Bibliography / References

Persometrics' services rely on the research reported in the following articles, among other.

Researchers from Murcia, Spain review fermentation processes as factors for melatonin production and discuss the theoretical impacts of melatonin on sleep disorders, Multiple Schlerosis, Parkinson's disease and other pathophysiological conditions.

Published in Molecules

Researchers from School of Medicine at Aristotle University of Thessaloni, WHO Europe, Moscow, department of nutrition at the University of Copenhagen perform a thorough meta analysis scoping 48 studies (from some 2500 identified studies filtered to match preset criteria), showing the pros and cons of a vegan diet. The authors separate deficiencies and actual (negative) health outcome.

Published in Clinical Nutrition

This paper elucidates factors that affect the cortisol awakening response (CAR), notably separating different sleep parameters.

Published in Psychoneuroendocrinology

This database, compiled, published and maintained by the Swiss Federal Food Safety and Veterinary Office has been used to generate ratios of macronutrient lists in our reports. It is a comprehensive database, citing nearly 300 world-wide sources, including whitepapers, laboratory analyses and nutritional information provided from the industry. Access the raw data here, in French or German , or visit their platform.

From the abstract: the purpose of this review is to summarize the food ingredients that have been suggested in published literature to increase testosterone levels. A review of previously reported animal studies suggested that 5 representative nutritional components, 7 food ingredients, and 25 supplements were associated with testosterone.

Not published in a peer-riewed journal with impressive impact factor, Persometrics treats the authors' conclusions with caution, but the study lends some support to existing hypotheses and has been incorporated in our reports.

Published in the Journal of men's health

Illucidates the important role of sleep quality in predicting or diagnosing burnout.

Published in Comprehensive Psychoneuroendocrinology

Early life stress has an impact on how the Hypothalamic Pituitary Adrenal (HPA) axis develops during puberty. The associations between inter-related HPA-dependent hormones are here found to depend on severity of stress before puberty. The study sheds light on the development of the HPA axis and factors influencing Cortisol/DHEA-s relations, important for our Extended Stress Report.

Published in Psychoneuroendocrinology

From the abstract: this study investigates modifications and relationship between physiological stress markers after a preseason period between elite footballers. Twenty-four elite soccer players participated in this study. Physical load, mood, morning and evening concentrations of cortisol and testosteronewere all measured. Cortisol is strongly associated with mood. A decrease in testosterone to cortisol ratio of more than 30% indicates incomplete recovery, residual fatigue, and impaired competitive performance. Since the change was non-existent in these players, this suggests that the players had adequate coping with the stresses of training.

Published in the Journal of Strength and Conditioning Research

Deepak Gupta and collaborators at the Department of Medicine, Mahatma Gandhi Medical College and Hospital Jaipur look athe link between testosterone and type 2 diabetes. Testosterone levels are not only lower in men with type 2 DM, but also that the risk of developing type 2 DM is increased in men with low testosterone levels


Published in: International Journal of Science and Healthcare Research

Even though pregnancy has a strong influence on hormone levels, Leff-Gelman and colleagues show that the DHEA-S to cortisol ratio is related to anxiety also in pregnant women in their last trimester


Published in: BMC Psychiatry

Swiss researchers from Basel, Solothurn and Kermanshah (Iran) shows interdependence of cortisol reactivitity to a known stress test (TSST) of mental difficulties.


Published in the Journal of Clinical Medecine

Explores biochemical markers of overtraining syndrome.

Published in Journal of Athletic Training


Brian G. Keevil and Jo Adaway make a case for Free Testosterone in clinical practise and give details regarding measurement and analysis.


Published in: Journal of Steroid Biochemistry and Molecular Biology

Highly collaborative study between Marcos Martin-Rincon and colleaggues from University of Las Palmas de Gran Canaria, as well as researchers from a range of institutions (Spain, Sweden, Norway, and Canada). The researchers investigate fat free weight during energe deficiency.


Published in: Stress

Describes Pulsatile ultradian secretion of cortisol, including the cortisol awakening response.


