Body fat distribution, insulin resistance, and metabolic diseases

Gender Differences in the Control of Energy Homeostasis

The world is experiencing an epidemic of obesity and its concomitant health problems. One implication is that the normally robust negative feedback system that controls energy homeostasis must be responding to different inputs than in the past. In this review we discuss the influence of gender on the efficacy of adiposity hormones as they interact with food intake control systems in the brain. Specifically, the levels of insulin and leptin in the blood are correlated with body fat, insulin being related mainly to visceral fat and leptin to subcutaneous fat. Since females carry more fat subcutaneously and males carry more fat viscerally, leptin correlates better with total body fat in females and insulin correlates better in males. High visceral fat and plasma insulin are also risk factors for the complications of obesity, including type-2 diabetes, cardiovascular problems, and certain cancers, and these are more prevalent in males. Consistent with these systemic differences, the brains of females are more sensitive to the catabolic actions of low doses of leptin whereas the brains of males are more sensitive to the catabolic action of low doses of insulin. The implications of this are discussed.

Psychosocial stress in South African patients with type 2 diabetes

Objective: Diabetes mellitus is considered an emotionally and behaviourally demanding condition which adds to the stress of a patient’s daily living. There is a paucity of literature in South Africa regarding stress and diabetes. This study therefore aims to identify the areas and contributory factors of psychosocial stress in South African patients with diabetes.Method: A cross-sectional study was conducted at two public facilities and five private medical practices on the north coast of KwaZulu-Natal, South Africa. The Questionnaire on Stress in Diabetes – Revised was administered to 401 participants.Results: Eighteen percent of the sample reported having extreme psychosocial stress. Depression, physical complaints and self-medication/diet were the main areas which contributed to high psychosocial stress. Factors that also contributed to high levels of psychosocial stress were low educational level, unemployment, female gender, attending the public sector and high HbA1c levels.Conclusion: Psychosocial stress affects metabolic control in patients with diabetes, thereby increasing the risks of long-term complications.

11β-Hydroxysteroid Dehydrogenase Type 1(11β-HSD1) mediates insulin resistance through JNK activation in adipocytes

Glucocorticoids are used to treat a number of human diseases but often lead to insulin resistance and metabolic syndrome. 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is a key enzyme that catalyzes the intracellular conversion of cortisone to physiologically active cortisol. Despite the known role of 11β-HSD1 and active glucocorticoid in causing insulin resistance, the molecular mechanisms by which insulin resistance is induced remain elusive. The aim of this study is to identify these mechanisms in high fat diet (HFD) experimental models. Mice on a HFD were treated with 11β-HSD1 inhibitor as well as a JNK inhibitor. We then treated 3T3-L1-derived adipocytes with prednisone, a synthetic glucocorticoid, and cells with 11β-HSD1 overexpression to study insulin resistance. Our results show that 11β-HSD1 and JNK inhibition mitigated insulin resistance in HFD mice. Prednisone stimulation or overexpression of 11β-HSD1 also caused JNK activation in cultured adipocytes. Inhibition of 11β-HSD1 blocked the activation of JNK in adipose tissue of HFD mice as well as in cultured adipocytes. Furthermore, prednisone significantly impaired the insulin signaling pathway, and these effects were reversed by 11β-HSD1 and JNK inhibition. Our study demonstrates that glucocorticoid-induced insulin resistance was dependent on 11β-HSD1, resulting in the critical activation of JNK signaling in adipocytes.

Energetic stress: The reciprocal relationship between energy availability and the stress response

The worldwide epidemic of metabolic syndromes and the recognized burden of mental health disorders have driven increased research into the relationship between the two. A maladaptive stress response is implicated in both mental health disorders and metabolic disorders, implicating the hypothalamic-pituitary-adrenal (HPA) axis as a key mediator of this relationship. This review explores how an altered energetic state, such as hyper- or hypoglycemia, as may be manifested in obesity or diabetes, affects the stress response and the HPA axis in particular. We propose that changes in energetic state or energetic demands can result in "energetic stress" that can, if prolonged, lead to a dysfunctional stress response. In this review, we summarize the role of the hypothalamus in modulating energy homeostasis and then briefly discuss the relationship between metabolism and stress-induced activation of the HPA axis. Next, we examine seven mechanisms whereby energetic stress interacts with neuroendocrine stress response systems, including by glucocorticoid signaling both within and beyond the HPA axis; by nutrient-induced changes in glucocorticoid signaling; by impacting the sympathetic nervous system; through changes in other neuroendocrine factors; by inducing inflammatory changes; and by altering the gut-brain axis. Recognizing these effects of energetic stress can drive novel therapies and prevention strategies for mental health disorders, including dietary intervention, probiotics, and even fecal transplant.

Assessing the Causality Factors in the Association between (Abdominal) Obesity and Physical Activity among the Newfoundland Population-A Mendelian Randomization Analysis

A total of 1,263 adults from Newfoundland and Labrador were studied in the research. Body mass index (BMI) and percent trunk fat (PTF) were analyzed as biomarkers for obesity. The Mendelian randomization (MR) approach with two single-nucleotide polymorphisms in the fat-mass and obesity (FTO) gene as instruments was employed to assess the causal effect. In both genders, increasing physical activity significantly reduced BMI and PTF when adjusted for age and the FTO gene. The effect of physical activity was stronger on PTF than BMI. Direct observational analyses showed significant increase in BMI/PTF when physical activity decreased. A similar association in MR analyses was not significant. The association between physical activity and BMI/PTF could be due to reversed causality or common confounding factors. Our study provides insights into the causal contributions of obesity to physical activity in adults. Health intervention strategies to increase physical activity among adults should include some other plans such as improving diet for reducing obesity.

Self-Perceived Emotional Distress and Diabetes Risk Among Young Men

INTRODUCTION

There are mixed data regarding the effect of emotional distress on diabetes risk, especially among young adults. This study assessed the effect of self-perceived emotional distress on diabetes incidence among young men.

METHODS

Incident diabetes during a mean follow-up of 6.3 (4.3) years was assessed among 32,586 men (mean age, 31.0 [5.6] years) of the Metabolic, Lifestyle, and Nutrition Assessment in Young Adults cohort with no history of diabetes between 1995 and 2011. Emotional distress was assessed by asking participants as part of a computerized questionnaire: Are you preoccupied by worries or concerns that affect your overall wellbeing? Time-dependent Cox models were applied. Data analysis took place between 2014 and 2015.

RESULTS

There were 723 cases of diabetes during 206,382 person-years. The presence of distress was associated with a 53% higher incidence of diabetes (95% CI=1.08, 2.18, p=0.017) after adjustment for age, BMI, fasting plasma glucose, family history of diabetes, triglyceride and high-density lipoprotein cholesterol levels, education, cognitive performance, white blood cell count, physical activity, and sleep quality. These results persisted when distress, BMI, physical activity, and smoking status were treated as time-dependent variables (hazard ratio=1.66, 95% CI=1.21, 2.17, p=0.002). An adjusted hazard ratio of 2.14 (95% CI=1.04, 4.47, p=0.041) for incident diabetes was observed among participants persistently reporting emotional distress compared with those persistently denying it.

CONCLUSIONS

Sustained emotional distress contributes to the development of diabetes among young and apparently healthy men in a time-dependent manner. These findings warrant awareness by primary caregivers when stratifying diabetes risk.

Fasting-induced liver GADD45β restrains hepatic fatty acid uptake and improves metabolic health

Recent studies have demonstrated that repeated short‐term nutrient withdrawal (i.e. fasting) has pleiotropic actions to promote organismal health and longevity. Despite this, the molecular physiological mechanisms by which fasting is protective against metabolic disease are largely unknown. Here, we show that, metabolic control, particularly systemic and liver lipid metabolism, is aberrantly regulated in the fasted state in mouse models of metabolic dysfunction. Liver transcript assays between lean/healthy and obese/diabetic mice in fasted and fed states uncovered “growth arrest and DNA damage‐inducible” GADD45β as a dysregulated gene transcript during fasting in several models of metabolic dysfunction including ageing, obesity/pre‐diabetes and type 2 diabetes, in both mice and humans. Using whole‐body knockout mice as well as liver/hepatocyte‐specific gain‐ and loss‐of‐function strategies, we revealed a role for liver GADD45β in the coordination of liver fatty acid uptake, through cytoplasmic retention of FABP1, ultimately impacting obesity‐driven hyperglycaemia. In summary, fasting stress‐induced GADD45β represents a liver‐specific molecular event promoting adaptive metabolic function.

