Reference intervals and variation for urinary epinephrine, norepinephrine and cortisol in healthy men and women in Denmark

Impact of 24 h shifts on urinary catecholamine in emergency physicians: a cross-over randomized trial

24-h shift (24 hS) exposed emergency physicians to a higher stress level than 14-h night shift (14 hS), with an impact spreading on several days. Catecholamines are supposed to be chronic stress biomarker. However, no study has used catecholamines to assess short-term residual stress or measured them over multiple shifts. A shift-randomized trial was conducted to study urinary catecholamines levels of 17 emergency physicians during a control day (clerical work on return from leave) and two working day (14 hS and 24 hS). The Wilcoxon matched-pairs test was utilized to compare the mean catecholamine levels. Additionally, a multivariable generalized estimating equations model was employed to further analyze the independent relationships between key factors such as shifts (compared to control day), perceived stress, and age with catecholamine levels. Dopamine levels were lower during 24 hS than 14 hS and the control day. Norepinephrine levels increased two-fold during both night shifts. Epinephrine levels were higher during the day period of both shifts than on the control day. Despite having a rest day, the dopamine levels did not return to their normal values by the end of the third day after the 24 hS. The generalized estimating equations model confirmed relationships of catecholamines with workload and fatigue. To conclude, urinary catecholamine biomarkers are a convenient and non-invasive strong measure of stress during night shifts, both acutely and over time. Dopamine levels are the strongest biomarker with a prolonged alteration of its circadian rhythm. Due to the relation between increased catecholamine levels and both adverse psychological effects and cardiovascular disease, we suggest that emergency physicians restrict their exposure to 24 hS to mitigate these risks.

Urinary levels of cortisol but not catecholamines are associated with those of 8-hydroxy-2'-deoxyguanosine in uncomplicated primary hypertension

OBJECTIVES

The relationships between stress hormones and oxidative DNA damage have not yet been explored in human hypertension. We investigated the associations of urinary levels of cortisol or catecholamines with those of 8-hydroxy-2'-deoxyguanosine, a marker of oxidative DNA damage in primary hypertension.

METHODS

Untreated 156 primary hypertensives without apparent cardiovascular diseases were entered into the study. Following blood sampling after an overnight fast, 24-h blood pressure monitoring and 24-h urinary sampling were performed simultaneously to determine 24-h averaged values for blood pressure and urinary levels of cortisol, catecholamines and 8-hydroxy-2'-deoxyguanosine.

RESULTS

Urinary cortisol significantly correlated positively with urinary 8-hydroxy-2'-deoxyguanosine in all studied participants (r = 0.334, P < 0.001). Contrary, either urinary adrenaline or urinary noradrenaline did not significantly correlate with urinary 8-hydroxy-2'-deoxyguanosine (r = 0.050, P = 0.553 or r = 0.063, P = 0.435). Additionally, the positive association of urinary cortisol with urinary 8-hydroxy-2'-deoxyguanosine remained highly significant after the adjustments for multiple confounders of oxidative stress such as age, gender, body mass index, smoking status, 24-h blood pressure, C-reactive protein and estimated glomerular filtration rate (partial r = 0.323, P < 0.001), although only approximately 10% of the variance in urinary cortisol was attributable to differences in urinary 8-OHdG (partial r2 = 0.104). Thus, our data indicate that cortisol but not catecholamines could at least partially contribute to the occurrence of oxidative DNA damage in primary hypertensives.

CONCLUSION

The present study suggested the possibility that the overactivation of hypothalamic-pituitary-adrenal axis rather than sympathoadrenal system could enhance oxidative stress and attendant DNA oxidation in uncomplicated primary hypertension.

