Behavioral antecedents of coronary heart disease and atherosclerosis

Stressor-Evoked Brain Activity, Cardiovascular Reactivity, and Subclinical Atherosclerosis in Midlife Adults

BACKGROUND

Cardiovascular responses to psychological stressors have been separately associated with preclinical atherosclerosis and hemodynamic brain activity patterns across different studies and cohorts; however, what has not been established is whether cardiovascular stress responses reliably link indicators of stressor-evoked brain activity and preclinical atherosclerosis that have been measured in the same individuals. Accordingly, the present study used cross-validation and predictive modeling to test for the first time whether stressor-evoked systolic blood pressure responses statistically mediated the association between concurrently measured brain activity and a vascular marker of preclinical atherosclerosis in the carotid arteries.

METHODS AND RESULTS

Six hundred twenty-four midlife adults (aged 28-56 years, 54.97% women) from 2 different cohorts underwent 2 information-conflict functional magnetic resonance imaging tasks, with concurrent systolic blood pressure measures collected. Carotid artery intima-media thickness was measured by ultrasonography. A mediation framework that included harmonization, cross-validation, and penalized principal component regression was then used. Brain areas where functional magnetic resonance imaging activity exhibited reliable direct and indirect effects were identified through bootstrapping. Sensitivity analysis further tested the robustness of findings after accounting for prevailing levels of cardiovascular disease risk and brain imaging data quality. Task-averaged patterns of functional magnetic resonance imaging activity across distributed brain areas exhibited a generalizable association with carotid artery intima-media thickness, which was reliably mediated by an area under the curve measure of aggregate systolic blood pressure reactivity. Importantly, this effect held in sensitivity analyses. Implicated brain areas in this mediation included the ventromedial prefrontal cortex, anterior cingulate cortex, insula, and amygdala.

CONCLUSIONS

These novel findings support a link between stressor-evoked brain activity and preclinical atherosclerosis, which is accounted for by individual differences in corresponding levels of stressor-evoked cardiovascular reactivity.

Comparison of autonomic stress reactivity in young healthy versus aging subjects with heart disease

BACKGROUND

The autonomic response to acute emotional stress can be highly variable, and pathological responses are associated with increased risk of adverse cardiovascular events. We evaluated the autonomic response to stress reactivity of young healthy subjects and aging subjects with coronary artery disease to understand how the autonomic stress response differs with aging.

METHODS

Physiologic reactivity to arithmetic stress in a cohort of 25 young, healthy subjects (< 30 years) and another cohort of 25 older subjects (> 55 years) with CAD was evaluated using electrocardiography, impedance cardiography, and arterial pressure recordings. Stress-related changes in the pre-ejection period (PEP), which measures sympathetic activity, and high frequency heart rate variability (HF HRV), which measures parasympathetic activity, were analyzed as primary outcomes.

RESULTS

Mental stress reduced PEP in both groups (p<0.01), although the decrease was 50% greater in the healthy group. Mean HF HRV decreased significantly in the aging group only (p = 0.01).

DISCUSSION

PEP decreases with stress regardless of health and age status, implying increased sympathetic function. Its decline with stress may be attenuated in CAD. The HF HRV (parasympathetic) stress reactivity is more variable and attenuated in younger individuals; perhaps this is related to a protective parasympathetic reflex.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02657382.

Psychosocial risk and management of physical diseases

During the 40 years since the Yale conference on Behavioral Medicine and the founding of the Journal of Behavioral Medicine considerable progress has been made in understanding the role of psychosocial risk and management of physical diseases. We here describe the development of these fundamental concepts from early research on stress through studies of the Type A behavior pattern to more contemporary approaches to the relationship between psychosocial risks and benefits in relation to disease processes. This includes the relationship of psychosocial risk to cancers, cardiovascular diseases (CVD), cardiometabolic disorders, Human Immunodeficiency Virus (HIV)/Acquired Human Immune Deficiency Syndrome. During the past 40 years the effects of prolonged distress responses in the pathogenesis of some cancers and CVD have been well-established and modifiable behavioral, cognitive and social factors have been shown to produce favorable outcome components in the management of such diseases as breast cancer, coronary heart disease and HIV.

Flavour-enhanced cortisol release during gum chewing

There is some evidence to suggest that chewing gum reduces chronic stress. However, it remains controversial how the taste and odour properties of chewing gum influence stress. The present study was designed to investigate this issue in human subjects. Using an enzyme-linked immunosorbent assay, we tested salivary cortisol concentration, which is thought to be a stress marker, in 96 adults who chewed gum with different combinations of taste and odour. Subjects could discriminate between the types of gum without prior information. Salivary cortisol concentrations were highest and lowest for the subjects who chewed the most flavourful gum and the least flavourful gum, respectively. These findings suggest that the salivary cortisol level during gum chewing is not a marker of negative emotions (i.e., stressful conditions) as traditionally considered but, rather, an index of positive emotions that can facilitate biological responses to overcome stressful conditions.

Blood pressure regulation in stress: focus on nitric oxide-dependent mechanisms

Stress is considered a risk factor associated with the development of various civilization diseases including cardiovascular diseases, malignant tumors and mental disorders. Research investigating mechanisms involved in stress-induced hypertension have attracted much attention of physicians and researchers, however, there are still ambiguous results concerning a causal relationship between stress and long-term elevation of blood pressure (BP). Several studies have observed that mechanisms involved in the development of stress-induced hypertension include increased activity of sympathetic nervous system (SNS), glucocorticoid (GC) overload and altered endothelial function including decreased nitric oxide (NO) bioavailability. Nitric oxide is well known neurotransmitter, neuromodulator and vasodilator involved in regulation of neuroendocrine mechanisms and cardiovascular responses to stressors. Thus NO plays a crucial role in the regulation of the stress systems and thereby in the BP regulation in stress. Elevated NO synthesis, especially in the initial phase of stress, may be considered a stress-limiting mechanism, facilitating the recovery from stress to the resting levels via attenuation of both GC release and SNS activity as well as by increased NO-dependent vasorelaxation. On the other hand, reduced levels of NO were observed in the later phases of stress and in subjects with genetic predisposition to hypertension, irrespectively, in which reduced NO bioavailability may account for disruption of NO-mediated BP regulatory mechanisms and accentuated SNS and GC effects. This review summarizes current knowledge on the role of stress in development of hypertension with a special focus on the interactions among NO and other biological systems affecting blood pressure and vascular function.