Associations of smoking with overall obesity, and central obesity: a cross-sectional study from the Korea National Health and Nutrition Examination Survey (2010-2013)

OBJECTIVES

The association between smoking and obesity is a significant public health concern. Both are preventable risk factors of cardiovascular disease and a range of other conditions. However, despite numerous previous studies, no consensus has emerged regarding the effect of smoking on obesity. We therefore carried out a novel study evaluating the relationship between smoking and obesity.

METHODS

A total of 5,254 subjects aged 19 years or older drawn from the 2010-2013 Korea National Health and Nutrition Examination Survey were included in this cross-sectional study. Smoking was examined both in terms of smoking status and the quantity of cigarettes smoked by current smokers. Multiple logistic regression analysis was used to assess the association between smoking and obesity. Overall obesity was defined as a body mass index (BMI) ≥25 kg/m(2), and central obesity was defined as a waist circumference ≥90 cm for males and ≥85 cm for females. We adjusted for the possible confounding effects of age, sex, physical activity, alcohol consumption, and the presence of hypertension or diabetes.

RESULTS

A statistically significant difference in central obesity according to smoking status was identified. Current smokers were more likely to be centrally obese than never-smokers (adjusted odds ratio,1.30; 95% confidence interval, 1.02 to 1.67). However, no significant association was found between smoking and obesity defined by BMI. Moreover, among current smokers, no statistically significant association was found between the daily amount of smoking and obesity or central obesity.

CONCLUSIONS

Smoking was positively associated with central obesity. Current smokers should be acquainted that they may be more prone to central obesity.

Moderate Exercise Prevents Functional Remodeling of the Anterior Pituitary Gland in Diet-Induced Insulin Resistance in Rats: Role of Oxidative Stress and Autophagy

A sustained elevation of glucocorticoid production, associated with the establishment of insulin resistance (IR) could add to the deleterious effects of the IR state. The aim of this study is to analyze the consequences of long-term feeding with a sucrose-rich diet (SRD) on Pomc/ACTH production, define the underlying cellular processes, and determine the effects of moderate exercise (ME) on these parameters. Animals fed a standard chow with or without 30% sucrose in the drinking water were subjected to ME. Circulating hormone levels were determined, and pituitary tissues were processed and analyzed by immunobloting and quantitative real-time PCR. Parameters of oxidative stress (OxS), endoplasmic reticulum stress, and autophagy were also determined. Rats fed SRD developed a decrease in pituitary Pomc/ACTH expression levels, increased expression of antioxidant enzymes, and induction of endoplasmic reticulum stress and autophagy. ME prevented pituitary dysfunction as well as induction of antioxidant enzymes and autophagy. Reporter assays were performed in AtT-20 corticotroph cells incubated in the presence of palmitic acid. Pomc transcription was inhibited by palmitic acid-dependent induction of OxS and autophagy, as judged by the effect of activators and inhibitors of both processes. Long-term feeding with SRD triggers the generation of OxS and autophagy in the pituitary gland, which could lead to a decline in Pomc/ACTH/glucocorticoid production. These effects could be attributed to an increase in fatty acids availability to the pituitary gland. ME was able to prevent these alterations, suggesting additional beneficial effects of ME as a therapeutic strategy in the management of IR.

Comparing the Ability of Anthropometric Indicators in Identifying Metabolic Syndrome in HIV Patients

BACKGROUND

Highly active antiretroviral therapy (HAART) can cause side effects in HIV patients, as the metabolic syndrome. Early identification of risk for development of cardiovascular diseases using available reliable and practical methods is fundamental. On this basis, the aim of this study was to compare the effectiveness of anthropometric indicators to identify metabolic syndrome in HIV patients on HAART.

METHODS

It is a cross-sectional study. A number of 280 stable HIV patients were studied. It measured weight, height, waist circumference (WC), hip circumference (HP), thigh circumference (TC) and calculated body mass index (BMI), body adiposity index (BAI), waist to hip ratio (WHR) and waist to thigh ratio (WTR). There was also a performance of biochemical tests of lipid profile and fasting glucose. Systemic blood pressure was measured. The criteria proposed by the National Cholesterol Education Program III (NCEP-ATP III) to metabolic syndrome classification was used. Individuals were divided in groups with or without metabolic alterations and their anthropometric indicators were compared. Receiver operating characteristic (ROC) curves were designed for each anthropometric indicator using the metabolic syndrome classification to identify sensitivity and specificity.

RESULTS

WC was a good tool to identify each metabolic disorder separately: total cholesterol (only females, p<0.05), triglycerides (only males, p<0.001), HDL cholesterol (p<0.05), LDL cholesterol (p<005) and fasting glycemic (p<005). WC also showed the best performance to identify metabolic syndrome in both genders (areas under the curve (AUCs): 0.79 and 0.76 for male and female, respectively), while BAI proved to be an inadequate indicator (AUCs: 0.63 and 0.67 for males and females), respectively, in this population.

CONCLUSIONS

The central adiposity measure (WC) had the best performance to identify metabolic syndrome, and it is a convenient, cheap and reliable tool that can be used in clinical practice routinely to prevent cardiovascular complications in HIV patients.

An 8-Year Prospective Study of Depressive Symptoms and Change in Insulin From Adolescence to Young Adulthood

OBJECTIVE

To evaluate whether depressive symptoms predict change in fasting insulin among adolescents followed into young adulthood. We hypothesized that higher depressive symptoms would predict increased insulin and that puberty and race/ethnicity would moderate this relationship.

METHODS

Data came from the Princeton School District Study, a school-based longitudinal cohort of non-Hispanic black and white adolescents (2001-2011). Depressive symptoms, fasting insulin, and body mass index were measured at baseline (adolescence) and 8 years later (young adulthood) in 685 participants. Puberty was assessed using a validated protocol measuring sex steroids and physical changes. The primary outcome was change in fasting insulin. Analyses accounted for age, sex, race, parental education, baseline insulin, body mass index z score, puberty, and time to follow-up.

RESULTS

At baseline, depressive symptoms were correlated with insulin (ρ = 0.13, p = .001). High baseline insulin predicted insulin change (B = -11.50, standard error [SE] = 2.30, p < .001). Depressive symptoms also predicted insulin change, but only for pubertal adolescents (B = -0.23, SE = 0.11, p = .038). This relationship was moderated by race (p = .047); depressive symptoms predicted insulin change only among pubertal black adolescents (p = .030), not white (p = .49), and in the direction opposite that hypothesized (Bblacks = -0.51, SE = 0.23). Post hoc analyses revealed that pubertal black adolescents with high depressive symptoms had the highest baseline insulin, which stayed high across the follow-up period.

CONCLUSIONS

Among pubertal black adolescents, elevated depressive symptoms are associated with increased risk for sustained hyperinsulinemia from adolescence into adulthood. These youths may be particularly vulnerable for Type 2 diabetes.