Published in Psychoneuroendocrinology

There has been widespread discussions and responses to this article but the main take-home message remains: physician burnout consistently relates to reduced quality of care, and there are strategies that reduce burnout, targetting not only with the workplace but the individual himself or herself.

Lead author: Daniel S. Tawfik at the Department of Pediatrics, Stanford University School of Medicine.

Published in Mayo Clin Proc.

Researchers at Kennesaw University and Hofstra University studied changes in cortisol, testosterone and their ratio in function of workout intensity and in function of time points leading up to a competition. Crossfit (R) was used to achieve High-Intensity Functional Training. Findings point to the importance for athletes and coaches of monitoring these hormones (and above all their ratio) when seeking consistency of workouts.

Published in Sports

Authors: Mangine, van Dusseldorp, Feito, Holmes, et al.

The study conducted by Eran Segal and colleagues at the Weizman institute suggests that we are asking the wrong question when searching for the right diet and should instead be looking for individualised diets. The researchers used blood sugar spikes as a biomarker for food reactivity and followed some 800 participants longitudinally showing that people differ in their response to food stuffs. An experimental follow-up (diet-intervention) confirmed: the one and same food could have opposite spike patterns for two people. Persometrics finds this a compelling first step to individualised nutrition, and especially promising that the authors incorporate the microbiome in their research, which has been used for our stress reports and has also figured on our social media outlets.

Published in: Current Opinion in Biotechnology

Karine Spiegel, Rachel Leproult, Mireille L’Hermite-Balériaux, Georges Copinschi, Plamen d. Penev, and Eve van Cauter from Universities of Chicago and Brussels (ULB) investigated links between sleep quality (notably how long the participants were allowed to sleep: 4, 8 or 12 hours) and the endocrine system. Sleep restriction decreased leptin, and increased evening cortisol, even when people did not perceive the restriction as stressful. Showing that sleep may have an effect on appetite and in turn obesity. 12 hour slots (no sleep restriction) produced better biomarkers even though participants only slept just over 9 hours in average.

Taken together, we use this information in our guidance of stress reports and also for current development of our sleep reports.

Published in: The Journal of Clinical Endocrinology & Metabolism

Medical researchers in Denmark showed disturbance in daily melatonin rhythm in patients with diabetic retinopathy

Published in: Sleep Medicine

Authors: Ba-ali, Shakoor; Brøndsted, Adam Elias; Andersen, Henrik Ullits; Sander, Birgit; Jennum, Jørgen, and Lund-andersen, Henrik

This study was carried out by two of Persometrics's very own (hosted and funded by the Brain Mind Institute at the EPFL). Feel free to contact us for a copy. We showed that dominant males (as measured through questionnaires tapping the wish and propensity to seek to dominate others) are faster than their less dominant counter-parts. The speed advantage was shown in both behavioural tasks (of which there were a variety) and in physiological measurements (EEG). It is believed that this fast reaction time creates an advantage which is what leads men to be treated differently by others, in turn creating the dominant personality trait. We say dominant "men" because we did not study females, not because it does not apply to females. Questionnaire will be available on persometrics.com soon!

Authors: Janir da Cruz*, João Rodrigues*, John C Thoresen*, Vitaly Chicherov, Patrícia Figueiredo, Michael H Herzog, Carmen Sandi

* = ("joint first authors")

Published in: Cerebral Cortex

Giauque and colleagues (from University of Lausanne and University of Geneva) report an extensive study wherein they collected data from questionnaires of some 1700 respondents (more than 7000 were sent out). A take-home message is that perceived stress may mediate the link between job resources and turnouver intention in large international organisations. Changing our perception of stressors gets us a long way.

Published in: International Journal of Human Resource Management

Authors: Giauque, D., Anderfuhren-Biget, S., and Varone, F.

Explores causation of demands and cortisol awakening response and shows the interaction with affect/emotional states the days prior to the sampling in relation to the CAR.


Background reading for stress profiling.


Published in: Developmental Psychology

Frenetic, underchallenged, and worn-out subtypes of burnout are proposed. The authors of this chapter look into prelavence in students too, reporting a study where 509 university students filled out several questionnaires, including adapted versions of the Maslach Burnout Inventory and the Burnout Clinical Subtypes Questionnaire. The study three burnout subtypes was also found in students. and further prposoe differen pathways to burnout.