Exogenous protease supplementation to the diet enhances growth performance, improves nitrogen utilization, and reduces stress in finishing pigs

We have conducted this experiment to evaluate a new exogenous protease in finishing pigs' growth performance, nutrient digestibility, gas emission, blood profiles, and meat quality. A total of 200 pigs of 52.15 ± 2.31 kg average body weight (BW) were divided into four dietary treatments named as: CON, basal diet; TRT1, basal diet + 0.05% protease; TRT2, basal diet + 0.1% protease; TRT3, basal diet + 1.5% protease. Each treatment consisted of 10 pens, where five pigs were allotted to each pen according to their body weight and sex. The dietary treatments were allotted to the pens in a randomized block design. During this 10-week-long experiment, BW, average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F) were calculated for Week 0-5, Week 6-10, and the overall period. During Week 6-10, ADG was higher in TRT2 and TRT3 than in the CON and TRT1 groups. At the same time, a linear increase was observed in ADG and G:F of the pigs. In addition, the final BW of pigs' was linearly increased by protease supplementation. On Week 10, there was a linear trend of increase (p = 0.0575) in crude protein digestibility and a trend of linear reduction (p = 0.0651) in NH₃ gas emission. In blood profile, cortisol presented a linear decrease in both Week 5 (p = 0.251) and Week 10 (p = 0.0585). In addition, increasing doses of protease showed a trend of linear increase (p = 0.0592) in creatinine, whereas linear reduction was observed in the concentration of epinephrine (p = 0.0636) and norepinephrine (p = 0.0167) during Week 10. In conclusion, protease supplementation helped in improving daily gain in finishing pigs through protein digestibility with associated reduction of ammonia emission and blood stress hormones.

Urinary Metabolomic Study in a Healthy Children Population and Metabolic Biomarker Discovery of Attention-Deficit/Hyperactivity Disorder (ADHD)

OBJECTIVES

Knowledge of the urinary metabolomic profiles of healthy children and adolescents plays a promising role in the field of pediatrics. Metabolomics has also been used to diagnose disease, discover novel biomarkers, and elucidate pathophysiological pathways. Attention-deficit/hyperactivity disorder (ADHD) is one of the most common psychiatric disorders in childhood. However, large-sample urinary metabolomic studies in children with ADHD are relatively rare. In this study, we aimed to identify specific biomarkers for ADHD diagnosis in children and adolescents by urinary metabolomic profiling.

METHODS

We explored the urine metabolome in 363 healthy children aged 1-18 years and 76 patients with ADHD using high-resolution mass spectrometry.

RESULTS

Metabolic pathways, such as arachidonic acid metabolism, steroid hormone biosynthesis, and catecholamine biosynthesis, were found to be related to sex and age in healthy children. The urinary metabolites displaying the largest differences between patients with ADHD and healthy controls belonged to the tyrosine, leucine, and fatty acid metabolic pathways. A metabolite panel consisting of FAPy-adenine, 3-methylazelaic acid, and phenylacetylglutamine was discovered to have good predictive ability for ADHD, with a receiver operating characteristic area under the curve (ROC-AUC) of 0.918. A panel of FAPy-adenine, N-acetylaspartylglutamic acid, dopamine 4-sulfate, aminocaproic acid, and asparaginyl-leucine was used to establish a robust model for ADHD comorbid tic disorders and controls with an AUC of 0.918.

Sex difference in sympathetic nervous system activity and blood pressure in hypertensive patients

Increased sympathetic nervous system (SNS) activity leads to increased risk of cardiovascular morbidity and mortality. This study investigated whether there were sex differences in SNS activity among Chinese patients with hypertension. Ethnic Chinese non‐diabetic hypertensive patients aged 20–50 years were enrolled in Taiwan. A total of 970 hypertensive patients (41.0 ± 7.2 years) completed the study, 664 men and 306 women. They received comprehensive evaluations including office blood pressure (BP) measurement, 24‐h ambulatory BP monitoring, and 24‐h urine sampling assayed for catecholamine excretion. Compared to women, men were younger, had higher body mass index (BMI), office systolic BP (SBP), office diastolic BP (DBP), 24‐h ambulatory BP, and 24‐h urine catecholamine excretion. In men, 24‐h urine total catecholamine levels were correlated with 24‐h SBP (r = 0.103, p = .008) and 24‐h DBP (r = 0.083, p = .033). In women, however, there was no correlation between 24‐h urine total catecholamine levels and 24‐h ambulatory BP. Multivariate linear regression indicated that being male (β = 1.65, 95% confidence interval [CI] 0.01–3.29, p = .048) and 24‐h urine total catecholamine (β = 5.03, 95% CI 0.62–9.44, p = .025) were both independently associated with 24‐h SBP; being male was independently associated with 24‐h DBP (β = 3.55, 95% CI 2.26–4.85, p < .001). In conclusion, Chinese men with hypertension had higher SNS activity than women, and SNS activity was independently associated with 24‐h ambulatory BP in men rather than in women. These findings suggest that different hypertensive treatment strategies should be considered according to patient sex.