An economy of scales: A selective review of obesity's economic causes, consequences, and solutions

This paper reviews the economic research on obesity, covering topics such as the measurement of, and trends in, obesity, the economic causes of obesity (e.g. the monetary price and time cost of food, food assistance programs, income, education, macroeconomic conditions, and peer effects), and the economic consequences of obesity (e.g. lower wages, a lower probability of employment, and higher medical care costs). It also examines the extent to which obesity imposes negative externalities, and economic interventions that could potentially internalize such externalities, such as food taxes, subsidies for school-based physical activity programs, and financial rewards for weight loss. It discusses other economic rationales for government intervention with respect to obesity, such as imperfect information, time inconsistent preferences, and irrational behavior. It concludes by proposing a research agenda for the field. Overall, the evidence suggests that there is no single dominant economic cause of obesity; a wide variety of factors may contribute a modest amount to the risk. There is consistent evidence regarding the economic consequences of obesity, which are lower wages and higher medical care costs that impose negative externalities through health insurance. Studies of economic approaches to preventing obesity, such as menu labeling, taxes on energy-dense foods, and financial rewards for weight loss find only modest effects on weight and thus a range of policies may be necessary to have a substantial effect on the prevalence of obesity.

Social exclusion changes histone modifications H3K4me3 and H3K27ac in liver tissue of wild house mice

Wild house mice form social hierarchies with aggressive males defending territories, in which females, young mice and submissive adult males share nests. In contrast, socially excluded males are barred from breeding groups, have numerous bite wounds and patches of thinning fur. Since their feeding times are often disrupted, we investigated whether social exclusion leads to changes in epigenetic marks of metabolic genes in liver tissue. We used chromatin immunoprecipitation and quantitative PCR to measure enrichment of two activating histone marks at 15 candidate loci. The epigenetic profiles of healthy males sampled from nest boxes differed significantly from the profiles of ostracized males caught outside of nests and showing bite wounds indicative of social exclusion. Enrichment of histone-3 lysine-4 trimethylation (H3K4me3) changed significantly at genes Cyp4a14, Gapdh, Nr3c1, Pck1, Ppara, and Sqle. Changes at histone-3 lysine-27 acetylation (H3K27ac) marks were detected at genes Fasn, Nr3c1, and Plin5. A principal components analysis separated the socialized from the ostracized mice. This was independent of body weight for the H3K4me3 mark, and partially dependent for H3K27ac. There was no separation, however, between healthy males that had been sampled from two different nests. A hierarchical cluster analysis also separated the two phenotypes, which was independent of body weight for both markers. Our study shows that a period of social exclusion during adult life leads to quantitative changes in histone modification patterns in mouse liver tissue. Similar epigenetic changes might occur during the development of stress-induced metabolic disorders in humans.

Impact of exercise training without caloric restriction on inflammation, insulin resistance and visceral fat mass in obese adolescents

BACKGROUND

Exercise training has been shown to improve cardiometabolic health in obese adolescents.

OBJECTIVES

Evaluate the impact of a 12-week exercise-training programme (without caloric restriction) on obese adolescents' cardiometabolic and vascular risk profiles.

METHODS

We measured systemic markers of oxidation, inflammation, metabolic variables and endothelial function in 20 obese adolescents (OB) (age: 14.5 ± 1.5 years; body mass index: 34.0 ± 4.7 kg m(-2) ) and 20 age- and gender-matched normal-weight adolescents (NW). Body composition was assessed by magnetic resonance imagery. Peak aerobic capacity and maximal fat oxidation were evaluated during specific incremental exercise tests. OB participated in a 12-week exercise-training programme.

RESULTS

OB presented lower peak aerobic capacity (24.2 ± 5.9 vs. 39.8 ± 8.3 mL kg(-1)  min(-1) , P < 0.05) and maximal fat oxidation compared with NW (P < 0.05). OB displayed greater F2t-Isoprostanes (20.5 ± 6.7 vs. 13.4 ± 4.2 ng mmol(-1) creatinine), Interleukin-1 receptor antagonist (IL-1Ra) (1794.8 ± 532.2 vs. 835.1 ± 1027.4 pg mL(-1) ), Tumor Necrosis Factor-α (TNF-α) (2.1 ± 1.2 vs. 1.5 ± 1.0 pg mL(-1) ), Soluble Tumor Necrosis Factor-α Type II Receptor (sTNFαRII), leptin, insulin, homeostasis model assessment of insulin resistance, version 2 (HOMA2-IR), high-sensitive C-reactive protein, triglycerides and lower adiponectin and high-density lipoprotein cholesterol (all P < 0.05). After exercise training, despite lack of weight loss, VO2peak (mL.kg(-1) .min(-1) ) and maximal fat oxidation increased (P < 0.05). IL-1Ra and IFN-gamma-inducible protein 10 (IP-10) decreased (P < 0.05). Insulin and HOMA2-IR decreased (14.8 ± 1.5 vs. 10.2 ± 4.2 μUI mL(-1) and 1.9 ± 0.8 vs. 1.3 ± 0.6, respectively, P < 0.05). Change in visceral fat mass was inversely associated with change in maximal fat oxidation (r = -0.54; P = 0.024). The subgroup of participants that lost visceral fat mass showed greater improvements in triglycerides, insulin resistance and maximal fat oxidation.

CONCLUSION

Our data confirms the role of exercise training on improving the inflammatory profile and insulin resistance of OB in the absence of weight loss. However, those who lost a greater amount of visceral fat mass showed greater benefits in terms of insulin profile, triglycerides and maximal fat oxidation.

Prevalence of and Risk Factors for Type 2 Diabetes Mellitus in Vietnam: A Systematic Review

This systematic review examined trends in the prevalence of type 2 diabetes mellitus (T2DM) and identified its risk factors among adults in Vietnam. PubMed, Web of Science, Wiley Online Library, and Scopus databases were searched to identify relevant literature. The search yielded 10 studies, including 2 national surveys and 8 regional investigations. National prevalence estimates of T2DM were 2.7% in 2002 and 5.4% in 2012. The estimates for the northern region were 1.4% in 1994 and 3.7% in 2012 and those for the southern region were 3.8% in 2004, 7.0% in 2008, and 12.4% in 2010. The major determinants of T2DM included older age, urban residence, high levels of body and abdominal fat, physical inactivity, sedentary lifestyle, genetic factors, and hypertension. The prevalence rate by gender was variable in both national and regional studies. There was insufficient information available on some potentially important risk factors such as smoking, dietary intake, income, and educational level. Our review signifies a rapidly growing prevalence of T2DM in Vietnam and suggests that extra effort is required to prevent and control this disease.

Mechanisms involved in developmental programming of hypertension and renal diseases. Gender differences

BACKGROUND

A substantial body of epidemiological and experimental evidence suggests that a poor fetal and neonatal environment may "program" susceptibility in the offspring to later development of cardiovascular, renal and metabolic diseases.

MATERIALS AND METHODS

This review focuses on current knowledge from the available literature regarding the mechanisms linking an adverse developmental environment with an increased risk for cardiovascular, renal and metabolic diseases in adult life. Moreover, this review highlights important sex-dependent differences in the adaptation to developmental insults.

RESULTS

Developmental programming of several diseases is secondary to changes in different mechanisms inducing important alterations in the normal development of several organs that lead to significant changes in birth weight. The different diseases occurring as a consequence of an adverse environment during development are secondary to morphological and functional cardiovascular and renal changes, to epigenetic changes and to an activation of several hormonal and regulatory systems, such as angiotensin II, sympathetic activity, nitric oxide, COX2-derived metabolites, oxidative stress and inflammation. The important sex-dependent differences in the developmental programming of diseases seem to be partly secondary to the effects of sex hormones. Recent studies have shown that the progression of these diseases is accelerated during aging in both sexes.

CONCLUSIONS

The cardiovascular, renal and metabolic diseases during adult life that occur as a consequence of several insults during fetal and postnatal periods are secondary to multiple structural and functional changes. Future studies are needed in order to prevent the origin and reduce the incidence and consequences of developmental programmed diseases.

