The contribution of psychosocial stress to the obesity epidemic: an evolutionary approach

Assessing the stress-buffering effects of social support for exercise on physical activity, sitting time, and blood lipid profiles

OBJECTIVE

This study tested the hypothesized stress-buffering effects of social support on physical activity, sitting time, and blood lipid profiles.

PARTICIPANTS

537 college students.

METHODS

College students volunteered to self-report stress, social support for exercise, physical activity and sitting time, and provided blood samples to assess lipid profiles in this cross-sectional study.

RESULTS

Lower stress was associated with higher vigorous physical activity (β = -0.1, t = -2.9, p = .004). Higher social support was associated with higher moderate (β = 0.2, t = 2.0, p = .042), vigorous (β = 0.5, t = 5.4, p < .001), and total (β = 0.1, t = 3.2, p = .001) physical activity, and lower sitting time on weekdays (β = -0.1, t = -3.3, p = .001) and weekends (β = -0.2, t = -3.6, p < .001). Social support moderated the association between stress and sitting time on weekdays.

CONCLUSIONS

Stress reduction and fostering social support may be important strategies for promoting physical activity and reducing sedentary behaviors in college students. Additional strategies are needed to buffer the deleterious effects of stress.

Analysis of influence of physical health factors on subjective wellbeing of middle-aged and elderly women in China

PURPOSE

Despite a maturing literature on the association between subjective wellbeing (SWB) and mental condition, little is known regarding the happiness-physical health relation in China, among middle-aged and elderly women (MAEW) in particular. This study aimed to understand the effect of physical health on the SWB of MAEW in China.

METHODS

Data from the 2014 and 2018 China Family Panel Study were used to analyse the SWB of women over the age of 45 years. In addition, descriptive statistics was used to describe the population distribution and panel ordered logit regression for regression analysis.

RESULTS

Majority of the respondents reported satisfactory SWB, and the proportion of the respondents who were very happy and happy was more than 68%. In terms of health factors, self-rated health, 2-week morbidity and BMI were significantly related to the SWB of MAEW (all P-values < 0.05). Physical exercise (P-value < 0.01) was positively associated with SWB, whereas smoking status and drinking status were not related to SWB. In addition, demographic indicators, such as registered residence (P-value < 0.01), income (P-value < 0.01) and social status (P-value < 0.01), significantly affected the SWB of MAEW.

CONCLUSION

This study showed that MAEW's physical health could affect their SWB. Increased attention should be paid to the physical health of MAEW to improve their SWB. Policy mechanisms could be designed to motivate MAEW to take the initiative to engage in regular physical activity to improve their SWB. In addition, increased attention be paid to groups with low socioeconomic status and high stress, especially those who are employed, to improve residents' happiness.

The hypothalamus for whole-body physiology: from metabolism to aging

Obesity and aging are two important epidemic factors for metabolic syndrome and many other health issues, which contribute to devastating diseases such as cardiovascular diseases, stroke and cancers. The brain plays a central role in controlling metabolic physiology in that it integrates information from other metabolic organs, sends regulatory projections and orchestrates the whole-body function. Emerging studies suggest that brain dysfunction in sensing various internal cues or processing external cues may have profound effects on metabolic and other physiological functions. This review highlights brain dysfunction linked to genetic mutations, sex, brain inflammation, microbiota, stress as causes for whole-body pathophysiology, arguing brain dysfunction as a root cause for the epidemic of aging and obesity-related disorders. We also speculate key issues that need to be addressed on how to reveal relevant brain dysfunction that underlines the development of these disorders and diseases in order to develop new treatment strategies against these health problems.

Sleep Deprivation: Effects on Weight Loss and Weight Loss Maintenance

This narrative review presents the findings from intervention studies on the effects of sleep deprivation on eating habits, metabolic rate, and the hormones regulating metabolism, and discusses their relevance to weight loss efforts. Disturbed sleeping patterns lead to increased energy intake, partly from excessive snacking, mainly on foods high in fat and carbohydrates. The studies focused mainly on the effects of sleep duration, but also of sleep quality, on dietary intake during weight loss trials, and on weight loss maintenance. It is important to explore sleep routines that could enhance the efforts of obese and overweight people to lose weight, maintain their weight loss, and improve their overall health.

Patient periprocedural stress in cardiovascular medicine: friend or foe?

Stress, a disruption of homeostasis, is an unavoidable part of everyday life. In medical procedures, stress profoundly affects both operators and patients. Although the stress reaction has evolved to aid survival of physical trauma, it may also be harmful, by aggravating the baseline medical condition and/or creating new stress-related medical problems. Stress responses comprise several protective mechanisms that are particularly relevant in the clinical setting (e.g., a procoagulatory state and blood loss counteraction, preservation of blood perfusion pressure, prevention of hypoglycemia, enhanced immune response). Beneficial psychological effects prevent recurrence of traumatic memories, and promote patient compliance and positive lifestyle changes. In contrast, overt acute stress responses may lead to severe pathological conditions such as cytokine storm, post-traumatic stress disorder, takotsubo syndrome, deep venous thrombosis and pulmonary embolism, myocardial infarction, life-threatening arrhythmias and sudden cardiac death. There is also evidence that stress exposure may promote atherosclerosis and reduce long-term benefits from the intervention (increase in major adverse clinical events, in-stent restenosis, etc.). Insights into the role of stress on the operator’s performance have recently led to the introduction of counteractive measures such as simulation training. Conversely, very little is known about the effect of the patient’s periprocedural stress on the outcomes of cardiovascular procedures. Recent data show that the patient periprocedural stress affects the well-being of whole families. This review, focused on topics particularly relevant to cardiovascular interventions, provides a mechanistic insight into beneficial and harmful effects of periprocedural patient stress, including the array of available stress-relieving measures.

The future of human malnutrition: rebalancing agency for better nutritional health

The major threat to human societies posed by undernutrition has been recognised for millennia. Despite substantial economic development and scientific innovation, however, progress in addressing this global challenge has been inadequate. Paradoxically, the last half-century also saw the rapid emergence of obesity, first in high-income countries but now also in low- and middle-income countries. Traditionally, these problems were approached separately, but there is increasing recognition that they have common drivers and need integrated responses. The new nutrition reality comprises a global ‘double burden’ of malnutrition, where the challenges of food insecurity, nutritional deficiencies and undernutrition coexist and interact with obesity, sedentary behaviour, unhealthy diets and environments that foster unhealthy behaviour. Beyond immediate efforts to prevent and treat malnutrition, what must change in order to reduce the future burden? Here, we present a conceptual framework that focuses on the deeper structural drivers of malnutrition embedded in society, and their interaction with biological mechanisms of appetite regulation and physiological homeostasis. Building on a review of malnutrition in past societies, our framework brings to the fore the power dynamics that characterise contemporary human food systems at many levels. We focus on the concept of agency, the ability of individuals or organisations to pursue their goals. In globalized food systems, the agency of individuals is directly confronted by the agency of several other types of actor, including corporations, governments and supranational institutions. The intakes of energy and nutrients by individuals are powerfully shaped by this ‘competition of agency’, and we therefore argue that the greatest opportunities to reduce malnutrition lie in rebalancing agency across the competing actors. The effect of the COVID-19 pandemic on food systems and individuals illustrates our conceptual framework. Efforts to improve agency must both drive and respond to complementary efforts to promote and maintain equitable societies and planetary health.