Published in: Stress

A much welcome review article, assessing increases in Testosterone as well as basal levels, and their relationship to adaptations to resistance training. Authors Hooper (Ohio State University and Armstrong State University) and colleagues point out the caution required when drawing inferences between testosterone and adaptations, in large owing to many studies failing to confirm this. Persometrics takes into account in our sports packages where we look at intra-individual as well as inter-individual relationships between exercise, diet, testosterone and performance.


Published in: Sports Medicine

This report guided our sampling procedures.


Published in: Psychoneuroendocrinology

Background reading for our stress profiling reports.

Published in: Biological Research for Nursing

Background for stress reports.

Published in: Psychoneuroendocrinology

Absence Management Report in partnership with The CIPD is the professional body for HR and people development. Used by Persometrics as general background reading (see For Business page)

Published in: Cipd

Summary

Diet and lifestyle, but also individual differences are important, for combatting the detrimental effects of stress.

Published in: Physiology and Behavior

Gilda Ennis, Scott Moffat and Christopher Hertzog performed cognitive testing (episodic memory, working memory and processing speed) and checked for links between cortisol secretion patterns. Further demographics were also included in analyses. We have used this article to help shape procedures and parameters in our stress report.


Published in: Brain and Cognition

A large number of medical students were followed and predictors of burnout tested. Socially prescribed perfectionism (mediated through self-efficacy) was a strong predictor of academic burnout.


Published in: Korean of medical education

Smyth and her colleagues at Westminster (London) show the importance of correct timing and on self-report time estimates and their impact on the cortisol awakening response. A delay from cortisol secretion to its detection in saliva was also confirmed. Their findings have been helpful to guide the sampling timings of our own reports.


Published in: Psychoneuroendocrinology

This multidisciplinary study, crossing nursing, mental health, psychiatry and biomedical sciences departments at University of Alberta shows how cortisol concentrations and cortisol patterns are linked with memory performance and brain structure (more specifically volume of subsections of the hippocampus)


Published in: Journal of Affective Disorders

Psychometric profiling. This study shows norms for males and females in systematizing and empathizing and is featured in our empathy questionnaire.


Published in: Journal of Research in Personality

Summary

Background reading for stress profile reports.


Published in: Psychoneuroendocrinology

Summary

Background reading for the stress profile reports.


Published in: European Journal of Sports and Exercise Science

Cross-sectional study by Cañadas-De la Fuente and colleagues on burnout in nurses. Looks at risk-factors and prevalence. Used in our stress reports.

Published in: International Journal of Nursing Studies

Summary

Background reading for the stress profile reports.


Published in: BMC Psychology

Boesch and colleagues at University of Zurich, ETH Zurich and University of Western Ontario, show a link between cortisol in hair and stress, humidity, temperature as well as socioeconomic factors and physiological data such as sweating. Stress through military trainig could not be detected in cortisol concentrations in hair, whereas meteorological data could predict some variance, showing that this technique is experimental and requires stringent control of external variables. Inter-subject factors predicted concentrations as well. Persometrics’s take is that this technique is best used to compare one’s own state across different times.

Published in: Stress

Harris, Endresen, Tangen, Hansen, Garde, and Eriksen at the universities of Oslo, Bergen, and Copenhagen performed an extensive screening for psychiatric disorders and showed no effect on the cortisol parameters of interest. Limited findings cannot be used to draw conclusions because there were too many confounding factors in this study, no control group, no initial group definition of disorders, and a limited age group (which could explain why there were no signifant results).

Published in: Psychiatry Research

Another study confirms the links between cortisol awakening response and neural mechanisms underlying cognitive function and memory.

Published in International Journal of Psychophysiology

The researchers report predicting factors of different stress-related illnesses, with a focus on the HPA axis.

Published in Journal of Abnormal Psychology

This research from the university of Colorado has been featured on our social media outlets.

Published in: Emotion

Background reading. This thesis provides good references and insights for the stress reports.