Comprehensive, robust, and sensitive UPLC-MS/MS analysis of free biogenic monoamines and their metabolites in urine

Biogenic monoamines, including catecholamines and serotonin are important hormones and neurotransmitters. Abnormal urinary levels of biogenic monoamines and their metabolites are associated with smoking, neuroendocrine tumors, as well as neurological and cardiovascular diseases. Measurements of free biogenic monoamines and their metabolites have been challenging because of low concentrations in complex biological matrices. Current methods require extensive enrichment and removal of interfering substances and can analyze only basic or acidic compounds in a single run. We developed a simple and robust dilute-and-shoot method capable of measuring 10 analytes, including free biogenic monoamines and their metabolites in human urine. The assay enables sensitive measurements of analytes within expected sample concentration ranges. To assess the assay's efficacy, we measured urinary levels of free biogenic monoamines and their metabolites in 255 non-smokers and 191 smokers. Our data show that while smokers had significantly higher urinary levels of free catecholamines and metanephrines, there was a decrease in levels of biogenic amine metabolites synthesized through the monoamine oxidase pathway - homovanillic acid and vanillylmandelic acid. The method could be used for high throughput measurement of the range of free biogenic amines and their metabolites in urine under a variety of different conditions.

Exploring the multidimensional complex systems structure of the stress response and its relation to health and sleep outcomes

To gain a comprehensive understanding of the multidimensional complex systems structure of the stress response and related health outcomes, we utilized network analysis in a sample of 328 healthy participants in two steps. In a first step, we focused on associations between measures of basal hypothalamic-pituitary-adrenal axis functioning and subjective stress perceptions. In a second step, we linked these diverse stress-related measures to biomarkers and self-reports of health and sleep. Overall, measures clustered depending on their method of assessment, with high correlations between different saliva-based indices of diurnal cortisol regulation, between cortisol and cortisone levels in hair, between different biological health indicators (systemic inflammatory activity and body mass index), between state (experience sampling) and trait (questionnaire-based) self-reports of stress and wellbeing, and between different self-reports of sleep. Bridges between clusters suggested that if individuals perceive stress throughout their daily lives this is reflected in their total salivary cortisol output possibly contributing to long-term cortisol accumulation in hair. Likewise, earlier awakening time may contribute to cortisol accumulation in hair via an influence on awakening cortisol processes. Our results show that while meaningful connections between measures exist, stress is a highly complex construct composed of numerous aspects. We argue that network analysis is an integrative statistical approach to address the multidimensionality of the stress response and its effects on the brain and body. This may help uncover pathways to stress-related disease and serve to identify starting points for prevention and therapeutic intervention.

Physiological reactions to long-term fishing in the Barents Sea

Background

Fishing in distant waters for months may induce physiological stress.

Aims

To assess the physiological stress reactions in fishermen working for 2-3 months continuously in 6-h shifts on trawlers in the Barents Sea.

Methods

The crew of five trawlers fishing in the Barents Sea from January to April 2004 were invited to participate. In the week before and 5-7 days after the trip, the following measures were collected: salivary cortisol four times a day, 24-h urinary cortisol, blood pressure, heart rate, serum cholesterol, serum high-density lipoprotein (HDL-cholesterol), HbA1c (glycosylated haemoglobin) and weight. In addition, 24-h urinary cortisol, blood pressure and heart rate were measured three times. A questionnaire on health, social conditions and work environment was obtained after the trip.

Results

In total, 136 men agreed to participate. Full data were obtained for 96 fishermen (70%). A significant decrease in salivary and urinary cortisol was found during the trip. Adjustment for age, body mass index, smoking, shift work schedule and time of day for sample collection did not change this finding. Systolic and diastolic blood pressure declined significantly and remained significantly lower after the trip compared to before the trip. Serum cholesterol/HDL ratio declined significantly, whereas triglycerides, HbA1c and weight were unchanged.