Stress Management as an Effective Complementary Therapeutic Strategy for Weight Loss in Children and Adolescents with Obesity: A Systematic Review of Randomized Controlled Trials

Lifestyle intervention programs, including mindfulness and stress management/emotional control training techniques have been infrequently studied in children. The aim of this systematic review was to assess whether implementing stress management/emotional control training strategies in the context of a body weight loss program in children and adolescents is associated with improved body weight outcome in this age group. A systematic literature search was conducted to identify relevant studies published before 31 December 2020 in the following databases: Medline (PubMed), Scopus, and Cochrane Central Registry of Controlled Trials. Only randomized clinical trials (RCTs) on mindfulness or stress management in children and adolescents with obesity were included in this systematic review. Six RCTs fulfilled the study inclusion criteria and included intervention (112 subjects) and control (137 subjects) groups. The interventions used were Mindfulness-Based Stress Reduction therapy for 8 weeks (three studies), a mindfulness-based group program for adolescents (one study), and Mindful Eating Intervention for 6 weeks (one study) and 10 weeks (one study). The intervention group demonstrated reduced adiposity markers as compared to controls in four of the six included studies. The presented studies support the hypothesis that a structured, mindfulness-based intervention program may lead to a decrease in the biomarkers of obesity.

Social support, nutrition and health among women in rural Bangladesh: complex tradeoffs in allocare, kin proximity and support network size

Malnutrition among women of reproductive age is a significant public health concern in low- and middle-income countries. Of particular concern are undernutrition from underweight and iron deficiency, along with overweight and obesity, all of which have negative health consequences for mothers and children. Accumulating evidence suggests that risk for poor nutritional outcomes may be mitigated by social support, yet how social support is measured varies tremendously and its effects likely vary by age, kinship and reproductive status. We examine the effects of different measures of social support on weight and iron nutrition among 677 randomly sampled women from rural Bangladesh. While we find that total support network size mitigates risk for underweight, other results point to a potential tradeoff in the effects of kin proximity, with nearby adult children associated with both lower risk for underweight and obesity and higher risk for iron deficiency and anaemia. Social support from kin may then enhance energy balance but not diet quality. Results also suggest that a woman's network of caregivers might reflect their greater need for help, as those who received more help with childcare and housework had worse iron nutrition. Overall, although some findings support the hypothesis that social support can be protective, others emphasize that social relationships often have neutral or negative effects, illustrating the kinds of tradeoffs expected from an evolutionary perspective. The complexities of these effects deserve attention in future work, particularly within public health, where what is defined as 'social support' is often assumed to be positive. This article is part of the theme issue 'Multidisciplinary perspectives on social support and maternal-child health'.

Predictors of Anxiety in the COVID-19 Pandemic from a Global Perspective: Data from 23 Countries

Prior and ongoing COVID-19 pandemic restrictions have resulted in substantial changes to everyday life. The pandemic and measures of its control affect mental health negatively. Self-reported data from 15,375 participants from 23 countries were collected from May to August 2020 during the early phases of the COVID-19 pandemic. Two questionnaires measuring anxiety level were used in this study—the Generalized Anxiety Disorder Scale (GAD-7), and the State Anxiety Inventory (SAI). The associations between a set of social indicators on anxiety during COVID-19 (e.g., sex, age, country, live alone) were tested as well. Self-reported anxiety during the first wave of the COVID-19 pandemic varied across countries, with the maximum levels reported for Brazil, Canada, Italy, Iraq and the USA. Sex differences of anxiety levels during COVID-19 were also examined, and results showed women reported higher levels of anxiety compared to men. Overall, our results demonstrated that the self-reported symptoms of anxiety were higher compared to those reported in general before pandemic. We conclude that such cultural dimensions as individualism/collectivism, power distance and looseness/tightness may function as protective adaptive mechanisms against the development of anxiety disorders in a pandemic situation.

Linking Psychosocial Stress Events, Psychological Disorders and Childhood Obesity

There is scientific evidence that supports a strong association between early exposure to stressful life events and the presence of health complications throughout adulthood and, to a lesser extent, in adolescence and childhood. The aim of this study was to examine the accumulation of Psychosocial Stress Events (PSE) and the prevalence of mental disorders in children from 8 to 12 years. The association between these factors and child weight measurements was analysed. A cross-sectional study was conducted among 200 children classified by weight status (obesity, overweight and normal-weight). The assessment was carried out in primary care centres and primary schools. An experienced team carried out a structured medical-psychosocial history and a semi-structured interview aimed at identifying an early diagnosis of psychological disorders. Children filled out a questionnaire to evaluate PSE. The obesity group presented the greatest accumulation of PSE and highest prevalence of psychiatric diagnosis, compared to overweight and normal-weight children. To exceed four or more stressful events was positively associated with psychological problems and child body mass index (BMI z-score). A predictive model confirmed the interaction between a larger number of PSE and the occurrence of a psychiatric diagnosis as variables that predispose children by 26.2 times more to increased weight status. In conclusion, the accumulation of PSE in the family, school and social environments of the children was related to greater psychological distress. If not managed, the likelihood of suffering from other health complications, such as excess weight, may increase. It is important to monitor these variables to ensure positive health outcomes while specifically addressing childhood obesity. This is especially relevant for children from a disadvantaged social background and disharmonious family environments.

Barocrinology: The Endocrinology of Obesity from Bench to Bedside

Obesity has reached pandemic proportions. Hormonal and metabolic imbalances are the key factors that lead to obesity. South Asian populations have a unique phenotype, peculiar dietary practices, and a high prevalence of consanguinity. Moreover, many lower middle-income countries lack appropriate resources, super-specialists, and affordability to manage this complex disorder. Of late, there has been a substantial increase in both obesity and diabesity in India. Thus, many more patients are being managed by different types of bariatric procedures today than ever before. These patients have many types of endocrine and metabolic disturbances before and after bariatric surgery. Therefore, these patients should be managed by experts who have knowledge of both bariatric surgery and endocrinology. The authors propose “Barocrinology”, a novel terminology in medical literature, to comprehensively describe the field of obesity medicine highlighting the role of knowing endocrine physiology for understating its evolution, insights into its complications and appreciating the changes in the hormonal milieu following weight loss therapies including bariatric surgery. Barocrinology, coined as a portmanteau of “baro” (weight) and endocrinology, focuses upon the endocrine and metabolic domains of weight physiology and pathology. This review summarizes the key pointers of bariatric management from an endocrine perspective.

The role of CREB and BDNF in neurobiology and treatment of Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia worldwide. β-amyloid peptide (Aβ) is currently assumed to be the main cause of synaptic dysfunction and cognitive impairments in AD, but the molecular signaling pathways underlying its neurotoxic consequences have not yet been completely explored. Additional investigations regarding these pathways will contribute to development of new therapeutic targets. In context, developing evidence suggest that Aβ decreases brain-derived neurotrophic factor (BDNF) mostly by lowering phosphorylated cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) protein. In fact, it has been observed that brain or serum levels of BDNF appear to be beneficial markers for cognitive condition. In addition, the participation of transcription mediated by CREB has been widely analyzed in the memory process and AD development. Designing pharmacologic or genetic therapeutic approaches based on the targeting of CREB-BDNF signaling could be a promising treatment potential for AD. In this review, we summarize data demonstrating the role of CREB-BDNF signaling pathway in cognitive status and mediation of Aβ toxicity in AD. Finally, we also focus on the developing intervention methods for improvement of cognitive decline in AD based on targeting of CREB-BDNF pathway.