Protein and lipid oxidative damage in healthy students during and after exam stress

Oxidative damage at cellular level is thought to be one of the mechanisms in the pathogenesis of psychological stress (anxiety). The aim of this study was to investigate lipid and protein oxidative damage in exam anxiety conditions. Blood samples were collected in two stages (during the exam period and post vacation) from 51 healthy female students after responding to Beck Anxiety Inventory (BAI) and test anxiety questionnaire. Protein carbonyl, total thiol and malondialdehyde (MDA) levels were determined in serum. Participants reported significantly higher levels of subjective anxiety during the exam period than post vacation. Also the level of total thiol was significantly lower during the exam period compared with post vacation (p<0.001). Meanwhile, protein carbonyl and MDA levels during the exams were significantly higher than those in post-exam period (p<0.01). During the exam period, there was a negative correlation between serum total thiol levels and the severity of anxiety (r=-0.45, p<0.01). A significant positive correlation between the changes in serum protein carbonyl and MDA levels, also between those markers and anxiety score was found during the exam period. The high level of protein carbonyl and MDA, also low level of total thiol during the exam period demonstrated an oxidative damage to proteins and lipids in stress conditions. Our results suggest that oxidative damage to cellular compounds may be one of the mechanisms involved in the pathogenesis of anxiety.

Relationship of Psychosocial Risk Factors, Certain Personality Traits and Myocardial Infarction in Indians: A Case-control Study

Objective:

To investigate the relationship of psychosocial factors (lack of social support, stress and subjective well-being) and personality traits with myocardial infarction (MI).

Materials and Methods:

A case–control study involving 100 cases and 100 matched controls was conducted in Lok Nayak Hospital, New Delhi.

Results:

Stress over 1 year was significantly higher in cases (P < 0.001). However, difference was not significant when scores of social support (P = 0.2), Presumptive Stressful Life Event (PSLE) over lifetime (P = 0.058) and subjective well-being (P = 0.987) were compared. MI was significantly associated with hyperactive (P < 0.001), dominant (P = 0.03), egoistic (P < 0.001) and introvert (P < 0.001) personalities.

Conclusion:

Certain personality traits and recent stress may be important risk factors of MI, especially in Indians. The finding may have implications on the preventive strategies planned for MI patients.

A review of neuroimaging studies of stressor-evoked blood pressure reactivity: emerging evidence for a brain-body pathway to coronary heart disease risk

An individual's tendency to show exaggerated or otherwise dysregulated cardiovascular reactions to acute stressors has long been associated with increased risk for clinical and preclinical endpoints of coronary heart disease (CHD). However, the 'brain-body' pathways that link stressor-evoked cardiovascular reactions to CHD risk remain uncertain. This review summarizes emerging neuroimaging research indicating that individual differences in stressor-evoked blood pressure reactivity (a particular form of cardiovascular reactivity) are associated with activation patterns in corticolimbic brain areas that are jointly involved in processing stressors and regulating the cardiovascular system. As supported empirically by activation likelihood estimates derived from a meta-analysis, these corticolimbic areas include divisions of the cingulate cortex, insula, and amygdala--as well as networked cortical and subcortical areas involved in mobilizing hemodynamic and metabolic support for stress-related behavioral responding. Contextually, the research reviewed here illustrates how behavioral medicine and health neuroscience methods can be integrated to help characterize the 'brain-body' pathways that mechanistically link stressful experiences with CHD risk.

Behavioural Medicine: The Application of Behaviour Therapy to Physical Health

Three typical areas of application of behavioural medicine are described: biofeedback, relaxation training, and various cognitive behavioural procedures. It is argued that biofeedback has led to few useful clinical treatments but both relaxation and more complex procedures and methods of analysis can contribute to the prevention and treatment of disease. This is illustrated with examples from the literature on headache and the prevention and treatment of coronary heart disease and cancer.

Relation of chronic and episodic stressors to psychological distress, reactivity, and health

This study tested the hypothesis that exposure to chronic stressors, which reflect persistent, negative life situations, would have greater physiological, psychological, and physical health costs than exposure to episodic or intermediate-length stressors, which reflect relatively transient, negative life situations. We also tested whether cardiovascular reactivity, conceptualized as a marker of underlying pathophysiological states, would mediate the relation between chronic stress and psychological distress and illness. Participants were 75 male and 75 female college students. Compared with students experiencing few chronic life stressors, students experiencing many chronic life stressors had exaggerated cardiovascular responses to acute challenges, delayed recovery to resting levels of cardiovascular functioning after the acute challenges, elevated psychological distress levels, and they reported more illnesses. None of the outcomes was associated with the number of episodic or intermediate-length life stressors students experienced. Cardiovascular reactivity did not mediate the stress-distress or stress-illness associations. The results suggest that ongoing stressors that are static are more detrimental to health and well-being than are episodic of change-related stressors.

Cardiovascular reactivity in cardiovascular disease: "once more unto the breach"

Discussed here are conceptual and methodologic issues that bear on the role of behaviorally evoked cardiovascular reactivity in cardiovascular disease. It is argued that recent criticisms concerning the validity of cardiovascular reactivity as a stable dimension of individual differences arise from inadequacies of measurement prevalent in prior literature. With standardization of test stimuli and application of psychometric principles lo protocol development, assessment of reactivity are found to be highly reliable and, in turn, to demonstrate the dispositional nature of this construct. Recent studies also document an underlying heterogeneity of hemodynamic reactions to stress, with distinct cardiac and vascular components. Because hemodynamic adjustments show some plasticity under differing task conditions, responses seen in particular contexts reflect influences of both an individual-specific response potential and response-eliciting properties of the stimulus. On the question of disease relevance, it is concluded that cardiovascular reactivity cannot yet be considered an established risk factor for either coronary heart disease or hypertension. However, the preponderance of existing clinical, experimental. and epidemiologic evidence is consistent with such an association and warrants further study in the context or population-based, prospective investigation.

