The activity of the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system in relation to waist/hip circumference ratio in men

Challenges in timing and mode of delivery in morbidly obese women

Globally obesity is increasing especially in the reproductive age group. Pregnant women with obesity have higher complication and intervention rates. They are also at increased risk of stillbirth and intrapartum complications. Although organisations like NICE, RCOG, ACOG and WHO have published guidelines and recommendations on care of pregnant women with obesity the evidence from which Grade A recommendations can be made on timing and how to deliver is limited. The current advice is therefore to have discussions with the woman on risks to help her make an informed decision about timing, place, and mode of delivery. Obesity is an independent risk factor for pregnancy complications including diabetes, hypertension and macrosomia. In those with these complications, the timing of delivery is often influenced by the severity of the complication. As an independent factor, population based observational studies in obese women have shown an increase in the risk of stillbirth. This risk increases linearly with weight from overweight through to class II obesity, but then rises sharply in those with class III obesity by at least 10-fold beyond 42 weeks when compared to normal weight women. This risk of stillbirth is notably higher in obese women from 34 weeks onwards compared to normal weight women. One modifiable risk factor for stillbirth as shown from various cohorts of pregnant women is prolonged pregnancy. Research has linked obesity to prolonged pregnancy. Although the exact mechanism is yet unknown some have linked this to maternal dysregulation of the hypothalamic pituitary adrenal axis leading to hormonal imbalance delaying parturition. For these women the two dilemmas are when and how best to deliver. In this review, we examine the evidence and make recommendations on the timing and mode of delivery in women with obesity. For class I obese women there are no differences in outcome with regards to timing and mode of delivery when compared to lean weight women. However, for class II and III obesity, planned induction or caesarean sections may be associated with a lower perinatal morbidity and mortality although this may be associated with an increased in maternal morbidity especially in class III obesity. Studies have shown that delivery by 39 weeks is associated with lower perinatal mortality compared to delivering after in these women. On balance the evidence would favour planned delivery (induction or caesarean section) before 40 weeks of gestation. In the morbidly obese, apart from the standard lower transverse skin incision for CS, there is evidence that a supraumbilical transverse incision may reduce morbidity but is less cosmetic. Irrespective of the option adopted, it is important to discuss the pros and cons of each.

Socio-demographic and psychosocial predictors of salivary cortisol from older male participants in the Speedwell prospective cohort study

INTRODUCTION

Associations between measures of socio-economic position and cortisol remain controversial. We examined the association between social class and cortisol reactivity in an aging male population.

METHODS

The Speedwell cohort study recruited 2348 men aged 45-59 years from primary care between 1979 and 1982 (phase I) where occupational social class was used to classify socioeconomic position. Men were seen on four more occasions, the last being between 1997 and 1999 (phase 5) when salivary samples were obtained capturing cortisol reactivity to stressors (cognitive test and venepuncture) and circadian variations (awakening and night-time cortisol levels, circadian slope and area under curve) at morning and afternoon clinic sessions. Longitudinal association between social class at phase 3 and log-transformed salivary cortisol measures at phase 5 was assessed using multivariable linear regression adjusted for variables associated with sampling time and age as a potential confounder, stratified by time of clinic session. We also explored possible mediation by psychosocial factors (e.g. work dislike) and health-related factors (e.g. waist-to-hip ratio and high-density lipoprotein cholesterol).

RESULTS

From 1768 living men, 1003 men (57%) attended a clinic at phase five, 854 participants (85% of attendees) returned home cortisol samples (mean age 71.7 years). We found little evidence of association between social class and baseline cortisol (i.e. prior to stress), cortisol response to stressors, and cortisol diurnal variation. However, we found lower social class was associated with higher and delayed post-stress recovery cortisol for participants that visited the clinic in the morning (adjusted β coefficient for manual versus non-manual 0.25 ng/ml; 95% CI: 0.06-0.48; P = 0.008). This association did not appear to be mediated by any of the measured psychosocial or health-related factors.

CONCLUSION

Our data did not show an overall association between social class and cortisol variability either diurnal or in response to a stressor. Lower social class was associated with a slower time to recover from exposure to stress in the morning, thereby increasing overall cortisol exposure. These findings provide some evidence for a mechanism that may contribute to the association between lower social class and a higher risk of adverse health outcomes.

Potential mechanisms linking psychological stress to bone health

Chronic psychological stress affects many body systems, including the skeleton, through various mechanisms. This review aims to provide an overview of the factors mediating the relationship between psychological stress and bone health. These factors can be divided into physiological and behavioural changes induced by psychological stress. The physiological factors involve endocrinological changes, such as increased glucocorticoids, prolactin, leptin and parathyroid hormone levels and reduced gonadal hormones. Low-grade inflammation and hyperactivation of the sympathetic nervous system during psychological stress are also physiological changes detrimental to bone health. The behavioural changes during mental stress, such as altered dietary pattern, cigarette smoking, alcoholism and physical inactivity, also threaten the skeletal system. Psychological stress may be partly responsible for epigenetic regulation of skeletal development. It may also mediate the relationship between socioeconomic status and bone health. However, more direct evidence is required to prove these hypotheses. In conclusion, chronic psychological stress should be recognised as a risk factor of osteoporosis and stress-coping methods should be incorporated as part of the comprehensive osteoporosis-preventing strategy.

The Relationship between Autonomic Regulation of Cardiovascular Function and Body Composition

Background

We investigated whether the results of autonomic function tests correlate with body composition and shape in healthy young people.

Methods

We conducted cardiovascular reflex tests (heart rate [HR] and blood pressure [BP] responses to the Valsalva maneuver and HR response to deep breathing) and the tilt table test with 32 subjects (19 males; mean age, 22.1±1.9 years). Participants also completed an anthropometric measurement sequence (weight; height; upper arm, hips, and waist circumference; triceps and subscapular skinfold), bioelectric impedance testing, and hand grip strength measurements.

Results

Markers of obesity, other anthropometric measures, functional measures, and the basal metabolic rate (BMR) were significantly positively correlated with systolic BP (SBP) and diastolic BP (DBP) in both the supine and tilted positions. There was a positive correlation between the difference in HR (ΔHR) between the tilt and supine body positions and markers of obesity, the functional marker of dominant handgrip strength, and BMR. Participants with a body mass index (BMI) <25 kg/m² had significantly lower median values of ΔHR, DBP in the tilt-test, SBP at rest, and SBP in the tilt-test than participants who had a BMI ≥25 kg/m² (10.55 vs. 21.95 bpm, P=0.003; 77.55 vs. 90.05 mmHg, P=0.045; 113.45 vs. 140.55 mmHg, P=0.013; 117.00 vs. 135.25 mmHg, P=0.006, respectively). Body fat percentage was identified as an independent positive predictor (β=0.993; 95% confidence interval [CI], 0.070 to 1.916; P=0.036) and body water percentage was an independent negative predictor of tilted SBP (β=-1.370; 95% CI, -2.634 to 0.106; P=0.035).

Conclusion

High sympathetic activity, as evaluated by cardiovascular regulation, correlates with a high share of adipose tissue in young healthy persons.

