HF prognosis. Methods Patients (n = 70; mean [standard deviation] age = 66.2 [7.6] years) were randomized to an 8-week gratitude journaling intervention or treatment as usual. Baseline (T1) assessments included the six-item Gratitude Questionnaire, resting heart rate variability (HRV), and an inflammatory biomarker index. At T2 (midintervention), the six-item Gratitude Questionnaire was measured. At T3 (postintervention), T1 measures were repeated but also included a gratitude journaling task. Results The gratitude intervention was associated with improved trait gratitude scores (F = 6.0, p = .017, &eegr;2 = 0.10), reduced inflammatory biomarker index score over time (F = 9.7, p = .004, &eegr;2 = 0.21), and increased parasympathetic HRV responses during the gratitude journaling task (F = 4.2, p = .036, &eegr;2 = 0.15), compared with treatment as usual. However, there were no resting preintervention to postintervention group differences in HRV (p values > .10). Conclusions Gratitude journaling may improve biomarkers related to HF morbidity, such as reduced inflammation; large-scale studies with active control conditions are needed to confirm these findings. Trial Registration: Clinicaltrials.gov identifier: NCT01615094

Acute exercise enhancement of pneumococcal vaccination response: a randomised controlled trial of weaker and stronger immune response

Acute exercise at the time of vaccination can enhance subsequent immune responses. However, the potential benefit of this effect will be its efficacy in boosting poor responses, and thus protection in at-risk populations. The current study tested the effect of exercise on the response to either a full- or half-dose Pneumococcal (Pn) vaccination to elicit stronger and weaker responses. Subjects were 133 young healthy adults, randomised to one of four groups: exercise or control task, receiving a full- or half-dose Pn vaccination. Prior to vaccination, exercise groups completed a 15 min arm and shoulder exercise task, control groups rested quietly. Antibody levels to 11 Pn strains were evaluated at baseline and 1-month. Across all participants, exercise groups showed significantly greater increase in antibody levels than control groups. When doses were compared, it emerged that those who exercised had significantly larger responses than those who rested in the half-dose group, but in the full-dose groups responses were similar. This data indicates the effectiveness of exercise as a vaccine adjuvant, particularly in weaker responses. Thus, given the potential public health benefits of no-cost behavioural intervention to enhance response to vaccination, testing in at-risk populations should be pursued.

Mediators of the relationship between race and allostatic load in African and White Americans.

OBJECTIVE Allostatic load (AL) is a cumulative index of physiological dysregulation, which has been shown to predict cardiovascular events and all-cause mortality. On average, African Americans (AA) have higher AL than their White American (WA) counterparts. This study investigated whether differences in discrimination, negative affect-related variables (e.g., experience and expression of anger, depression), and health practices (e.g., exercise, alcohol use, smoking, subjective sleep quality) mediate racial differences in AL. METHOD Participants included healthy, AA (n = 76) and WA (n = 100), middle-aged (Mage = 35.2 years) men (n = 98) and women (n = 78). Questionnaires assessed demographics, psychosocial variables, and health practices. Biological data were collected as part of an overnight hospital stay-AL score was composed of 11 biomarkers. The covariates age, gender, and socioeconomic status were held constant in each analysis. RESULTS Findings showed significant racial differences in AL, such that AA had higher AL than their WA counterparts. Results of serial mediation indicated a pathway whereby racial group was associated with discrimination, which was then associated with increased experience of anger and decreased subjective sleep quality, which were associated with AL (e.g., race → discrimination → experience of anger → subjective sleep quality → AL); in combination, these variables fully mediated the relationship between race and AL (p < .05). CONCLUSION These results suggest that discrimination plays an important role in explaining racial differences in an important indictor of early disease through its relationship with negative affect-related factors and health practices. (PsycINFO Database Record

Metabolic predictors of inflammation, adhesion, and coagulability in healthy younger-aged adults

Elevated levels of inflammatory biomarkers are associated with the pathophysiology of cardiovascular diseases and are predictors of cardiovascular events. The objective of this study was to determine the unique contributions of metabolic factors as predictors of inflammation (C‐reactive protein (CRP) and interleukin‐6 (IL‐6)), adhesion (soluble intercellular adhesion molecule‐1 (sICAM‐1)), and coagulation (D‐dimer) in healthy younger‐aged adults. Participants were 83 women and 92 men (mean age 30.04 years, s.d. ± 4.8, range 22–39) of normal weight to moderate obese weight (mean BMI 24.4 kg/m2, s.d. ± 3.35, range 17–32). The primary data analytical approaches included Pearson correlation and multiple linear regression. Circulating levels of CRP, IL‐6, sICAM‐1, and D‐dimer were determined in plasma. Higher levels of CRP were independently associated with higher BMI, a greater waist‐to‐hip ratio, female gender, and higher triglycerides (P < 0.001). Higher IL‐6 levels were independently associated with a greater waist‐to‐hip ratio (P < 0.01). Higher levels of sICAM‐1 were independently associated with higher BMI, higher triglycerides, and lower insulin resistance (P < 0.001). Higher D‐dimer levels were independently associated with higher BMI and being female (P < 0.001). Having a higher BMI was most consistently associated with elevated biomarkers of inflammation, adhesion, and coagulation in this sample of healthy younger‐aged adults, although female gender, insulin resistance, and lipid levels were also related to the biomarkers. The findings provide insight into the adverse cardiovascular risk associated with elevated body weight in younger adults.