Hydration status and cardiovascular function: effects of hydration enhancement on cardiovascular function at rest and during psychological stress

This study examined the effects of a 3-day enhanced hydration regimen on resting cardiac function and reactivity to acute stress. Healthy volunteers (14 male, 14 female) were assigned to one of two groups: Enhanced Hydration and Normal Hydration Group. Participants in the Enhanced Group were given six 1-l bottles of water and instructed to drink two bottles a day in addition to normal fluid intake for 3 days preceding their laboratory session; no extra water was given to the Normal Group. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), cardiac output (CO), stroke volume (SV), and total peripheral resistance (TPR) were recorded during a 10-min baseline, 6-min Paced Auditory Serial Addition Test (PASAT), 5-min recovery, 5-min intermediate baseline, and 3-min Cold Pressor Test. Repeated-measures ANOVA revealed a significant Hydration GroupxTask interaction for DBP during the cold pressor (p<0.01) with the Enhanced Group exhibiting greater DBP reactivity to cold stress relative to the Normal Group. Analysis revealed significant Hydration GroupxGender interactions for SV and TPR (p<0.05) at rest and during both the PASAT and Cold Pressor Test. Females in the Enhanced Group displayed higher SV and lower TPR relative to Enhanced Group males, whereas females in the Normal Group displayed lower SV and greater TPR relative to Normal Group males. These results suggest that 3-day hydration enhancement influences blood pressure reactivity in both men and women, and that long-term hydration enhancement is related to resting gender differences in cardiac function.

Reduced quality of life after myocardial infarction in women compared with men

BACKGROUND

Psychosocial factors have been suggested as risk factors for atherosclerotic disease.

HYPOTHESIS

The purpose of the present study was to examine whether there is a gender difference in quality of life after a myocardial infarction with modem treatment of acute ischemic heart disease.

METHODS

In all, 123 men and women aged between 31 and 80 years, and with a hospital-diagnosed myocardial infarction occurring 1-12 months prior to inclusion, were studied. Minor symptoms evaluation profile (MSEP) was used to estimate quality of life at entry.

RESULTS

Age, hemodynamic data, smoking habits, as well as laboratory data, concomitant cardiovascular disease, and revascularization rate did not differ between men and women. Women had significantly more negative feelings regarding all the estimated dimensions of quality of life (Contentment, Vitality, and Sleep) than did men.

CONCLUSION

Self-assessed quality of life after a myocardial infarction was significantly lower among women than among men despite similar age, treatment, and hemodynamic and laboratory data. The causal relationship is however, not known. Further studies are needed to evaluate the underlying mechanism of this observation. This may lead to the development of novel treatment strategies in female patients after a myocardial infarction.

Effects of exercise on cardiovascular outcomes in monkeys with risk factors for coronary heart disease

OBJECTIVE

Exercise reduces the risk for coronary heart disease. However, the mechanisms mediating the beneficial effects of exercise remain ambiguous. In particular, it is uncertain whether exercise inhibits the development of atherosclerosis, a major pathobiologic process underlying heart disease.

METHODS AND RESULTS

To address this question, adult male monkeys were fed an atherogenic diet while assigned to one of four experimental conditions for 34 months: 1) runner/no group disruption, ie, "stable" (n=19); 2) runner plus frequent social group disruption, ie, "unstable" (n=19); 3) sedentary/stable (n=15); or 4) sedentary/unstable (n=18). Neither exposure to exercise nor social group disruption significantly affected the resulting coronary artery atherosclerosis extent or lumen areas (all ANOVA values, P>0.05). When compared with sedentary individuals, exercise animals had lower resting heart rates (119.0+/-3 vs 132.0+/-3 bpm, P=0.002), greater echocardiographically measured left ventricular ejection fractions (77.2+/-0.01% vs 73.8+/-0.01%, P=0.02), greater quantitative angiographically measured dilation of coronary arteries to phenylephrine (2.6+/-1% vs -3.7+/-1% change from baseline diameter, P=0.003), and a reduced cortisol response to an adrenocorticotropin challenge. These measures were not significantly affected by social condition.

CONCLUSIONS

Thus, exercise improved some measures of cardiovascular health and reduced stress responsivity but did not inhibit progression of coronary artery atherosclerosis or promote positive artery remodeling. It is concluded that exercise may exert cardioprotective effects without influencing atherosclerosis extent.

Rat sex and strain differences in responses to stress

Sensitivity to stress has been linked to the development of a variety of physical and psychological disorders. Studies to-date have focused on extreme stress phenotypes, have studied mostly male responses, have used limited dependent variables, and have included a limited number of measurement time points. The present experiment was designed to address these limitations. Feeding, body weight, open-field activity, acoustic startle reflex (ASR), and prepulse inhibition (PPI) responses of adult male and female Sprague-Dawley and Long-Evans rats to daily immobilization stress (20 min/day) were evaluated for 3 weeks. Stress significantly decreased feeding and body weight of males but generally not of females. Effects were greatest in Long-Evans males. Stress decreased 15-min activity levels for males on Stress Day 1, but not on other days. Stress did not affect 15-min activity levels of Long-Evans females but decreased 15-min activity levels of Sprague-Dawley females on every measurement day. ASR responses to stress differed based on rat strain; percent PPI responses differed based on rat strain and sex. Stress increased startle responses of Sprague-Dawley males and females but not of Long-Evans males and females. Stress reduced PPI of Long-Evans females on every measurement day but not of other groups. These findings indicate that strain and sex of rat is important to consider in evaluating behavioral and physiological responses to stress.

Social environment influences the progression of atherosclerosis in the watanabe heritable hyperlipidemic rabbit

BACKGROUND

Although there is evidence that emotionally stressful behavior can accelerate the progression of atherosclerosis, there is less data to support the notion that affiliative social behavior can slow disease progression. The present study examines the influence of social environment on the progression of atherosclerosis in the Watanabe Heritable Hyperlipidemic (WHHL) rabbit, a model that spontaneously develops lesions because of a genetic defect in lipoprotein clearance.

