35,468 research outputs found

    Sex differences in exercise-mediated changes in diet preference and its associated cognitive and metabolic outcomes

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    The modern environment contributes to the obesity epidemic by encouraging a sedentary lifestyle and increased intake of highly processed, energy dense foods. Females are more prone to develop disordered feeding behaviors, such as binge eating, and the prevalence of obesity is greater in females than males. However, obesity-related metabolic and cognitive dysregulation is more severe in males. One mechanism by which exercise may protect against these negative outcomes and restore energy homeostasis is through changes in macronutrient selection, specifically decreasing intake of high fat (HF) food. Sex differences in the susceptibility, outcomes, and exercise as a treatment intervention for obesity, however, have not been well-characterized. Moreover, how factors including diet, cognition, and peripheral metabolic function interact to potentially perpetuate the viscous feedback loop of maladaptive eating behavior and obesity in a sex-specific fashion is poorly understood. The goal of this dissertation was to investigate sex differences in the efficacy of exercise at attenuating the adverse cognitive and metabolic outcomes associated with long-term HF feeding. To this end, our lab has established a voluntary wheel running (WR) and two-diet choice model in rats. Using this paradigm, we found that the simultaneous introduction of WR and HF diet resulted in complete HF diet avoidance in WR rats whereas sedentary (Sed) rats maintained HF diet preference. There is also a sex difference in exercise-mediated changes in diet preference where male rats maintain HF diet avoidance and females reverse their initial HF diet avoidance. Chapter 2 examines the role of gonadal hormones on the expression and maintenance of HF diet avoidance during acute exercise. Chapter 3 extends the voluntary WR and two-diet choice paradigm used in Chapter 2 to assess sex differences in peripheral metabolic function and behavioral flexibility resulting from chronic HF feeding. In Chapter 4, an additional assessment of cognitive behavior was added where heightened impulsivity, a behavior associated with poor dietary self-regulation, binge eating, and obesity, was examined as both a potential vulnerability factor for and outcome of palatable diet preference. To more accurately mimic the fat and carbohydrate intake in the modern environment, HF was replaced with a Western diet (WD). Impulsive choice was assessed before and after long-term WD exposure and preference in addition to WD-mediated metabolic adaptions. Results suggest that female, but not male, sex hormones as well as developmental factors are important for the expression of sex-typical diet choice patterns during exercise. The ability for exercise to improve peripheral metabolism, including glucose tolerance and insulin sensitivity, was greater in males than females. Although cognitive performance was only moderately improved in rats of both sexes, exercise did appear to have a beneficial effect on cognition. Taken together, the studies in this dissertation contribute to the knowledge of how sex differences in diet preference and exercise interact and lead to sex-specific physiological and behavioral adaptations.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste

    Testing the nomological network for the Personal Engagement Model

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    The study of employee engagement has been a key focus of management for over three decades. The academic literature on engagement has generated multiple definitions but there are two primary models of engagement: the Personal Engagement Model of Kahn (1990), and the Work Engagement Model (WEM) of Schaufeli et al., (2002). While the former is cited by most authors as the seminal work on engagement, research has tended to focus on elements of the model and most theoretical work on engagement has predominantly used the WEM to consider the topic. The purpose of this study was to test all the elements of the nomological network of the PEM to determine whether the complete model of personal engagement is viable. This was done using data from a large, complex public sector workforce. Survey questions were designed to test each element of the PEM and administered to a sample of the workforce (n = 3,103). The scales were tested and refined using confirmatory factor analysis and then the model was tested determine the structure of the nomological network. This was validated and the generalisability of the final model was tested across different work and organisational types. The results showed that the PEM is viable but there were differences from what was originally proposed by Kahn (1990). Specifically, of the three psychological conditions deemed necessary for engagement to occur, meaningfulness, safety, and availability, only meaningfulness was found to contribute to employee engagement. The model demonstrated that employees experience meaningfulness through both the nature of the work that they do and the organisation within which they do their work. Finally, the findings were replicated across employees in different work types and different organisational types. This thesis makes five contributions to the engagement paradigm. It advances engagement theory by testing the PEM and showing that it is an adequate representation of engagement. A model for testing the causal mechanism for engagement has been articulated, demonstrating that meaningfulness in work is a primary mechanism for engagement. The research has shown the key aspects of the workplace in which employees experience meaningfulness, the nature of the work that they do and the organisation within which they do it. It has demonstrated that this is consistent across organisations and the type of work. Finally, it has developed a reliable measure of the different elements of the PEM which will support future research in this area

    Face processing in young adults with autism and ADHD: an event related potentials study