Pathways to inflammation in adolescence through early adversity, childhood depressive symptoms, and body mass index: A prospective longitudinal study of Chilean infants

Early adversity, depression, and obesity are associated with increases in low-grade inflammation. However, there are few prospective and longitudinal studies to elucidate how these associations unfold in children. The present study used latent growth curve models to examine pathways between family adversity in infancy, depressive symptoms in childhood, body mass index (BMI) in childhood, and inflammation in adolescence (age = 16-18). The study is an adolescent follow-up of infants from working-class communities around Santiago, Chile, who participated in a preventive trial of iron supplementation at 6 months of age. Anthropometrics, stressful life events, maternal depression, socioeconomic status, and developmental assessments were measured at 12 months, 5 years, 10 years, and adolescence. In adolescence, participants provided blood samples for high-sensitivity C-reactive protein (hsCRP) assessment. Greater exposure to early adversity in the form of interpersonal conflict stress in infancy indirectly associated with increased hsCRP through its association to increased intercept and slope of childhood BMI. Depressive symptoms at any time were not directly or indirectly associated with increased hsCRP. These findings contribute to our understanding of how early family adversity and its associations with obesity and depressive symptoms across childhood are linked to low-grade, chronic inflammation in adolescence. The model identified as best capturing the data supported the pivotal role of childhood BMI in explaining how early-life adversity is associated with inflammation in adolescence.

The economic gradient of obesity in Mexico: Independent predictive roles of absolute and relative wealth by gender

Despite the vast literature on the economic gradient of obesity, no study investigates the independent predictive roles of absolute and relative standards of living using a large nationally representative adult sample. This gap limits our ability to discern 'material' and 'psychosocial' pathways to obesity as well as our understanding of the role played by economic inequality in the growing obesity epidemic. Using a large and nationally representative Mexican dataset, we find that absolute wealth and relative deprivation are independently related to obesity, and that such relationships are patterned by sex. Absolute wealth predicts body mass index as well as abdominal obesity according to an inverted-U shape for both sexes, and more markedly so for females. Relative deprivation predicts higher body mass index for females and higher waist circumference for both sexes, with highly relatively deprived females being 24.29% (95% CI [24.26, 24.31]) more likely to be obese and 34.46% (95% CI [34.40,34.53]) more likely to be abdominal obese, and highly relatively deprived males being 14.91% (95% CI [14.88,14.93] more likely to be abdominal obese. Our results offer a new perspective on the economic gradient of obesity and highlight the potential impact of economic inequality, especially for women. Greater awareness of the independent and sex-specific roles of the absolute and relative facets of economic status is needed to better understand and address the obesity epidemic.

Obese mice exposed to psychosocial stress display cardiac and hippocampal dysfunction associated with local brain-derived neurotrophic factor depletion

INTRODUCTION

Obesity and psychosocial stress (PS) co-exist in individuals of Western society. Nevertheless, how PS impacts cardiac and hippocampal phenotype in obese subjects is still unknown. Nor is it clear whether changes in local brain-derived neurotrophic factor (BDNF) account, at least in part, for myocardial and behavioral abnormalities in obese experiencing PS.

METHODS

In adult male WT mice, obesity was induced via a high-fat diet (HFD). The resident-intruder paradigm was superimposed to trigger PS. In vivo left ventricular (LV) performance was evaluated by echocardiography and pressure-volume loops. Behaviour was indagated by elevated plus maze (EPM) and Y-maze. LV myocardium was assayed for apoptosis, fibrosis, vessel density and oxidative stress. Hippocampus was analyzed for volume, neurogenesis, GABAergic markers and astrogliosis. Cardiac and hippocampal BDNF and TrkB levels were measured by ELISA and WB. We investigated the pathogenetic role played by BDNF signaling in additional cardiac-selective TrkB (cTrkB) KO mice.

FINDINGS

When combined, obesity and PS jeopardized LV performance, causing prominent apoptosis, fibrosis, oxidative stress and remodeling of the larger coronary branches, along with lower BDNF and TrkB levels. HFD/PS weakened LV function similarly in WT and cTrkB KO mice. The latter exhibited elevated LV ROS emission already at baseline. Obesity/PS augmented anxiety-like behaviour and impaired spatial memory. These changes were coupled to reduced hippocampal volume, neurogenesis, local BDNF and TrkB content and augmented astrogliosis.

INTERPRETATION

PS and obesity synergistically deteriorate myocardial structure and function by depleting cardiac BDNF/TrkB content, leading to augmented oxidative stress. This comorbidity triggers behavioral deficits and induces hippocampal remodeling, potentially via lower BDNF and TrkB levels. FUND: J.A. was in part supported by Rotary Foundation Global Study Scholarship. G.K. was supported by T32 National Institute of Health (NIH) training grant under award number 1T32AG058527. S.C. was funded by American Heart Association Career Development Award (19CDA34760185). G.A.R.C. was funded by NIH (K01HL133368-01). APB was funded by a Grant from the Friuli Venezia Giulia Region entitled: "Heart failure as the Alzheimer disease of the heart; therapeutic and diagnostic opportunities". M.C. was supported by PRONAT project (CNR). N.P. was funded by NIH (R01 HL136918) and by the Magic-That-Matters fund (JHU). V.L. was in part supported by institutional funds from Scuola Superiore Sant'Anna (Pisa, Italy), by the TIM-Telecom Italia (WHITE Lab, Pisa, Italy), by a research grant from Pastificio Attilio Mastromauro Granoro s.r.l. (Corato, Italy) and in part by ETHERNA project (Prog. n. 161/16, Fondazione Pisa, Italy). Funding source had no such involvement in study design, in the collection, analysis, interpretation of data, in the writing of the report; and in the decision to submit the paper for publication.

DNA methylation markers in obesity, metabolic syndrome, and weight loss

The fact that not all individuals exposed to the same environmental risk factors develop obesity supports the hypothesis of the existence of underlying genetic and epigenetic elements. There is suggestive evidence that environmental stimuli, such as dietary pattern, particularly during pregnancy and early life, but also in adult life, can induce changes in DNA methylation predisposing to obesity and related comorbidities. In this context, the DNA methylation marks of each individual have emerged not only as a promising tool for the prediction, screening, diagnosis, and prognosis of obesity and metabolic syndrome features, but also for the improvement of weight loss therapies in the context of precision nutrition. The main objectives in this field are to understand the mechanisms involved in transgenerational epigenetic inheritance, and featuring the nutritional and lifestyle factors implicated in the epigenetic modifications. Likewise, DNA methylation modulation caused by diet and environment may be a target for newer therapeutic strategies concerning the prevention and treatment of metabolic diseases.

The Interplay between Maternal Nutrition and Stress during Pregnancy: Issues and Considerations

BACKGROUND

Several studies about humans and animals have separately examined the effects of prenatal nutrition and stress on fetal development, pregnancy, and birth outcomes, and subsequent child health and disease risk. Although substantial evidence from non-pregnant literature supports the presence of bidirectional interactions between nutrition and stress at various psychological, behavioral, and physiological levels, such interaction effects have not yet been systematically examined in the context of pregnancy.