METHODS AND RESULTS

WHHL rabbits were assigned to 1 of 3 social or behavioral groups: an unstable group, in which unfamiliar rabbits were paired daily, with the pairing switched each week; a stable group, in which littermates were paired daily for the entire study; and an individually caged group. The stable group exhibited more affiliative social behavior and less agonistic behavior than the unstable group and significantly less aortic atherosclerosis than each of the other 2 groups. Although the unstable and individually caged groups had comparable aortic lesion areas, the severity of the disease progressed faster in the unstable group, as indexed by a larger area of calcification and increased fibrous cap thickness in complex lesions. The unstable group showed increased agonistic behavior and signs of chronic adrenocortical and gonadal activation, whereas the individually caged group was relatively sedentary, had low glucocorticoid levels, and was hyperinsulinemic compared with the other groups.

CONCLUSIONS

The present study demonstrates that social environment can slow, as well as accelerate, the progression of atherosclerosis. It also emphasizes the importance of behavioral factors in atherogenesis, even in a model of disease with strong genetic determinants.

Stress, inflammation and cardiovascular disease

Various psychosocial factors have been implicated in the etiology and pathogenesis of certain cardiovascular diseases such as atherosclerosis, now considered to be the result of a chronic inflammatory process. In this article, we review the evidence that repeated episodes of acute psychological stress, or chronic psychologic stress, may induce a chronic inflammatory process culminating in atherosclerosis. These inflammatory events, caused by stress, may account for the approximately 40% of atherosclerotic patients with no other known risk factors. Stress, by activating the sympathetic nervous system, the hypothalamic-pituitary axis, and the renin-angiotensin system, causes the release of various stress hormones such as catecholamines, corticosteroids, glucagon, growth hormone, and renin, and elevated levels of homocysteine, which induce a heightened state of cardiovascular activity, injured endothelium, and induction of adhesion molecules on endothelial cells to which recruited inflammatory cells adhere and translocate to the arterial wall. An acute phase response (APR), similar to that associated with inflammation, is also engendered, which is characterized by macrophage activation, the production of cytokines, other inflammatory mediators, acute phase proteins (APPs), and mast cell activation, all of which promote the inflammatory process. Stress also induces an atherosclerotic lipid profile with oxidation of lipids and, if chronic, a hypercoagulable state that may result in arterial thromboses. Shedding of adhesion molecules and the appearance of cytokines, and APPs in the blood are early indicators of a stress-induced APR, may appear in the blood of asymptomatic people, and be predictors of future cardiovascular disease. The inflammatory response is contained within the stress response, which evolved later and is adaptive in that an animal may be better able to react to an organism introduced during combat. The argument is made that humans reacting to stressors, which are not life-threatening but are "perceived" as such, mount similar stress/inflammatory responses in the arteries, and which, if repetitive or chronic, may culminate in atherosclerosis.

The role of gender and family support on dietary compliance in an African American adolescent hypertension prevention study

Social support experiences vary markedly across gender groups, and little is known about the role of social support in promoting healthy dietary compliance in African American adolescents who are at increased risk for developing hypertension. This study examined the relation between gender, dietary social support, and compliance to a low sodium diet. Casual blood pressures were also examined in relation to dietary compliance and gender One hundred eighty-four healthy African American adolescents (83 boys, 101 girls) participated in an intensive 5-day low sodium diet (50 mEq/24 hr) as part of a hypertension prevention program. Emotional dietary social support from family members and friends was measured at baseline. Compliance was defined as urinary sodium excretion of < or = 50 mEq/24 hr at postsodium restriction. The results indicated a significant Gender x Compliance effect for positive family support (p < .05). Girls who were compliant reported higher levels of dietary support from family members (19.2 +/- 7.8) than boys who were compliant (16.9 +/- 7.0). In contrast, boys who were compliant reported lower levels of dietary support from family members (16.9 +/- 7.0) than boys who were not compliant (20.2 +/- 7.5). Systolic blood pressure showed a trend toward decreasing in compliant participants (104.4 +/- 8.4 vs. 101.7 +/- 8.0, mm Hg, p < .06), but the effect diminished when Quetelet Index (kg/m2) was controlled for in the analyses (p < .12). These results suggest that higher levels of emotional dietary support from family members are associated with better adherence to short-term sodium restriction for African American girls as compared to boys. Further research is needed to determine the long-term impact of social support on sodium restriction in adolescent populations.

The terrible twos--anger and anxiety. Hazardous to your health

Anxiety and anger are hazardous to health. This article offers a selective review of research that illustrates how anxiety and anger increase vulnerability to illnesses, compromise the immune system, increase lipid levels, exacerbate pain, and increase the risk of death from cardiovascular disease and from all sources of death. Possible mechanisms for such effects are identified, including the role of cardiovascular reactivity. Finally, data are provided on Anxiety Management Training, a brief, structured psychological intervention that has proven effective in anxiety as well as anger management.

Differences in stress reactivity of laboratory macaques measured by heart period and respiratory sinus arrhythmia

Some laboratory primates are more likely than others to react to anxiety-provoking stressors. Individuals that overreact to stressors may experience diminished psychological well-being and would be inappropriate for some experiments. The differences between reactive and nonreactive individuals may be reflected in heart period and respiratory sinus arrhythmia (RSA). Using surface electrodes and radio telemetry, we measured these two cardiac variables in seven male and ten female singly caged longtailed macaques (Macaca fascicularis) when they were exposed to two stressors, a sudden noise (whistle test) and an unfamiliar technician wearing capture gloves (glove test). Behavior was videotaped during both tests. For the whistle test, cardiac data were recorded before, during, and after two 1 minute whistle blasts separated by 90 min. For the glove test, data were recorded in 1 minute blocks every 8 minutes over 96 minutes before, during, and after 1 minute exposure to the gloved technician. Heart period was decreased and RSA was suppressed during both the whistle and glove exposures. After the whistle test, the cardiac activity of most subjects returned to baseline levels within 10 minutes. The glove test produced more extended suppression, with greater individual differences, than the whistle test. There were greater individual differences in RSA than in heart period. These enhanced individual differences were used to define stress reactors that differed from nonreactors in their cardiac data profiles. Of 16 subjects that completed the glove test, five were identified as reactors.