Estrogens prevent metabolic dysfunctions induced by circadian disruptions in female mice

Circadian disruption has become a significant factor contributing to the epidemics of obesity and insulin resistance. However, interventions to treat metabolic dysfunctions induced by circadian disruptions are limited. The ovarian hormone, estrogen, produces important antiobesity and antidiabetic effects in female animals and has profound effects on daily behavioral rhythms. Here, we show that in female mice depleted with endogenous estrogens, a jet-lag paradigm induced visceral fat accumulation and systemic insulin resistance, which were associated with altered expression of multiple circadian genes in the visceral fat depot. Interestingly, all these jet-lag-induced deficits were completely rescued in female mice supplemented with exogenous estrogens. We further examined 24-hour oscillations of circadian genes in adipose tissues in female mice with estrogen depletion or replacement and showed that expression levels of the circadian gene, period circadian protein homolog 2, oscillate in visceral adipose tissue in an estrogen-dependent manner. Together, our results indicate that estrogens interact with the intrinsic circadian clock in adipose tissue and prevent abnormal lipid accumulation caused by circadian disruptions.

Exposure to traffic noise and markers of obesity

OBJECTIVES

Limited evidence suggests adverse effects of traffic noise exposure on the metabolic system. This study investigates the association between road traffic noise and obesity markers as well as the role of combined exposure to multiple sources of traffic noise.

METHODS

In a cross-sectional study performed in 2002-2006, we assessed exposure to noise from road traffic, railways and aircraft at the residences of 5075 Swedish men and women, primarily from suburban and semirural areas of Stockholm County. A detailed questionnaire and medical examination provided information on markers of obesity and potential confounders. Multiple linear and logistic regression models were used to assess associations between traffic noise and body mass index (BMI), waist circumference and waist-hip ratio using WHO definitions of obesity.

RESULTS

Road traffic noise was significantly related to waist circumference with a 0.21 cm (95% CI 0.01 to 0.41) increase per 5 dB(A) rise in L(den). The OR for central obesity among those exposed to road traffic noise ≥ 45 dB(A) was 1.18 (95% CI 1.03 to 1.34) in comparison to those exposed below this level. Similar results were seen for waist-hip ratio (OR 1.29; 95% CI 1.14 to 1.45) but not for BMI (OR 0.89; 95% CI 0.76 to 1.04). Central obesity was also associated with exposure to railway and aircraft noise, and a particularly high risk was seen for combined exposure to all three sources of traffic noise (OR 1.95; 95% CI 1.24 to 3.05).

CONCLUSIONS

Our results suggest that traffic noise exposure can increase the risk of central obesity. Combined exposure to different sources of traffic noise may convey a particularly high risk.

Lower urinary tract symptoms are associated with low levels of serum serotonin, high levels of adiponectin and fasting glucose, and benign prostatic enlargement

OBJECTIVE

The aim of this study was to test whether lower urinary tract symptoms (LUTS) and urinary incontinence are associated with the metabolic syndrome (MetS). The association between LUTS and benign prostatic enlargement (BPE) was also investigated.

MATERIAL AND METHODS

A cross-sectional, representative risk factor analysis of LUTS, as measured by the International Prostate Symptom Score (IPSS), and urinary incontinence was conducted. Among 950 representative individuals, aged 69-81 years, the association between clinical, anthropometric, endocrine, metabolic and inflammatory factors on the one hand, as both major and minor aspects of MetS, and LUTS and urinary incontinence, on the other hand, was analysed. The prostate gland volume was measured in a subgroup of 155 randomly selected individuals and the association between LUTS and BPE was estimated.

RESULTS

No significant association was found between LUTS or urinary incontinence and the major aspects of the MetS. However, in a multivariate analysis, serum serotonin showed an independent negative correlation with LUTS and with urinary incontinence while fasting serum glucose and serum adiponectin showed a positive correlation with LUTS. Furthermore, in a subgroup of 155 individuals, the prostate gland volume correlated positively with LUTS.

CONCLUSIONS

The study did not show an association between LUTS or urinary incontinence and the major components of the MetS. However, serum serotonin showed an independent negative correlation with LUTS and with urinary incontinence while fasting serum glucose and serum adiponectin showed a positive correlation with LUTS. The data confirm the general knowledge that BPE may be one of the causative factors of LUTS.

Fetal growth and cardio-metabolic risk factors in the 20-year-old offspring

OBJECTIVE

To investigate the association between prenatal growth patterns as estimated by biparietal diameter and cardio-metabolic risk at 20 years.

DESIGN

Follow-up study.

SETTING

Denmark 1988-2009.

POPULATION

Two cohorts of children born between 1988 and 1990 (n=707) and followed up in 2008-2009 (n=333-509).

METHODS

We have access to biparietal diameter from early ultrasound scan and birthweight. For each gender, biparietal diameter and birthweight, gestational age-specific growth-z-scores were calculated. A change in growth trajectory was depicted as a shift in z-score for the two growth measures. Multiple linear regression modeling was used to estimate associations between biparietal diameter and birthweight z-scores and later cardio-metabolic risk factors as well as estimating whether changing growth trajectory was associated with later cardio-metabolic risk.

MAIN OUTCOME MEASURES

Self-reported anthropometrics and clinically measured blood pressure, heart rate and biochemical measures associated with cardio-metabolic health.

RESULTS

After adjustments, biparietal diameter was not associated with any of the outcomes. Birthweight was positively associated with both adult height and weight and inversely associated with insulin, triglyceride and insulin resistance. Also, the data indicated a U-shaped association between growth in the second half of pregnancy and adult body mass index among individuals with a low biparietal diameter in mid-pregnancy.

CONCLUSION

Different patterns of intrauterine growth may be associated with later risk of cardio-metabolic disease.

Long-term aircraft noise exposure and body mass index, waist circumference, and type 2 diabetes: a prospective study

BACKGROUND

Long-term aircraft noise exposure may increase the risk of cardiovascular disease, but no study has investigated chronic effects on the metabolic system.

OBJECTIVES

The aim of this study was to investigate effects of long-term aircraft noise exposure on body mass index (BMI), waist circumference, and type 2 diabetes. Furthermore, we explored the modifying effects of sleep disturbance.

METHODS

This prospective cohort study of residents of Stockholm County, Sweden, followed 5,156 participants with normal baseline oral glucose tolerance tests (OGTT) for up to 10 years. Exposure to aircraft noise was estimated based on residential history. Information on outcomes and confounders was obtained from baseline and follow-up surveys and examinations, and participants who developed prediabetes or type 2 diabetes were identified by self-reported physician diagnosis or OGTT at follow-up. Adjusted associations were assessed by linear, logistic, and random-effects models.

RESULTS

The mean (± SD) increases in BMI and waist circumference during follow-up were 1.09 ± 1.97 kg/m2 and 4.39 ± 6.39 cm, respectively. The cumulative incidence of prediabetes and type 2 diabetes was 8% and 3%, respectively. Based on an ordinal noise variable, a 5-dB(A) increase in aircraft noise was associated with a greater increase in waist circumference of 1.51 cm (95% CI: 1.13, 1.89), fully adjusted. This association appeared particularly strong among those who did not change their home address during the study period, which may be a result of lower exposure misclassification. However, no clear associations were found for BMI or type 2 diabetes. Furthermore, sleep disturbances did not appear to modify the associations with aircraft noise.

CONCLUSIONS

Long-term aircraft noise exposure may be linked to metabolic outcomes, in particular increased waist circumference.

Effect of FTO Gene and Physical Activity Interaction on Trunk Fat Percentage Among the Newfoundland Population

OBJECTIVE

To explore the effect of FTO gene and physical activity interaction on trunk fat percentage.

DESIGN AND METHODS

Subjects are 3,004 individuals from Newfoundland and Labrador whose trunk fat percentage and physical activity were recorded, and who were genotyped for 11 single-nucleotide polymorphisms (SNPs) in the FTO gene. Subjects were stratified by gender. Multiple tests and multiple regressions were used to analyze the effects of physical activity, variants of FTO, age, and their interactions on trunk fat percentage. Dietary information and other environmental factors were not considered.

RESULTS

Higher levels of physical activity tend to reduce trunk fat percentage in all individuals. Furthermore, in males, rs9939609 and rs1421085 were significant (α = 0.05) in explaining central body fat, but no SNPs were significant in females. For highly active males, trunk fat percentage varied significantly between variants of rs9939609 and rs1421085, but there is no significant effect among individuals with low activity. The other SNPs examined were not significant in explaining trunk fat percentage.