Conclusions

Working up to 3 months on 6-h shifts, 84 h a week, with moderate physical activity, even in artificial light and cold weather on a ship, did not result in increased physiological stress.

Morning vaccination enhances antibody response over afternoon vaccination: A cluster-randomised trial

OBJECTIVES

Older adults are less able to produce a protective antibody response to vaccinations. One factor that contributes to this is immune ageing. Here we examined whether diurnal variations in immune responses might extend to the antibody response to vaccination.

DESIGN

We utilised a cluster-randomised trial design.

SETTING

24 General Practices (GPs) across the West Midlands, UK who were assigned to morning (9-11am; 15 surgeries) or afternoon (3-5pm; 9 surgeries) vaccination times for the annual UK influenza vaccination programme.

PARTICIPANTS

276 adults (aged 65+ years and without a current infection or immune disorder or taking immunosuppressant medication).

INTERVENTIONS

Participants were vaccinated in the morning or afternoon between 2011 and 2013.

MAIN OUTCOME MEASURES

The primary outcome was the change in antibody titres to the three vaccine influenza strains from pre-vaccination to one month post-vaccination. Secondary outcomes of serum cytokines and steroid hormone concentrations were analysed at baseline to identify relationships with antibody responses.

RESULTS

The increase in antibody levels due to vaccination differed between morning and afternoon administration; mean difference (95% CI) for H1N1 A-strain, 293.3 (30.97-555.66) p=.03, B-strain, 15.89 (3.42-28.36) p=.01, but not H3N2 A-strain, 47.0 (-52.43 to 146.46) p=.35; those vaccinated in the morning had a greater antibody response. Cytokines and steroid hormones were not related to antibody responses. No adverse events were reported.

CONCLUSIONS

This simple manipulation in the timing of vaccine administration to favour morning vaccination may be beneficial for the influenza antibody response in older adults, with potential implications for vaccination strategies generally.

TRIAL REGISTRATION

This trial is registered with the ISRCTN (ISRCTN70898162).

Neurally mediated syncope: Is it really an endothelial dysfunction?

OBJECTIVE

Syncope is a common problem in children and adolescents. Neurally mediated syncope is the most frequent form of this disorder. Although several studies have evaluated the pathophysiology of neurally mediated syncope, it is still not completely understood.

METHODS

We performed a cross-sectional study that included 27 patients aged 5-20 years with unexplained syncope and 30 healthy subjects as a control group. All subjects in both groups were assessed for endothelial function by investigating the following physical and chemical factors: flow-mediated dilation (FMD), intima-media thickness (IMT), circulating vascular cell adhesion molecule (VCAM), intercellular adhesion molecule (ICAM)], and endothelial leucocyte adhesion molecule (E-selectin), as well as epinephrine and norepinephrine. The data were statistically analyzed utilizing the SPSS 20.Significant differences between the groups in terms of mean scores were assessed using an independent sample t-test.

RESULTS

Mean FMD was significantly higher in the syncope case group than in the control group (p=0.028). There was no significant difference in IMT between the two groups; however, mean levels of ICAM (p=0.02) and VCAM (p=0.008) were significantly higher in the case group than in the control group. The levels of E-selectin also increased in the case group, but not to a statistically significant extent. The mean levels of epinephrine (p=0.01) were significantly lower in the case group than in the control group, and the level of norepinephrine serum decreased slightly, but not significantly, in the syncope patients.

CONCLUSION

Our results showed that an endothelial dysfunction or augmented endothelial function might exist in patients with neurally mediated syncope.

The importance of choosing the appropriate matrix to validate a bioanalytical method according to the study needs

Sylvain Lachance is a Bioanalytical Scientific Expert in the Bioanalytical Division of inVentiv Health Clinical Quebec City's (Canada) site, a CRO offering clinical, commercial and consulting services to the healthcare industry. He is responsible for following up on the conduct of bioanalytical method development activities by enhancing the scientific and technical knowledge of the researchers, bioanalytical project coordinators and of the laboratory technicians. He assists bioanalytical project coordinators in investigations during bioanalyses and method validations. He has been working in the Bioanalytical Division of inVentiv Health Clinical for over 16 years, working as a Research Scientist, Chromatographic Specialist and Scientific Expert. He has worked on multiple method developments in HPLC and LC–MS/MS, specifically on troubleshooting. He has been involved in more than 70 posters and publications in the bioanalytical field for different scientific meetings.

