Individual Differences in the Diurnal Cortisol Response to Stress

Positive Emotional Support in Premutation Carrier Mothers of Adolescents and Adults With Fragile X Syndrome: Gene by Environment Interactions

We examined the benefit of emotional support on daily health in premutation carrier mothers of adolescents and adults with fragile X syndrome (n = 114), and whether this benefit was moderated by the mother's genetic status (FMR1 CGG repeat length). In an 8-day daily diary, maternal daily health was assessed subjectively through self-reported number of physical health symptoms and physiologically via cortisol awakening response. Multilevel lagged-day models indicated that premutation carrier mothers with midrange CGG repeats derived less health benefit from a day with high positive emotional support than those with lower or higher numbers of repeats within the premutation range. The data support the influence of both genetic and environmental influences on the health of this population.

Effects of balneotherapy and spa therapy on levels of cortisol as a stress biomarker: a systematic review

Balneotherapy and spa therapy are well-known practices, even though limited evidence has been produced about their biological effects. This systematic review primarily aims at assessing if balneotherapy, mud/peloid therapy, and spa therapy may influence cortisol levels. Secondarily, it aims at understanding if these interventions may improve stress resilience. PubMed/Medline, Embase, and Cochrane Library were searched for relevant articles in English or Italian about studies involving healthy and sub-healthy subjects or patients with a diagnosed disease about effects of balneotherapy, mud/peloid therapy, and spa therapy on serum and salivary cortisol levels. Fifteen studies involving 684 subjects were included. Five studies investigated biological effects of balneotherapy alone. Two of them reported significant changes of cortisol levels in healthy participants. The other three studies reported no significant variations in patients with rheumatic conditions. No studies investigated biological effects of mud/peloid therapy alone. Ten studies investigated biological effects of spa therapy with or without included mud/peloid therapy, and in all but two studies, significant variations of cortisol levels were reported. Our main findings suggest that balneotherapy may have the potential to influence cortisol levels in healthy subjects, in such a way as to improve stress resilience. Spa therapy with or without included mud/peloid therapy demonstrated the same potential to influence cortisol levels also in sub-healthy subjects and in patients with a diagnosed disease. Therefore, balneotherapy and spa therapy may be considered as useful interventions for the management of stress conditions. Further investigation is needed because of limited available data.

Differential sensitivity to life stress in FMR1 premutation carrier mothers of children with fragile X syndrome

OBJECTIVE

The premutation of the FMR1 gene (defined as between 55 and 200 CGG repeats) is estimated to affect 1 in 149 females and 1 in 643 males, and some people who carry the FMR1 premutation display signs of impairment.

METHOD

This study focuses on 82 premutation carrier mothers (M age = 51.4 years; SD = 7.7) of adolescent and adult children with fragile X syndrome (FXS). A Gene × Environment interaction approach examined the ways in which the experience of negative life events interacts with genetic vulnerability to predict depressive symptoms, anxiety, and daily cortisol levels.

RESULTS

The associations of life events with all 3 dependent measures were associated with CGG repeat length but in a curvilinear manner. Mothers with midsize CGG repeats who experienced above-average numbers of negative life events in the previous year had more depressive symptoms and anxiety and had a blunted cortisol awakening response, as compared with those with higher or lower repeat lengths. However, mothers with midsize CGG repeats who experienced below-average numbers of negative life events in the previous year had the lowest levels of depressive symptoms and anxiety, and they exhibited the typical cortisol response to awakening, meeting the criteria for differential susceptibility.

CONCLUSIONS

This research extends our understanding of the phenotypic effects of the expansion of the FMR1 gene, and it adds to the growing literature on the curvilinear relationship between CGG repeat length and mental and physical health.

Cortisol response to behavior problems in FMR1 premutation mothers of adolescents and adults with fragile X syndrome: A diathesis-stress model

Mothers of adolescents and adults with fragile X syndrome (FXS) are faced with high levels of parenting stress. The extent to which mothers are negatively impacted by this stress, however, may be influenced by their own genetic status. The present study uses a diathesis-stress model to examine the ways in which a genetic vulnerability in mothers with the premutation of the FMR1 gene interacts with child-related environmental stress to predict their morning cortisol levels. Seventy-six mothers of an adolescent or adult with FXS participated in an 8-day telephone diary study in which they reported on the behavior problems of their son or daughter with FXS each day. We analyzed salivary cortisol collected from mothers at awakening and 30 minutes after awakening on 4 of these days. The results indicated that mothers with greater genetic vulnerability had a lower level of cortisol on mornings following days when their son or daughter with FXS manifested more episodes of behavior problems, whereas mothers with less genetic risk evinced the opposite pattern of higher morning cortisol in response to their child's behavior problems. This finding contributes to our understanding of gene-by-environment interactions and highlights the importance of interventions to alleviate parenting stress in mothers raising children with FXS.

