KaMala S. Thomas

To assess, to control, to exclude: Effects of biobehavioral factors on circulating inflammatory markers☆

Behavioral scientists have increasingly included inflammatory biology as mechanisms in their investigation of psychosocial dynamics on the pathobiology of disease. However, a lack of standardization of inclusion and exclusion criteria and assessment of relevant control variables impacts the interpretation of these studies. The present paper reviews and discusses human biobehavioral factors that can affect the measurement of circulating markers of inflammation. Keywords relevant to inflammatory biology and biobehavioral factors were searched through PubMed. Age, sex, and hormonal status, socioeconomic status, ethnicity and race, body mass index, exercise, diet, caffeine, smoking, alcohol, sleep disruption, antidepressants, aspirin, and medications for cardiovascular disease are all reviewed. A tiered set of recommendations as to whether each variable should be assessed, controlled for, or used as an exclusion criteria is provided. These recommendations provide a framework for observational and intervention studies investigating linkages between psychosocial and behavioral factors and inflammation.

The toll of ethnic discrimination on sleep architecture and fatigue.

Most work on ethnicity tends to focus on daytime health rather than how aspects of ethnicity affect nighttime functioning. The current study examined how discrimination and ethnic identity relate to sleep architecture and fatigue in 37 African Americans and 56 Caucasian Americans. The authors conducted sleep monitoring with standard polysomnography. African Americans had less slow-wave sleep and reported more physical fatigue than did Caucasian Americans (ps < .05). The authors conducted path analyses to examine relationships between ethnic identity, perceived discrimination, sleep, and fatigue. Perceived discrimination mediated ethnic differences in Stage 4 sleep and physical fatigue. Individuals who reported experiencing more discrimination had less Stage 4 sleep and reported experiencing greater physical fatigue (ps < .05). Although ethnic identity did not mediate ethnic differences in sleep latency, there was a significant relationship between ethnic identity and sleep latency, indicating that individuals who felt more connected to their ethnic group had more difficulty falling asleep while in the hospital (p < .05). These observations suggest that the effects of stress related to ones ethnic group membership carry over into sleep.

Sleep depth and fatigue: Role of cellular inflammatory activation

Individuals with underlying inflammation present with a high prevalence of non-specific co-morbid symptoms including sleep disturbance and fatigue. However, the association between cellular expression of proinflammatory cytokines, alterations of sleep depth and daytime fatigue has not been concurrently examined. In healthy adults (24-61 years old), evening levels of monocyte intracellular proinflammatory cytokine production were assessed prior to evaluation of polysomnographic sleep and measures of fatigue the following day. Stimulated monocyte production of interleukin-6 (IL-6), but not tumor necrosis factor α (TNF-α), was negatively associated with slow wave sleep (ΔR²=.17, p=.029). In contrast, stimulated monocyte production of IL-6 was positively associated with rapid-eye movement (REM) sleep duration during the first sleep cycle (ΔR²=.26, p<.01). Moreover, evening stimulated production of IL-6 was associated with fatigue the following day (ΔR²=.17, p=.05). Mediation analyses showed that slow wave sleep, but not REM sleep duration, mediated the relationship between evening levels of IL-6 production and daytime fatigue. These results indicate that increases in stimulated monocyte production of IL-6 may be associated with decreases in slow wave sleep and increases in REM sleep duration. Relative loss of slow wave sleep may be one pathway through which cellular inflammation leads to daytime fatigue.

Disrupted Sleep in Breast and Prostate Cancer Patients Undergoing Radiation Therapy: The Role of Coping Processes

Background: Sleep problems are a common complaint in cancer patients that have been understudied.

Job Strain, Ethnicity, and Sympathetic Nervous System Activity

Several studies have demonstrated that blacks have heightened pressor sensitivity in response to the &agr;-agonist, phenylephrine. However, studies examining whether psychosocial factors contribute to this difference are scarce. We examined the effects of job strain on pressor sensitivity in 76 whites and 46 blacks who were enrolled in a study of stress, sleep, and blood pressure. Responses to phenylephrine were examined at an inpatient clinical research center. After a 3-minute baseline period, a 100-microgram phenylephrine bolus was administered to participants intravenously. To measure catecholamines, 24-hour urine samples were also collected from participants. There was a significant relationship between job strain and pressor sensitivity, such that individuals with low decisional control and high job demands experienced a greater increase in diastolic pressure after receiving phenylephrine. Low decisional control was also associated with decreased baroreflex sensitivity. There was an interaction between ethnicity and job control on blood pressure responses to phenylephrine and on 24-hour urinary norepinephrine levels. Blacks who perceived less control experienced a greater increase in diastolic pressure after receiving phenylephrine and had elevated norepinephrine levels. These findings suggest possible mechanisms by which job strain may be associated with cardiovascular disease.

Cancer-related masculine threat, emotional approach coping, and physical functioning following treatment for prostate cancer.

