Self-reported stressors, symptom complaints and psychobiological functioning I: Cardiovascular stress reactivity

Testing adverse childhood experiences (ACEs) as a potential moderator of the association between current chronic stress and cardiovascular reactivity

Motivated by mixed findings regarding the relationship between chronic stress and cardiovascular reactivity, the current study aimed to investigate whether adverse childhood experiences (ACEs) serve as a potential moderator of the association between current chronic stress and cardiovascular reactivity. Incidence of ACEs, levels of current chronic stress, and heart rate (HR) reactivity to a mental arithmetic stress task were measured in 111 participants (age = 20.83, 76 % female, 66 % White). ACEs were measured using the Childhood Trauma Questionnaire and current chronic stress was measured using the Perceived Stress Scale. Moderation analyses were conducted with HR reactivity as the outcome and ACEs as the moderator. Results indicated that a greater amount of current chronic stress was significantly associated with relatively blunted HR reactivity (β = -0.25, p = 0.03) even after controlling for sociodemographic variables. Exposure to ACEs was not significantly related to HR reactivity, (all p ≥ 0.66), and there was no significant interaction between current chronic stress and ACE exposure in predicting HR reactivity, (all p ≥ 0.44). These results show that current chronic stress is associated with relatively blunted HR reactivity and that exposure to ACEs does not moderate the relationship between chronic stress and cardiac stress reactivity.

Life events are associated with elevated heart rate and reduced heart complexity to acute psychological stress

The current study examined whether the exposure to life events and reported impact of life events are associated with altered cardiac reactivity to an acute psychological stressor. Participants (N = 69) completed the Life Experience Survey (LES) and Positive and Negative Affect Schedule (PANAS) and undertook a standardized social-evaluative stress task. Cardiac activity was measured via heart rate and non-linear heart rate variability (HRV) indices Sample Entropy, SD1, SD2 and SD1/SD2 ratio. Heart rate and non-linear HRV were measured before, during and after stress exposure. Findings suggest higher heart rate reactivity in individuals reporting higher number and impact of negative and total life events. Decreases in Sample Entropy were evident for number as well as impact of life events. No associations were found for SD1, SD2 and SD1/SD2 ratio. Findings suggest that life-events are associated with elevated heart rate and diminished heart rate complexity in response to acute stress.

Involvement of stress in the pathogenesis of autoimmune thyroid disease: a prospective study

BACKGROUND

An association between stress and autoimmune thyroid disease (AITD) (especially Graves' hyperthyroidism) has been reported, but all studies so far on this topic have been retrospective.

OBJECTIVE

To evaluate prospectively the relationship between stress and (i) de novo occurrence of thyroid antibodies and (ii) development of overt autoimmune hyper-/hypothyroidism.

STUDY DESIGN

Two nested case-control studies in a prospective cohort of 790 euthyroid women who were 1st or 2nd degree relatives of AITD patients. Follow-up was five year, with annual assessments including questionnaires on stressful life events, daily hassles, and mood. In study A, cases were subjects who developed TPO-Ab but remained euthyroid during follow-up (called event). In study B, cases were subjects who developed overt hypothyroidism (TSH>5.7 mU/l and FT4<9.3 pmol/l) or overt hyperthyroidism (TSH<0.4 mU/l and FT4>20.1 pmol/l) during follow-up (called event). For each case, two controls were selected, matched for age and duration of follow-up; controls in study A remained TPO-Ab negative, and in study B remained without overt hyper-/hypothyroidism.

OUTCOMES

Contrast in questionnaire responses between cases and controls at baseline, at one year prior to the event and at time of event.

RESULTS

Exposure to stress was not different between subjects who developed or did not develop TPO-Ab (study A). No differences were observed in stress questionnaires between hyper-/hypothyroid cases and controls at any time point, but hypothyroid cases had less negative feelings than controls at the time of diagnosis (study B).

CONCLUSION

The data suggest that stress is not involved in the pathogenesis of AITD.

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.

Life events and acute cardiovascular reactions to mental stress: a cohort study

OBJECTIVE

This study addressed the issue of whether frequent exposure to life events is associated with aggravation or blunting of cardiovascular reactions to acute mental stress.

METHODS

In a substantial cohort of 585 healthy young adults, systolic and diastolic blood pressure and pulse rate were recorded at rest and in response to a mental arithmetic stress task. Participants indicated, from a list of 50 events, those they had experienced in the last year.