Ann Lévesque obtained her PhD in Biochemistry at the Université Laval in Québec City in 1994 studying the biological actions of peptide analogs of the gastrin releasing peptide in the growth inhibition of cancer cells. Prior to joining inVentiv Health Clinical, she held management positions at other Contract Research Organizations. Her publications include over 100 posters, 17 scientific articles and book chapters in the clinical biochemistry and bioanalytical fields. Within inVentiv Health, Dr. Lévesque is responsible for managing the R&D and sample analysis teams performing bioanalytical analysis of small molecules and peptides. She is also acting as the Biomedical Laboratory Director accountable for the oversight of all activities related to the safety testing of samples from subjects enrolled in early stage clinical trials. Since joining the Bioanalytical Division, Dr. Lévesque has been instrumental in the great success of the laboratory by developing a culture of quality, innovation and value.

Validation guidelines from different agencies mainly recommend that matrix effect should be studied with hemolyzed and hyperlipidemic samples, while the European agency requires also to investigate matrix effect on special population. When studies are done in countries with different dietary habits, or when a medication is administered to decrease the concentration of the endogenous compounds, should the matrix effect in these conditions be evaluated? Herein, three case studies are described to show the importance of choosing the appropriate matrix for the bioanalytical method validations and for their use to analyze the study samples according to the conditions required by the clinical trials. The case studies presented are related to the use of the testosterone, Omega-3 and cortisol methods.

Predictors of plasma and urinary catecholamine levels in normotensive and hypertensive men and women

Age, sex, hypertension and dietary sodium are proposed to affect plasma and urinary catecholamines. Yet no prior study has examined the simultaneous effects of these factors within the same study population, so results may have been confounded by factors not determined. We investigate, for the first time, the impact of simultaneously determined predictors of plasma and urinary catecholamines, and the relationship of catecholamines with the diagnosis of hypertension. Hypertensive and normotensive subjects (n=308) were studied off antihypertensives in liberal and low sodium balance. Twenty-four hour urinary catecholamines (norepinephrine and epinephrine) were measured. Plasma catecholamines were measured supine after overnight fast. Repeated measures multivariate linear regression models examined effect of sex, race, age, body mass index, dietary salt (liberal salt vs. low salt), hypertension status, and mean arterial pressure on plasma and urinary catecholamines. Logistic regression determined the relationship of catecholamines with diagnosis of hypertension. Dietary sodium restriction and increasing age predicted increased plasma and urinary norepinephrine, with sodium restriction having greatest effect. Female sex predicted lower urinary and plasma epinephrine. Neither plasma nor urinary catecholamines predicted the diagnosis of hypertension. In summary, specific demographic factors variably impact catecholamines and should be considered when assessing catecholamines in research and clinical settings.

Building-related symptoms and stress indicators

This study aims to study physiological stress indicators in relation to prevalence of building-related symptoms (BRS) among teachers employed in three selected schools in Copenhagen. Three hypotheses were studied: (i) Perceived psychosocial work environment was associated with BRS; (ii) Perceived psychosocial work environment (job strain) was associated with physiological strain; (iii) BRS was associated with physiological strain. We found a tendency among women of an association between job strain and being BRS positive. Also an association between job strain and physiological strain was observed among women. Being BRS positive was not associated with single physiological stress indicators with the exception of a higher level free testosterone in serum among BRS-positive women.

PRACTICAL IMPLICATIONS

Including physiological stress indicators may be a supplementary measure to questionnaires when studying the association between the psychosocial work environment and building-related symptoms (BRS). In this study, job strain was associated with physiological strain among women. Being BRS positive was not associated with single physiological stress indicators with the exception of a higher level free testosterone in serum among BRS-positive women. This study should be regarded as a preliminary study because of its small number of participants.