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    Background: Atypicalities in perception and interpretation of faces and emotional facial expressions have been reported in both autism and attention-deficit/hyperactivity disorder (ADHD) during childhood and adulthood. Investigation of face processing during young adulthood (18 to 25 years), a transition period to full-fledged adulthood, could provide important information on the adult outcomes of autism and ADHD. Methods: In this study, we investigated event-related potentials (ERPs) related to visual face processing in autism, ADHD, and co–occurring autism and ADHD in a large sample of young adults (N = 566). The groups were based on the Diagnostic Interview for ADHD in Adults 2.0 (DIVA-2) and the Autism Diagnostic Observation Schedule-2 (ADOS-2). We analyzed ERPs from two passive viewing tasks previously used in childhood investigations: (1) upright and inverted faces with direct or averted gaze; (2) faces expressing different emotions. Results: Across both tasks, we consistently found lower amplitude and longer latency of N170 in participants with autism compared to those without. Longer P1 latencies and smaller P3 amplitudes in response to emotional expressions and longer P3 latencies for upright faces were also characteristic to the autistic group. Those with ADHD had longer N170 latencies, specific to the face-gaze task. Individuals with both autism and ADHD showed additional alterations in gaze modulation and a lack of the face inversion effect indexed by a delayed N170. Conclusion: Alterations in N170 for autistic young adults is largely consistent with studies on autistic adults, and some studies in autistic children. These findings suggest that there are identifiable and measurable socio-functional atypicalities in young adults with autism

    Internet gaming disorder and aggression: A meta-analysis of teenagers and young adults

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    Background and aimsInternet gaming disorder (IGD) and aggression (AG) are widespread phenomena around the world. Numerous studies have explored the relationship between the two but findings from such studies are inconsistent. The meta-analysis aimed to evaluate the relationship between IGD and AG as well as identify the variables moderating the relationship.MethodStudies investigating the relationship between IGD and AG were searched using selected terms to identify studies published from 1999 to 2022 on CNKI, Wanfang Data, Chongqing VIP Information Co., Ltd. (VIP), Baidu scholar, ProQuest dissertations, Taylor & Francis, Springer, Web of Science, Google Scholar, Elsevier Science (Science Direct), EBSCO, and PsycINFO. The identified studies were pooled and analyzed.ResultsA total of 30 samples comprising 20,790 subjects were identified. Results showed that there was a moderate relationship between IGD and AG (r = 0.300, 95%CI [0.246, 0.353]). Moderator analysis revealed that the relationship between IGD and AG was moderated by the region, age, and survey year.ConclusionThis meta-analysis indicated that people with a higher level of IGD might show more aggression, and people with more aggression might have a higher level of IGD. The correlation coefficient between IGD and AG was significantly higher in Asia than in Europe, higher in primary school than in middle school and university, and higher by increasing year. Overall, our findings provide a basis for developing prevention and intervention strategies against IGD and AG.Systematic review registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022375267, 42022375267

    Suicidal Behavior in Eating Disorders

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    Many studies have shown that people with eating disorders have higher rates of suicidal ideation, suicide attempts, and completed suicide than the general population. One of the diseases with the highest suicide rate among psychiatric disorders is anorexia nervosa. Some hypotheses have been proposed to explain possible causes of increased suicidal behavior in eating disorders. Some conditions common to eating disorders and suicidal behavior, such as dissatisfaction with the body and interoceptive deficits, have been cited. It has been conclusively shown that psychiatric comorbidity, especially the co-diagnosis of depression, increases the risk of suicide in patients with eating disorders. However, increased suicidal behavior in eating disorders cannot be explained by comorbidity alone. The interpersonal psychological theory of suicide (IPTS), developed by Joiner, aims to understand why people commit suicide and to explain the differences in individual suicidal behavior. Some researchers have thought that the increased suicidal behavior of people with eating disorders, especially anorexia nervosa patients, is expected from the perspective of IPTS. The compensatory behaviors of patients with eating disorders, such as vomiting or chronic restrictive food intake, are painful and challenging actions for the body. It can be considered that repeated encounters with painful and challenging experiences form a habit in the individual and reduce pain avoidance. When viewed from the IPTS perspective, decreased pain avoidance may explain the increased suicide attempts and completed suicides of individuals. Clinicians working with eating disorder patients must conduct regular and comprehensive assessments of suicide. Comorbidities such as major depression, anxiety disorder, and substance-use disorder should not be overlooked in patients with eating disorders and should be taken seriously

    Nutrition and cognitive health: A life course approach

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    Multiple factors affect cognitive health, such as age-related changes in the brain, injuries, mood disorders, substance abuse, and diseases. While some cannot be changed, evidence exists of many potentially possibly modifiable lifestyle factors: diet, physical activity, cognitive and social engagement, smoking and alcohol consumption which may stabilize or improve declining cognitive function. In nutrition, the focus has been mainly on its role in brain development in the early years. There is a strong emerging need to identify the role of diet and nutrition factors on age-related cognitive decline, which will open up the use of new approaches for prevention, treatment or management of age-related disorders and maintaining a good quality of life among older adults. While data on effect of high protein diets is not consistent, low-fat diets are protective against cognitive decline. Several micronutrients like B group vitamins and iron, as well as many polyphenols play a crucial role in cognitive health. Mediterranean, Nordic, DASH, and MIND diets are linked to a lower risk of cognitive decline and dementia. The relationship between the gut microbiome and brain function through the gut-brain axis has led to the emergence of data on the beneficial effects of dietary fibers and probiotics through the management of gut microbes. A “whole diet” approach as well as macro- and micro-nutrient intake levels that have protective effects against cardiovascular diseases are most likely to be effective against neurodegenerative disorders too. Young adulthood and middle age are crucial periods for determining cognitive health in old age. The importance of cardio metabolic risk factors such as obesity and hypertension, smoking and physical inactivity that develop in middle age suggest that preventive approaches are required for target populations in their 40s and 50s, much before they develop dementia. The commonality of dementia risk with cardiovascular and diabetes risk suggests that dementia could be added to present non-communicable disease management programs in primary healthcare and broader public health programs