Shifts of the hormonal rhythms of melatonin and cortisol after a 4 h bright‐light pulse in different diurnal types

If applied during corresponding times of the individual melatonin profiles, bright light shifts the circadian phase equally, irrespective of diurnal type. We examined 32 young men: 10 morning types, 11 evening types, and 11 with no predisposition; 16 with high and 16 with low melatonin production. Each completed a 40 h session that included two consecutive nights during which the participants remained, apart from two short breaks during the second day, in bed under an illumination level of 30 lux. A 4 h bright light pulse was applied just after the expected individual melatonin onset the first night to cause a delay of the hormonal profile the second night. Salivary levels of melatonin and cortisol were determined hourly. Melatonin was delayed by 108 min, and cortisol offset and onset by 47 and 110 min, respectively. The cortisol quiescent period (start and end of the quiescent period being defined by the decrease below and the increase above 60% of the average cortisol production between 18:00 and 09:00 h) was prolonged. In contrast to the other subgroups, the delay of melatonin synthesis was about 0.5 h shorter in morning types, and their cortisol quiescent period was shortened. The present study leads to the hypothesis that, despite individually scheduled light exposure, morning types are potentially disadvantaged due to elevated cortisol levels, if persisting, in career night workers.

Impact of stressors in a natural context on release of cortisol in healthy adult humans: a meta-analysis

Increased hypothalamic-pituitary-adrenal (HPA) activation, culminating in elevated circulating cortisol levels is a fundamental response to stressors. In animals, this neuroendocrine change is highly reliable and marked (approximately 5-10-fold elevations), whereas in humans, the increase of cortisol release is less pronounced, and even some potent life-threatening events (anticipation of surgery) only elicit modest cortisol increases. Meta-analysis of factors that influenced the increase of cortisol release in a laboratory context pointed to the importance of social evaluative threats and stressor controllability in accounting for the cortisol rise. The present meta-analysis, covering the period from 1978 through March 2007, was undertaken to identify the factors most closely aligned with cortisol increases in natural settings. It appeared that stressor chronicity was fundamental in predicting cortisol changes; however, this variable is often confounded by the stressor type, the stressor's controllability, as well as contextual factors, making it difficult to disentangle their relative contributions to the cortisol response. Moreover, several experiential factors (e.g. previous stressor experiences) may influence the cortisol response to ongoing stressors, but these are not readily deduced through a meta-analysis. Nevertheless, there are ample data suggesting that stressful events, through their actions on cortisol levels and reactivity, may influence psychological and physical pathology.

Poor sleep the night before an experimental stress task is associated with reduced cortisol reactivity in healthy women

Sleep disruption is a growing problem that may have serious health effects. As stress-induced increases in cortisol are thought to be a key adaptive process it is important to examine how this response is affected by sleep. The current study investigated the association of four sleep parameters (objective/subjectively measured sleep quality and quantity) and subsequent salivary cortisol reactivity (maximal change from baseline) to an experimental stressor in 53 healthy women. Objective actigraphy monitoring and self-report diaries were used to assess sleep. Results revealed that individuals with lower objective sleep quality (wake percentage during sleep) had a blunted response to the experimental stressor. No associations were found between cortisol reactivity and actigraphy-derived sleep quantity, or either of the self-reported sleep variables. Results are discussed with regard to the possible adverse health effects that may result from poor sleep quality and a blunted cortisol response to stress.

Exhaustion is associated with reduced habituation of free cortisol responses to repeated acute psychosocial stress

We investigated the association between exhaustion and the habituation of free cortisol responses to repeated stress exposure. The study comprised 25 healthy male subjects (38-59 years) who were confronted three times with the Trier Social Stress Test. Mean cortisol responses showed the well-known general habituation effect. A two-way interaction day by exhaustion (p<0.05) indicated that mean cortisol responses vary across stress sessions depending on the extent of exhaustion. Linear regression revealed a negative dose-response relationship between exhaustion and the degree of habituation (p<0.02). We identified 19 individuals showing a response habituation (negative slope) and 6 individuals showing a response sensitization over the three sessions (positive slope) with the latter reporting higher exhaustion scores. It might be hypothesized that impaired habituation to repeated exposure to the same stressor could reflect a state of increased vulnerability for allostatic load. Absence of normal habituation might be one potential mechanism how exhaustion relates to increased disease vulnerability.