Status, stress, and atherosclerosis: the role of environment and individual behavior

Atherosclerosis induced by moderate hyperlipoproteinemia in group-housed cynomolgus monkeys differs significantly between animals of dominant and subordinate social status. The nature of this association also varies by sex, and in males, by stability of the social environment. Dominant males develop more extensive atherosclerosis than subordinates when housed in unstable, but not stable, social groups; in contrast, subordinate females develop greater atherosclerosis than dominants, and do so irrespective of the conditions of social housing. Experimental investigations reveal that the first of these associations (males) is mediated by concomitant sympathoadrenal activation and the second (females) by ovarian impairment associated with the stress of social subordination. We believe our findings offer clues to the neuroendocrine mediation of behavioral influences on coronary artery disease in humans. This is particularly true where these influences reflect asymmetries in the power or status relationships among individuals within similar social environments, or when dimensions of temperament or disposition give rise to such relationships. We propose that these data also may be informative regarding the pathophysiological sequelae of social stratification (in which disease incidence varies by class membership within populations), but only where social environments engendered by class inequalities exacerbate status-dependent behavioral differences among individuals within communities of associates.

Childhood attachment and loss experiences affect adult cardiovascular and cortisol function

OBJECTIVE

This study proposes to test the hypothesis that early loss of a parent, coupled with poor quality family relationships, would result in long-term increased cardiovascular and cortisol reactivity to stress.

METHODS

Subjects included 30 university students who lost one parent before age 16, and 31 control subjects. Blood pressure (BP) was measured continuously during 5-minute baseline and recovery periods, and during each of 2 tasks--viewing a 7-minute video clip depicting the death of a parent, and giving a 3-minute impromptu speech (1-hour rest between tasks). Salivary cortisol samples were collected immediately before each task, and at 5 and 20 minutes posttask. Quality of family relationships (FR) was measured using the Moos Family Environment Scale.

RESULTS

Repeated-measures analysis of covariance revealed significant main effects on BP of both parental loss and FR for both tasks (all p values < .05) such that subjects who lost a parent or reported poor quality FR showed higher BP across all periods. The loss by FR by period interaction was not significant. An FR by period interaction was found for cortisol during the movie, in which poor quality FR subjects showed increased cortisol, whereas all others showed decreases. A loss by period interaction was found for cortisol during the speech, in which cortisol increased in loss subjects and decreased in non-loss subjects.

CONCLUSIONS

These findings indicate that both childhood loss of a parent and poor quality of caretaking are associated with long-term increases in BP and altered neurohormonal responses to stress.

Psychosocial stress-induced heart rate reactivity and atherogenesis: cause or correlation?

The relationship between heart rate reactivity and atherogenesis is examined. Data from empirical studies are presented which support theoretical suggestions that it is the heart rate itself rather than the increase in heart rate following the onset of a stressor which is causally related to the development of arterial atherosclerosis. Several directions for research which will clarify this issue are discussed, with recent developments in the detection of atherosclerosis suggested as forming the basis of more reliable investigation of the effects of cardiac output variables upon arterial atherogenesis.

Influence of academic examination stress on hematological measurements in subjectively healthy volunteers

Some recent reports showed that a brief exposure to a mental stressor during 3-20 min may induce hematological changes in humans. The aim of the present study was to examine the effects of academic examination stress on erythron variables, such as the number of red blood cells (RBC), hemoglobin (Hb), hematocrit (Ht), mean corpuscular volume (MCV), mean cell Hb (MCH), mean cell Hb concentration (MCHC), RBC distribution width (RDW), and serum iron and transferrin (Tf). The above variables were determined in 41 students in three conditions, i.e. the stress condition (the day before a difficult oral exam) and two baseline conditions, i.e. a few weeks earlier and later. At the same occasions, subjects completed the Perceived Stress Scale (PSS), the state version of the State-Trait Anxiety Inventory (STAI) and the Profile of Mood States (POMS). Academic examination stress significantly increased Ht, Hb, MCV, MCH and MCHC and significantly decreased RDW. There were significant relationships between the stress-induced changes in the PSS, STAI and POMS scores and those in Ht, Hb, MCV and MCH (allpositive) and RDW (negative). It is concluded that academic examination stress induces significant hematological changes indicative of an increased number of large RBC and increased hemoglobinisation, which cannot be explained by shifts of fluid out of the intravascular space, concentrating non-diffusible blood constituents.

Behaviorally elicited heart rate reactivity and atherosclerosis in ovariectomized cynomolgus monkeys (Macaca fascicularis)

It has been hypothesized that atherogenesis is accelerated among individuals who exhibit heightened cardiovascular reactions to psychologic stress. We have reported previously that the coronary atherosclerosis of cholesterol-fed, male and reproductively intact (premenopausal) female cynomolgus monkeys was exacerbated in animals that experienced the largest heart rate (HR) reactions to a fear-eliciting laboratory stressor. In this article, we report a similar relationship among 20 female monkeys that were rendered estrogen-deficient (by ovariectomy) and subsequently treated with replacement of both estrogen and progesterone. At the beginning of a 30-month study period, animals were fitted with ECG telemetry devices, and their HRs were recorded under baseline and stressed conditions. Stress HR measurements were obtained during a standard challenge involving threatened capture and physical handling of the animals. As part of a related experiment, monkeys were then ovariectomized and, for the remainder of the study, administered 17 beta-estradiol (continuously) and progesterone (cyclically) by subcutaneous Silastic implant (Dow Corning). Animals consumed a cholesterol-containing diet throughout, and HR measurements were repeated in the 24th month. At necropsy, the magnitude of animals' HR responses to stress correlated significantly with intimal area measurements in the left anterior descending and circumflex coronary arteries (r = .59 and r = .57, respectively; P < .009). This association was due to a marked exacerbation of coronary atherosclerosis in animals comprising the upper third of the reactivity distribution. Although total and HDL cholesterol concentrations also covaried with HR reactivity, the greater atherosclerosis of "high" HR reactors persisted after statistical adjustment for concomitant variability in plasma lipids. HR reactivity was unrelated to blood pressure, body weight, or social behavior.