The effect of yoga practice on glycemic control and other health parameters in the prediabetic state: A systematic review and meta-analysis

A systematic review and meta-analysis was conducted to investigate the effects of yoga on glycemic control, lipid profiles, body composition and blood pressure in people in the pre-diabetic state. Studies on the effectiveness of yoga on population groups under high risk for diabetes, called prediabetic or suffering from metabolic syndromes were extracted from a thorough search of PubMed, Scopus, Cochrane Library, EBSCO and IndMED databases. Both Randomised Controlled Trial (RCT) and non-RCT studies were included in the systematic review and meta-analysis. Studies published between Jan 2002 and Dec 2018 were included. Studies were considered for evaluation if they investigated a yoga intervention to prevent T2DM, against a control group, while also reporting glycemic control and other health parameters of T2DM management. Summary effect sizes and 95% confidence intervals (CI) were calculated using the Comprehensive Meta-Analysis software in addition to publication bias. Of the 46,500 identified studies, 14 studies with 834 participants of whom were 50% women, were found to be eligible for inclusion in our systematic review. Our quantitative synthesis included 12 randomized control trials and 2 non-randomized control trials, with the follow-up period ranging from 4 to 52 weeks. Compared to controls, yoga intervention improved fasting blood glucose (FBG) [Standard Mean Difference (SMD -0.064 mg/dL (95% CI -0.201 to 0.074)]; low density lipoprotein (LDL) [SMD-0.090 mg/dL (95% CI -0.270 to 0.090)]; triglycerides [SMD -0.148 mg/dL (95% CI -0.285 to -0.012)]; total cholesterol [SMD -0.058 mg/dL (95% CI -0.220 to 0.104)] and systolic blood pressure [SMD -0.058 mm Hg (95% CI -0.168 to 0.053)]. This meta-analysis uncovered clinically improved effects of yoga intervention on glycemic control, lipid profiles and other parameters of T2DM management in prediabetic population. These results suggest that yoga intervention may be considered as a comprehensive and alternative approach to preventing T2DM. Further adequately powered, well designed RCTs are needed to support our findings and investigate the long-term effects of yoga in T2DM patients.

Evaluation of the hypothalamic-pituitary-adrenal axis in a case series of familial partial lipodystrophy

BACKGROUND

Familial partial lipodystrophy (FPL) is a rare genetic disease characterized by body fat abnormalities that lead to insulin resistance (IR). Clinical conditions linked to milder IR, such as type 2 diabetes (T2D) and metabolic syndrome, are associated with abnormalities of the hypothalamic-pituitary-adrenal (HPA) axis, but little is known about its activity in FPL.

METHODS

Patients meeting the clinical criteria for FPL were subjected to anthropometric, biochemical and hormone analyses. A genetic study to identify mutations in the genes encoding peroxisome proliferator-activated receptor gamma (PPARγ) was performed. Polycystic ovary syndrome and hepatic steatosis were investigated, and the patient body compositions were analyzed via dual X-ray energy absorptiometry (DXA). The HPA axis was assessed via basal [cortisol, adrenocorticotrophic hormone (ACTH), cortisol binding globulin, nocturnal salivary cortisol and urinary free cortisol (UFC)] as well as dynamic suppression tests (cortisol post 0.5 mg and post 1 mg dexamethasone).

RESULTS

Six patients (five female and one male) aged 17 to 42 years were included. In DXA analyses, the fat mass ratio between the trunk and lower limbs (FMR) was > 1.2 in all phenotypes. One patient had a confirmed mutation in the PPARγ gene: a novel heterozygous substitution of p. Arg 212 Trp (c.634C>T) at exon 5. HPA sensitivity to glucocorticoid feedback was preserved in all six patients, and a trend towards lower basal serum cortisol, serum ACTH and UFC values was observed.

CONCLUSIONS

Our findings suggest that FPL is not associated with overt abnormalities in the HPA axis, despite a trend towards low-normal basal cortisol and ACTH values and lower UFC levels. These findings suggest that the extreme insulin resistance occurring in FPL may lead to a decrease in HPA axis activity without changing its sensitivity to glucocorticoid feedback, in contrast to the abnormalities in HPA axis function in T2D and common metabolic syndrome.

Basal autonomic activity, stress reactivity, and increases in metabolic syndrome components over time

CONTEXT

Basal autonomic nervous system (ANS) functioning has been linked to the metabolic syndrome (MetS), but the role of ANS reactivity in response to stress remains unclear.

OBJECTIVE

To examine cross-sectionally and longitudinally to what extent ANS basal level and stress reactivity are related to MetS.

DESIGN

2-year and 6-year data from a prospective cohort: the Netherlands Study of Depression and Anxiety.

SETTING

Participants were recruited from the general community, primary care, and mental health care organizations.

PARTICIPANTS

1922 respondents (mean age=43.7years).

MAIN OUTCOME MEASURES

Indicators of ANS functioning were heart rate (HR), respiratory sinus arrhythmia (RSA) and pre-ejection period (PEP). ANS stress reactivity was measured during a cognitively challenging stressor and a personal-emotional stressor. MetS components included triglycerides, high-density lipoprotein cholesterol, blood pressure, glucose and waist circumference.

RESULTS

Cross-sectional analyses indicated that higher basal HR, lower basal values of RSA and PEP, and higher RSA reactivity during cognitive challenge were related to less favorable values of almost all individual MetS components. Longitudinal analyses showed that higher basal HR and shorter basal PEP predicted 4-year increase in many MetS abnormalities. Higher RSA stress reactivity during cognitive challenge predicted 4-year increase in number of MetS components.

CONCLUSION

Higher basal sympathetic, lower basal parasympathetic activity, and increased parasympathetic withdrawal during stress are associated with multiple MetS components, and higher basal sympathetic activity predicts an increase in metabolic abnormalities over time. These findings support a role for ANS dysregulation in the risk for MetS and, consequently, the development of cardiovascular disease.

Sex-related differences in the association of salivary cortisol levels and type 2 diabetes. Findings from the cross-sectional population based KORA-age study

BACKGROUND

Dysregulation in the cortisol secretion may have a role in the development of type 2 diabetes although conflicting evidence on the particular cortisol secretion patterns and type 2 diabetes demands further investigations. We aim to examine the association of cortisol levels and diurnal secretion patterns with prevalence of type 2 diabetes and HbA1c levels as well as the potential impact of sex and adiposity on this association.

METHODS

A cross-sectional analysis was conducted among 757 participants (aged 65-90 years) of the population-based KORA (Cooperative Health Research in the Region of Augsburg)-Age study. Multivariate regression analyses were employed to examine the association between salivary cortisol (measured upon waking (M1), 30min after awakening (M2), and in the late night (LNSC)) and type 2 diabetes as well as glycated hemoglobin (HbA1c) with adjustments for potential confounders.

RESULTS

In the total sample population, an elevated LNSC level was observed in type 2 diabetes patients compared to non-patients (P=0.04). In sex-stratified analyses, diabetic men showed a greater Cortisol Awakening Response (CAR) (P=0.02). Diabetic women had significantly elevated LNSC levels (P=0.04). HbA1c was positively associated with both CAR and LNSC levels but was negatively associated with M1 to LNSC ratio.

CONCLUSION

In this aged population, type 2 diabetes is associated with dysregulated cortisol secretion characterized by distinct sex specific diurnal patterns.

Examining the mediating roles of binge eating and emotional eating in the relationships between stress and metabolic abnormalities

To test whether binge eating and emotional eating mediate the relationships between self-reported stress, morning cortisol and the homeostatic model of insulin resistance and waist circumference. We also explored the moderators of gender and age. Data were from 249 adults (mean BMI = 26.9 ± 5.1 kg/m(2); mean age = 28.3 ± 8.3 years; 54.2% male; 69.5% white) recruited from the community who were enrolled in a cross-sectional study. Participants completed a comprehensive assessment panel of psychological and physiological assessments including a morning blood draw for plasma cortisol. We found negative relationships between stress and morning cortisol (r = -0.15 to -0.21; p < 0.05), and cortisol and the homeostatic model of insulin resistance and waist circumference (r = -0.16, -0.25, respectively; p < 0.05). There was not statistical support for binge eating or emotional eating as mediators and no support for moderated mediation for either gender or age; however, gender moderated several paths in the model. These include the paths between perceived stress and emotional eating (B = 0.009, p < 0.001), perceived stress and binge eating (B = 0.01, p = 0.003), and binge eating and increased HOMA-IR (B = 0.149, p = 0.018), which were higher among females. Among women, perceived stress may be an important target to decrease binge and emotional eating. It remains to be determined what physiological and psychological mechanisms underlie the relationships between stress and metabolic abnormalities.