    Comparing the autism phenotype in children born extremely preterm and children born at term

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    BACKGROUND AND OBJECTIVE: It has been well established that children born preterm are at an increased risk of developing Autism Spectrum Disorder (ASD), and that risk increases as gestational age decreases. However, there is limited knowledge on how the ASD phenotype in preterm-born children compares to ASD presentation in children born at term. The objective of this study is to compare ASD core symptoms and characteristics commonly associated with ASD in children born extremely preterm (EP) and children born at term. METHODS: Extremely preterm (EP) participants (n=59) from the Extremely Low Gestational Age Newborn (ELGAN) Study who met diagnostic criteria for ASD at approximately 10 years of age were matched with term participants (n=59) from the Simons Simplex Collection (SSC) on age, sex, and nonverbal IQ. Differences in core ASD symptomatology were evaluated using the Autism Diagnostic Interview-Revised (ADI-R), an in-depth parent interview, and the Autism Diagnostic Observation Schedule, 2nd edition (ADOS-2), a semi-structured clinical observation assessment. Developmental milestones, anthropometrics, seizure disorder, and psychiatric symptoms were also investigated as associated characteristics of ASD. Analyses excluding multiplex EP individuals and their term matches, as well female-only analyses, were also conducted. RESULTS: On the ADI-R, the EP group had lower scores (decreased symptom severity) on verbal communication, specifically stereotypic language, and restricted and repetitive behaviors (RRBs). However, no between-group differences were observed with direct observation based on the ADOS-2 assessment. The EP group was more likely to have delayed speech milestones, lower height, weight, and head circumference, and lower rates of depression and anxiety symptoms. When 7 multiplex EP participants and their term control matches were eliminated from the sample, there were no differences from the primary analyses. Female-only analyses were similar to primary analyses on core ASD symptomatology findings. Regarding associated characteristics, females only differed on height, head circumference, and anxiety symptoms. CONCLUSIONS: Accounting for age, sex, nonverbal IQ, and prior ASD diagnosis status, EP children had less severe stereotypic language and RRB symptoms compared to term children based on ADI-R parent report, but exhibited no differences on parent-reported nonverbal communication or reciprocal social interaction symptoms, or with direct observation of social affective and repetitive and restricted ASD symptoms on the ADOS-2. EP children with ASD also showed decreased physical growth and delayed language relative to those born at term, possibly reflecting the developmental effects of being born EP. In sum, the ASD phenotype was generally similar between EP and term born children, with the exception of less severity of retrospectively parent-reported stereotypic behaviors, lower physical growth parameters, and increased delays in language milestones among EP born children with ASD

    Modulation of Attentional Bias to Drug and Affective Cues by Therapeutic and Neuropsychological Factors in Patients With Opioid Use Disorder on Methadone Maintenance Therapy

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    Objective: Abnormal selective attention to drug cues and negative affect is observed in patients with substance dependence, and it is closely associated with drug addiction and relapse. Methadone maintenance is an effective replacement therapy to treat heroin addiction, which significantly reduces the relapse rate. The present study examines whether the patients with opioid use disorder on chronic methadone maintenance therapy exhibit abnormal attentional bias to drug cues and negative-affective cues. Moreover, its relation to therapeutic and neuropsychological factors is also examined.Methods: Seventy-nine patients with opioid use disorder under chronic methadone maintenance therapy and 73 age-, sex-, and education-matched healthy controls were recruited and assessed for attentional bias to drug cues and negative affect using a dot-probe detection task. Correlational analysis was used to examine the relationships between the attentional bias and the demographic, therapeutic, and neuropsychological factors.Results: No significant overall patient-control group difference is observed in drug-related or negative-affective-related attentional bias scores. In the patient group, however, a significant negative correlation is found between the attentional bias scores to negative-affective cues and the duration of methadone treatment (p = 0.027), with the patients receiving longer methadone treatment showing less attentional avoidance to negative-affective cues. A significant positive correlation is found between the negative affect-induced bias and the impulsivity score (p = 0.006), with more impulsive patients showing higher attentional avoidance to negative affective cues than less impulsive patients. Additionally, the patients detect a smaller percentage of probe stimuli following the drug (p = 0.029) or negative-affective pictures (p = 0.009) than the healthy controls.Conclusion: The results of the present study indicate that the patients under chronic methadone maintenance therapy show normalized attentional bias to drug and negative-affective cues, confirming the involuntary attention of the patients is not abnormally captured by external drug or negative-affective clues. Our findings also highlight that the attentional avoidance of negative-affective cues is modulated by the duration of methadone treatment and the impulsivity level in the patients