CONCLUSIONS

Homozygous male carriers of non-obesity risk alleles at rs9939609 and rs1421085 will have significant reduction in central body fat from physical activity in contrast to homozygous males of the obesity-risk alleles. The additive effect of these SNPs is found in males with high physical activity only.

Role of human pregnane X receptor in high fat diet-induced obesity in pre-menopausal female mice

Obesity is a complex metabolic disorder that is more prevalent among women. Until now, the only relevant rodent models of diet-induced obesity were via the use of ovariectomized ("postmenopausal") females. However, recent reports suggest that the xenobiotic nuclear receptor pregnane X receptor (PXR) may contribute to obesity. Therefore, we compared the roles of mouse and human PXRs in diet-induced obesity between wild type (WT) and PXR-humanized (hPXR) transgenic female mice fed either control or high-fat diets (HFD) for 16 weeks. HFD-fed hPXR mice gained weight more rapidly than controls, exhibited hyperinsulinemia, and impaired glucose tolerance. Fundamental differences were observed between control-fed hPXR and WT females: hPXR mice possessed reduced estrogen receptor α (ERα) but enhanced uncoupling protein 1 (UCP1) protein expression in white adipose tissue (WAT); increased protein expression of the hepatic cytochrome P450 3A11 (CYP3A11) and key gluconeogenic enzymes phosphoenolpyruvate carboxykinase and glucose 6-phosphatase, and increased total cholesterol. Interestingly, HFD ingestion induced both UCP1 and glucokinase protein expression in WT mice, but inhibited these enzymes in hPXR females. Unlike WT mice, CYP3A11 protein, serum 17β-estradiol levels, and WAT ERα expression were unaffected by HFD in hPXR females. Together, these studies indicate that the hPXR gene promotes obesity and metabolic syndrome by dysregulating lipid and glucose homeostasis while inhibiting UCP1 expression. Furthermore, our studies indicate that the human PXR suppresses the protective role of estrogen in metabolic disorders. Finally, these data identify PXR-humanized mice as a promising in vivo research model for studying obesity and diabetes in women.

Estrogen or raloxifene during postmenopausal weight loss: adiposity and cardiometabolic outcomes

OBJECTIVE

Estrogen-based hormone therapy (HT) attenuates abdominal fat gain after menopause, but whether HT improves abdominal fat loss during weight loss is unknown. It was hypothesized that HT or a selective estrogen receptor modulator (raloxifene) would augment reductions in abdominal visceral fat during weight loss when compared to placebo, potentially increasing improvements in glucose tolerance and lipid profile.

METHODS

Healthy postmenopausal women (n = 119; age 50-70 yr) underwent a 6-month weight-loss (primarily exercise) intervention with randomization to raloxifene (60 mg/d), HT (conjugated estrogens, 0.625 mg/d), or placebo. Outcomes were change in total and abdominal (visceral and subcutaneous) fat mass, lipid profile, and fasting and post-challenge glucose and insulin.

RESULTS

Neither HT nor raloxifene augmented loss of total or abdominal fat mass during exercise-induced weight loss when compared with placebo. Weight loss-induced improvements in risk factors were similar among the three groups, except for a greater reduction in fasted glucose in the HT group (difference in change [95%CI] from placebo; -0.40 [-0.76, -0.05]) and greater reductions in LDL (-0.36 [-0.63, -0.09]) and increases in HDL (0.15 [0.07, 0.24]) in both treatment groups.

CONCLUSIONS

Postmenopausal HT and raloxifene did not increase abdominal fat loss during weight loss, but did improve some cardiometabolic outcomes.

Prenatal ethanol exposure enhances the susceptibility to metabolic syndrome in offspring rats by HPA axis-associated neuroendocrine metabolic programming

OBJECTIVE

The present study was designed to demonstrate that prenatal ethanol exposure (PEE) could enhance the susceptibility of high-fat diet-induced metabolic syndrome (MS) in adult male offspring via a hypothalamic-pituitary-adrenal (HPA) axis-associated neuroendocrine metabolic programmed mechanism.

METHODS

Pregnant Wistar rats were intragastricly administrated ethanol 4 g/kg·d from gestational day 11 until term delivery. All male offspring were fed with high-fat diet after weaning, exposed to an unpredictable chronic stress at postnatal week (PW) 17 and sacrificed at PW20.

RESULTS

In PEE group, body weight presented a "catch-up growth" pattern, and the HPA axis exhibited a lower basal activity but an enhanced sensitivity to chronic stress, leading to increased levels of serum glucose, insulin, insulin resistant index, total cholesterol and low-density lipoprotein-cholesterol, and decreased levels of high-density lipoprotein-cholesterol. Furthermore, many lipid droplets and vacuolar degeneration were observed in the hypothalamus, pituitary gland and liver.

CONCLUSIONS

PEE induces enhanced susceptibility to MS in adult offspring fed with high-fat diet, and the underlying mechanism involves a HPA axis-associated neuroendocrine metabolic programming alteration.

Combined impact of cardiorespiratory fitness and visceral adiposity on metabolic syndrome in overweight and obese adults in Korea

Background

Obesity, especially visceral obesity, is known to be an important correlate for cardiovascular disease and increased mortality. On the other hand, high cardiorespiratory fitness is suggested to be an effective contributor for reducing this risk. This study was conducted to determine the combined impact of cardiorespiratory fitness and visceral adiposity, otherwise known as fitness and fatness, on metabolic syndrome in overweight and obese adults.

Methods

A total of 232 overweight and obese individuals were grouped into four subtypes according to their fitness level. This was measured by recovery heart rate from a step test in addition to visceral adiposity defined as the visceral adipose tissue area to subcutaneous adipose tissue area ratio (VAT/SAT ratio). Associations of fitness and visceral fatness were analyzed in comparison with the prevalence of metabolic syndrome.

Results

The high visceral fat and low fitness group had the highest prevalence of metabolic syndrome [Odds Ratio (OR) 5.02; 95% Confidence Interval (CI) 1.85–13.61] compared with the reference group, which was the low visceral adiposity and high fitness group, after adjustments for confounding factors. Viscerally lean but unfit subjects were associated with a higher prevalence of metabolic syndrome than more viscerally obese but fit subjects (OR 3.42; 95% CI 1.27–9.19, and OR 2.70; 95% CI 1.01–7.25, respectively).

Conclusions

Our study shows that visceral obesity and fitness levels are cumulatively associated with a higher prevalence of metabolic syndrome in healthy overweight and obese adults. This suggests that cardiorespiratory fitness is a significant modifier in the relation of visceral adiposity to adverse metabolic outcomes in overweight and obese individuals.

Diabetes and obesity: new data on mechanisms and intervention trials

The increase in obesity and Type 2 diabetes on a global scale has heightened interest in how to counteract this epidemic. Improved lifestyle is a fundamental approach but other remedies, such as drugs and surgery, have also been tested. One question requiring further research is what happens after weight loss. Ongoing studies will try to address this question, including the Swedish Obese Subjects (SOS) study, and the Look Action for HEAlth in Diabetes (Look AHEAD) trial in the USA, the latter looking at obese Type 2 diabetes patients.

Sex differences in the relation of body composition to cardiovascular parameters and functions in Korean adolescents: a school-based study

OBJECTIVE

Obesity in adolescence is associated with increased cardiovascular risk. The patterns of obesity and body composition differ between boys and girls. It is uncertain how body composition correlates with the cardiovascular system and whether such correlations differ by sex in adolescents.

METHODS

Body composition (fat-free mass (FFM), adipose mass, waist circumference (WC)) and cardiovascular parameters and functions were studied in 676 healthy Korean adolescents aged 12-16 years. Partial correlation and path analyses were done.

RESULTS

WC correlated with stroke volume (SV) and cardiac output (CO), systolic blood pressure (SBP) and pulse pressure (PP), cardiac diastolic function (ratio of early to late filling velocity (E/A ratio)), and vascular function (pulse wave velocity (PWV)) in boys. Adipose mass was related to SV, CO, SBP, PP, left ventricular mass (LVM), and PWV in girls - and to E/A ratio in both sexes. FFM affected SV, CO, SBP, and PP in both sexes and LVM in boys. Cardiac systolic functions had no relation with any body composition variable in either sex.