High-protein meal challenge reveals the association between the salivary cortisol response and metabolic syndrome in police officers

OBJECTIVES

Policing is considered a high-stress occupation and officers have elevated cardiovascular morbidity and mortality. To investigate a potential connection, we evaluated the association between salivary cortisol response to a high-protein meal challenge and the metabolic syndrome (MetSyn), a subclinical disorder associated with increased cardiovascular risk.

METHODS

Cross-sectional data were from the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) Study (2004-2009). MetSyn was defined as having ≥3 components: abdominal obesity, hypertension, elevated triglycerides, reduced high-density lipoprotein cholesterol, and glucose intolerance. Officers provided five saliva samples for cortisol analysis, one before challenge (high-protein shake) and four at 15-min intervals thereafter, where the usual response is increase. Regression models were used to examine trends in mean number of MetSyn components across quartiles of area under the curve (AUC) salivary cortisol. Patterns of mean cortisol response were assessed by MetSyn status using repeated-measures analysis of covariance.

RESULTS

Prevalence of MetSyn was 25.7% among 373 officers (74.0% male). The mean count of MetSyn components decreased (1.89, 1.75, 1.55, 1.37; P < 0.01) across increasing quartiles of AUC salivary cortisol. Mean salivary cortisol decreased from baseline (5.55, 4.58, 4.47, 4.79, 4.75 nmol/l) in officers with MetSyn and increased (5.08, 5.82, 5.92, 5.82, 5.60 nmol/l) in their counterparts. The test for interaction between MetSyn status and time of saliva collection was statistically significant (P < 0.001).

CONCLUSIONS

Reduced cortisol response to a high-protein meal challenge may be associated with MetSyn. Future longitudinal studies could provide useful evidence for planning intervention studies on cardiovascular risk among police officers.

Endocrine stress responses and risk of type 2 diabetes mellitus

This study was carried to ascertain whether stress responses are associated with abnormalities in glucose tolerance, insulin sensitivity and pancreatic beta cell function and risk of type 2 Diabetes Mellitus. Salivary cortisol, a marker of hypothalamic-pituitary-adrenal (HPA) axis and salivary α-amylase, a marker of sympathetic nervous system (SNS) were compared in 125 subjects of newly detected diabetes mellitus (NDDM) and normal glucose tolerance (NGT) subjects who were diagnosed on the basis of oral glucose tolerance test (OGTT). Assessment of stress in them was done through stress scales - presumptive stressful life events scale (PSLES), perceived stress scale (PSS) and sense of coherence (SOC) and correlated with these and other stress response markers. Significantly higher 10 pm salivary cortisol and post dexamethasone salivary cortisol were found in NDDM subjects as compared to NGT. 10 pm salivary cortisol correlated significantly with fasting plasma glucose (FPG), 2 h plasma glucose (2h PG) and glycated hemoglobin (HbA1c) while post dex salivary cortisol correlated with 2h PG, HbA1c and salivary α-amylase with 2h PG. Stepwise logistic regression analysis showed that body mass index (OR: 1.840), SOC (OR: 0.688) and 10 pm salivary cortisol (OR: 1.427) were the strongest predictors of NDDM. The results of the present study indicate that NDDM subjects display significantly higher chronic stress and stress responses when compared to subjects with NGT. Chronic stress and endocrine stress responses are significantly associated with glucose intolerance, insulin resistance and diabetes mellitus.

Circadian Clocks and the Interaction between Stress Axis and Adipose Function

Many physiological processes and most endocrine functions show fluctuations over the course of the day. These so-called circadian rhythms are governed by an endogenous network of cellular clocks and serve as an adaptation to daily and, thus, predictable changes in the organism's environment. Circadian clocks have been described in several tissues of the stress axis and in adipose cells where they regulate the rhythmic and stimulated release of stress hormones, such as glucocorticoids, and various adipokine factors. Recent work suggests that both adipose and stress axis clock systems reciprocally influence each other and adrenal-adipose rhythms may be key players in the development and therapy of metabolic disorders. In this review, we summarize our current understanding of adrenal and adipose tissue rhythms and clocks and how they might interact to regulate energy homoeostasis and stress responses under physiological conditions. Potential chronotherapeutic strategies for the treatment of metabolic and stress disorders are discussed.

Blunted glucocorticoid and mineralocorticoid sensitivity to stress in people with diabetes

Psychological stress may contribute to type 2 diabetes but mechanisms are still poorly understood. In this study, we examined whether stress responsiveness is associated with glucocorticoid and mineralocorticoid sensitivity in a controlled experimental comparison of people with type 2 diabetes and non-diabetic participants. Thirty-seven diabetes patients and 37 healthy controls underwent psychophysiological stress testing. Glucocorticoid (GR) and mineralocorticoid sensitivity (MR) sensitivity were measured by dexamethasone- and prednisolone-inhibition of lipopolysaccharide (LPS)-induced interleukin (IL) 6 levels, respectively. Blood pressure (BP) and heart rate were monitored continuously, and we periodically assessed salivary cortisol, plasma IL-6 and monocyte chemotactic protein (MCP-1). Following stress, both glucocorticoid and mineralocorticoid sensitivity decreased among healthy controls, but did not change in people with diabetes. There was a main effect of group on dexamethasone (F(1,74)=6.852, p=0.013) and prednisolone (F(1,74)=7.295, p=0.010) sensitivity following stress at 45 min after tasks. People with diabetes showed blunted stress responsivity in systolic BP, diastolic BP, heart rate, IL-6, MCP-1, and impaired post-stress recovery in heart rate. People with Diabetes had higher cortisol levels as measured by the total amount excreted over the day and increased glucocorticoid sensitivity at baseline. Our study suggests that impaired stress responsivity in type-2 diabetes is in part due to a lack of stress-induced changes in mineralocorticoid and glucocorticoid sensitivity.

Impact of Adiposity and Fat Distribution on the Dynamics of Adrenocorticotropin and Cortisol Rhythms

Obesity impacts many hormonal systems, including pituitary hormones, as well as insulin and leptin. In this review we discuss articles which investigate the influence of obesity on the hypothalamic-pituitary-adrenal (HPA) axis. Different techniques have been used to assess the function of the HPA-axis in obesity, including measuring fasting and/or late evening levels of adrenocorticotropic hormone (ACTH) and (free) cortisol in plasma and saliva, studying feedback with dexamethasone or cortisol, and evaluating responsiveness of the system to corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) or ACTH 1-29. In addition, more elaborate studies investigated 24-h secretion patterns, analyzed with deconvolution techniques to quantitate pulsatile secretion rates of cortisol and less often ACTH. Other investigators used timed infusions of labeled cortisol for the estimation of the 24-h secretion rate, clearance rate and distribution volume. Many studies relied on the 24-h urinary excretion of free cortisol, but for quantitation of the 24-h secretion, measurement of all cortisol-derived metabolites is required. Several studies have applied modern liquid chromatography-tandem-mass spectrometry techniques to measure these metabolites. The picture emerging from all these studies is that, first, ACTH secretion is amplified, likely via enhanced forward drive; and, second, serum cortisol levels are normal or even low, associated with a normal 24-h cortisol secretion per liter distribution volume determined by deconvolution, but enhanced when based on the increased total distribution volume associated with obesity. Increased cortisol secretion was also established by isotope dilution studies and reports based on the measurement of all urinary cortisol metabolites. The responsiveness of the adrenal gland to ACTH is diminished. The studies do not address quantitative aspects of cortisol-cortisone metabolism on individual organs, including liver, central and peripheral fat, intestine, skin, and muscle.