SUMMARY

This paper discusses the multifaceted and multilevel relationship between nutrition and stress. It then reviews the currently available observational and experimental evidence in animals and humans regarding the interplay between maternal psychosocial stress, dietary intake, and nutritional state during pregnancy, and implications for maternal and child health-related outcomes. Key Messages: During pregnancy, maternal psychosocial stress, dietary behavior, and nutritional state likely regulate and counter-regulate one another. Emerging evidence suggests that omega-3 fatty acids may attenuate maternal psychosocial stress, and that high maternal pre-pregnancy body mass index exacerbates unhealthy dietary behaviors under high-stress conditions. Longitudinal studies are warranted in order to understand the interplay between prenatal psychosocial stress, diet, and stress- and nutrition-related biomarkers to obtain further insight and inform the development and design of future, more effective intervention trials for improved maternal and child health outcomes.

Lower cognitive functioning as a predictor of weight gain in bipolar disorder: a 12-month study

OBJECTIVE

In cross-sectional studies, elevated body mass index (BMI) is associated with cognitive impairment in bipolar disorder (BD). We investigated the direction of this association by prospectively examining changes in BMI and cognition.

METHOD

We measured BMI and performance in six cognitive domains over 12 months in 80 adolescent and young adult BD patients and 46 healthy comparison subjects (HS). Ninety-three percent of patients received pharmacotherapy and 84% were euthymic. We used repeated-measures ancova and longitudinal mixed models to investigate whether (i) higher BMI and increasing BMI over time predicted lower subsequent cognitive functioning, and (ii) lower cognitive functioning and changes in cognition predicted increasing BMI.

RESULTS

Neither baseline BMI nor BMI change predicted lower cognitive functioning. Lower baseline scores in attention, verbal memory, working memory, and a composite measure of global cognition predicted increasing BMI in patients and HS. In patients, lower cognitive functioning remained associated with increasing BMI when clinical and treatment variables were adjusted for. Improvement in working memory predicted a smaller subsequent BMI increase in patients.

CONCLUSION

Lower cognitive functioning in specific domains predicts increasing BMI in patients with BD and healthy young adults. Targeting cognition may be important for minimizing weight gain in BD.

Association between Hair Cortisol Concentration and Adiposity Measures among Children and Parents from the "Healthy Start" Study

Background

Previous studies have suggested a direct association between hair cortisol concentration (HCC) and Body Mass Index (BMI), as well as other adiposity measures. However, these studies have mostly been conducted among adult populations.

Objective

To examine the association between HCC and different measures of adiposity among a selected group of children predisposed to obesity and their parents.

Methods

We conducted a cross-sectional study based on 363 children and their parents (301 mothers and 231 fathers) participating in the “Healthy Start” study. Linear regression analysis was used to investigate associations between HCC and adiposity measures while taking into account possible confounding factors. Analyses were performed examining the association between HCC and BMI, fat mass and fat free mass index Z-scores, as well as waist circumference and waist-hip ratio among the children. Likewise, the association between HCC and BMI among the parents was explored. Finally, we examined the association between parental HCC and children’s adiposity measures.

Results

HCC was directly associated with a higher BMI among the fathers (0.49 kg/m² [95% CI: 0.09, 0.90, P = 0.02] per 100 pg/mg) and the mothers (0.93 kg/m² [95% CI: 0.24, 1.61, P = 0.01] per 100 pg/mg). We found no clear evidence of an association between HCC and adiposity measures among children. However, a high maternal HCC was associated with a high fat mass index and low fat free mass index z-score in the offspring (0.14 SD [95% CI: 0.02, 0.26, P = 0.02] and -0.17 SD [95% CI: -0.30, -0.05, P = 0.01] per 100 pg/mg, respectively).

Conclusions

Our study found no evidence of an association between HCC and measures of adiposity among children predisposed to obesity. However, HCC may be directly associated with BMI among men and women, and maternal HCC may be related to a higher fat mass and a lower fat free mass among their children.

Harsh parenting, physical health, and the protective role of positive parent-adolescent relationships

RATIONALE

Harsh, abusive and rejecting behavior by parents toward their adolescents is associated with increased risk of many developmental problems for youth.

OBJECTIVE

In the present study we address behaviors of co-parents that might help disrupt the hypothesized health risk of harsh parenting.

METHOD

Data come from a community study of 451 early adolescents followed into adulthood. During early adolescence, observers rated both parents separately on harshness towards the adolescent. Adolescents reported on their physical health at multiple assessments from age 12 through age 20, and on parental warmth.

RESULTS

Harsh parenting predicted declines in adolescent self-reported physical health and increases in adolescent body mass index (BMI). Although the health risk associated with harshness from one parent was buffered by warmth from the other parent, warmth from the second parent augmented the association between harshness from the first parent and change over time in adolescent BMI.

CONCLUSION

As appropriate, preventive interventions should include a focus on spousal or partner behaviors in their educational or treatment programs. Additional research is needed on the association between self-reported physical health and BMI in adolescence.

Costs of Foraging Predispose Animals to Obesity-Related Mortality when Food Is Constantly Abundant

Obesity is an important medical problem affecting humans and animals in the developed world, but the evolutionary origins of the behaviours that cause obesity are poorly understood. The potential role of occasional gluts of food in determining fat-storage strategies for avoiding mortality have been overlooked, even though animals experienced such conditions in the recent evolutionary past and may follow the same strategies in the modern environment. Humans, domestic, and captive animals in the developed world are exposed to a surplus of calorie-rich food, conditions characterised as ‘constant-glut’. Here, we use a mathematical model to demonstrate that obesity-related mortality from poor health in a constant-glut environment should equal the average mortality rate in the ‘pre-modern’ environment when predation risk was more closely linked with foraging. It should therefore not be surprising that animals exposed to abundant food often over-eat to the point of ill-health. Our work suggests that individuals tend to defend a given excessive level of reserves because this level was adaptive when gluts were short-lived. The model predicts that mortality rate in constant-glut conditions can increase as the assumed health cost of being overweight decreases, meaning that any adaptation that reduced such health costs would have counter-intuitively led to an increase in mortality in the modern environment. Taken together, these results imply that efforts to reduce the incidence of obesity that are focussed on altering individual behaviour are likely to be ineffective because modern, constant-glut conditions trigger previously adaptive behavioural responses.

A Conceptual Framework for the Expansion of Behavioral Interventions for Youth Obesity: A Family-Based Mindful Eating Approach

BACKGROUND

Currently, over 30% of US youth are overweight and 1 in 6 have metabolic syndrome, making youth obesity one of the major global health challenges of the 21st century. Few enduring treatment strategies have been identified in youth populations, and the majority of standard weight loss programs fail to adequately address the impact of psychological factors on eating behavior and the beneficial contribution of parental involvement in youth behavior change.

METHODS

A critical need exists to expand treatment development efforts beyond traditional education and cognitive-behavioral programs and explore alternative treatment models for youth obesity. Meditation-based mindful eating programs represent a unique and novel scientific approach to the current youth obesity epidemic given that they address key psychological variables affecting weight.

RESULTS

The recent expansion of mindfulness programs to include family relationships shows the immense potential for broadening the customarily individual focus of this intervention to include contextual factors thought to influence youth health outcomes.

CONCLUSIONS

This article provides an overview of how both mindful eating and family systems theory fits within a conceptual framework in order to guide development of a comprehensive family-based mindful eating program for overweight youth.