CONCLUSION

In adolescence, the interdependence of the cardiovascular system and the body composition differs between sexes. Understanding of those relations is required to control adolescent obesity and prevent adult cardiovascular disease.

Psychosocial stress predicts abnormal glucose metabolism: the Australian Diabetes, Obesity and Lifestyle (AusDiab) study

BACKGROUND

The evidence supporting a relationship between stress and diabetes has been inconsistent.

PURPOSE

This study examined the effects of stress on abnormal glucose metabolism, using a population-based sample of 3,759, with normoglycemia at baseline, from the Australian Diabetes, Obesity and Lifestyle study.

METHODS

Perceived stress and stressful life events were measured at baseline, with health behavior and anthropometric information also collected. Oral glucose tolerance tests were undertaken at baseline and 5-year follow-up. The primary outcome was the development of abnormal glucose metabolism (impaired fasting glucose, impaired glucose tolerance, and type 2 diabetes), according to WHO 1999 criteria.

RESULTS

Perceived stress predicted incident abnormal glucose metabolism in women but not men, after multivariate adjustment. Life events showed an inconsistent relationship with abnormal glucose metabolism.

CONCLUSIONS

Perceived stress predicted abnormal glucose metabolism in women. Healthcare professionals should consider psychosocial adversity when assessing risk factor profiles for the development of diabetes.

Examining the association between salivary cortisol levels and subclinical measures of atherosclerosis: the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

To investigate the association between salivary cortisol and two markers of subclinical cardiovascular disease (CVD), coronary calcification (CAC), and ankle-brachial index (ABI).

METHODS

Data from an ancillary study to the Multi-Ethnic Study of Atherosclerosis (MESA), the MESA Stress Study, were used to analyze associations of salivary cortisol data collected six times per day over three days with CAC and ABI. The authors used mixed models with repeat cortisol measures nested within persons to determine if specific features of the cortisol profile were associated with CAC and ABI.

RESULTS

A total of 464 participants were included in the CAC analysis and 610 in the ABI analysis. The mean age of participants was 65.6 years. A 1-unit increase in log coronary calcium was associated with a 1.77% flatter early decline in cortisol (95% CI: 0.23, 3.34) among men and women combined. Among women low ABI was associated with a steeper early decline (-13.95% CI: -25.58, -3.39) and a marginally statistically significant flatter late decline (1.39% CI: -0.009, 2.81). The cortisol area under the curve and wake to bedtime slope were not associated with subclinical CVD.

CONCLUSIONS

This study provides weak support for the link between cortisol and measures of subclinical atherosclerosis. We found an association between some features of the diurnal cortisol profile and coronary calcification and ABI but associations were not consistent across subclinical measures. There are methodological challenges in detecting associations of cortisol measures at a point in time with health outcomes that develop over a lifetime. Studies of short-term mechanisms linking stress to physiological processes related to the development of early atherosclerosis may be more informative.

What about non-alcoholic fatty liver disease as a new criterion to define metabolic syndrome?

Non-alcoholic fatty liver disease (NAFLD) is currently not a component of the diagnostic criteria for metabolic syndrome (MetS); however, the development of NAFLD has some common mechanisms with the development of MetS, as they share the pathophysiologic basis of insulin resistance. It is also recognized that NAFLD is the hepatic manifestation of MetS. To define MetS, the presence of at least three of the proposed criteria is required, and sometimes it is sufficient to have only one laboratory value, modified by diet or drugs, for the classification of MetS. Ultrasonographically-detected NAFLD (US-NAFLD) is more stable, only changing during the middle- to long-term. Although controversies over MetS continue, and considering that abdominal ultrasonography for diagnosing NAFLD has high specificity and guidelines to modify the natural course of NAFLD by diet composition or lifestyle have not yet been established, why should we not introduce US-NAFLD as a new criterion to define MetS?

Protocol variations in arm position influence the magnitude of waist girth

Waist girth is recognised as a better predictor of obesity, particularly abdominal obesity, compared to other measures. Although several protocols for waist girth exist, arm position is either ignored, or not specified in unambiguous terms. Therefore, the purpose of this study was to determine if arm position influenced anthropometric waist girth measurement. Waist girth was measured in 92 adults (19 males, 73 females) with arms relaxed, abducted, horizontal, folded across the chest (three variations) and raised vertically. Duplicate measures, in all positions, were recorded by a single International Society for the Advancement of Kinanthropometry (ISAK)-trained technician to a precision of 0.2% technical error of measurement (TEM). Arm position had a significant effect (P < 0.001) on waist girth. Male participants had greater waist girth than females (P < 0.001) and the waist girth differences across the varying arm positions exhibited a significant position-by-gender interaction (P < 0.001). The arm position-by-body mass index (BMI) category interaction was also significant (P = 0.016) with greater differences observed at higher BMI. These findings suggest caution in comparing results of different studies where arm position is not specified and indicate that the arm position corresponding to the ISAK protocol has the lowest error and is therefore recommended.

Physical activity and cardiovascular risk factors at menopause: the Nord-Trøndelag health study

BACKGROUND

Lowered physical activity levels may partially explain changes in metabolic risk factors in women after menopause.

OBJECTIVES

To evaluate the association between physical activity and metabolic risk factors at baseline and after 11 years, as well as the change in that association over time in women who were premenopausal and ≥ 40 years at baseline.

METHODS

Subjects in a Norwegian population-based health survey answered questionnaires and had body and serum measurements during 1995-1997 (HUNT 2) and in a follow-up study during 2006-2008 (HUNT 3). Repeated-measures analyses were used to estimate the association between physical activity and metabolic factors, adjusting for age, smoking status, education, alcohol intake, and parity. Adjustment for hormonal treatment and medication was made, as appropriate.

RESULTS

In women remaining premenopausal, a higher physical activity score in HUNT 3 was associated with lower weight (p < 0.01) and waist-hip ratio (p < 0.01) and higher high density lipoprotein (HDL) cholesterol in HUNT 3 (p < 0.01). In women that were postmenopausal by the time of follow-up, a higher physical activity score in HUNT 3 was associated with lower weight (p < 0.01), waist-hip ratio (p < 0.01), triglycerides (p < 0.01), and higher total cholesterol (p < 0.05), HDL cholesterol (p < 0.01), and diastolic blood pressure (p < 0.05) in HUNT 3. The association of total physical activity score with weight and waist-hip ratio was stronger in HUNT 3 than in HUNT 2 (p < 0.01).

CONCLUSION

Increased physical activity may reduce the risk of adverse outcomes and use of pharmacological management in women of menopausal age.

Stressful life events and the onset of chronic diseases among Australian adults: findings from a longitudinal survey

OBJECTIVES

This article examines the link between stressful life events and illness by considering both onset and reoccurrence of chronic illnesses. Using longitudinal data, we estimate the extent to which life events increase the likelihood of depression or anxiety, type 2 diabetes, cancer, coronary heart disease, circulatory disease, asthma and emphysema among Australian adults aged ≥21 years.

METHODS

Longitudinal data were obtained from the nationally representative Household, Income and Labour Dynamics in Australia panel survey collected at waves 3 (2003), 7 (2007) and 9 (2009). Participants (N = 9222) answered life events questions relating to the preceding 12 months and chronic illnesses lasting (or expected to last for) 6 months. Weighted pooled and random effects logistic regressions were performed, controlling for confounders and previous illness, and also performed on subsamples delineated by reported illnesses in wave 3.

RESULTS

Work-related stress [odds ratio (OR) = 1.54, P < 0.001] was positively associated with the onset of depression or anxiety. Personal stress increased the likelihood of the onset of depression or anxiety (OR = 1.70, P < 0.001), type 2 diabetes (OR = 1.47, P < 0.05) and circulatory diseases (OR = 1.72, P < 0.05), while family-related stress increased the likelihood of the onset of heart (OR = 1.32, P < 0.01) and circulatory diseases (OR = 1.32, P < 0.05).