Adrenal Clocks and the Role of Adrenal Hormones in the Regulation of Circadian Physiology

The mammalian circadian timing system consists of a master pacemaker in the suprachiasmatic nucleus (SCN) and subordinate clocks that disseminate time information to various central and peripheral tissues. While the function of the SCN in circadian rhythm regulation has been extensively studied, we still have limited understanding of how peripheral tissue clock function contributes to the regulation of physiological processes. The adrenal gland plays a special role in this context as adrenal hormones show strong circadian secretion rhythms affecting downstream physiological processes. At the same time, they have been shown to affect clock gene expression in various other tissues, thus mediating systemic entrainment to external zeitgebers and promoting internal circadian alignment. In this review, we discuss the function of circadian clocks in the adrenal gland, how they are reset by the SCN and may further relay time-of-day information to other tissues. Focusing on glucocorticoids, we conclude by outlining the impact of adrenal rhythm disruption on neuropsychiatric, metabolic, immune, and malignant disorders.

Physiological responses to psychological stress: importance of adiposity in men aged 50-70 years

We tested the hypothesis that overweight/obese men aged 50-70 years will have a greater salivary cortisol, salivary alpha amylase and heart rate (HR) responses to psychological stress compared with age matched lean men. Lean (BMI=20-25 kg/m(2); n=19) and overweight/obese (BMI=27-35 kg/m(2); n=17) men (50-70 years) were subjected to a well-characterised psychological stress (Trier Social Stress Test, TSST) at 1500 h. Concentrations of cortisol and alpha amylase were measured in saliva samples collected every 7-15 min from 1400 to 1700 h. HR was recorded using electrocardiogram. Body weight, BMI, percentage body fat, resting systolic and diastolic blood pressure and mean arterial pressure were significantly higher (P<0.05) in overweight/obese men compared with lean men. Both groups responded to the TSST with a substantial elevation in salivary cortisol (372%), salivary alpha amylase (123%) and HR (22%). These responses did not differ significantly between the groups (time×treatment interaction for salivary cortisol, salivary alpha amylase and HR; P=0.187, P=0.288, P=0.550, respectively). There were no significant differences between the groups for pretreatment values, peak height, difference between pretreatment values and peak height (reactivity) or area under the curve for salivary cortisol, salivary alpha amylase or HR (P>0.05 for all). The results showed that, for men with a moderate level of overweight/obesity who were otherwise healthy, the response of salivary cortisol, salivary alpha amylase and HR to acute psychological stress was not impaired.

Deconstructing the roles of glucocorticoids in adipose tissue biology and the development of central obesity

Central obesity is associated with insulin resistance and dyslipidemia. Thus, the mechanisms that control fat distribution and its impact on systemic metabolism have importance for understanding the risk for diabetes and cardiovascular disease. Hypercortisolemia at the systemic (Cushing's syndrome) or local levels (due to adipose-specific overproduction via 11β-hydroxysteroid dehydrogenase 1) results in the preferential expansion of central, especially visceral fat depots. At the same time, peripheral subcutaneous depots can become depleted. The biochemical and molecular mechanisms underlying the depot-specific actions of glucocorticoids (GCs) on adipose tissue function remain poorly understood. GCs exert pleiotropic effects on adipocyte metabolic, endocrine and immune functions, and dampen adipose tissue inflammation. GCs also regulate multiple steps in the process of adipogenesis. Acting synergistically with insulin, GCs increase the expression of numerous genes involved in fat deposition. Variable effects of GC on lipolysis are reported, and GC can improve or impair insulin action depending on the experimental conditions. Thus, the net effect of GC on fat storage appears to depend on the physiologic context. The preferential effects of GC on visceral adipose tissue have been linked to higher cortisol production and glucocorticoid receptor expression, but the molecular details of the depot-dependent actions of GCs are only beginning to be understood. In addition, increasing evidence underlines the importance of circadian variations in GCs in relationship to the timing of meals for determining their anabolic actions on the adipocyte. In summary, although the molecular mechanisms remain to be fully elucidated, there is increasing evidence that GCs have multiple, depot-dependent effects on adipocyte gene expression and metabolism that promote central fat deposition. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.

Concurrent and longitudinal associations between diurnal cortisol and body mass index across adolescence

PURPOSE

Childhood and adolescent obesity have reached epidemic levels; however, little is known about the psychobiological underpinnings of obesity in youth and whether these differ from the mechanisms identified in adults. The current study examines concurrent (i.e., measured at the same point in time) and longitudinal (i.e., using earlier cortisol measures to predict later body mass index [BMI]) associations between diurnal cortisol and BMI across adolescence.

METHODS

Adolescent diurnal cortisol was measured over 3 days at each 11, 13, and 15 years. Hierarchical linear modeling was used to extract average measures of predicted morning, afternoon, evening levels of cortisol and the diurnal slope at each assessment. Adolescent BMI (kg/m(2)) was measured at 11, 13, 15, and 18 years. Sex, family socioeconomic status, mother's BMI, pubertal status, and adolescent mental health were examined as possible confounding variables.

RESULTS

Linear regressions revealed that blunted patterns of adolescent cortisol were associated with increased measures of BMI across adolescence both concurrently and longitudinally, particularly when examining measures of cortisol in early adolescence. Multinomial logistic regressions extended the linear regression findings beyond BMI scores to encompass categories of obesity.

CONCLUSIONS

The current study builds on previous research documenting diurnal cortisol-obesity findings in adults by demonstrating similar findings exist both concurrently and longitudinally in adolescents. Findings suggest the association between cortisol and BMI is developmentally influenced and that blunted diurnal cortisol patterns can be identified in overweight individuals at a younger age than previously thought.

Low bone mineral density is associated with metabolic syndrome in South Korean men but not in women: The 2008-2010 Korean National Health and Nutrition Examination Survey

We examined the relationships between bone mineral density (BMD) and metabolic syndrome in 6,659 men and 7,826 women from South Korean. After adjusting for age, body mass index (BMI), tobacco and alcohol use, and regular exercise, low BMD is especially associated with metabolic syndrome in South Korean men.

PURPOSE

This study examined the relationships between BMD and metabolic syndrome (MS) in South Korean adults.

METHODS

A total of 14,485 adults (6,659 men and 7,826 women) in the Korea National Health and Nutrition Examination Survey conducted from 2008 to 2010 were analyzed. We used multivariable regression models to examine the relationship between low BMD and MS. We calculated homeostasis model assessment and insulin resistance (HOMA-IR). MS was defined according to AHA/NHLBI criteria for Asians. BMD was measured at the lumbar spine (LS), femur neck (FN), total hip (TH), trochanter, and intertrochanter.

RESULTS

After adjustment for age, BMI, tobacco and alcohol use, and regular exercise, the TH and FN BMD were significantly lower in men with MS than in men without MS (p < 0.05). However, there were no differences in premenopausal and postmenopausal women. In men, BMD was positively correlated with BMI, and high density lipoprotein cholesterol, but was negatively correlated with insulin, HOMA-IR, and triglyceride at all three sites (p < 0.05). Along with an increase of BMD (0.1 g/cm²), the odds ratios (ORs) for obesity and abdominal obesity were all greater than 1 at all sites in both genders. The ORs for hypertension and MS were 0.937 (0.879-0.998) and 0.899 (0.840-0.962), respectively at FN, and the OR for diabetes mellitus was 1.103 (1.017-1.196) at LS in men. In postmenopausal women, the OR for hypertension was 1.133 (1.029-1.246) at LS.