Change in Neighborhood Socioeconomic Status and Weight Gain: Dallas Heart Study

INTRODUCTION

Despite a proposed connection between neighborhood environment and obesity, few longitudinal studies have examined the relationship between change in neighborhood socioeconomic deprivation, as defined by moving between neighborhoods, and change in body weight. The purpose of this study is to examine the longitudinal relationship between moving to more socioeconomically deprived neighborhoods and weight gain as a cardiovascular risk factor.

METHODS

Weight (kilograms) was measured in the Dallas Heart Study (DHS), a multiethnic cohort aged 18-65 years, at baseline (2000-2002) and 7-year follow-up (2007-2009, N=1,835). Data were analyzed in 2013-2014. Geocoded addresses were linked to Dallas County, TX, census block groups. A block group-level neighborhood deprivation index (NDI) was created. Multilevel difference-in-difference models with random effects and a Heckman correction factor (HCF) determined weight change relative to NDI change.

RESULTS

Forty-nine percent of the DHS population moved (263 to higher NDI, 586 to lower NDI, 47 within same NDI), with blacks more likely to move than whites or Hispanics (p<0.01), but similar baseline BMI and waist circumference were observed in movers versus non-movers (p>0.05). Adjusting for HCF, sex, race, and time-varying covariates, those who moved to areas of higher NDI gained more weight compared to those remaining in the same or moving to a lower NDI (0.64 kg per 1-unit NDI increase, 95% CI=0.09, 1.19). Impact of NDI change on weight gain increased with time (p=0.03).

CONCLUSIONS

Moving to more-socioeconomically deprived neighborhoods was associated with weight gain among DHS participants.

Sociodemographic Differences in the Association Between Obesity and Stress: A Propensity Score-Matched Analysis from the Korean National Health and Nutrition Examination Survey (KNHANES)

Few population-based studies have used an econometric approach to understand the association between two cancer risk factors, obesity and stress. This study investigated sociodemographic differences in the association between obesity and stress among Korean adults (6,546 men and 8,473 women). Data were drawn from the Korean National Health and Nutrition Examination Survey for 2008, 2009, and 2010. Ordered logistic regression models and propensity score matching methods were used to examine the associations between obesity and stress, stratified by gender and age groups. In women, the stress level of the obese group was found to be 27.6% higher than the nonobese group in the ordered logistic regression; the obesity effect on stress was statistically significant in the propensity score-matched analysis. Corresponding evidence for the effect of obesity on stress was lacking among men. Participants who were young, well-educated, and working were more likely to report stress. In Korea, obesity causes stress in women but not in men. Young women are susceptible to a disproportionate level of stress. More cancer prevention programs targeting young and obese women are encouraged in developed Asian countries.

Inverse association of des-acyl ghrelin with worksite blood pressure in overweight/obese male workers

BACKGROUND

Job strain, defined as a combination of high job demands and low job control, has been reported to elevate blood pressure (BP) during work. Meanwhile, a recent experimental study showed that ghrelin blunted the BP response to such mental stress. In the present study, we examined the hypothesis that des-acyl ghrelin may have some beneficial effects on worksite BP through modulating the BP response to work-related mental stress, i.e., job strain.

METHODS

Subjects were 34 overweight/obese male day-shift workers (mean age 41.7 ± 6.7 years). No subjects had received any anti-hypertensive medication. A 24-h ambulatory BP monitoring was recorded every 30 min on a regular working day. The average BP was calculated for Work BP, Morning BP, and Home BP. Job strain was assessed using the short version of the Japanese Job Content Questionnaire.

RESULTS

Des-acyl ghrelin showed significant inverse correlations with almost all BPs except Morning SBP, Morning DBP, and Home DBP. In multiple regression analysis, des-acyl ghrelin inversely correlated with Work SBP after adjusting for confounding factors. Des-acyl ghrelin was also negatively associated with BP changes from Sleep to Morning, Sleep to Work, and Sleep to Home.

CONCLUSIONS

Des-acyl ghrelin was inversely associated with Worksite BP, suggesting a unique beneficial effect of des-acyl ghrelin on Worksite BP in overweight/obese male day-shift workers.

A longitudinal analysis of maternal depressive symptoms and children's food consumption and weight outcomes

OBJECTIVE

Maternal depressive symptoms negatively impact mothers' parenting practices and children's development, but the evidence linking these symptoms to children's obesity is mixed.

DESIGN

We use a large sample to examine contemporaneous and lagged associations between maternal depressive symptoms and children's BMI, obesity and food consumption, controlling for background characteristics.

SETTING

Data from the Early Childhood Longitudinal Study-Birth Cohort (ECLS-B), a longitudinal study of children from infancy through kindergarten in the USA, were collected at four waves from 2001 to 2007, when children were 9 months, 2 years, 4 years and 5½years of age, through surveys, child assessments and observations.

SUBJECTS

A sub-sample of children from the ECLS-B is used (n 6500).

RESULTS

Between 17 % and 19 % of mothers reported experiencing depressive symptoms; 17 % to 20 % of children were obese. Maternal depressive symptoms were associated with a small decrease in the likelihood her child was obese (0·8 percentage points) and with lower consumption of healthy foods. The duration of maternal depressive symptoms was associated with higher BMI (0·02 sd) among children whose parents lacked college degrees.

CONCLUSIONS

Results indicate that mothers' depressive symptoms have small associations with children's food consumption and obesity. Among children whose parents lack college degrees, persistent maternal depressive symptoms are associated with slightly higher child BMI. Findings highlight the need to control for depression in analyses of children's weight. Interventions that consider maternal depression early may be useful in promoting healthy weight outcomes and eating habits among children.

A new model of the role of psychological and emotional distress in promoting obesity: conceptual review with implications for treatment and prevention

The lack of significant treatment and prevention progress highlights the need for a more expanded strategy. Given the robust association between socioeconomic factors and obesity, combined with new insights into how socioeconomic disadvantage affects both behaviour and biology, a new causal model is proposed. The model posits that psychological and emotional distress is a fundamental link between socioeconomic disadvantage and weight gain. At particular risk are children growing up in a disharmonious family environment, mainly caused by parental socioeconomic disadvantage, where they are exposed to parental frustrations, relationship discord, a lack of support and cohesion, negative belief systems, unmet emotional needs and general insecurity. Without adequate resilience, such experiences increase the risk of psychological and emotional distress, including low self-esteem and self-worth, negative emotions, negative self-belief, powerlessness, depression, anxiety, insecurity and a heightened sensitivity to stress. These inner disturbances eventually cause a psycho-emotional overload, triggering a cascade of weight gain-inducing effects including maladaptive coping strategies such as eating to suppress negative emotions, chronic stress, appetite up-regulation, low-grade inflammation and possibly reduced basal metabolism. Over time, this causes obesity, circular causality and further weight gain. Tackling these proposed root causes of weight gain could potentially improve both treatment and prevention outcomes.

Neighborhood-level socioeconomic deprivation predicts weight gain in a multi-ethnic population: longitudinal data from the Dallas Heart Study

OBJECTIVE

The aim of this study is to examine a relationship between neighborhood-level socioeconomic deprivation and weight change in a multi-ethnic cohort from Dallas County, Texas and whether behavioral/psychosocial factors attenuate the relationship.

