Factors Associated With Obesity in Adult Women: Respiratory Exchange Ratio, Heart Rate Variation and Body Image

Study Overview
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Brief Summary
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The prevalence of obesity all over the world has increased year by year, and how to effectively prevent and treat obesity has become an important health care issue. Many adjustable and nonadjustable causes of obesity have been proposed, such as unbalanced eating habits, lack of physical activity, psychological factors, and genes. The practice guidelines recommended lifestyle modification interventions which include diet control combined with regular exercise as the core treatment for obesity, but the effects on different ethnic groups are not ideal. In order to provide more choices for future weight loss intervention, it would be important to find out more risk factors for obesity. Previous studies have shown that lower sympathetic activity assessed by heart rate variability was related to obesity; obese men have higher respiratory exchange rates which might indicate they are more likely to use carbohydrates as a source of energy, and therefore, fat cannot be effectively consumed and led to an accumulation in the body. Furthermore, previous studies showed that Asians are less satisfied with their body image than other races, and women are more dissatisfied than men. Poor body image will lead to a series of effects, such as changes in eating habits, hormonal changes, depression, etc., eventually forming a vicious circle of obesity. However, most aforementioned Asians in these studies are immigrants living in overseas areas such as the Americas, and cannot fully represent the ethnic groups in Asia. Therefore, the purpose of this study are (1) to investigate the physiological and psychological factors influence obesity in adult women, including respiratory exchange rate, heart rate variability, and body image, and (2) to examine the correlations among these risk factors and different degree of obesity.

Detailed Description
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Methods: This is a cross-sectional design study. Subjects were recruited from Taipei city. Inclusion criteria are women aged between 20 and 50 years old and have willing to participate to this study. Subjects will be excluded as follows: (1) taking medications that affect weight or hormones; (2) fluctuation of weight exceeds 2 kg within 3 months before the enrolled in study; (3) any condition that causes the subject fail to complete the test paper, such as: cognitive problems; (4) diagnosed with mental illness; (5) pregnancy or menopause. The assessments include: obesity-related indicators (height, weight, waist and hip circumference, percentage of body fat), respiratory exchange ratio, heart rate variability, body image (multi-directional self-body relationship questionnaire (MBSRQ), figure rating scale (FRS)), physical activity (Seven-days Physical Activity Recall, 7-d PAR), eating behavior (Three-Factor Eating Questionnaire, revised 18-item, TFEQ-18), and depression (Mongomery-Asberg Depression Rating Scale, MADRS). Statistical analysis will be performed by using SPSS version 18 (SPSS Inc, Chicago: SPSS Inc.), and significant level would be set at 0.05. Analysis of variance (ANOVA) will be used to examine the differences of all measured variables among different degrees of obesity groups. In addition, we will use multiple linear regression analysis to examine whether overweight and obesity are significantly related to respiratory exchange rate, heart rate variability and body image.

Official Title
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Factors Associated With Obesity in Adult Women: Respiratory Exchange Ratio, Heart Rate Variation and Body Image

Conditions
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Obesity

Intervention / Treatment
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* Device: Respiratory exchange ratio
* Device: Heart rate variability
* Device: Body composition
* Behavioral: Eating behavior
* Behavioral: Physical activity recall
* Behavioral: Depression
* Behavioral: Body image


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 20-50 years old, premenopausal Exclusion Criteria: Taking medications that affect weight or hormones Fluctuation of weight exceeds 2 kg within 3 months before the enrolled in study Any condition that causes the subject fail to complete the test paper, such as: cognitive problems Diagnosed with mental illness Pregnancy or menopause