CONCLUSIONS

Low BMD was especially associated with MS in South Korean men.

Daily life events influence the results of the Dexamethasone Suppression Test in healthy women

Although the Dexamethasone Suppression Test (DST) plays an important role in psychosomatic research, confounding factors limit the sensitivity and specificity of the DST. The aim of this study was to investigate the relationship between the intensity of daily life stressors and DST results in healthy participants after controlling the confounding factors. The subjects of this study consisted of 75 healthy volunteers. The intensity of daily life events was assessed using the Taiwanese version of the Recent Life Change Questionnaire (RLCQ). Neuroticism was assessed using the Maudsley Personality Inventory (MPI). The Dexamethasone Suppression Test (DST) was also performed. The regression model showed that daily life events (RLCQ score) were correlated significantly with cortisol level on day 1 and D% only in women. This finding implies that daily life events should be considered as an independent variable in women in further studies when the DST is applied.

Altered response to neuroendocrine challenge linked to indices of the metabolic syndrome in healthy adults

Metabolic syndrome (MetS) is characterized by central obesity, hypertension, insulin resistance, and hypercholesterolemia. Hypothalamic-pituitary-adrenal (HPA) axis activity is frequently abnormal in MetS, and excessive cortisol exposure may be implicated in metabolic derangements. We investigated the hypothesis that cortisol and adrenocorticotropic hormone (ACTH) responses to a standardized neuroendocrine challenge test would be associated with indices of MetS in a community sample of healthy adults. Healthy adults, 125 men and 170 women, without significant medical problems or chronic medications were recruited from the community. Participants completed the dexamethasone/corticotropin-releasing hormone (Dex/CRH) test, and anthropometric measurements, blood pressure, glycosylated hemoglobin (HbA1c), and cholesterol were measured. Participants reported on their history of early life stress and recent stress, as well as mood and anxiety symptoms. Cortisol and ACTH responses to the Dex/CRH test were negatively associated with measures of central adiposity (p<0.001) and blood pressure (p<0.01), and positively associated with HDL cholesterol (p<0.01). These findings remained significant after controlling for body mass index (BMI). Measures of stress and anxiety and depressive symptoms were negatively correlated with cortisol and ACTH responses in the Dex/CRH test but were not related to MetS indices. That altered HPA axis function is linked to MetS components even in a healthy community sample suggests that these processes may be involved in the pathogenesis of MetS. Identification of premorbid risk processes might allow for detection and intervention prior to the development of disease.

Mediation and moderation of the association between cynical hostility and systolic blood pressure in low-income women

Hostility may be related to risk factors for cardiovascular disease (CVD), such as blood pressure. However, the process by which hostility affects blood pressure is not fully understood. The current study sought to evaluate abdominal obesity (waist-to-hip ratio [WHR]) as a potential mediator and modifier of the relationship between cynical hostility and systolic blood pressure (SBP) in a group of disadvantaged women. Path analysis and multiple regression models were used to identify mediating and moderating pathways in the relationship between cynical hostility and SBP. Results indicate a significant interaction between WHR and cynical hostility. WHR was a partial mediator and significant moderator of the association between hostility and blood pressure. These findings highlight the potential importance of examining abdominal obesity and psychosocial factors as conjunctive determinants of CVD and risk factors for related metabolic conditions.

Occupational Stress

Occupational stress can affect physiological and psychological homeostasis. In addition, the occupational challenges associated with firefighting and law enforcement have been linked to increased mortality ratios for ischemic heart disease when compared with other population cohorts. Laboratory studies have shown that the exacerbation of stress hormones (eg, catecholamines) following dual challenge (physical and psychological stress) may affect immune system responses, which may partially explain the link between cardiovascular disease and inflammation. Physical fitness has been shown to attenuate both cardiovascular and inflammatory cytokine responses following physical and/or psychological stress; however, criteria for safe and effective occupation-specific fitness levels have not been established. In addition, firefighters and police officers have high overweight and obesity rates, which also contribute significantly to the development of cardiovascular disease. Future investigation on the possible interaction (additive or synergistic) of obesity and psychological stress on the development of cardiovascular diseases in these professions is warranted, and a criterion for fitness level should be established for safe and effective participation in occupation-related activities.

A review of weight control strategies and their effects on the regulation of hormonal balance

The estimated prevalence of obesity in the USA is 72.5 million adults with costs attributed to obesity more than 147 billion dollars per year. Though caloric restriction has been used extensively in weight control studies, short-term success has been difficult to achieve, with long-term success of weight control being even more elusive. Therefore, novel approaches are needed to control the rates of obesity that are occurring globally. The purpose of this paper is to provide a synopsis of how exercise, sleep, psychological stress, and meal frequency and composition affect levels of ghrelin, cortisol, insulin GLP-1, and leptin and weight control. We will provide information regarding how hormones respond to various lifestyle factors which may affect appetite control, hunger, satiety, and weight control.

Effects of hyperlipidaemia on glucocorticoid metabolism: results of a randomized controlled trial in healthy young women

OBJECTIVE

It is well established that the hypothalamic-pituitary-adrenal (HPA) axis is altered in obese individuals. Hyperlipidaemia with elevated levels of free fatty acids (FFAs) is also frequently seen in obesity and in the metabolic syndrome. We hypothesized, therefore, that hyperlipidaemia may alter the activity of the HPA axis.

PATIENTS AND METHODS

The effects of hyperlipidaemia, including increased circulating FFAs, on ACTH secretion and cortisol metabolism were analysed in 13 healthy young women during the early follicular phase of two subsequent cycles. We administered a 20% lipid/heparin (LHI) or a saline/heparin infusion (SHI) using a crossover design in random order for 330 min. A detailed characterization of glucocorticoid metabolism was performed by measurement of plasma ACTH, cortisol and urinary excretion rates of adrenal glucocorticoids and the glucocorticoid metabolites.

RESULTS

We observed that LHI-induced hyperlipidaemia elevated serum cortisol levels compared to SHI. No changes in plasma ACTH levels, daily urinary excretion rates of adrenal glucocorticoids, glucocorticoid precursors/metabolites and the calculated activities of the 5α-reductase, 3β-hydroxysteroid dehydrogenase (HSD), 11-, 17-, 21-hydroxylase and 11β-HSD 1 or 2 were found.

CONCLUSION

Our randomized controlled trial suggests that the adrenal sensitivity to ACTH may be enhanced by LHI-induced hyperlipidaemia in normal-weight healthy young women. This effect might contribute to the disturbances of the HPA axis described in women with abdominal obesity and impaired lipid metabolism.

Metabolic syndrome--psycho neuropathogenesis and human brain evolution

AIM

Metabolic syndrome (MS) is a major risk factor for coronary artery disease. Heightened hypothalamo-pituitary-adrenal axis activity is associated with pathogenesis of MS. Life style, food habits and physical activity also play critical role in the pathogenesis of MS. However, the precise neurophysiology behind chronic stress leading on to such effects is unknown.

MATERIALS AND METHODS

Review of recent animal and human studies have shown the subtle differences in morphological changes associated with chronic stress between medial prefrontal cortex and amygdaloid complex.

RESULT

The loss of dendritic spines in pyramidal neurons of medial prefrontal cortex, dendritic hypertrophy in basolateral amygdala and dendritic loss in central nucleus of amygdala causes increased basal output from amygdaloid complex to HPA axis and other targets whose networks are evolutionarily well conserved.

CONCLUSION

The increased HPA axis activity, elevated blood pressure and appetite for high calorie diet leads to MS. The evolution of isocortex in primates and associated regression in size of limbic structures predisposed to increased synaptic noise in amygdaloid complex which in turn cause heighetened output from amygdala during chronic stress.