Stress reports

Published in: Psychoneuroendocrinology

Summary

Psychometric and stress profiling. This was also featured on our Emotional Intelligence questionnaire.

Published in: Annals of Neurosciences

This study, which actually looked at gender differences in attitudes to choosing to study science in Switzerland, was used to obtain Swiss norms in our empathy questionnaire.


Published in: International Journal of Science Education

This research on gut microbiome composition was used to guide our feedback for lifestyle advice. The study characterized fecal samples and looked at the link between diet and different types of bacteria enterotypes, especially Bacteroides and Prevotella.

Authors: Wu, Gary D; Chen, Jun; Hoffmann, Christian; Bittinger, Kyle; Chen, Ying-yu; Sue, A; Bewtra, Meenakshi; Knights, Dan; Walters, William a; Knight, Rob; Gilroy, Erin; Gupta, Kernika; Baldassano, Robert; Nessel, Lisa; and Li, Hongzhe


Published in: Science

Published in: European Neuropsychopharmacology

This Viewpoint by Cryan and Mahony at University College Cork Stress gives a breakdown on enteric bacterial fingerprints and the importance of the microbiome in mental and physical wellness.

Published in: Neurogastroenterology and Motility

We value this research from Leiden University medical Center and Leiden University (NL) which shows that basal cortisol cannot predict burnout on large scale on its own, nor can the CAR predict burnout after the fact (which is what is shown in correlational studies). We hold the importance of psychometric data in conjunction with hormonal, and point to the cortisol index which is important immediately before, not after, a burnout.

Authors: Danhof-Ponta, Tineke van Veenb, Frans G. Zitman

Published in: Journal of Psychosomatic Research

Stress reports and psychometric profiling.


Published in: Journal of Personality and Social Psychology

Used to shape our stress reports

Published in: International Journal of Nursing Studies

Background reading.

Used to shape our Stress reports, notably regarding personalised lifestyle advice.

Published in: Journal of Nutrition

Background reading for our stress profiling reports.

Published in: Psychoneuroendocrinology

This study conducted by researchers at McGill (Montreal) confirms both the usefulness and complexity of the cortisol awakening response as a biomarker associated with mental illnesses and their treatment. This has been used in our stress reports.

Published in: Complementary Therapies in Clinical Practice

This research has shaped our stress profile reports, both in questionnaires and in feedback.

Published in: British Journal of Nutrition

Summary

Background reading for stress profiling.


Published in: Psychoneuroendocrinology

Hill, Hall and Appleton from York St. John university and university of Bedfordshire separate socially prescribed and self-oriented perfectionism in their link with burnout in young athletes. The pathway from perfectionism to burnout differed depending on the sub-facet of perfectionism.

Published in: Anxiety, Stress and Coping

This research shows the prevalence of stress in Switzerland.

Published in: SECO

Reviews boundaries of burnout against depression and anxiety, especially in the academic field.

Published in: Revista Latinoamericana de Psicologia

Angela Clow, Frank Hucklebridge, and Lisa Thorn’s research on diurnal rhythms of cortisol, its Awakening Response and the Suprachiasmatic nucleus. This paper has been used to shape our understanding of the complex cortisol awakening response and in turn to guide our Stress reports.

Published in: International Review of Neurobiology

Background reading for stress profiling.

Published in: Complementary Therapies in Clinical Practice

Summary

Background reading for the stress profile reports.


Published in: Psychoneuroendocrinology

This review of neuroimaging stress studies, written by Dedovic, D'Aguiar, and Pruessner, points to the importance of the prefrontal and limbic regions the psychosocial stress, and was used general background reading.

Published in: Canadian Journal of Psychiatry

This meta-analysis by Chida and Steptoe looks at the link between the Cortisol Awakening Response (CAR) and a range of psychosocial difficulties, including Burnout and fatigue; Depression and anxiety; HPA axis; Job stress; Positive well-being; and Posttraumatic stress disorder (PTSD). They show how predictions of Cortisol Awakening Response (CAR) has been inconclusive in a range of studies. However, their findings point to an important distinction of looking at the different ways of analysing CAR (respect to baseline or to ground, CARi or CARtot). Persometrics always combines Psychometric data when making sense of hormone data.