METHODS

Non-movers (those in the same neighborhood throughout the study period) aged 18-65 (N=939) in Dallas Heart Study (DHS) underwent weight measurements between 2000 and 2009 (median 7-year follow-up). Geocoded home addresses defined block groups; a neighborhood deprivation index (NDI) was created (higher NDI=greater deprivation). Multi-level modeling determined weight change relative to NDI. Model fit improvement was examined with adding physical activity and neighborhood environment perceptions (higher score=more unfavorable perceptions) as covariates. A significant interaction between residence length and NDI was found (p-interaction=0.04); results were stratified by median residence length (11 years).

RESULTS

Adjusting for age, sex, race/ethnicity, smoking, and education/income, those who lived in neighborhood >11 years gained 1.0 kg per one-unit increment of NDI (p=0.03), or 6 kg for those in highest NDI tertile compared with those in the lowest tertile. Physical activity improved model fit; NDI remained associated with weight gain after adjustment for physical activity and neighborhood environment perceptions. There was no significant relationship between NDI and weight change for those in their neighborhood ≤11 years.

CONCLUSIONS

Living in more socioeconomically deprived neighborhoods over a longer time period was associated with weight gain in DHS.

Neck circumference is a predictor of metabolic syndrome and obstructive sleep apnea in short-sleeping obese men and women

BACKGROUND

The constellation of metabolic syndrome, although controversial with regard to its clinical usefulness, is epidemiologically related to increased diabetes risk and cardiovascular mortality. Our goal was to investigate the associations among neck circumference (NC), obstructive sleep apnea syndromes (OSAS), and metabolic syndrome in obese men and women sleeping less than 6.5 hr per night.

METHODS

This was a cross-sectional study of obese men and premenopausal obese women sleeping less than 6.5 hr per night. We enrolled 120 individuals (92 women), age 40.5±6.9 years and body mass index (BMI) 38.6±6.5 kg/m(2). Metabolic syndrome severity was assessed by a score and OSAS was defined as a respiratory disturbance index (RDI) ≥5. Metabolic end endocrine parameters were measured, and sleep duration was determined by actigraphy and validated questionnaires.

RESULTS

Metabolic syndrome was found in 41% and OSAS in 58% (28% had both). Subjects with metabolic syndrome were 3 years older and more often Caucasian; they had higher RDI scores, larger NC, more visceral fat, lower serum adiponectin, higher 24-hr urinary norepinephrine (NE) excretion, and lower growth hormone concentrations. A NC of ≥38 cm had a sensitivity of 54% and 58% and a specificity of 70% and 79% in predicting the presence of metabolic syndrome and OSAS, respectively. RDI, adiponectin, and NC accounted for approximately 30% of the variability in the metabolic syndrome score, as estimated by an age-, gender-, and race-corrected multivariate model (R(2)=0.376, P<0.001).

CONCLUSION

Greater NC is associated with OSAS and metabolic syndrome in short-sleeping obese men and premenopausal obese women. Addition of NC to the definition of metabolic syndrome should be considered and needs to be validated in future studies.

The effects of stress on physical activity and exercise

BACKGROUND

Psychological stress and physical activity (PA) are believed to be reciprocally related; however, most research examining the relationship between these constructs is devoted to the study of exercise and/or PA as an instrument to mitigate distress.

OBJECTIVE

The aim of this paper was to review the literature investigating the influence of stress on indicators of PA and exercise.

METHODS

A systematic search of Web of Science, PubMed, and SPORTDiscus was employed to find all relevant studies focusing on human participants. Search terms included "stress", "exercise", and "physical activity". A rating scale (0-9) modified for this study was utilized to assess the quality of all studies with multiple time points.

RESULTS

The literature search found 168 studies that examined the influence of stress on PA. Studies varied widely in their theoretical orientation and included perceived stress, distress, life events, job strain, role strain, and work-family conflict but not lifetime cumulative adversity. To more clearly address the question, prospective studies (n = 55) were considered for further review, the majority of which indicated that psychological stress predicts less PA (behavioral inhibition) and/or exercise or more sedentary behavior (76.4 %). Both objective (i.e., life events) and subjective (i.e., distress) measures of stress related to reduced PA. Prospective studies investigating the effects of objective markers of stress nearly all agreed (six of seven studies) that stress has a negative effect on PA. This was true for research examining (a) PA at periods of objectively varying levels of stress (i.e., final examinations vs. a control time point) and (b) chronically stressed populations (e.g., caregivers, parents of children with a cancer diagnosis) that were less likely to be active than controls over time. Studies examining older adults (>50 years), cohorts with both men and women, and larger sample sizes (n > 100) were more likely to show an inverse association. 85.7 % of higher-quality prospective research (≥ 7 on a 9-point scale) showed the same trend. Interestingly, some prospective studies (18.2 %) report evidence that PA was positively impacted by stress (behavioral activation). This should not be surprising as some individuals utilize exercise to cope with stress. Several other factors may moderate stress and PA relationships, such as stages of change for exercise. Habitually active individuals exercise more in the face of stress, and those in beginning stages exercise less. Consequently, stress may have a differential impact on exercise adoption, maintenance, and relapse. Preliminary evidence suggests that combining stress management programming with exercise interventions may allay stress-related reductions in PA, though rigorous testing of these techniques has yet to be produced.

CONCLUSIONS

Overall, the majority of the literature finds that the experience of stress impairs efforts to be physically active. Future work should center on the development of a theory explaining the mechanisms underlying the multifarious influences of stress on PA behaviors.

Taking two to tango: a role for ghrelin receptor heterodimerization in stress and reward

The gut hormone, ghrelin, is the only known peripherally derived orexigenic signal. It activates its centrally expressed receptor, the growth hormone secretagogue receptor (GHS-R1a), to stimulate food intake. The ghrelin signaling system has recently been suggested to play a key role at the interface of homeostatic control of appetite and the hedonic aspects of food intake, as a critical role for ghrelin in dopaminergic mesolimbic circuits involved in reward signaling has emerged. Moreover, enhanced plasma ghrelin levels are associated with conditions of physiological stress, which may underline the drive to eat calorie-dense "comfort-foods" and signifies a role for ghrelin in stress-induced food reward behaviors. These complex and diverse functionalities of the ghrelinergic system are not yet fully elucidated and likely involve crosstalk with additional signaling systems. Interestingly, accumulating data over the last few years has shown the GHS-R1a receptor to dimerize with several additional G-protein coupled receptors (GPCRs) involved in appetite signaling and reward, including the GHS-R1b receptor, the melanocortin 3 receptor (MC3), dopamine receptors (D1 and D2), and more recently, the serotonin 2C receptor (5-HT2C). GHS-R1a dimerization was shown to affect downstream signaling and receptor trafficking suggesting a potential novel mechanism for fine-tuning GHS-R1a receptor mediated activity. This review summarizes ghrelin's role in food reward and stress and outlines the GHS-R1a dimer pairs identified to date. In addition, the downstream signaling and potential functional consequences of dimerization of the GHS-R1a receptor in appetite and stress-induced food reward behavior are discussed. The existence of multiple GHS-R1a heterodimers has important consequences for future pharmacotherapies as it significantly increases the pharmacological diversity of the GHS-R1a receptor and has the potential to enhance specificity of novel ghrelin-targeted drugs.

Psychosocial predictors of 4-year BMI change in overweight and obese children in primary care

OBJECTIVE

This study aimed to determine whether (1) initial and/or (2) changes in psychosocial functioning predict body mass index (BMI) z-score change over 4 years in overweight/mildly obese 5- to 9-year old children presenting to primary care.