OBJECTIVE Aspects of masculinity and gender role, particularly those that are traditional and restrictive, are related to poorer physical and psychological outcomes in men with cancer. This longitudinal study uses a cancer-specific assessment to determine whether cancer-related masculine threat (CMT) predicts prostate-related (i.e., urinary, bowel, sexual) functioning over time, and whether cancer-related emotional approach coping (EAC) processes explain these relationships. Whether coping self-efficacy and emotional suppression explain effects of CMT on EAC also is tested. METHODS Sixty-six men (M age = 65.76; SD = 9.04) who underwent radical prostatectomy and/or radiation therapy for localized prostate cancer within two years were assessed on physical and psychological variables at study entry (T1), and two (T2) and four (T3) months later. RESULTS Analyses controlling for baseline functioning and age revealed that CMT predicted declines in (T1 to T3) urinary (B = -.21, p < .05), bowel (B = -.24, p < .05), and sexual (B = -.17, p < .05) function. CMT also predicted decreased emotional processing (T1 to T2), but not emotional expression. Decreased emotional processing predicted declining prostate-related functioning and helps explain the effect of CMT on bowel and sexual (but not urinary) functioning. Low coping self-efficacy (p < .05), but not emotional suppression, was a mechanism by which CMT predicted emotional processing. CONCLUSIONS The extent to which men believe that cancer is inconsistent with their masculinity exacerbates declines in prostate-related functioning following cancer treatment. CMT likely shapes coping responses and negatively affects the efficacy of emotion-directed coping. Emotion-regulating coping processes, particularly the ability to process cancer-related emotions, appears to be one pathway through which gender role affects recovery from prostate cancer.

Which Measures of Obesity Are Related to Depressive Symptoms and in Whom

The authors asked which obesity measurements were associated with depressive symptoms, whether this relationship differed by gender, and whether controlling for fatigue and response bias affected the relationship. A sample of 129 subjects (66 men, 63 women), with a mean age of 36.9 years and a mean Body Mass Index (BMI) of 26.4 participated in the study. Depressive symptoms, levels of fatigue, response bias, and anthropometrics were assessed. In women, but not men, BMI and percent of ideal body weight were related to depression. However, percent of body fat did not show a relationship with depression after controlling for fatigue and response bias. These findings suggest that womens depressive symptoms are more influenced by body size than body fat composition, whereas mens depressive symptoms seem to be unrelated to obesity.

Ethnicity, perceived discrimination, and vascular reactivity to phenylephrine

Objectives: This study examined relationships among ethnicity, perceived discrimination, and vascular reactivity to phenylephrine (PE). Methods: Seventy-six white patients and 46 black patients were studied at an inpatient clinical research center in response to a bolus intravenous injection of 100 &mgr;g PE. Self-report questionnaires assessed perceived discrimination. Results: After controlling for body surface area, number of cigarettes smoked, and baseline blood pressure, black patients had greater vascular reactivity to PE than white patients (p = .01). There was also a significant relationship between perceived discrimination and diastolic blood pressure responsiveness to PE (p < .05). Path analyses revealed that perceived discrimination mediated the relationship between ethnicity and diastolic pressor responses. Individuals who perceived more discrimination had a larger increase in diastolic blood pressure in response to PE. Conclusion: These data suggest perceived discrimination is associated with increased blood pressure responsiveness to PE. BP = blood pressure; BSA = body surface area; HTN = hypertension; CVD = cardiovascular disease; PE = phenylephrine; SBP = systolic blood pressure; DBP = diastolic blood pressure; SEE = Scale of Ethnic Experience.

Post-traumatic disorder symptoms and blunted diurnal cortisol production in partners of prostate cancer patients

Prostate cancer (PC) is the most common cancer diagnosed in men, and research suggests that coping with this illness can cause significant distress in patients as well as their partners. This study examined the relationship of caregiving for a partner with PC with diurnal cortisol output in women between the ages of 42 and 75 years old. Participants were women whose partners had PC (n = 19) and women who were in relationships with men with no diagnosed medical illness (n = 26). Women provided saliva samples (4 times per day over 3 days) in their natural environment. The Structured Clinical Interview for DSM-IV Axis-I Disorders was also conducted to assess for the presence of post-traumatic stress disorder (PTSD) and major depression. Partners of men with PC had lower daily cortisol output across the three days than controls, F(1,444.08) = 20.72, p<.001). They were also more likely to report PTSD symptoms with 68.4% of PC partners fulfilling criteria for sub-threshold PTSD as compared to 23.1% of controls (χ(2) = 11.30, p = .01). Mixed model analyses revealed that the presence of sub-threshold PTSD symptoms significantly predicted cortisol production, F(1,419.64) = 5.10, p<.01). Regardless of caregiver status, women who reported at least sub-threshold PTSD symptoms had lower cortisol production than those with no PTSD symptoms. Major depression did not explain differences in cortisol production between partners of PC patients and controls. Although these findings are preliminary, they highlight the importance of developing interventions aimed at reducing risk of psychopathology in partners of men with PC.

Preliminary investigation of the advertising and availability of PREPs, the new "safe" tobacco products.

The tobacco industry recently introduced a new set of “safe” cigarettes and nicotine delivery devices that purportedly entail reduced tobacco-related disease risk due to their lower level of some carcinogens and toxins. Little is know about the biological impact of these potential reduced exposure products (PREPs) and nothing is known about their advertising and availability. Hence, two pilot studies were conducted to examine the latter issues for the first time. In Study 1, we examined tobacco ads in 10 popular magazines 1998–2002 and found that only 1% of ads were for PREPs. In Study 2, we attempted to purchase PREPs in a random sample of 113 small stores and found that only 4.4% sold any PREP. These preliminary findings tentatively suggest that the industry might not yet be heavily invested in products that have the potential to increase tobacco use by decreasing its perceived harm. Studies with larger samples are recommended.