Influence of Long-Term Exposure to an Air-conditioned Environment on the Diurnal Cortisol Rhythm

In the present study, the influence of the long-term use of air-conditioning in summer on the cortisol rhythm was examined by measuring the rhythm in subjects who had been exposed to air-conditioning for a short [S] or long [L] time. Investigations were conducted twice in July and September. Atmospheric temperature and relative humidity near the subjects were measured for three days in each season. Saliva samples for cortisol analysis were collected every 2 hours during the daytime beginning at 8:00 h with subsequent sampling times at 10:00, 12:00, 14:00, 16:00, 18:00, 20:00 and 22:00 h. A questionnaire on sleep and duration of air-conditioning use was also undertaken. Ambient mean temperature was higher in the S group (mean+/-SD; 30.8+/-1.2 degrees C in July, 28.0+/-0.8 degrees C in September) than in the L group (28.0+/-1.2 degrees C in July, 27.3+/-1.0 degrees C in September) (p<0.01), while mean relative humidity did not differ. There were no differences in bedtime, waking time and sleeping hours either between groups or months. Diurnal patterns of salivary cortisol rhythm in July and September were similar in the S group, but the L group had a delayed rise of morning cortisol secretion in September compared with July. These results suggest that long-term exposure to an air-conditioned environment might adversely affect the human cortisol rhythm.

Equity and working time: a challenge to achieve

Equity is a humanitarian issue that gained strength during the transition from the 20th to the 21st century due to the mounting global discussion and social crisis involving human rights, health, and work. This article aims at (1) introducing the concept of equity as it applies to work environments, particularly to situations involving demanding work schedules, (2) discussing the role of science in equity issues related to work, (3) introducing a new scientific society dedicated to working-time issues, and (4) presenting an overview of new research on working time and health as addressed by the series of manuscripts published in this special issue of Chronobiology International devoted to the XVIth International Symposium on Night and Shiftwork, held in Santos, Brazil, November 2003. The concept of equity has a political as a well as a scientific dimension. Many worldwide organizations, e.g., civil society, academia, and occupational health research institutions, advocate prompt actions toward equity as a strategy to attain sustainable development and to reduce poverty. The analyses of current tendencies in work settings reveal a general situation of disrespect for equity principles, which is expressed by heavy workloads, long work hours, poor work conditions, and deregulation of established labor laws, mainly in (but not restricted to) developing countries. In spite of the great contribution of science in the past five decades, obstacles stand in the way of effectively improving good working conditions, particularly in times of precarious employment. The Working Time Society is a new scientific society that aims at promoting research into working time and health and offers practical advice on how to minimize adverse effects of working hours on workers' health and well-being. An updated view of the research on working times and health includes studies on the relationship between work schedules, worker health, and well-being; effects of night and shiftwork on the internal synchronization of circadian rhythms and laboratory and field interventions; new methods of investigation or new approaches in shift-work studies; and prediction of risks in night and shift work. Current tendencies of work organization contribute to the amplification of inequality across groups and populations, revealing that equity remains a challenge to achieve.

Methodological aspects of shift-work research

A major issue in shift-work research is to understand the possible ways in which shift work can impact performance and health. Nearly all body functions, from those of the cellular level to those of the entire body, are circadian rhythmic. Disturbances of these rhythms as well as the social consequences of odd work hours are of importance for the health and well-being of shift workers. This article reviews a number of common methodological issues which are of relevance to epidemiological studies in this area of research. It discusses conceptual problems regarding the use of the term "shift work," and it underscores the need to develop models that explain the mechanisms of disease in shift workers.

Autonomic activity, pain, and perceived health in patients on sick leave due to stress-related illnesses

OBJECTIVE

The aim of the present study was to compare autonomic activity, pressure-pain thresholds, and subjective assessments of health and behavior between patients with stress-related illnesses and healthy control subjects.

METHODS

Twenty sick-listed patients with stress-related illnesses and 20 age- and gender-matched healthy subjects performed tests of autonomic regulation and algometric tests, and completed questionnaires about physical and mental health and behavioral patterns.

RESULTS

Patients exhibited higher autonomic reactivity to cognitive and physical laboratory tasks (p < 0.05), and had lower pressure-pain thresholds in the shoulders and lower back than healthy control subjects (p < 0.05). Furthermore, the patients rated considerably poorer health and health behavior than the control subjects (p < 0.05).

CONCLUSIONS

The results indicate an engagement of the autonomic nervous system in stress-related illnesses. Furthermore, they show that patients with stress-related illnesses experience symptoms of musculoskeletal pain, and it is therefore recommended that assessments of musculoskeletal pain be incorporated in the clinical examinations and the rehabilitation of patients with stress-related illnesses.