RESULTS

There was an overall association between life events and blunted cardiovascular reactivity that was driven by variations in the frequency of exposure to desirable events. The total number of events and the number of personal events were negatively associated with systolic blood pressure and pulse rate reactions to acute stress, whereas the number of work-related events was negatively associated with diastolic blood pressure and pulse rate reactivity. The negative association between total events and systolic blood pressure reactivity was stronger for women than men, whereas men exposed to frequent undesirable events showed enhanced diastolic blood pressure reactivity. The blunting of pulse rate reactivity associated with frequent personal life events was evident particularly for those who had a relatively large number of close friends.

CONCLUSION

The nature and extent of the association between life events exposure and stress reactivity in young adults depends on the valence of the events together with the sex of the individual and their social network size.

Life events and hemodynamic stress reactivity in the middle-aged and elderly

Recent versions of the reactivity hypothesis, which consider it to be the product of stress exposure and exaggerated hemodynamic reactions to stress that confers cardiovascular disease risk, assume that reactivity is independent of the experience of stressful life events. This assumption was tested in two substantial cohorts, one middle-aged and one elderly. Participants had to indicate from a list of major stressful life events up to six they had experienced in the previous 2 years. They were also asked to rate how disruptive and stressful they were, at the time of occurrence and now. Blood pressure and pulse rate were measured at rest and in response to acute mental stress. Those who rated the events as highly disruptive at the time of exposure and now exhibited blunted systolic blood pressure reactions to acute stress. The present results suggest that acute stress reactivity may not be independent of stressful life events experience.

Stress is not associated with thyroid peroxidase autoantibodies in euthyroid women

OBJECTIVE

Multiple genes and environmental factors play a role in the etiology of autoimmune thyroid disease (AITD). In Graves' hyperthyroidism, stress is such an environmental factor, but whether it plays a role in Hashimoto's hypothyroidism is unknown. We used validated questionnaires to evaluate an association between TPO antibodies, an early marker for AITD, and self-reported stress.

SUBJECTS AND METHODS

Recently Experienced Stressful Life Events, Daily Hassles, and mood (tendency to report positive and negative affects) were assessed in 759 euthyroid subjects.

RESULTS

TPO antibodies were found in 183/759 (24%) of subjects. The TPO-Ab positive subjects were older (39.7+/-12 vs. 34.2+/-12 years; p<.001) than the TPO-Ab negative subjects, but the number of daily hassles (24+/-14 vs. 25+/-14; p=.24), the number of stressful life events (10+/-6 vs. 11+/-6; p=.09), and the scores on the affect scales (22.1+/-7.4 vs. 22.2+/-7.3; p=.89 for negative affect and 38.2+/-5.1 vs. 38.3+/-5.3; p=.91 for positive affect) were similar in TPO-Ab positive and TPO- Ab negative subjects.

CONCLUSIONS

We found no association between recently experienced stressful life events, daily hassles or mood and the presence of TPO antibodies in these euthyroid women.

Moderation of physiological stress responses by personality traits and daily hassles: less flexibility of immune system responses

Previously we demonstrated that stressors varying on the dimension of mental effort and controllability have distinctive effects on cardiovascular, endocrine and immune system responses. The purpose of the present study was to relate individual differences in physiological stress responsivity to task appraisal and stress-induced mood changes (issue 1), trait characteristics (issue 2) and daily hassles (issue 3). Appraisal and mood changes did not mediate the differential effects of the stressors. The trait characteristics, aggression and external locus of control and daily hassles moderated the effect of the stressor on physiological parameters, especially immune parameters. Moreover, the moderation effect was different in the high versus the low effort stress task. High aggression, high external locus of control and more daily hassles were associated with increased reactivity in the low effort condition and decreased reactivity in the high effort condition, which is suggested to reflect less differentiated responding to changing task demands and hence, less flexibility in the immune system.

The role of negative and positive affectivity on perceived stress-subjective health relationships

This article reviews the arguments that support the approach regarding the 'inflationary' influence of the negative affectivity (NA) trait, or neuroticism, on relationships between perceived stress (e.g. different means of self-report of psychosocial stress such as major life events or daily stress) and subjective physical health (e.g. somatic symptomatology, health complaints). It has been explained that the said inflationary effect could distort the interpretation of the results that are found if it is done in terms of stress-objective health relationships (known in terms of health behavior, biological markers, morbidity and mortality) and that, in this sense, the NA would be a contaminant. This is why it has been suggested that in these cases, the effect of NA on predictor and criterion relationships should be controlled. The present critical review doesn't support these conclusions. Also, this paper deals with the empirical analysis of some matters that refer to one of the arguments mentioned, namely that NA is a general and penetrating factor that impregnates perceived stress (we will focus on daily stress or hassles) and subjective health measures (we will focus on somatic symptoms), as well as its relationships. We also analyze the role of positive affectivity (PA). The empirical analysis carried out uses a combination of within and interindividual methods. Contrary to the hypothesis regarding the moderating effects (specifically, inflationary) of NA on relationships between daily stress and somatic symptomatology, NA has only presented direct significant effects on both variables (between subjects), while its moderating effects are modest and non-significant. However, PA appears not to have any direct significant effects, but it does have moderating effects (specifically, buffering effects). Finally, we discuss the implications of these findings and we make some suggestions for future research.