CONCLUSIONS

Independent of personal characteristics and key health measures (body mass index, hypertension and disability), these findings suggest that work-related, personal and family-related stressful life events contribute to the development and/or course of chronic diseases.

Stress and Its Effects on Glucose Metabolism and 11β-HSD Activities in Rats Fed on a Combination of High-Fat and High-Sucrose Diet with Glycyrrhizic Acid

Chronic stress has been shown to have a strong link towards metabolic syndrome (MetS). Glycyrrhizic acid (GA) meanwhile has been shown to improve MetS symptoms caused by an unhealthy diet by inhibiting 11 β -HSD 1. This experiment aimed to determine the effects of continuous, moderate-intensity stress on rats with and without GA intake on systolic blood pressure (SBP) across a 28-day period, as well as glucose metabolism, and 11 β -HSD 1 and 2 activities at the end of the 28-day period. Adaptation to the stressor (as shown by SBP) resulted in no significant defects in glucose metabolism by the end of the experimental duration. However, a weakly significant increase in renal 11 β -HSD 1 and a significant increase in subcutaneous adipose tissue 11 β -HSD 1 activities were observed. GA intake did not elicit any significant benefit in glucose metabolism, indicating that the stress response may block its effects. However, GA-induced improvements in 11 β -HSD activities in certain tissues were observed, although it is uncertain if these effects are manifested after adaptation due to the withdrawal of the stress response. Hence the ability of GA to improve stress-induced disturbances in the absence of adaptation needs to be investigated further.

Perceived stress and incidence of Type 2 diabetes: a 35-year follow-up study of middle-aged Swedish men

AIM

To explore incident cases of diagnosed diabetes over 35 years of follow-up in relation to self-perceived stress at baseline.

METHODS

This was a population-based random sample of 7251 men derived from the Primary Prevention Trial Study, aged 47-56 years at baseline and without prior history of diabetes, coronary heart disease and stroke. Incident diabetes was identified from hospital discharge and death registries as principal or secondary diagnosis. Cox proportional hazards regression was used to evaluate the potential association between stress and diabetes.

RESULTS

During a 35-year follow-up, a total of 899 men were identified with diabetes. The crude incidence was 5.2 per 1000 persons-years. At baseline, 15.5% men reported permanent stress related to conditions at work or home. After adjusting for age and competing risk of death, the estimated 35-year conditional probability of diabetes in men with permanent stress was 42.6%, compared with 31.0% for those with periodic stress and 31.2% with no stress. In age-adjusted Cox regression analysis, men with permanent stress had a higher risk of diabetes [hazard ratio 1.52 (95% CI 1.26-1.82)] compared with men with no (referent) or periodic stress [hazard ratio 1.09 (95% CI 0.94-1.27)]. The association between stress and diabetes was slightly attenuated but remained significant after adjustment for age, socio-economic status, physical inactivity, BMI, systolic blood pressure and use of anti-hypertensive medication [hazard ratio 1.45 (95% CI 1.20-1.75)]. When examining principal diagnosis of diabetes cases separately from secondary diagnoses cases, the excess risk of diabetes associated with permanent stress remained significant both in age (only) and multivariable adjusted models.

CONCLUSION

Self-perceived permanent stress is an important long-term predictor of diagnosed diabetes, independently of socio-economic status, BMI and other conventional Type 2 diabetes risk factors.

G protein-coupled estrogen receptor in energy homeostasis and obesity pathogenesis

Obesity and its related metabolic diseases have reached a pandemic level worldwide. There are sex differences in the prevalence of obesity and its related metabolic diseases, with men being more vulnerable than women; however, the prevalence of these disorders increases dramatically in women after menopause, suggesting that sex steroid hormone estrogens play key protective roles against development of obesity and metabolic diseases. Estrogens are important regulators of several aspects of metabolism, including body weight and body fat, caloric intake and energy expenditure, and glucose and lipid metabolism in both males and females. Estrogens act in complex ways on their nuclear estrogen receptors (ERs) ERα and ERβ and transmembrane ERs such as G protein-coupled estrogen receptor. Genetic tools, such as different lines of knockout mouse models, and pharmacological agents, such as selective agonists and antagonists, are available to study function and signaling mechanisms of ERs. We provide an overview of the evidence for the physiological and cellular actions of ERs in estrogen-dependent processes in the context of energy homeostasis and body fat regulation and discuss its pathology that leads to obesity and related metabolic states.

Adrenocortical regulation, eating in the absence of hunger and BMI in young children

The purpose of this study was to examine relations among adrenocortical regulation, eating in the absence of hunger, and body mass index (BMI) in children ages 5-9years (N=43). Saliva was collected before and after the Trier Social Stress Test for Children (TSST-C), and was later assayed for cortisol. Area under the curve with respect to increase (AUCi) was used as a measure of changes in cortisol release from baseline to 60min post-TSST-C. Age- and sex-specific BMI scores were calculated from measured height and weight, and eating in the absence of hunger was assessed using weighed food intake during a behavioral procedure. We also included a measure of parents' report of child impulsivity, as well as family demographic information. Participants were stratified by age into younger (5-7years) and older (8-9years) groups. In younger children, parents' reports of child impulsivity were significantly and positively associated with BMI; cortisol AUCi was not associated with BMI or eating in the absence of hunger. In older children, however, greater stress-related cortisol AUCi was related to higher BMI scores and greater energy intake in the absence of hunger. The results suggest that cortisol AUCi in response to psychosocial stress may be linked to problems with energy balance in children, with some variation by age.

The GH/IGF-1 Axis in Obesity: Physiological and Pathological Aspects

The cluster of cardiovascular risk factors-abdominal obesity, dyslipidaemia, insulin resistance and hypertension-has been recognized as the core of the metabolic syndrome. Adults with severe growth hormone (GH) deficiency have, to a large extent, features of the metabolic syndrome, and there is a strong inverse association between visceral fat accumulation and blunted GH secretion in adults. Hyposomatotropism in abdominal obesity has therefore been suggested to be of importance for its metabolic consequences. However, the underlying pathophysiological mechanisms are poorly understood. Prevalence of the metabolic syndrome is steadily increasing worldwide. Overnutrition and sedentary habits are the stigmata of modern society that predispose genetically susceptible individuals to develop central obesity and other features of the metabolic syndrome including glucose intolerance, hypertension and dyslipidemia. Although there are still no unified definitions of the syndrome, it is clear that this condition is associated with an increased risk for development of cardiovascular disease (CVD) and diabetes mellitus (DM). In this review, we discuss current evidence regarding alterations in the GH-IGF- 1 axis in abdominal obesity and its possible impact on other features of the metabolic syndrome.

The limited screening value of insulin-like growth factor-I as a marker for alterations in body composition in very long-term adult survivors of childhood cancer

BACKGROUND

The clinical relevance of low IGF-I levels, caused by cranial radiotherapy, in adult childhood cancer survivors has not been studied extensively. We evaluated whether IGF-I is a useful marker for altered body composition and growth hormone deficiency (GHD) in this group.

PROCEDURE

We analyzed retrospective data from 610 adult childhood cancer survivors, retrieved from the late effects clinic. Median age at diagnosis was 6 years (interquartile range 3-11) and follow-up time was 18 years (13-24). We assessed IGF-I standard deviation scores (SDS), anthropometrical measures, growth hormone stimulation tests in patients with clinical signs of GHD, and measures of body composition (assessed by dual X-ray absorptiometry, Lunar Prodigy).