Preventive medicine and screening in older adults

PURPOSE

To review important current issues, studies, recommendations and controversies relating to preventive medicine and screening in older people. STUDY SELECTION/DATA ABSTRACTION: MEDLINE searches for literature on prevention and screening with regard to older adults as well as each individual condition reviewed; bibliographical reviews of textbooks, journal articles, government and advocacy organization task force reports, and recommendations. Important information synthesized and discussed qualitatively.

DATA SYNTHESIS

Data and recommendations are presented for most common preventive services, including primary prevention and screening for cardiovascular diseases and risk factors, common malignancies, endocrine and infectious diseases, osteoporosis, sensory deficits, and dementia.

CONCLUSIONS

The goal of preventive medicine in older people should be not only reduction of premature morbidity and mortality but preservation of function and quality of life. Attempts to prevent diseases of old age should start in youth; the older the patient, the less likely the possibility or value of primary and secondary prevention, and the greater the stress must be on tertiary prevention. Age 85 is proposed as a general cutoff range beyond which conventional screening tests are unlikely to be of continued benefit; however, care must always be individualized. Emphasis should be on offering the best proven and most effective interventions to the individuals at highest risk of important problems such as cardiovascular diseases, malignancies, infectious and endocrine diseases, and other important threats to function in older people. Breast cancer screening, smoking cessation, hypertension treatment, and vaccination for infectious diseases are thus far among the most firmly proven and well accepted specific preventive measures, with physical exercise also being particularly promising. Although more research is needed, a current working approach is necessary and possible. A summary table of recommendations and information tools such as reminders or flowsheets may be valuable in helping the physician carry out prevention and screening programs.

Relationship of trait, Type A behavior, and physical fitness variables to cardiovascular reactivity and coronary heart disease risk potential

PURPOSE

This research investigated the effects of individual characteristics on cardiovascular reactivity, and in turn on the potential for developing coronary heart disease.

DESIGN

Path analysis was performed using LISREL, a structural equation modeling program providing maximum likelihood estimators and goodness-of-fit measures.

SETTING

Data were collected during a health assessment program, from participants attending a Department of Defense senior service school.

SUBJECTS

Participants were 134 senior-ranking male military and civilian employee volunteers, representing approximately 84% of all students in training.

MEASURES

Five individual characteristics, four measures of cardiovascular reactivity, and one coronary heart disease risk potential variable were investigated. These included Physical Fitness, Type A behavior, Trait Anger and Trait Anxiety, Diastolic and Systolic Blood Pressure measures, and Coronary Heart Disease Risk.

RESULTS

Significant path coefficients (critical ratios > 2) indicated that the mean diastolic blood pressure under a video stress condition was predictive of increased potential of developing coronary heart disease (.51), while hard driving Type A behavior was a cardiovascular reactivity antecedent associated with an increase in coronary heart disease risk directly (.14) and indirectly (.39). Physical fitness, on the other hand, had a positive affect in that increased fitness was related to lower cardiovascular reactivity when participants were stressed (-.58).

CONCLUSIONS

Physical fitness is indirectly beneficial in reducing coronary heart disease risk potential by reducing an individual's diastolic blood pressure response, while scoring high as a Type A Hard Driving personality increases cardiovascular reactivity and coronary heart disease risk. This study is limited to middle-aged males who were generally healthy and displayed concern for their health.

Psychosocial factors, sex differences, and atherosclerosis: lessons from animal models

OBJECTIVE

Premenopausal women, compared with men, are relatively spared from coronary heart disease and the underlying atherosclerosis. Our purpose has been to elucidate the reason for this difference and to explore the role of behavioral factors in this phenomenon.

METHODS

Studies employed socially housed cynomolgus macaques (Macaca fascicularis) fed an atherogenic diet and subjected to behavioral observations. Ovariectomy, with or without hormone replacement, was used to test specific hypotheses about estrogen's role in the protection of females from atherosclerosis and coronary heart disease.

RESULTS

Female macaques, like women, are resistant to atherosclerosis. However, this resistance is modified by social status-dominant monkeys develop little atherosclerosis, whereas subordinates resemble males in the amount of lesion that occurs. Subordinate females also are characterized by hypercortisolemia, behavioral dysfunction, and impaired ovarian function; the resulting low concentrations of circulating estrogen perhaps explain their accelerated atherosclerosis. Notably, atherosclerosis is exacerbated in ovariectomized monkeys but is suppressed in association with pregnancy, a hyperestrogenic state. Moreover, exogenous estrogen (an oral contraceptive) inhibits atherosclerosis in premenopausal social subordinates.

CONCLUSIONS

To the extent that our results apply to women, they highlight the potential importance of behavioral stressors and their effects on estrogen activity in the premenopausal development of atherosclerosis. The triad of hypercortisolism, ovarian impairment, and psychiatric morbidity found in monkeys also occurs in women and may represent a high-risk state for disorders of the cardiovascular system and perhaps, other estrogen-sensitive tissues.

Variations in plasma lipid concentration during examination stress

The effect of psychological stress on plasma lipids was studied in 40 law students (20 men and 20 women). Plasma cholesterol, triglyceride, and apolipoprotein concentrations were examined at the beginning of the quarter and during the week before final examinations. Cortisol, blood pressure, and heart rate, and self-reports of stress and workload were also measured to verify that examinations were associated with increased stress levels. Perceived stress, perceived workload, and cortisol increased before examinations. Low density lipoprotein cholesterol (LDL-C) increased 5.8 +/- 13.9 mg/dL, and apolipoprotein B (apo B) increased 2.9 +/- 4.0 mg/dL. High density lipoprotein cholesterol decreased in women only. These changes were not due to changes in dietary intake or indexes of plasma volume. However, changes in cortisol and changes in LDL-C and apo B were associated, suggesting a neuroendocrine component to the effects. These results suggest that episodic, stressful situations may lead to potentially atherogenic changes in lipid and lipoprotein concentrations.