Autonomic nervous system function in chronic exogenous subclinical thyrotoxicosis and the effect of restoring euthyroidism

CONTEXT

Knowledge on the relationship between the autonomic nervous system and subclinical hyperthyroidism is mainly based upon cross-sectional studies in heterogeneous patient populations, and the effect of restoration to euthyroidism in subclinical hyperthyroidism has not been studied.

OBJECTIVE

We investigated the long-term effects of exogenous subclinical hyperthyroidism on the autonomic nervous system and the potential effects of restoration of euthyroidism.

DESIGN

This was a prospective single-blinded, placebo-controlled, randomized trial.

SETTING

The study was performed at a university hospital.

PATIENTS

A total of 25 patients who were on more than 10-yr TSH suppressive therapy after thyroidectomy was examined.

INTERVENTION

Patients were studied at baseline and subsequently randomized to a 6-month thyroid hormone substitution regimen to obtain either euthyroidism or maintenance of the subclinical hyperthyroid state.

MAIN OUTCOME MEASURES

Urinary excretion of catecholamines and heart rate variability were measured. Baseline data of the subclinical hyperthyroidism patients were compared with data obtained in patients with hyperthyroidism and controls.

RESULTS

Urinary excretion of norepinephrine and vanillylmandelic acid was higher in the subclinical hyperthyroidism patients compared with controls and lower compared with patients with overt hyperthyroidism. Heart rate variability was lower in patients with hyperthyroidism, intermediate in subclinical hyperthyroidism patients, and highest in the healthy controls. No differences were observed after restoration of euthyroidism.

CONCLUSIONS

Long-term exogenous subclinical hyperthyroidism has effects on the autonomic nervous system measured by heart rate variability and urinary catecholamine excretion. No differences were observed after restoration to euthyroidism. This may indicate the occurrence of irreversible changes or adaptation during long-term exposure to excess thyroid hormone that is not remedied by 6-month euthyroidism.

Preliminary evidence that morning vaccination is associated with an enhanced antibody response in men

Variation in response to vaccination, particularly in vulnerable groups, provides a strong rationale for developing vaccine adjuvants. If there were consistent diurnal variation in immune response, this could inform a simple intervention for enhancing vaccine efficacy. Data from two studies are presented examining morning versus afternoon vaccine administration; in the first, hepatitis A vaccine was administered to young adults, and in the second, influenza vaccine to older community-based adults. Men, but not women, vaccinated in the morning mounted a better peak antibody response to both hepatitis A and the A/Panama influenza strain. These results indicate that it would be worthwhile testing this effect in a large randomized control trial with vaccination during time periods representing the extremes of hormonal and cytokine diurnal rhythms.

A cross-sectional study evaluating the relationship between cortisol suppression and asthma control in patients with difficult asthma

AIM

To examine the relationship between cortisol suppression and asthma symptoms in patients with difficult asthma.

METHODS

Patients, referred to a specialist difficult asthma service and who fulfilled the criteria for difficult asthma, were recruited to the study in a sequential, unselected manner. At each clinic visit, all patients completed a validated asthma control questionnaire. For measuring cortisol suppression, early morning urinary cortisol [corrected for creatinine to give urinary cortisol creatinine ratio (UCC ratio)] was used. The urine samples were collected and stored at -70 degrees C until ready for analysis. Urinary cortisol was extracted (solid-phase extraction) and analysed using high-performance liquid chromatography. The Pearson correlation coefficient was used for correlation analysis while t-tests were used for between-group differences for normally distributed data. If the data were not normally distributed, nonparametric statistics were used. A P-value < 0.05 was considered statistically significant.

RESULTS

During the study period all the patients who attended the difficult asthma clinic and fulfilled the criteria for difficult asthma (n = 66) agreed to take part in the study. There were moderate to strong and significant associations between several measures of asthma control and UCC ratio. The correlation coefficient with five indicators of asthma control ranged between 0.3 and 0.5 (P < 0.05).

CONCLUSIONS

We have demonstrated a relationship between cortisol suppression and asthma control in difficult asthmatics on high-dose steroid therapy. We have proposed a model based on the relationship between symptom control and cortisol suppression, whereby both adherence and therapeutic adjustments could potentially be made. A properly controlled prospective clinical trial should examine the utility of this approach in clinical practice.