A nonlinear relationship of generalized and central obesity with diurnal cortisol secretion in the Whitehall II study

CONTEXT

Evidence for an association of measures of generalized and central obesity with salivary cortisol secretion is equivocal.

OBJECTIVE

The objective of this study was to assess the relationship between body mass index (BMI), waist circumference, and salivary cortisol.

DESIGN

The design was a cross-sectional study of BMI, waist circumference, and salivary cortisol from phase 7 (2002-2004) of the Whitehall II study.

SETTING

The occupational cohort was originally recruited in 1985-1988.

PARTICIPANTS

Participants included 2915 men and 1041 women aged 50-74 yr with complete information on height, weight and waist circumference, and cortisol secretion.

OUTCOME MEASURES

Saliva samples were taken on waking, waking plus 0.5, 2.5, 8, and 12 h, and bedtime for the assessment of cortisol. The cortisol awakening response and slope in diurnal secretion were calculated.

RESULTS

After adjustment for age, sex, social position, waking time, and time since waking of sample collection, increasing central and generalized obesity was associated with lower waking cortisol (P = 0.001). U-shaped associations were apparent between diurnal slope in salivary cortisol and both BMI and waist circumference (P < 0.0001 for quadratic term). For example, the shallowest (most adverse) slopes in salivary cortisol were associated with highest (>31 kg/m(2)) and lowest (<21 kg/m(2)) levels of BMI, and the steepest slopes were apparent for those with BMI of 26 kg/m(2), independently of the 12 covariates examined. No associations were apparent for the cortisol awakening response (P > 0.05).

CONCLUSION

The associations of measures of generalized and central obesity with diurnal slope in salivary cortisol are not linear in older adults. These nonlinear associations may explain previously described mixed findings.

The physical activity, stress and metabolic syndrome triangle: a guide to unfamiliar territory for the obesity researcher

Research aimed at deciphering the aetiology of obesity and the metabolic syndrome remains focused on two behavioural factors, namely diet and physical activity, even though epidemiologic research suggests that these two cornerstones of treatment and prevention account for only a small-to-moderate portion of the variance in these phenotypes. In recent years, this observation has prompted the intensified investigation of the pathogenic potential of factors that extend beyond the traditional concept of energy imbalance and examine the putative causes of this imbalance. Psychosocial stress has emerged as one such factor, raising the need for researchers to be informed about this expansive and complex literature. The purpose of this review is twofold (i) To introduce obesity researchers to fundamental concepts and historically important theoretical developments in the stress field and (ii) To outline the dyadic and triadic interactions between stress, physical activity and the metabolic syndrome. Although the expansion of the research focus to multiple, diverse and interacting putative causal agents will certainly increase the complexity of the research enterprise, this step seems essential for the comprehension and effective response to the continuing rise in the prevalence of obesity and the metabolic syndrome.

The cortisol awakening response and the metabolic syndrome in a population-based sample of middle-aged men and women

The objective was to explore the relationship between the cortisol awakening response (CAR) and the metabolic syndrome (MetS) as defined by the National Cholesterol Education Program criteria. The final study sample consisted of 91 women (14 with MetS) and 84 men (15 with MetS), aged 45 to 70 years, from a general population sample. The only exclusion criteria were no consent, pregnancy, or insufficient cortisol testing. On the day of measurement (weekday), salivary cortisol was sampled at awakening and 15 minutes after awakening. Relative CAR (CAR%) and the MetS were the main variables studied. Results showed that, in women with the MetS, cortisol at awakening was significantly lower (mean, 8.92 vs 12.33 nmol/L; P = .05) and the CAR was significantly higher (91.4% vs 36.5%, P < .001) than in women without the syndrome. Significant difference in the relative CAR was also present between men and women with MetS (38.5% and 91.4%, respectively; P = .02). No difference was seen in the awakening response comparing men with and without the MetS. In a regression model, the response to awakening was dependent on the MetS in women (F(1,89) = 13.19, P < .001); but the model was not significant in men. Furthermore, the awakening response was associated with more depressive symptoms in women (F(1,80) = 8.12, P = .01) and with weekday/weekend cortisol sampling in men (F(1,82) = 4.63, P = .03). The association between the relative CAR and the MetS remained significant but somewhat attenuated after adjusting for depressive symptoms (P = .01). Results indicate a sex difference in the CAR% in the presence of the MetS independent of depressive symptoms, a known correlate of the MetS.

Hypothalamic-pituitary-adrenal (HPA) axis functioning in relation to body fat distribution

OBJECTIVE

To relate hypothalamic-pituitary-adrenal (HPA) axis functioning and HPA feedback functioning to body fat distribution in normal weight to obese subjects.

PATIENTS

91 men and 103 women [age 18-45 years, BMI 19-35 kg/m(2), waist-to-hip ratio (WHR) 0.6-1.1].

MEASUREMENTS

Anthropometry, body composition using hydrodensitometry and deuterium dilution method, cortisol variability by measuring 5-h cortisol concentrations, HPA axis feedback functioning using a dexamethasone suppression test, and HPA axis functioning under a challenged condition consisting of a standardized high-intensity test with ingestion of 4 mg dexamethasone.

RESULTS

In men, an inverse relationship was observed between 5-h cortisol exposure (nmol/ml) and fat mass index (FMI) (kg/m(2)) (r = -0.55, P < 0.001). In women, relationships were observed between 5-h cortisol exposure (nmol/ml.min) and WHR (r = -0.49, P < 0.001), maximal workload (r = 0.32, P < 0.001) as well as oral contraceptive use (r = 0.38, P < 0.001). Similarly, in men, an inverse relationship was observed between negative feedback expressed as baseline concentrations minus post dexamethasone cortisol concentrations (nmol/ml) and FMI (r = -0.53, P < 0.001). In women, relationships were observed between negative feedback expressed as baseline concentrations minus post dexamethasone cortisol concentrations (nmol/ml) and WHR (r = -0.43, P < 0.001), maximal workload (r = 0.30, P < 0.001) as well as oral contraceptive use (r = 0.43, P < 0.001) in women. Moreover, an inverse relationship was observed between HPA axis functioning in a challenged condition expressed as percentage increase of cortisol concentrations after standardized high-intensity test with ingestion of 4 mg dexamethasone (%) and waist circumference (r = -0.21, P < 0.10) in men and WHR (r = -0.21, P < 0.05) in women. In men, strong positive relationships were observed between FMI and waist circumference (r = 0.85, P < 0.001), as well as waist-to-hip ratio (r = 0.70, P < 0.001).

CONCLUSION

Disturbance of HPA axis functioning under basal and challenged conditions is related to visceral fat accumulation.

Do US Black Women Experience Stress-Related Accelerated Biological Aging?: A Novel Theory and First Population-Based Test of Black-White Differences in Telomere Length

We hypothesize that black women experience accelerated biological aging in response to repeated or prolonged adaptation to subjective and objective stressors. Drawing on stress physiology and ethnographic, social science, and public health literature, we lay out the rationale for this hypothesis. We also perform a first population-based test of its plausibility, focusing on telomere length, a biomeasure of aging that may be shortened by stressors. Analyzing data from the Study of Women's Health Across the Nation (SWAN), we estimate that at ages 49-55, black women are 7.5 years biologically "older" than white women. Indicators of perceived stress and poverty account for 27% of this difference. Data limitations preclude assessing objective stressors and also result in imprecise estimates, limiting our ability to draw firm inferences. Further investigation of black-white differences in telomere length using large-population-based samples of broad age range and with detailed measures of environmental stressors is merited.