Psychobiologic reactivity to stress and childhood respiratory illnesses: results of two prospective studies

Psychological stress is thought to undermine host resistance to infection through neuroendocrine-mediated changes in immune competence. Associations between stress and infection have been modest in magnitude, however, suggesting individual variability in stress response. We therefore studied environmental stressors, psychobiologic reactivity to stress, and respiratory illness incidence in two studies of 236 preschool children. In Study 1, 137 3- to 5-year-old children from four childcare centers underwent a laboratory-based assessment of cardiovascular reactivity (changes in heart rate and mean arterial pressure) during a series of developmentally challenging tasks. Environmental stress was evaluated with two measures of stressors in the childcare setting. The incidence of respiratory illnesses was ascertained over 6 months using weekly respiratory tract examinations by a nurse. In Study 2, 99 5-year-old children were assessed for immune reactivity (changes in CD4+, CD8+, and CD19+ cell numbers, lymphocyte mitogenesis, and antibody response to pneumococcal vaccine) during the normative stressor of entering school. Blood for immune measures was sampled 1 week before and after kindergarten entry. Environmental stress was indexed with parent reports of family stressors, and a 12-week respiratory illness incidence was measured with biweekly, parent-completed symptom checklists. The two studies produced remarkably similar findings. Although environmental stress was not independently associated with respiratory illnesses in either study, the incidence of illness was related to an interaction between child care stress and mean arterial pressure reactivity (beta = .35, p < .05) in Study 1 and to an interaction between stressful life events and CD19+ reactivity (beta = .51, p < .05) in Study 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemoconcentration and stress: a review of physiological mechanisms and relevance for cardiovascular disease risk

Elevated levels of hematocrit and hemoglobin have been identified as an independent risk factor for the development of a number of diseases, including hypertension, coronary heart disease, and stroke. A growing body of evidence also indicates that elevations in hematocrit and hemoglobin are present in situations involving both physical and mental stressors. This paper reviews the evidence linking decreases in plasma volume causing hemoconcentration with hemodynamic adjustments associated with activation of the sympathetic nervous system, and the potential relevance of stress-induced hemoconcentration in triggering deleterious cardiovascular events. The importance of blood viscosity in understanding the effects of hemoconcentration is discussed, along with the need to evaluate the degree of hemoconcentration during stress for accurate interpretation of changes in certain blood constituents.

Lowering of body temperature affects human platelet functions and norepinephrine release

The effect of lowering body temperature on plasma epinephrine, norepinephrine, and platelet density distribution and volume was studied in a placebo-controlled double-blind study. Lowering of body core temperature was induced by either exposure to a cold environment at a temperature of 5 degrees C (CT) or by a single dose of the 5-HT1A agonist ipsapirone (IPS). A third group exposed to an ambient temperature of 28 degrees C was given placebo (PLAC). All of the three groups were investigated in a climate chamber. In the CT group the density distribution of blood platelet subpopulations was shifted to an increase in less dense platelets that were more sensitive towards aggregation-inducing agents. The mean platelet volume in this subpopulation was decreased. Epinephrine was not affected, whereas the increase of norepinephrine was correlated with an increase of platelets that were more sensitive to aggregation-inducing agents in the CT group but not in the PLAC and IPS groups.

The pathogenicity of behavior and its neuroendocrine mediation: an example from coronary artery disease

Although it is frequently hypothesized that perturbations of the body's principal axes of neuroendocrine response, especially the sympathetic-adrenomedullary and pituitary-adrenocortical systems, mediate psychosocial influences on disease, evidence directly supporting this hypothesis is sparse at best and, for most disease entities, nonexistent. In this article, we illustrate a research strategy aimed at elucidating the role of behavior in disease pathogenesis by focusing on a single pathologic process--disease of the coronary vasculature--and emphasizing experimental evidence linking such disease to both behavior and sympathoadrenal activation in nonhuman primates. In cynomolgus monkeys, it is found that several psychosocial variables, e.g., social instability, behavioral dominance (in males), and subordination (in females), promote coronary atherogenesis, either independently or in interaction. Animals exhibiting a heightened cardiac responsivity to stress (reactions of probable sympathetic origin) also develop the most extensive coronary lesions and beta-adrenoreceptor blockade prevents the behavioral exacerbation of atherosclerosis. Social stress causes injury to arterial endothelium (also preventable by adrenoreceptor blockade) and, among chronically stressed animals, impairs endothelium-dependent vasomotor responses of the coronary arteries. It is suggested that similar research programs might elucidate the influence of behavior and neuroendocrine factors on the pathogenesis of other disease states and conditions, including susceptibility to infection.

Fish oil treatment decreases superoxide anions in the myocardium and coronary arteries of atherosclerotic monkeys

BACKGROUND

This experiment sought to determine the effects of fish oil on superoxide anion production in the myocardium and coronary arteries of atherosclerotic monkeys. Recent evidence indicates that dietary supplementation with fish oil preserves normal vasomotion of atherosclerotic coronary arteries and reduces damage to the myocardium after ischemia and reperfusion, although the mechanisms remain unclear.

METHODS AND RESULTS

Adult male cynomolgus monkeys were fed an atherogenic diet with (n = 15) or without (n = 15) half the fat calories from fish oil. After 12 months, chemiluminescence of lucigenin was used to measure superoxide anion production in coronary arteries and myocardium after 1 hour of ischemia and 2 hours of reperfusion. The signals were calibrated with known quantities of xanthine and xanthine oxidase. Superoxide anion production in ischemic myocardium was (mean +/- SEM, nmol/mg dry wt per minute) 1 +/- 1 and 4 +/- 1 in monkeys fed fish oil and not fed fish oil, respectively (P < .05). Superoxide anion production in coronary arteries not exposed to ischemia and reperfusion was (nmol/mg dry wt per minute) 4 +/- 1 and 8 +/- 2 in monkeys fed fish oil and not fed fish oil, respectively (P < .05). Superoxide anion production in coronary arteries was (nmol/mg dry wt per minute) 5 +/- 2 and 16 +/- 3 in monkeys fed fish oil and not fed fish oil after ischemia and reperfusion, respectively (P < .05).

CONCLUSIONS

Dietary supplementation with fish oil reduced vascular superoxide anion production and prevented the increase in vascular and myocardial superoxide anion production that accompanied ischemia and reperfusion. These phenomena may underlie some of the beneficial cardiovascular effects of fish oil.