Published in: Biological Psychology

Background reading for stress reports. Shaped our sampling procedure.

Published in: International Journal of Psychophysiology

Research conducted at University College London by Bhattacharyya (UCL), Molloy and Steptoe (National University of Ireland, Galway), relating cortisol to coronary heart disease and depression. Important to our stress reports.

Published in: Journal of Psychosomatic Research

Stress reports, psychometric profiling

Published in: Health Psychology

This seminal article is one where Christina Maslach presents the factorial properties of burnout, proposing the syndrome as affecting those with people-oriented jobs, feeling callouc

Published in: Human Relations

This study by Ditzen et al compared men with or without social support and their psychological and physiological response to stress. This research featured on our social media outlets.

Published in: Journal of Psychosomatic Research

Summary

Background reading for the stress profile reports.


Published in: Progress in Brain Research

Background reading for stress reports, especially on personalised lifestyle advice.

Published in: Psychoneuroendocrinology

Psychometric profiling and stress profiling reports.

Published in: Journal of Psychosomatic Research

Guided our cortisol sampling procedure.

Published in: Psychoneuroendocrinology

Psychometric profiling, burnout, stress reports.

Published in: Journal of Psychology: Interdisciplinary and Applied

This study from Utrecht by C. S. De Kloet and colleagues looked at Corticosteroid binding globulin; Cortisol; Dexamethasone suppression test in post traumatic stress disorder. Through salivary testing, differences in total secretion and secretion patterns were found between patients and controls.

Published in: Psychoneuroendocrinology

Summary

Background reading for the stress profile reports. Hormone data alone is not enough, as these authors show.


Published in: Psychoneuroendocrinology

Summary

Background reading for the stress profile reports.

Selection of 20 items of the IPIP database by Donnellan, Oswald and Baird with colleagues at Rice University has been used in our Psychometric profiling. You can perform this test on our website.

Published in: Psychological Assessment

Background reading for stress profiling.

Published in: Psychosomatic Medicine

Summary

Background reading for stress profile reports.


Published in: Psychosomatic Medicine

Background reading for stress profiling.

Published in: Biological Psychology

Psychometric profiling.

Published in: Psychosomatic Medicine

This research from University of Texas and Kansas State University, by Best, Stapleton and Downey, relates Burnout to Core self-evaluations, Job satisfaction and perceived organizational constraints and has been important for our stress reports and psychometric profiling. The authors also give information on how to deal with burnout depending on situational and personal constraints.

Published in: Journal of Occupational Health Psychology

This study by Broadley & Korszun and colleagues was conducted on 36 participants between hospitals at Torquay, London, Birmingham and Cardiff and shows that blocking cortisol production with metyrapone stopped baroreflex sensitivity impairment, thus suggesting that the link between stress and coronary heart disease and sudden cardiac death is mediated by cortisol, the stress hormone.

Published in: Journal of the American College of Cardiology

This book covers the extensive nutritional research dubbed The China Study. Many references are used to create personalised lifestyle reports.

Publisher: BenBella Books, Inc.

Stress profiling report.

Published in: J Physiol Pharmacol

Background reading for stress profiling.

Published in: Psychoneuroendocrinology

Summary

Background reading for stress profile reports.


Published in: British Journal of Psychiatry

Stress profile reports. Used for personalised dietary feedback.

Published in: Medical hypotheses

Bergdahl and Bergdahl at the The Arctic University of Norway studied more than 1000 individuals and show links between gender, anxiety, medication and salivary flow. Their research has guided our sampling procedures and data sense-making.

Published in: Psychoneuroendocrinology

This fun experiment, which studied hormone behaviour in spectators of a basket match, showed that spectators' testosterone is linked to the performance (points per minute) rather than outcome.


Published in: Hormones and Behaviour

Background reading for the stress profile reports.


Published in: Psychosomatic Medicine

Provides some background reading for stress reports.