Uplifts and Sleep

Recently, there has been a growth of interest in factors that play a protective role in sleep. This study is an exploratory analysis investigating relations between daily hassles and uplifts (events appraised as pleasant) and measures of subjective and polysomnography (PSG)-assessed sleep in a group of healthy adults (N = 135). Hassles and uplifts were assessed with the Combined Hassles and Uplifts Scale (CHUS), subjective sleep was assessed with the Pittsburgh Sleep Quality Index (PSQI), and objective sleep was assessed with standard PSG. After controlling for covariates, uplifts intensity was associated with subjective sleep and PSG-assessed sleep. Specifically, increased uplifts intensity was associated with better subjective sleep, decreased time slept in Stage 2 sleep, and increased time slept in slow wave sleep (SWS). Ones perception of the magnitude of positive events may play a role in sleep and should be examined in future investigations.

Neighborhood problems and nocturnal blood pressure dipping.

OBJECTIVE Living in adverse neighborhood conditions has been linked with greater prevalence of cardiovascular disease (CVD). We aimed to learn whether perceived neighborhood problems are related to attenuated nocturnal blood pressure (BP) dipping, a risk factor for CVD morbidity. METHOD A sample of 133 adults (71 male, 62 female; 80 White, 53 Black) underwent 24-hr ambulatory blood pressure monitoring. The neighborhood problem scale (NPS) was used to assess neighborhood environmental stressors. RESULTS Nocturnal dipping in systolic (SBP), diastolic (DBP) and mean arterial (MAP) blood pressure was reduced in individuals with higher NPS scores (p < .05). Hierarchical regression analyses revealed that neighborhood problems explained 4%-6% of the variance in SBP, DBP, and MAP dipping (p < .05) even after adjusting for several theoretical confounders such as social status, age, gender, race, body mass index (BMI), smoking, exercise, depression and discrimination. CONCLUSION Neighborhood problems may contribute to attenuated BP dipping beyond the effect of known risk factors.

Leukocyte ß-adrenergic receptor sensitivity and depression severity in patients with heart failure.

Objectives Clinical outcomes are worse for patients with heart failure (HF) and elevated depression symptoms. Depression-related sympathoimmune dysregulation may be one mechanism leading to poorer HF prognosis. Sympathetically mediated adrenergic activity is known to regulate immune activity via &bgr;-adrenergic receptors (&bgr;-ARs). However, studies show conflicting relationships between leukocyte &bgr;-AR sensitivity and depression symptoms. The aim of this study was to determine in patients with HF the relationship of leukocyte &bgr;-AR sensitivity with two diverse measures of depression, self-report questionnaire versus clinical diagnostic interview. Methods Patients with HF (N = 73, mean [standard deviation] age = 56.3 [13.0]) completed the Beck Depression Inventory-1A and a modified Structured Clinical Interview for the DSM-IV. Leukocyte &bgr;-AR sensitivity was determined from isoproterenol-stimulated cyclic adenosine monophosphate levels; plasma norepinephrine and epinephrine were also assessed. Results Patients with major depression determined by Structured Clinical Interview for the DSM-IV had significantly higher &bgr;-AR sensitivity than did nondepressed patients (F(6,72) = 9.27, p = .003, &eegr;2 = 0.12). The Beck Depression Inventory-1A revealed a more complex relationship. Minimal, mild, and moderate-to-severe depression symptom groups had significant differences in &bgr;-AR sensitivity (F(7,72) = 7.03, p = .002, &eegr;2 = 0.18); mild symptoms were associated with reduced &bgr;-AR sensitivity and moderate-to-severe symptoms with higher &bgr;-AR sensitivity compared with patients with minimal depressive symptoms. Conclusions Clinical depression was associated with elevated &bgr;-AR sensitivity in patients with HF. By deconstructing depression measurements, a greater depth of information may be garnered to potentially reveal subtypes of depression symptoms and their relation to &bgr;-AR sensitivity.