Dissociated autonomic regulation during stress and physical complaints

OBJECTIVE

In order to evaluate the relevance of individual differences in the regulation of autonomic subsystems to psychosomatic processes, reactivity of the autonomic nervous system to an emotional stressor was related to the occurrence of physical complaints. In contrast to most other studies, the measures were related to the degree of actually experienced stress.

METHODS

In a large sample (n=111), electrodermal activity (EDA) and heart rate variability (HRV) were obtained at rest and during emotional stress. Physical complaints were assessed by a standardized symptom checklist providing subscales for different physiological systems.

RESULTS

Subjects who were actually stressed by the stress induction procedure but showed only weak reactivity of EDA, and subjects who were only slightly stressed but showed a marked EDA response reported a high amount of gastrointestinal complaints. A greater decrease of high-frequency HRV from the rest to the stress condition was associated with reports of relatively more cardiovascular complaints.

CONCLUSION

Findings indicate that the link between regulation of EDA and gastrointestinal functions has to be localized in higher brain structures and support the hypothesis that minor autonomic dysregulation may represent one pathway linking negative affect and the development of physical disorders.

Is somatization a habituation disorder? Physiological reactivity in somatization syndrome

The present study investigates whether physiological activity may play a part in maintaining the amplified perception of bodily processes typical for somatization. Eighty-one persons were classified into three groups by means of a structured clinical interview: 24 patients with somatization syndrome, 34 patients with somatization syndrome and comorbid major depression, and 23 healthy controls. Subjects completed four blocks of an attentional task, each of the blocks separated by resting periods. Physiological patterns demonstrated higher activity during mental tasks than during rest. The heart rate deceleration after changing from mental challenge to rest was less pronounced in the groups of patients with somatization syndrome than in controls. Moreover, patients with somatization syndrome reported feeling more and more tense during the investigation, while controls showed the tendency to habituate. The effects of heart rate and of feelings of tension partly replicated earlier findings, and demonstrated that physiological activity may interact with psychological processes in somatization.

Life event exposure, physiological reactivity, and psychological strain

The study tested the prediction that the experience of life events would be reflected in greater autonomic reactivity and that this might play a moderating role between reported stress and psychological symptoms. Eighty-seven undergraduates were screened with a life events scale and thirty-nine were allocated to three groups representing high, medium, and low life event scores. The General Health Questionnaire, Profile of Mood States, the Spielberger Trait Anxiety Scale, and the Marlowe-Crowne Scale were administered. Electrodermal activity and heart rate were recorded during an habituation series of tones and a digit-symbol substitution task. The groups differed both on the GHQ and the POMS and, also, in their physiological responses to the tones. Unexpectedly, the high life event group, compared to the other groups, appeared to display smaller physiological responses. The cognitive task resulted in elevated physiological activity but no consistent group differences. Cardiovascular reactivity moderated the relationship between life event scores and reported distress. These findings are discussed in relation to theories of psychophysiological adaptation to negative events.

Salivary MUC5B-mediated adherence (ex vivo) of Helicobacter pylori during acute stress

OBJECTIVE

Biochemical host defenses at mucosal sites, such as the oral cavity, play a key role in the regulation of microbial ecology and the prevention of infectious disease. These biochemical factors have distinct features, some of which benefit the host and some that benefit bacteria. We investigated the effects of acute stress on the salivary levels of the carbohydrate structure sulfo-Lewis (sulfo-Le), which is linked to the mucosal glycoprotein MUC5B. Sulfo-Le was recently identified as an adhesion molecule for Helicobacter pylori; therefore, we also measured saliva-mediated adherence (ex vivo) of H. pylori. The oral cavity is suspected to be involved in the transmission of H. pylori.

METHODS

Saliva was collected from 17 undergraduates before (baseline), during (stress), and after (recovery) exposure to a video showing surgical procedures. In addition, blood pressure, an impedance cardiogram, and an electrocardiogram were recorded.