Loneliness is a unique predictor of age-related differences in systolic blood pressure

A population-based sample of Caucasians, African Americans, and Latino Americans, 50-68 years of age (M = 57.5), from Cook County, Illinois (N = 229), was tested to examine how loneliness and co-occurring psychosocial factors (depressive symptoms, perceived stress, social support, and hostility) were related to indices of cardiovascular and endocrine functioning. Extending prior research, the authors found that loneliness was associated with elevated systolic blood pressure (SBP) and age-related increases in SBP, net of demographic variables, health behavior variables, and the remaining psychosocial factors. Loneliness was not associated with differences in autonomic or endocrine functioning. Although the results are limited by the cross-sectional methods used, they are consistent with the hypothesis that cardiovascular disease contributes to increased morbidity and mortality among lonely individuals.

Smoking and hormones in health and endocrine disorders

Smoking has multiple effects on hormone secretion, some of which are associated with important clinical implications. These effects are mainly mediated by the pharmacological action of nicotine and also by toxins such as thiocyanate. Smoking affects pituitary, thyroid, adrenal, testicular and ovarian function, calcium metabolism and the action of insulin. The major salient clinical effects are the increased risk and severity of Graves' hyperthyroidism and opthalmopathy, osteoporosis and reduced fertility. Smoking also contributes to the development of insulin resistance and hence type 2 diabetes mellitus. An important concern is also the effect of smoking on the foetus and young children. Passive transfer of thiocyanate can cause disturbance of thyroid size and function. Furthermore, maternal smoking causes increased catecholamine production, which may contribute to under perfusion of the foetoplacental unit.

Gender and ethnic differences in urinary stress hormones: the population-based Chicago Health, Aging, and Social Relations Study

Gender and ethnic disparities in cardiovascular disease and mortality have spurred interest in the epidemiology of stress hormone production. Greater disease burden among men and blacks raises the possibility of gender and ethnic differences in stress hormone production. The purpose of this study was to determine whether urinary stress hormones were higher among men and blacks in a population-based sample. Urinary hormone analysis permits a time-integrated assessment of the stress response system. However, differences in collection and standardization strategies have led to inconsistent findings. Subjects were an ethnically diverse population-based sample of 229 men and women aged 50–67 yr who provided an overnight urine specimen. Urine concentration was standardized using a traditional creatinine-based approach as well as a new method that accounts for muscle mass. With the use of creatinine standardization, no gender or ethnic differences were noted in epinephrine or cortisol production. Norepinephrine levels were higher among women compared with men ( P = 0.001), however. After accounting for muscle mass, we found that both epinephrine ( P = 0.018) and norepinephrine ( P = 0.033) levels were higher among men compared with women. No significant differences in cortisol production were found by gender or ethnicity. The consistency of these results with previous studies of 24-h urine samples suggests muscle mass should be accounted for when comparing overnight urinary hormone values across gender and ethnicity.

Two urinary catecholamine measurement indices for applied stress research: effects of time and temperature until freezing

Research on stress at work often involves the analysis of urinary adrenaline and noradrenaline. It is usually assumed that samples have to be cooled quickly and stored at refrigerator temperature before freezing. This is often difficult to achieve in field studies. This experimental study therefore tests the robustness of results when samples are not cooled immediately. Samples of 9 men and women, collected at 3 points in time, were immediately frozen, kept for a variable delay in a warm room, or stored in a refrigerator before freezing. Two indices were calculated: (a) the ratio of hormones to liquid volume, period of excretion, and body weight; and (b) the ratio of hormones to urinary creatinine. The reliability of high performance liquid chromatography analysis was satisfactory, as was the comparability of the 2 indices. Unfavorable storage up to 24 hr did not cause bacteria-driven decreases of catecholamines, regardless of storage temperature or sampling time. Results suggest high stability for at least 24 hr without cooling, provided the samples are immediately acidified. Cooling may therefore be handled less restrictively than has been assumed. The application of this research is to facilitate research in settings where samples are collected at different places, such as participants' homes or different workplaces.