DESIGN AND METHODS

Eligible participants (n = 258) were overweight/mildly obese children (IOTF criteria) recruited into the LEAP2 trial (ISRCTN52511065) from 3,958 children visiting general practitioners in Melbourne, Australia from May 2005 to July 2006. Predictors were change scores calculated from repeated measures of parent- and child-reported child health-related quality of life (PedsQL) and self-esteem; child-reported desire to be thinner; and parent-reported child weight concern. Outcome was measured BMI z-score change from baseline to 4 years.

RESULTS

The 189 respondents (61% female; 73% retention) showed little mean change in BMI z-score (-0.08) but wide variation (standard deviation 0.50, range -1.32 to 1.20). Only one baseline measure (better parent-reported PedsQL School Functioning) predicted improving BMI z-score. However, parents and children consistently reported that changes in psychosocial functioning (i.e., PedsQL Social and Global Self-esteem) were inversely related to BMI z-score change scores. The strongest predictors of decreases in BMI z-scores were changes in child-reported body-image variables, i.e., improvements in Physical Appearance Self-esteem (β =0.40, 95% CI -0.98 to -0.15, P < 0.01) and declines in Desire to be Thinner (β = 0.33, 95% CI 0.04 to 0.23, P < 0.01).

CONCLUSIONS

At presentation to primary care, it seems unlikely that targeting the psychosocial factors measured in this study would influence BMI z-score change in overweight/mildly obese children. Subsequent change in psychosocial well-being covaries with BMI z-score change and may have important adolescent ramifications; the causal directions for these associations require further research.

Stress and obesity as risk factors in cardiovascular diseases: a neuroimmune perspective

Obesity is now growing at an alarming rate reaching epidemic proportions worldwide thus increasing morbidity and mortality rates for chronic disease. But although we have ample information on the complications associated with obesity, precisely what causes obesity remains poorly understood. Some evidence attributes a major role to a low-grade chronic inflammatory state (neurogenic inflammation) induced in obesity by inflammatory mediators produced and secreted within the expanded activated adipocyte pool. Adipose tissue is an endocrine organ that secretes numerous adipose tissue-specific or enriched hormones, known as adipokines, cytokine-like molecules thought to play a pathogenic role in cardiovascular diseases. The imbalance between increased inflammatory stimuli and decreased anti-inflammatory mechanisms may depend on chronic stress. Hence the positive correlation found between stress, obesity and cardiovascular diseases. The chronic inflammatory state associated with insulin resistance and endothelial dysfunction is highly deleterious for vascular function. This review focuses on the proposed neuroimmunodulatory mechanisms linking chronic (psychological) stress, obesity and cardiovascular diseases.

Relationship between perceptions about neighborhood environment and prevalent obesity: data from the Dallas Heart Study

OBJECTIVES

Although psychosocial stress can result in adverse health outcomes, little is known about how perceptions of neighborhood conditions, a measure of environment-derived stress, may impact obesity. The association between perceptions of neighborhood environment and obesity (defined as body mass index [BMI] ≥ 30 kg/m(2) ) among 5,907 participants in the Dallas Heart Study, a multi-ethnic, probability-based sample of Dallas County residents was examined.

DESIGN AND METHODS

Participants were asked to respond to 18 questions about perceptions of their neighborhood. Factor analysis was used to identify three factors associated with neighborhood perceptions: neighborhood violence, physical environment, and social cohesion. Logistic regression analyses were performed to determine the relationship between each factor (higher quintile = more unfavorable perceptions) and the odds of obesity.

RESULTS

Decreasing age, income, and education associated with unfavorable overall neighborhood perceptions and unfavorable perceptions about specific neighborhood factors (P trend <0.05 for all). Increasing BMI was associated with unfavorable perceptions about physical environment (P trend <0.05) but not violence or social cohesion. After adjustment for race, age, sex, income, education, and length of residence, physical environment perception score in the highest quintile remained associated with a 25% greater odds of obesity (OR 1.25, [95% CI 1.03-1.50]). Predictors of obesity related to environmental perceptions included heavy traffic (OR 1.39, [1.17-1.64]), trash/litter in neighborhood (OR 1.27, [1.01-1.46]), lack of recreational areas (OR 1.21, [1.01-1.46]), and lack of sidewalks (OR 1.25, [95% CI 1.04-1.51]).

CONCLUSIONS

Thus, unfavorable perceptions of environmental physical conditions are related to increased obesity. Efforts to improve the physical characteristics of neighborhoods, or the perceptions of those characteristics, may assist in the prevention of obesity in this community.

Influence of stress in parents on child obesity and related behaviors

OBJECTIVE

To assess associations of the number of parent stressors and parent-perceived stress with obesity and related behaviors in their children.

METHODS

This cross-sectional analysis used data from the 2006 Southeastern Pennsylvania Household Health Survey in which 2119 parents/caregivers answered questions about themselves and their children (ages 3-17 years). Survey data were used to assess the main exposure variables: the number of stressors (measured using a stressor index) and parent-perceived stress (the response to a general stress question); child covariates (age, race/ethnicity, health quality, and gender); adult covariates (education, BMI, gender, poor sleep quality) and study outcomes (child obesity, fast-food consumption, fruit and vegetable consumption, and physical activity). To account for developmental differences, analyses were also stratified by age group (3-5, 6-8, 9-12, and 13-17 years). Analyses used multiple logistic regression, with results expressed as odds ratios and 95% confidence intervals.

RESULTS

The number of parent stressors was related to child obesity in unadjusted (1.12, 1.03-1.22, P = .007) and adjusted models (1.12, 1.03-1.23, P = .010). Parent-perceived stress was related to fast-food consumption in unadjusted (1.07, 1.03-1.10, P < .001) and adjusted (1.06, 1.02-1.10, P < .001) models.

CONCLUSIONS

The number of parent stressors was directly related to child obesity. Parent-perceived stress was directly related to child fast-food consumption, an important behavioral indicator of obesity risk. Clinical care models and future research that address child obesity should explore the potential benefits of addressing parent stressors and parent-perceived stress.

The evolution of human adiposity and obesity: where did it all go wrong?

Because obesity is associated with diverse chronic diseases, little attention has been directed to the multiple beneficial functions of adipose tissue. Adipose tissue not only provides energy for growth, reproduction and immune function, but also secretes and receives diverse signaling molecules that coordinate energy allocation between these functions in response to ecological conditions. Importantly, many relevant ecological cues act on growth and physique, with adiposity responding as a counterbalancing risk management strategy. The large number of individual alleles associated with adipose tissue illustrates its integration with diverse metabolic pathways. However, phenotypic variation in age, sex, ethnicity and social status is further associated with different strategies for storing and using energy. Adiposity therefore represents a key means of phenotypic flexibility within and across generations, enabling a coherent life-history strategy in the face of ecological stochasticity. The sensitivity of numerous metabolic pathways to ecological cues makes our species vulnerable to manipulative globalized economic forces. The aim of this article is to understand how human adipose tissue biology interacts with modern environmental pressures to generate excess weight gain and obesity. The disease component of obesity might lie not in adipose tissue itself, but in its perturbation by our modern industrialized niche. Efforts to combat obesity could be more effective if they prioritized 'external' environmental change rather than attempting to manipulate 'internal' biology through pharmaceutical or behavioral means.