RESULTS

During stressor exposure, participants reported increased state anxiety. In addition, stroke volume increased and heart rate decreased. The stressor induced a strong increase in salivary sulfo-Le concentration (U/ml), sulfo-Le output (U/min), sulfo-Le/total protein ratio (U/mg protein), and saliva-mediated adherence (ex vivo) of H. pylori. As expected, sulfo-Le concentration correlated with the adherence of H. pylori (r = 0.72, p < .05). It was demonstrated that the observed adherence was induced by MUC5B and that the carbohydrate structure sulfo-Le contributed to this process.

CONCLUSIONS

Our study demonstrated a direct link between stress-mediated biochemical changes and altered host-microbe interactions in humans. Increased bacterial adherence may be a contributing factor in the observed relationship between stress and susceptibility to infectious disease.

Physiological and emotional response to psychological stressors in psychiatric and psychosomatic disorders

Deviations from emotional and physiological homeostasis in humans occur under episodic, chronic, or traumatic stress experiences. These dysregulations can provoke emotional and physical disturbances that may result in stress-related psychiatric or psychosomatic disorders. This brief review discusses a variety of both naturally occurring and experimental stressors and the complexity of intervening variables on cardiovascular and hormonal dysregulations of the hypothalamic-pituitary-adrenal (HPA) axis. In addition to the type, intensity, and duration of the stressor, subject variables such as dispositional factors (e.g., age and sex), personality traits, and coping styles are considered. Finally, emotional and physiological stress responses to naturally occurring stressors and psychological challenge tests in depressed patients and anxiety disorder patients are presented and discussed. Stressors in humans induce emotional arousal, which leads to physiological activation of the central nervous system, an increase of hormones of the HPA axis, and coping reactions on the psychological and behavioral level. Depending on the type, intensity, and duration of the stressor, on personal and psychosocial resources of the individual, stressful situations may provoke emotional and physical disturbances. These dysfunctions may result in psychosomatic or psychiatric disorders. The following brief review intends to discuss a variety of stressors that have been examined in humans in order to gain insight into the complex relationship between physiological and behavioral stress reactions and the occurrence or maintenance of stress related psychosomatic and psychiatric disorders.

Does background stress heighten or dampen children's cardiovascular responses to acute stress?

OBJECTIVE

Does background stress heighten or dampen children's cardiovascular responses to acute stress?

METHOD

To address this question, the cardiovascular responses to four acute laboratory stressors of 150 children and adolescents were evaluated according to their self-reported background stress level. Background stress was determined during a standardized interview and was a priori classified according to its importance, frequency, and whether it was ongoing or resolved.

RESULTS

Results showed that children and adolescents who reported important stressors or stressors that were ongoing and frequent exhibited a larger increase in diastolic blood pressure and total peripheral resistance during all four laboratory stressors than their low stress counterparts. Additional analysis showed that the results could not be accounted for by sociodemographic variables or by the personality traits measured in this study.

CONCLUSIONS

Results suggest the importance of measuring background stress in understanding an individual's acute stress response.

Self-reported stressors, symptom complaints and psychobiological functioning-II: Psychoneuroendocrine variables

The present study examined resting endocrinological functioning and endocrine responsivity to new challenges as a function of self-reported stress load and symptomatology. Following a baseline period, four groups of male subjects (low-load/low-symptoms; low-load/high-symptoms; high-load/low-symptoms; high-load/high-symptoms) were exposed to stressful films, followed by a rest period. Blood samples were drawn after each film and after the rest condition, and urinary samples were collected during two nights preceding the experimental session. Neuroendocrine variables measured in plasma included adrenaline, noradrenaline, ACTH, cortisol, growth hormone, prolactin, and testosterone. The urinary samples were assayed for noradrenaline and adrenaline (in relation to creatinin). High-symptom subjects had significantly higher plasma levels of noradrenaline and overnight urinary adrenaline levels, whereas their cortisol levels tended to be lower as compared to the low-symptom group. The plasma noradrenaline/cortisol ratio was higher among the high-symptom subjects. However, upon controlling for neuroticism and life style factors (smoking and alcohol consumption), all but the effects on cortisol failed to meet significance criteria. Higher stress load was associated with higher plasma adrenaline responses during the laboratory session, irrespective of neuroticism or life-style measures. These results therefore suggest that in addition to measuring exposure to real-life stressors, it is also necessary to measure outcomes, such as symptoms, and to be aware of the effects of neuroticism and life-style when attempting to understand which specific psychosocial factors effect psychoendocrinological functioning.