Published in: Experimental Aging Research: An INternational Journal Devoted to the Scientific Study of the Aging Process

Richard Lynn's questionnaire follows a McClelland approach. The questionnaire, which correlates with a variety of personality constructs as well as external criteria, has been used in our Stress Reports.

Published in the British Journal of Psychology

Georg Alpers and colleagues who study Anxiety disorders and Behavior therapy at University of Salzburg looked into cortisol response in people who have a phobia against driving. As was expected, cortisol response to driving exposure followed both subjective ratings and could be predicted by prior knowledge regarding the phobia. This research has been used for our stress reactivity test.

Published in: Psychoneuroendocrinology

Study by Candy, Chalder and colleagues from Department of Immunology the School of Medicine and Institute of Psychiatry in London, looking at cortisol as a risk factor for Chronic fatigue. Results were inconclusive as regards to biological mechanisms responsible for the link between infectious mononucleosis and chronic fatigue from this study: rather, the factors that best predicted the illness changed over time.

Published in: Psychological Medicine

Cynthia Cordes, Thomas Dougherty and Michael Blum from Binghamton U, University of Missouri and Truman State University, provide data and path analysis looking at other variables that has been useful to shape our Stress reports.

Published in: Journal of Organisational Behaviour

Cohen and Williamson’s data from some 2300 participants provided norms and shaped our stress questionnaires.

Published in: The Social Psychology of Health

This study by De Vries, Michielsen and Van Heck at Tilburg University guided psychometric testing and was used in stress reports.

Published in: Occupational and Environmental Medicine

This experimental study by Demling and DeSanti at Brigham and Women’s Hospital, Boston, compared dietary and exercise interventions on overweight police officers. The outcome points to the importance of macronutrients and individual differences, and has guided our lifestyle advice in stress reports.

Published in: Annals of nutrition & metabolism

Background reading for adrenal stress profiling. Ehlert, Gaab and Heinrichs at the University of Zurich reports how cortisol parameters are linked to different psychiatric disorders

Published in: Biological Psychology

Background reading for adrenal stress profiling.

Published in: Life Sciences

Stress reports.

Published in: Psychoneuroendocrinology

Background reading for stress reports

Published in: Psychoneuroendocrinology

Researchers at Columbia University and Omaha, Nebraska-Lincoln determine effects of moderate versus low weightlifting effects on testosterone output during and after weight lifting.

Published in: Medicine and Science in Sports and Exercise

Provides some background reading for stress reports.

Published in: Experimental Aging Research: An International Journal Devoted to the Scientific Study of the Aging Process

This study describes one questionnaire that shaped our psychometric and adrenal profiling.

Published in: Psychosomatic medicine

Summary

Background reading for the stress profile reports.


Published in: Sports Medicine

Psychometric profiling.

Published in: Personnel Psychology

Background reading for the stress profile reports.


Published in: Psychoneuroendocrinology

Summary

Background reading.


Published in: Seco

Summary

Psychometric profiling.


Published in: Journal of Personality and Social Psychology

Summary

This extensive research article by Urhausen, Gabriel and Kindermann details overtraining and hormonal factors. Hormones are thought to be the best indicators of overreaching, and adjusting effort in accordance with individual tolerance.

Published in Sports Medicine.


Published in: Journal of Personality and Social Psychology

Summary

General reading.

Published in: Journal of the National Cancer Institute

Review by Karl Anderson (University of Texas) of the many papers showing the impact of diets (in terms of both micronutrients and micronutrients) on drug bioavailability and metabolism. This confirms the importance of food in health; if they do not trump medicinal treatment they do at least interact with how we may respond to it

Published in: Clinical Pharmacokinetics

Summary

Stress profile reports, individualised lifestyle advice.


Published in: Metabolism

Summary

Background reading for stress profiling.


Published in: Occupational and Environmental Medicine

Summary

Background reading for stress profiling.


Published in: European Jouranl of Applied Physiology

Summary

Background reading for stress profiling.


Published in: Environmental Health and Preventive Medicine

Background reading for stress profiling.


Published in: Psychological Reports

Summary

Background reading for stress profiling.


Published in: Work and Stress