Do US Black Women Experience Stress-Related Accelerated Biological Aging?: A Novel Theory and First Population-Based Test of Black-White Differences in Telomere Length

We hypothesize that black women experience accelerated biological aging in response to repeated or prolonged adaptation to subjective and objective stressors. Drawing on stress physiology and ethnographic, social science, and public health literature, we lay out the rationale for this hypothesis. We also perform a first population-based test of its plausibility, focusing on telomere length, a biomeasure of aging that may be shortened by stressors. Analyzing data from the Study of Women's Health Across the Nation (SWAN), we estimate that at ages 49-55, black women are 7.5 years biologically "older" than white women. Indicators of perceived stress and poverty account for 27% of this difference. Data limitations preclude assessing objective stressors and also result in imprecise estimates, limiting our ability to draw firm inferences. Further investigation of black-white differences in telomere length using large-population-based samples of broad age range and with detailed measures of environmental stressors is merited.

Neuroadrenergic dysfunction in obesity: an overview of the effects of weight loss

PURPOSE OF REVIEW

The prevalence of obesity is rising to epidemic proportions worldwide, and in tandem so is that of type 2 diabetes. Neuroadrenergic abnormalities, comprising increased resting sympathetic nervous system activity and blunted sympathetic neural responsiveness are recognized features of metabolic syndrome obesity, which contribute importantly to both the pathophysiology and adverse clinical prognosis of this high-risk population. Weight loss is recommended as first-line treatment for obesity. This review examines the effects of nonpharmacological weight loss on sympathetic nervous system function under basal and stimulated conditions.

RECENT FINDINGS

Human weight loss trials show that even moderate weight reduction is accompanied by significant attenuation in resting whole-body norepinephrine spillover rate and muscle sympathetic nerve activity, an improvement in cardiac autonomic modulation, and a reversal of blunted sympathetic responsiveness at both peripheral and central nervous system levels. Recent findings underscore the relevance of insulin resistance in mediating blunted sympathetic responsiveness to endogenous hyperinsulinemia induced by glucose ingestion. Impaired insulin transport across the blood-brain barrier may be one mechanism mediating these effects. Weight loss reverses blunted sympathetic responsiveness to glucose, which has implications for postprandial energy expenditure and body weight homeostasis.

SUMMARY

The autonomic dysfunction of obesity is reversible with weight loss, highlighting the importance of lifestyle intervention as a key therapeutic modality.

Measures of social position and cortisol secretion in an aging population: findings from the Whitehall II study

OBJECTIVE

To examine whether dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis associated with disadvantaged social position in working populations also occurs in older age groups.

METHODS

This study examines the association of several indicators of social position with two measures of cortisol secretion, a product of the HPA axis. We examined the cortisol awakening response (CAR), and slope of the decline in cortisol secretion across the day. We examine whether the association is mediated by behavioral, psychosocial, and biological factors in 3992 participants of phase 7 (2002-2004) of the Whitehall II study, who provided six salivary cortisol samples across the day.

RESULTS

In this older cohort (mean age = 61 years; range = 50-74 years), lowest social position (assessed by current or previous occupational grade and wealth) was associated with a flatter slope in the decline in cortisol secretion. For example, over the course of the day, men in the lowest employment grades had a reduction in their cortisol by 0.125 (nmol/L/h), which was a shallower slope than those in the high grades (-0.129 nmol/L/h). The difference in slopes by employment grade among men, but not women, was statistically significant (p = .003). The difference in slopes was explained primarily by poor health and sleep behaviors, although financial insecurity also played a role. No effects were apparent with the CAR or other measures of social position.

CONCLUSIONS

In men, poorer health and sleep behaviors (primarily smoking and short sleep duration), and financial insecurity mediate the impact of occupational status and wealth on cortisol secretion.

Pathogenesis of adolescent idiopathic scoliosis in girls - a double neuro-osseous theory involving disharmony between two nervous systems, somatic and autonomic expressed in the spine and trunk: possible dependency on sympathetic nervous system and hormones with implications for medical therapy

Anthropometric data from three groups of adolescent girls - preoperative adolescent idiopathic scoliosis (AIS), screened for scoliosis and normals were analysed by comparing skeletal data between higher and lower body mass index subsets. Unexpected findings for each of skeletal maturation, asymmetries and overgrowth are not explained by prevailing theories of AIS pathogenesis. A speculative pathogenetic theory for girls is formulated after surveying evidence including: (1) the thoracospinal concept for right thoracic AIS in girls; (2) the new neuroskeletal biology relating the sympathetic nervous system to bone formation/resorption and bone growth; (3) white adipose tissue storing triglycerides and the adiposity hormone leptin which functions as satiety hormone and sentinel of energy balance to the hypothalamus for long-term adiposity; and (4) central leptin resistance in obesity and possibly in healthy females. The new theory states that AIS in girls results from developmental disharmony expressed in spine and trunk between autonomic and somatic nervous systems. The autonomic component of this double neuro-osseous theory for AIS pathogenesis in girls involves selectively increased sensitivity of the hypothalamus to circulating leptin (genetically-determined up-regulation possibly involving inhibitory or sensitizing intracellular molecules, such as SOC3, PTP-1B and SH2B1 respectively), with asymmetry as an adverse response (hormesis); this asymmetry is routed bilaterally via the sympathetic nervous system to the growing axial skeleton where it may initiate the scoliosis deformity (leptin-hypothalamic-sympathetic nervous system concept = LHS concept). In some younger preoperative AIS girls, the hypothalamic up-regulation to circulating leptin also involves the somatotropic (growth hormone/IGF) axis which exaggerates the sympathetically-induced asymmetric skeletal effects and contributes to curve progression, a concept with therapeutic implications. In the somatic nervous system, dysfunction of a postural mechanism involving the CNS body schema fails to control, or may induce, the spinal deformity of AIS in girls (escalator concept). Biomechanical factors affecting ribs and/or vertebrae and spinal cord during growth may localize AIS to the thoracic spine and contribute to sagittal spinal shape alterations. The developmental disharmony in spine and trunk is compounded by any osteopenia, biomechanical spinal growth modulation, disc degeneration and platelet calmodulin dysfunction. Methods for testing the theory are outlined. Implications are discussed for neuroendocrine dysfunctions, osteopontin, sympathoactivation, medical therapy, Rett and Prader-Willi syndromes, infantile idiopathic scoliosis, and human evolution. AIS pathogenesis in girls is predicated on two putative normal mechanisms involved in trunk growth, each acquired in evolution and unique to humans.

Association between common mental disorder and obesity over the adult life course

BACKGROUND

Prospective data on the association between common mental disorders and obesity are scarce, and the impact of ageing on this association is poorly understood.

AIMS

To examine the association between common mental disorders and obesity (body mass index > or = 30 kg/m(2)) across the adult life course.

METHOD

The participants, 6820 men and 3346 women, aged 35-55 were screened four times during a 19-year follow-up (the Whitehall II study). Each screening included measurements of mental disorders (the General Health Questionnaire), weight and height.

RESULTS

The excess risk of obesity in the presence of mental disorders increased with age (P = 0.004). The estimated proportion of people who were obese was 5.7% at age 40 both in the presence and absence of mental disorders, but the corresponding figures were 34.6% and 27.1% at age 70. The excess risk did not vary by gender or according to ethnic group or socioeconomic position.

CONCLUSIONS

The association between common mental disorders and obesity becomes stronger at older ages.

Reproducibility of Morning Blood Pressure Surge and Its Relation to Blood Pressure Reactivity

This study examined the stability of the morning blood pressure surge (MBPS) and its relation to blood pressure (BP) reactivity in untreated hypertensives. Thirty-six participants completed a stress task at baseline. Ambulatory BP monitoring was carried out three times on a weekday. The MBPS demonstrated small reproducibility and large coefficient of variation. The MBPS correlated with nighttime BP (p = 0.001) but not morning BP or BP reactivity. Dippers had greater MBPS than did nondippers (p < 0.05). The MBPS provides distinct information that is different from the BP response to mental stress.

