Stress and Eating Behavior Among University Students - an Randomized Controlled Trial

Study Overview
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Brief Summary
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The high worldwide prevalence of overweight and obesity as well as metabolic and disease consequences, are well-documented. The positive energy balance underlying obesity is attributable to excess energy intake and/or insufficient energy expenditure. However, it seems that the increase in mean body weight can be sufficiently explained by increases in mean energy intake. It has been proposed that this overeating is partly caused by increased availability of highly processed energy dense, high reward foods. Psychosocial stress and sleep insufficiency is pervasive in industrialized societies. A growing body of evidence suggests stress to be involved in obesity, although it is unknown whether stress is a cause or consequence. Stress affecting dietary intake; skewing intake towards greater consumption of highly palatable energy dense foods, also referred to as high reward foods. A causal relationship between stress and reward seeking behavior is supported by findings from animal studies reporting rewarding behavior by consumption of sweet tasting food in response to a stressor. Our aim is to investigate differences in purchases of particular food-items in free living individuals, during a stressful (upcoming exam) and non-stressful (no upcoming exam) period. Hypothesis: Participants will purchase more high reward foods during the pre-exam period, compared to the control non-exam period.

Detailed Description
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STUDY METHODS Study design: The study is a randomized controlled two-armed cross-over intervention study. The study is carried out in 50 healthy university students, both genders. In random order the participants will be investigated during stressful-period (prior to an exam) and a non-stressful (control period) period. Each participant will take part in all together four visits, two in the stressful period and two visits in the non-stressful period. The study will take place, at the Department of Nutrition, Exercise and Sports (NEXS), Faculty of Science at the University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C. Recruitment will take place at the University of Copenhagen STATISTICAL ANALYSES Analysis of the primary outcome (food choices) will be based on an ANCOVA-type linear mixed model with the intervention and allocation order as the fixed effect and person as the random effect. Analysis will be performed using the software R, SAS, STATA or SPSS. Analyses, data processing and writing of the article are expected to extend over the study period and a year beyond.

Official Title
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StrEat - Stress and Eating Behavior

Conditions
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Stress

Intervention / Treatment
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* Other: University exam-period
* Other: University non-exam-period


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy, weight stabile (defined as no weight gain/loss >3 kg during the past three months) students at the University of Copenhagen Age > 18 years, men and women Exclusion Criteria: Purposefully seeking to lose or gain weight Diabetes. Blood donation < 1 week prior to the study and during the study Lactation, Pregnancy or planning of pregnancy during the study Inability, physically or mentally, to comply with the procedures required by the study- protocol, as evaluated by the investigator Participation in other clinical trials during the study Diagnosed with stress Daily use of medication influencing biomarkers of stress
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: University Exam Period<br>This visit takes place the week before an exam at the university assuming that this will induce a stress response. Measurements (see description elsewhere) are being taken within 1-2 weeks prior to an university exam. | Other: University exam-period<br>* This visit takes place one week prior to an exam at the university assuming that students will be stressed in this period.<br>|
| Placebo Comparator: University Non-exam Period<br>This visit takes place several weeks post and prior to an exam at the university assuming that students will not be stressed in this period. Measurements (see description elsewhere) are being taken in a control-period without exams (at least 4 weeks after and 4 weeks prior to an exam) | Other: University non-exam-period<br>* This visit takes place several weeks post and prior to an exam at the university assuming that students will not be stressed in this period.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Differences in purchase of high reward foods from the gift certificates between the exam-period and non-exam period. | The classification will be done blinded for the outcome assessor. | The outcome is assessed twice, once in the exam period (one week prior to an exam) and once in the non-exam period (four to five weeks prior and post an exam ) Data are analyzed after last subject last visit (May 2016) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Differences in Heart Rate Variability (HRV) based on a one minute breathing test between the exam-period and non-exam period. | The classification will be done blinded for the outcome assessor. | The outcome is assessed twice, once in the exam period (one week prior to an exam) and once in the non-exam period (four to five weeks prior and post an exam ) Data are analyzed after last subject last visit (May 2016) | 
| Differences in morning cortisol measured in saliva between the exam-period and non-exam period. | The classification will be done blinded for the outcome assessor. | The outcome is assessed twice, once in the exam period (one week prior to an exam) and once in the non-exam period (four to five weeks prior and post an exam ) Data are analyzed after last subject last visit (May 2016) | 
| Differences in insulin resistance measured by homeostatic model assessment (HOMA-IR) calculated from insulin and glucose measured in plasma between the exam-period and non-exam period. | The analyses will be done blinded for the outcome assessor. | The outcome is assessed twice, once in the exam period (one week prior to an exam) and once in the non-exam period (four to five weeks prior and post an exam ) Data are analyzed after last subject last visit (May 2016) | 
| Differences in Perceived Stress (Perceived Stress Scale, PSS) between the exam-period and non-exam period. | The analyses will be done blinded for the outcome assessor. | The outcome is assessed twice, once in the exam period (one week prior to an exam) and once in the non-exam period (four to five weeks prior and post an exam ) Data are analyzed after last subject last visit (May 2016) | 
| Differences in eating behavior using the Three factor eating questionnaire between the exam-period and non-exam period. | The analyses will be done blinded for the outcome assessor. | The outcome is assessed twice, once in the exam period (one week prior to an exam) and once in the non-exam period (four to five weeks prior and post an exam ) Data are analyzed after last subject last visit (May 2016) | 
| Differences in sleep habits using the Pittsburgh sleep quality index between the exam-period and non-exam period. | The analyses will be done blinded for the outcome assessor. | The outcome is assessed twice, once in the exam period (one week prior to an exam) and once in the non-exam period (four to five weeks prior and post an exam ) Data are analyzed after last subject last visit (May 2016) | 
| Differences in sleep duration measured by ActiGraph between the exam-period and non-exam period. | The analyses will be done blinded for the outcome assessor. | The outcome is assessed twice, in the exam period (one week prior to an exam) and in the non-exam period (four to five weeks prior and post an exam ) Data are analyzed after last subject last visit (May 2016) | 
| Differences in activity measured by ActiGraph between the exam-period and non-exam period. | The analyses will be done blinded for the outcome assessor. | The outcome is assessed twice,in the exam period (one week prior to an exam) and in the non-exam period (four to five weeks prior and post an exam ) Data are analyzed after last subject last visit (May 2016) | 
| Differences in blood pressure between the exam-period and non-exam period. | The analyses will be done blinded for the outcome assessor. | The outcome is assessed twice, once in the exam period (one week prior to an exam) and once in the non-exam period (four to five weeks prior and post an exam ) Data are analyzed after last subject last visit (May 2016) | 
| Differences in Perceived Stress ( questionaire: RESTQ-76 sport) between the exam-period and non-exam period. | The analyses will be done blinded for the outcome assessor. | The outcome is assessed twice, once in the exam period (one week prior to an exam) and once in the non-exam period (four to five weeks prior and post an exam ) Data are analyzed after last subject last visit (May 2016) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Stress, Eating