Antiatherogenic effects of beta-adrenergic blocking agents: theoretical, experimental, and epidemiologic considerations

Theoretical considerations and results from experimental studies in animal models suggest that long-term beta-adrenergic blockade should be antiatherogenic. Some of these experimental results indicate that beta-blockers could inhibit atherogenesis and thus prevent clinical events independently of any effects on blood pressure through concomitant reductions in heart rate, blood velocity and energy, endothelial permeability to lipoproteins, and the likelihood of plaque rupture. Any such independent inhibition of atherogenesis implies, in turn, that beta-blockers might be more desirable than alternative antihypertensive therapies in persons at high risk for atherosclerotic diseases. Results of the three major trials directly comparing beta-blockers to diuretics in the primary prevention of coronary heart disease among patients with hypertension were largely inconclusive. However, ancillary data from these and other trials are consistent in demonstrating that beta-adrenergic blockade is associated with anti-coronary heart disease effects and, thus, is perhaps antiatherogenic. A definitive evaluation of the antiatherogenic effects of beta-blockers is not forthcoming because no large clinical trials directly assessing the effect of these drugs on atherosclerosis have been done or are planned.

Psychosocial factors and chronic fatigue syndrome

This study investigated the number and severity of life events, Type A behaviour, coping strategies and social support differences between chronic fatigue and irritable bowel syndrome patients prior to illness and between these groups and healthy controls. Although few differences were found between the groups for life events, a number of interesting results emerged with regard to different aspects of Type A behaviour, various coping strategies and social support. These findings are discussed with respect to existing research in the field.

Effects of psychosocial stress on endothelium-mediated dilation of atherosclerotic arteries in cynomolgus monkeys

The objectives of this study were to determine if psychosocial stress impairs dilation through endothelium-derived relaxing factor (EDRF)-mediated mechanisms and if this effect is long lasting. Monkeys were fed an atherogenic diet for 36 mo while in one of three experimental conditions: (a) stable social groups ("unstressed," n = 6); (b) unstable social groups for the first half of the experiment and stable groups for the second half ("early stress," n = 8); and (c) stable groups for the first half of the experiment and unstable groups for the second half ("late stress," n = 6). Iliac arteries were studied in organ chambers containing Krebs' buffer and 10(-6) M indomethacin. Arteries from the late stress group had impaired dilation (shift of the dose-response curve down and to the right) to acetylcholine and the calcium ionophore A23187 (for both, P < 0.05), but not to nitroprusside (P > 0.05), compared with unstressed or early stress monkeys. NG-methyl-L-arginine reduced the dose-response curve to both acetylcholine and A23187 in the unstressed group and resulted in similar vascular responses among all three groups (P > 0.05). We conclude that current, but not previous, exposure to chronic stress impairs endothelium-mediated dilation of atherosclerotic iliac arteries of cynomolgus monkeys through an EDRF-mediated mechanism.

Social support as experienced by Roman Catholic priests: the influence of vocationally imposed network restrictions

This qualitative descriptive study explored the experience of social support as perceived by four Roman Catholic priests who are community caregivers subject to role-related stressors and who have vocational limitations placed on their social support networks. The data collection process consisted of two semistructured interviews employing open-ended questions. Content and concept analysis techniques yielded seven core themes (person-role disharmony, intimate connections, network leveling, moving networks, caregiver survival, vocation-person esteem, caring relationships), three prevailing themes (subsistent relationships, person-priest being, reciprocal fulfillment), and one contextual theme (presence). The priests actively sought support as a means of coping with the daily stress associated with their caregiving roles. Large and diffuse networks were unable to compensate for restrictions resulting from vows of celibacy, discord accompanying midlife transition, or conflicts associated with socially prescribed role expectations of the priesthood. The instability of their support networks resulting from mandatory transfers may have been a contributing factor. Existential presence, an enduring theme, was identified as an inherent quality of caregiving and social support.

Psychological, behavioral and biochemical risk factors for coronary artery disease among American and Italian male corporate managers

Differences in psychological, behavioral and biochemical risk factors for coronary artery disease (CAD) among male corporate managers of 2 countries (United States and Italy), with very different age-specific rates of mortality for CAD were evaluated. In all, 129 American (mean age 43 +/- 7 years) and 80 Italian (mean age 45 +/- 7 years) managers volunteered to participate in this study. Each subject was administered several questionnaires assessing various psychological and behavioral risk factors for CAD, and all 129 Americans and 55 of 80 Italians had their blood drawn between 8:00 and 9:30 AM after overnight fasting for the measurement of plasma levels of dehydroepiandrosterone-sulfate (DHEA-S), total cholesterol, triglycerides, and apolipoproteins A-I and B. Italian managers reported significantly more cynicism and hostility, and less enjoyment in leisure activities than did American ones. Furthermore, 40 Italian (51%) and only 18 American (14%) managers were smokers (this difference being statistically significant). Although no significant differences were found in factors positively related with CAD (cholesterol, triglycerides and apolipoprotein B), there were clear differences in parameters inversely correlated with the incidence of CAD. Italian managers had significantly lower levels of plasma DHEA-S and apolipoprotein A-I than did American ones. In conclusion, this study found that Italian managers had a significantly more unhealthy psychological and behavioral profile than did American ones, and had lower levels of those biochemical parameters (apolipoprotein A-I and DHEA-S) thought to have a protective role against development of CAD.

Lipids in psychological research: the last decade

We review the recent literature examining lipid changes during stressful experiences, and the psychological and constitutional differences that influence lipid levels at rest and that may modulate lipid response to stress. Mild forms of chronic or episodic stress are apparently not associated with alterations in lipids and lipoproteins, but severe forms of real or perceived stress do appear to alter lipid levels. Acute laboratory stress is frequently associated with short-term alterations in lipids and lipoproteins, but the significance of these changes is unclear. Several individual characteristics, such as heightened neuroendocrine or autonomic reactivity to stressors, Type A component behavior, and other aspects of personality, appear to be associated with an atherogenic lipid profile. Stress may influence lipid concentrations and metabolism through a variety of physiological and behavioral mechanisms, but none have been clearly elucidated. Future research should concentrate on understanding these mechanisms.