Salivary cortisol differs with age and sex and shows inverse associations with WHR in Swedish women: a cross-sectional study

BACKGROUND

Most studies on cortisol have focused on smaller, selected samples. We therefore aimed to sex-specifically study the diurnal cortisol pattern and explore its association with abdominal obesity in a large unselected population.

METHODS

In 2001-2004, 1811 men and women (30-75 years) were randomly selected from the Vara population, south-western Sweden (81% participation rate). Of these, 1671 subjects with full information on basal morning and evening salivary cortisol and anthropometric measurements were included in this cross-sectional study. Differences between groups were examined by general linear model and by logistic and linear regression analyses.

RESULTS

Morning and Delta-cortisol (morning - evening cortisol) were significantly higher in women than men. In both genders older age was significantly associated with higher levels of all cortisol measures, however, most consistently with evening cortisol. In women only, age-adjusted means of WHR were significantly lower in the highest compared to the lowest quartile of morning cortisol (p = 0.036) and Delta-cortisol (p < 0.001), respectively. Furthermore, when comparing WHR above and below the mean, the age-adjusted OR in women for the lowest quartile of cortisol compared to the highest was 1.5 (1.0-2.2, p = 0.058) for morning cortisol and 1.9 (1.3-2.8) for Delta-cortisol. All findings for Delta-cortisol remained after adjustments for multiple covariates and were also seen in a linear regression analysis (p = 0.003).

CONCLUSION

In summary, our findings of generally higher cortisol levels in women than men of all ages are novel and the stronger results seen for Delta-cortisol as opposed to morning cortisol in the association with WHR emphasise the need of studying cortisol variation intra-individually. To our knowledge, the associations in this study have never before been investigated in such a large population sample of both men and women. Our results therefore offer important knowledge on the descriptive characteristics of cortisol in relation to age and gender, and on the impact that associations previously seen between cortisol and abdominal obesity in smaller, selected samples have on a population level.

Enhanced cortisol production rates, free cortisol, and 11beta-HSD-1 expression correlate with visceral fat and insulin resistance in men: effect of weight loss

Controversy exists as to whether endogenous cortisol production is associated with visceral obesity and insulin resistance in humans. We therefore quantified cortisol production and clearance rates, abdominal fat depots, insulin sensitivity, and adipocyte gene expression in a cohort of 24 men. To test whether the relationships found are a consequence rather than a cause of obesity, eight men from this larger group were studied before and after weight loss. Daily cortisol production rates (CPR), free cortisol levels (FC), and metabolic clearance rates (MCR) were measured by stable isotope methodology and 24-h sampling; intra-abdominal fat (IAF) and subcutaneous fat (SQF) by computed tomography; insulin sensitivity (S(I)) by frequently sampled intravenous glucose tolerance test; and adipocyte 11beta-hydroxysteroid dehydrogenase-1 (11beta-HSD-1) gene expression by quantitative RT-PCR from subcutaneous biopsies. Increased CPR and FC correlated with increased IAF, but not SQF, and with decreased S(I). Increased 11beta-HSD-1 gene expression correlated with both IAF and SQF and with decreased S(I). With weight loss, CPR, FC, and MCR did not change compared with baseline; however, with greater loss in body fat than lean mass during weight loss, both CPR and FC increased proportionally to final fat mass and IAF and 11beta-HSD-1 decreased compared with baseline. These data support a model in which increased hypothalamic-pituitary-adrenal activity in men promotes selective visceral fat accumulation and insulin resistance and may promote weight regain after diet-induced weight loss, whereas 11beta-HSD-1 gene expression in SQF is a consequence rather than cause of adiposity.

Psychological coping styles and cortisol over the day in healthy older adults

Patterns of psychological coping are associated with a variety of health outcomes but the underlying pathways are not yet established. The purpose of this study was to assess the relationship between salivary cortisol output over the course of a day and coping style. Data were available from 350 men and 192 women with an average age of 60.9 years. Participants were drawn from the Whitehall II cohort, and had no history of cardiovascular disease. Individuals who were taking medication that might affect cortisol levels were also excluded. Saliva samples were provided on waking, then 0.5, 2.5, 8 and 12h after waking, and just before the participant went to sleep. Coping style was measured with a standard instrument, the COPE, and data were factor analysed to generate three factors: seeking social support, problem engagement and problem avoidance. The relationships between these factors and the cortisol awakening response (CAR), the slope of cortisol change over the day and total cortisol output over the day (excluding the waking period) were assessed using multiple linear regression. Cortisol output over the day was inversely associated with coping with stress by seeking social support (p=0.034) and by problem engagement (p=0.003), independently of age, gender, body mass index, smoking, depression, self-rated health, time of waking and income. Individuals who coped by problem engagement and seeking support had lower cortisol levels. Additionally, gender, BMI, smoking, self-rated health and time of waking were independently related to cortisol output over the day. There were no significant associations between coping and the CAR or cortisol slope over the day. The results indicate that adaptive coping styles are related to low levels of cortisol over the day, suggesting that neuroendocrine pathways may partly mediate relationships between psychological coping and health.

Maternal obesity, length of gestation, risk of postdates pregnancy and spontaneous onset of labour at term

OBJECTIVE

To investigate the effect of maternal body mass index (BMI) on postdates pregnancy, length of gestation and likelihood of spontaneous onset of labour at term.

DESIGN

Retrospective cohort study.

SETTING

Swedish Medical Birth Register.

POPULATION

A total of 186 087 primiparous women (of whom 143 519 had spontaneous onset of labour at term) who gave birth between 1998 and 2002.

METHODS

Mann-Whitney test, one-way analysis of variance, linear regression and single variable logistic regression.

MAIN OUTCOME MEASURES

Postdates pregnancy (>/=294 days or 42(+0) weeks), length of gestation and likelihood of spontaneous onset of labour at term.

RESULTS

About 6.8% of pregnancies delivered postdates. Higher maternal BMI (kg/m(2)) during the first trimester was associated with longer gestation (P < 0.001) as was a greater change in BMI between the first and third trimesters (BMI measured on admission prior to delivery) with mean (SD) gestation at delivery of 280.7 (8.6) and 283.2 (8.6) days for increases in BMI of <2 and >/=10 kg/m(2), respectively. Higher BMI during the first trimester was associated with a lower chance of spontaneous onset of labour at term. Compared with BMI 20 to <25 kg/m(2), the odds ratios (95% CI) for spontaneous onset of labour at term were 1.21 (1.15-1.27) for BMI of <20 kg/m(2), 0.71 (0.69-0.74) for BMI of 25 to <30 kg/m(2), 0.57 (0.54-0.60) for BMI of 30 to <35 kg/m(2) and 0.43 (0.40-0.47) for BMI of >/=35 kg/m(2). Higher BMI during the first trimester (BMI of >/=35 kg/m(2) compared with BMI of 20 to <25 kg/m(2)) was also associated with an increased risk of complications including stillbirth (OR 3.90, 95% CI 2.44-6.22), gestational diabetes (OR 5.61, 95% CI 4.61-6.83) and caesarean section (OR 2.39; 95% CI 2.20-2.59).

CONCLUSIONS

Higher maternal BMI in the first trimester and a greater change in BMI during pregnancy were associated with longer gestation and an increased risk of postdates pregnancy. Higher maternal BMI during the first trimester was also associated with decreased likelihood of spontaneous onset of labour at term and increased likelihood of complications.