RESULTS

In 58 cranially irradiated acute leukemia survivors (25 Gy (24-25)) and 56 locally irradiated brain tumor survivors (42 Gy (35-54)) we found significantly lower IGF-I SDS (P < 0.001), lower height SDS (P < 0.001), higher body mass index (P = 0.01), higher waist-hip ratio (WHR; P = 0.001), higher total fat percentage SDS (P < 0.001), and lower lean body mass SDS (P < 0.001), as compared to 452 not cranially irradiated survivors. IGF-I showed a weak inverse correlation with BMI (r = -0.12, P = 0.04), WHR (r = -0.15, P = 0.01), total fat percentage (r = - 0.14, P = 0.02), and a positive correlation with lean body mass (r = 0.15, P = 0.01). In patients with low IGF-I levels, IGF-I did not significantly differ between subjects with and without GHD as determined by GH-stimulation testing (P = 0.39).

CONCLUSION

This study shows that IGF-I has limited value as a marker for alterations in body composition in adult childhood cancer survivors.

The receptive function of hypothalamic and brainstem centres to hormonal and nutrient signals affecting energy balance

The hypothalamic arcuate nucleus (ARC) and the area postrema (AP) represent targets for hormonal and metabolic signals involved in energy homoeostasis, e.g. glucose, amylin, insulin, leptin, peptide YY (PYY), glucagon-like peptide 1 (GLP-1) and ghrelin. Orexigenic neuropeptide Y expressing ARC neurons are activated by food deprivation and inhibited by feeding in a nutrient-dependent manner. PYY and leptin also reverse or prevent fasting-induced activation of the ARC. Interestingly, hypothalamic responses to fasting are blunted in different models of obesity (e.g. diet-induced obesity (DIO) or late-onset obesity). The AP also responds to feeding-related signals. The pancreatic hormone amylin acts via the AP to control energy intake. Amylin-sensitive AP neurons are also glucose-responsive. Furthermore, diet-derived protein attenuates amylin responsiveness suggesting a modulation of AP sensitivity by macronutrient supply. This review gives an overview of the receptive function of the ARC and the AP to hormonal and nutritional stimuli involved in the control of energy balance and the possible implications in the context of obesity. Collectively, there is consistency between the neurophysiological actions of these stimuli and their effects on energy homoeostasis under experimental conditions. However, surprisingly little progress has been made in the development of effective pharmacological approaches against obesity. A promising way to improve effectiveness involves combination treatments (e.g. amylin/leptin agonists). Hormonal alterations (e.g. GLP-1 and PYY) are also considered to mediate body weight loss observed in obese patients receiving bariatric surgery. The effects of hormonal and nutritional signals and their interactions might hold the potential to develop poly-mechanistic therapeutic strategies against obesity.

Obesity is underestimated using body mass index and waist-hip ratio in long-term adult survivors of childhood cancer

Objective

Obesity, represented by high body mass index (BMI), is a major complication after treatment for childhood cancer. However, it has been shown that high total fat percentage and low lean body mass are more reliable predictors of cardiovascular morbidity. In this study longitudinal changes of BMI and body composition, as well as the value of BMI and waist-hip ratio representing obesity, were evaluated in adult childhood cancer survivors.

Methods

Data from 410 survivors who had visited the late effects clinic twice were analyzed. Median follow-up time was 16 years (interquartile range 11–21) and time between visits was 3.2 years (2.9–3.6). BMI was measured and body composition was assessed by dual X-ray absorptiometry (DXA, Lunar Prodigy; available twice in 182 survivors). Data were compared with healthy Dutch references and calculated as standard deviation scores (SDS). BMI, waist-hip ratio and total fat percentage were evaluated cross-sectionally in 422 survivors, in who at least one DXA scan was assessed.

Results

BMI was significantly higher in women, without significant change over time. In men BMI changed significantly with time (ΔSDS = 0.19, P<0.001). Percentage fat was significantly higher than references in all survivors, with the highest SDS after cranial radiotherapy (CRT) (mean SDS 1.73 in men, 1.48 in women, P<0.001). Only in men, increase in total fat percentage was significantly higher than references (ΔSDS = 0.22, P<0.001). Using total fat percentage as the gold standard, 65% of female and 42% of male survivors were misclassified as non-obese using BMI. Misclassification of obesity using waist-hip ratio was 40% in women and 24% in men.

Conclusions

Sixteen years after treatment for childhood cancer, the increase in BMI and total fat percentage was significantly greater than expected, especially after CRT. This is important as we could show that obesity was grossly underestimated using BMI and waist-hip ratio.

Interleukin-1 beta: a potential link between stress and the development of visceral obesity

Background

A disproportionate amount of body fat within the abdominal cavity, otherwise known as visceral obesity, best predicts the negative health outcomes associated with high levels body fat. Growing evidence suggests that repeated activation of the stress response can favor visceral fat deposition and that visceral obesity may induce low-grade, systemic inflammation which is etiologically linked to the pathogenesis of obesity related diseases such as cardiovascular disease and type 2 diabetes. While the obesity epidemic has fueled considerable interest in these obesity-related inflammatory diseases, surprisingly little research is currently focused on understanding the functions of inflammatory proteins in healthy, non-obese white adipose tissue (WAT) and their possible role in modulating stress-induced shifts in body fat distribution.

Hypothesis

The current review presents evidence in support the novel hypothesis that stress-evoked interleukin-1 beta (IL-1β) signaling within subcutaneous adipose tissue, when repeatedly induced, contributes toward the development of visceral obesity. It is suggested that because acute stressor exposure differentially increases IL-1β levels within subcutaneous adipose relative to visceral adipose tissue in otherwise healthy, non-obese rats, repeated induction of this response may impair the ability of subcutaneous adipose tissue to uptake energy substrates, synthesize and retain triglycerides, and/or adapt to positive energy balance via hyperplasia. Consequently, circulating energy substrates may be disproportionately shunted to visceral adipose tissue for storage, thus driving the development of visceral obesity.

Conclusions

This review establishes the following key points: 1) body fat distribution outweighs the importance of total body fat when predicting obesity-related disease risk; 2) repeated exposure to stress can drive the development of visceral obesity independent of changes in body weight; 3) because of the heterogeneity of WAT composition and function, an accurate understanding of WAT responses requires sampling multiple WAT depots; 4) acute, non-pathogenic stressor exposure increases WAT IL-1β concentrations in a depot specific manner suggesting an adaptive, metabolic role for this cytokine; however, when repeated, stress-induced IL-1β in non-visceral WAT may result in functional impairments that drive the development of stress-induced visceral obesity.

The Influence of Zygosity and Chorion Type on Fat Distribution in Young Adult Twins Consequences for Twin Studies

An adverse intra-uterine environment has been associated with abdominal fat distribution in singletons. Twins often have a low birth weight and a short gestation. Therefore, they may have an increased risk to develop abdominal obesity. Furthermore, monozygotic monochorionic twins (MZ MC) have a larger intra-pair birth weight difference compared to monozygotic dichorionic twins (MZ DC). If adult anthropometry is programmed in utero, this may affect the intra-pair correlations in adulthood and, consequently, also the results from the classic twin method to estimate genetic and environmental influences. In the present study, we compared the absolute values, the intra-pair differences, and the intra-pair correlations of body mass, height, BMI, and abdominal fat distribution of 424 MZ MC, MZ DC and dizygotic (DZ) twin pairs (aged 18–34 yrs). DZ, MZ DC and MZ MC twins did not differ for most anthropometric characteristics. Only MZ women tended (p = 0.03) to accumulate more abdominal fat compared to DZ twins. Overall, the contribution of zygosity and chorion type to adult anthropometry was rather low (≤ 1.7%). Although the intra-pair birth weight difference of MZ MC pairs (10.5% in men, 12.3% in women) was significantly larger compared to that of MZ DC pairs (6.9% and 9.2% resp.), the intra-pair differences in adult anthropometry were similar for both MZ twin types. Also the intra-pair correlations of MZ MC and MZ DC pairs were strikingly alike, suggesting no significant influence of the prenatal environment on adult concordance. In conclusion, the substantial difference in the prenatal environment of MZ MC and MZ DC twins did not result in a difference in intra-pair concordance of adult anthropometry and fat distribution. Therefore, we suggest that the chorion type of MZ twins does not bias the twin design and the estimation of the genetic contribution to adult anthropometry.