Interacting epidemics? Sleep curtailment, insulin resistance, and obesity

In the last 50 years, the average self-reported sleep duration in the United States has decreased by 1.5-2 hours in parallel with an increasing prevalence of obesity and diabetes. Epidemiological studies and meta-analyses report a strong relationship between short or disturbed sleep, obesity, and abnormalities in glucose metabolism. This relationship is likely to be bidirectional and causal in nature, but many aspects remain to be elucidated. Sleep and the internal circadian clock influence a host of endocrine parameters. Sleep curtailment in humans alters multiple metabolic pathways, leading to more insulin resistance, possibly decreased energy expenditure, increased appetite, and immunological changes. On the other hand, psychological, endocrine, and anatomical abnormalities in individuals with obesity and/or diabetes can interfere with sleep duration and quality, thus creating a vicious cycle. In this review, we address mechanisms linking sleep with metabolism, highlight the need for studies conducted in real-life settings, and explore therapeutic interventions to improve sleep, with a potential beneficial effect on obesity and its comorbidities.

Poor sleep quality and sleep apnea are associated with higher resting energy expenditure in obese individuals with short sleep duration

CONTEXT

Epidemiological studies reported an inverse or U-shaped relationship between sleep duration and weight. The relationship between sleep and resting energy expenditure (REE) has not been well characterized.

OBJECTIVE

The aim of the study was to determine the relationship between sleep, REE, and stress hormones.

DESIGN AND SETTING

We conducted a cross-sectional evaluation of a prospective cohort study at a tertiary referral research clinical center.

SUBJECTS

Subjects included 126 obese individuals (30 males, 96 females; age, 40.5 ± 6.9 yr; body mass index, 38.6 ± 6.5 kg/m(2); sleep duration, 360 ± 50 min/night; and sleep efficiency, 79.5 ± 7.5%).

MAIN OUTCOME MEASURE(S)

REE and respiratory quotient (RQ) were assessed by indirect calorimetry. Sleep duration and sleep efficiency were assessed by actigraphy. Sleep quality was estimated by questionnaires, and sleep apnea was evaluated by respiratory disturbance index (RDI). Morning plasma ACTH, serum cortisol, and 24-h urinary free cortisol and catecholamines were also measured.

RESULTS

RDI was positively correlated with REE adjusted by fat-free mass (r = 0.307; P = 0.003) and RQ (r = 0.377; P < 0.001). Sleep efficiency was inversely correlated with RQ (r = -0.200; P = 0.033). The relationship of RDI score and REE was stronger in men than women (P = 0.03). In women, serum cortisol was positively correlated (r = 0.407; P < 0.001), and Epworth sleepiness score tended to be inversely (r = -0.190; P = 0.086) correlated with adjusted REE. The RQ was positively related to RDI in women, whereas subjective sleep time was related to RQ in men. In a multiple regression model, RDI, serum cortisol, and urinary norepinephrine were directly related to REE, whereas serum cortisol also directly related to adjusted REE.

CONCLUSION

Poor sleep quality was associated with increased REE, a higher RQ indicating a shift from fat toward carbohydrate oxidation, and activation of the stress system.

Effects of Chronic Social Stress on Obesity

The prevalence of overweight and obesity has markedly increased during the past few decades. Stress has been suggested as one environmental factor that may contribute to the development of obesity. In this review, we discuss the role that exposure to chronic stress may play in the development of obesity, with particular attention to the effects of chronic psychosocial stress. Of particular importance is the effect that social stress has on dietary preference, food consumption, and regional distribution of adipose tissue. We present evidence from human and animal studies that links sympathetic nervous system and hypothalamic-pituitary-adrenal axis hyperactivity with visceral obesity, and that stress tends to alter the pattern of food consumption, and promotes craving of nutrient-dense "comfort foods." Lastly, we discuss the visible burrow system, a model of chronic social stress used in our laboratory to assess the effects of social subordination on behavioral and metabolic profile.

Beyond fast food and slow motion: weighty contributors to the obesity epidemic

Decreased physical activity and marketing-driven increased consumption of "junk" food, dubbed "The Big Two", are generally regarded as the most important contributors to the obesity epidemic. However, the full picture contains many more pieces of the puzzle. We address several additional issues and review current clinical developments in obesity research. In spite of dramatic advancements in our understanding of the adipose organ and its endocrine and immune products, the ultimate causes of the obesity epidemic remain elusive. Treatment is plagued by poor adherence to life style modifications, and available pharmacological options are marginally effective, often also associated with major side effects. Surgical treatments, albeit effective in decreasing body weight, are invasive and expensive. Thus, our approaches to finding the causes, improving the existing treatments, and inventing novel therapies must be manifold.

Acupuncture at ST36 prevents chronic stress-induced increases in neuropeptide Y in rat

Chronic stress, as seen in post-traumatic stress disorder, can exacerbate existing diseases. Electroacupuncture (EA) has been proposed to treat chronic stress, although information on its efficacy or mechanism(s) of action is limited. While many factors contribute to the chronic stress response, the sympathetic peptide, neuropeptide Y (NPY), has been shown to be elevated in chronic stress and is hypothesized to contribute to the physiological stress response. Our objective was to determine if EA at acupuncture point stomach 36 (ST36) is effective in mitigating cold stress-induced increase in NPY in rats. Both pretreatment and concomitant treatment with EA ST36 effectively suppressed peripheral and central NPY after 14 d of cold stress ( P < 0.05). The effect was specific, as NPY in Sham-EA rats was not different than observed in stress-only rats. Additionally, the effect of EA ST36 was long-lasting, as NPY levels remained suppressed despite early cessation of EA ST36, while exposure to cold stress was continued. In the paraventricular nucleus (PVN), it was notable that changes in NPY mirrored plasma NPY levels, and that the significant elevation in PVN Y1 receptor observed with stress was also prevented with EA ST36. The findings indicate that EA ST36 is effective in preventing one of the sympathetic pathways stimulated during chronic stress, and thus may be a useful adjunct therapy in stress-related disorders.

Chronic sleep deprivation and seasonality: implications for the obesity epidemic

Sleep duration has progressively fallen over the last 100 years while obesity has increased in the past 30 years. Several studies have reported an association between chronic sleep deprivation and long-term weight gain. Increased energy intake due to sleep loss has been listed as the main mechanism. The consequences of chronic sleep deprivation on energy expenditure have not been fully explored. Sleep, body weight, mood and behavior are subjected to circannual changes. However, in our modern environment seasonal changes in light and ambient temperature are attenuated. Seasonality, defined as cyclic changes in mood and behavior, is a stable personality trait with a strong genetic component. We hypothesize that the attenuation in seasonal changes in the environment may produce negative consequences, especially in individuals more predisposed to seasonality, such as women. Seasonal affective disorder, a condition more common in women and characterized by depressed mood, hypersomnia, weight gain, and carbohydrate craving during the winter, represents an extreme example of seasonality. One of the postulated functions of sleep is energy preservation. Hibernation, a phenomenon characterized by decreased energy expenditure and changes in the state of arousal, may offer useful insight into the mechanisms behind energy preservation during sleep. The goals of this article are to: a) consider the contribution of changes in energy expenditure to the weight gain due to sleep loss; b) review the phenomena of seasonality, hibernation, and their neuroendocrine mechanisms as they relate to sleep, energy expenditure, and body weight regulation.