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Female

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Non-overweight/obese & normal weight<br>Body mass index (BMI) < 24.0 kg/m^2 | Device: Respiratory exchange ratio<br>* Ask participants to supine on bed, using a ventilator hood cover upon their head. Measure respiratory exchange ratio for 15 minutes.<br>Device: Heart rate variability<br>* Ask participants to supine on bed for 10 minutes, connect electrodes on their right wrist. Measure heart rate variability for 5 minutes.<br>Device: Body composition<br>* Ask participants to supine on bed for 10 minutes, connect electrodes on their right wrist and right foot. Measure body composition.<br>Behavioral: Eating behavior<br>* Fill in questionnaire (Three-Factor Eating Questionnaire, revised 18-item, TFEQ-18).<br>Behavioral: Physical activity recall<br>* Fill in questionnaire (Seven-days Physical Activity Recall, 7-d PAR).<br>Behavioral: Depression<br>* Fill in questionnaire (Mongomery-Asberg Depression Rating Scale, MADRS).<br>Behavioral: Body image<br>* Fill in questionnaire (multi-directional self-body relationship questionnaire (MBSRQ), figure rating scale (FRS)).<br>|
| Overweight and obese<br>Body mass index (BMI) >= 24.0 kg/m^2 | Device: Respiratory exchange ratio<br>* Ask participants to supine on bed, using a ventilator hood cover upon their head. Measure respiratory exchange ratio for 15 minutes.<br>Device: Heart rate variability<br>* Ask participants to supine on bed for 10 minutes, connect electrodes on their right wrist. Measure heart rate variability for 5 minutes.<br>Device: Body composition<br>* Ask participants to supine on bed for 10 minutes, connect electrodes on their right wrist and right foot. Measure body composition.<br>Behavioral: Eating behavior<br>* Fill in questionnaire (Three-Factor Eating Questionnaire, revised 18-item, TFEQ-18).<br>Behavioral: Physical activity recall<br>* Fill in questionnaire (Seven-days Physical Activity Recall, 7-d PAR).<br>Behavioral: Depression<br>* Fill in questionnaire (Mongomery-Asberg Depression Rating Scale, MADRS).<br>Behavioral: Body image<br>* Fill in questionnaire (multi-directional self-body relationship questionnaire (MBSRQ), figure rating scale (FRS)).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Respiratory exchange ratio (RER) | Ask participants to supine on bed, using a ventilator hood cover upon their head. Measure respiratory exchange ratio for 15 minutes. Device used: Vmax® Encore Metabolic Cart, Carefusion Corporation, Yorba Linda, California (CA). Normal range: 0.7-1.0, greater value indicates more carbohydrates oxidation, while smaller value indicates more fat oxidation. | After filling in all questionnaires, lasting 15 minutes. | 
| Heart rate variability (HRV) | Ask participants to supine on bed for 10 minutes, connect electrodes on their right wrist. Measure heart rate variability for 5 minutes. Device used: SS1C, Enjoy Research Inc., Taiwan. High frequency (HF): greater value indicates active parasympathetic activity. Low frequency-high frequency ratio (LF/HF): greater value indicates active sympathetic activity. | After measuring respiratory exchange ratio, lasting 15 minutes. | 
| Body image | Fill in questionnaire (multi-directional self-body relationship questionnaire (MBSRQ)). There are 69 questions, each question scores 1-5 points. Sum up all points, greater value indicates better body image. | After filling in basic data questionnaire, lasting 10 minutes. | 
| Body image (evaluative component) | Figure rating scale (FRS) is used. Nine figures of women (from lean to obese) is provided, participants are asked to choose which figure fits her present and ideal appearance the most. Scoring 1-9 points, greater value indicates poorer body image. | After filling in multi-directional self-body relationship questionnaire (MBSRQ), lasting 5 minutes. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Body fat percentage | Ask participants to supine on bed for 10 minutes, connect electrodes on their right wrist and right foot. Measure body fat percentage. Device used: Maltron BioScan 920-2. Greater value indicates higher body fat percentage. | After measuring heart rate variability, lasting 5 minutes. | 
| Physical activity | Fill in questionnaire (Seven-days Physical Activity Recall, 7-d PAR). Participants are asked to recall average time spent in a week on sleeping and activities of different intensities (Unit: metabolic equivalent of tasks (METs)). Sleeping, mild activity, moderate activity, vigorous activity, very vigorous activity are calculated as 1, 1.5, 4, 6, 10 METs respectively. Sum up all METs, divided by 7, we can obtain average daily energy expenditure. Greater value indicates more physical activity done. | After filling in body image questionnaire, lasting 5 minutes. | 
| Eating behavior | Fill in questionnaire (Three-Factor Eating Questionnaire, revised 18-item, TFEQ-18). This questionnaire includes 18 questions, scoring 1-4 points, except question 18 (1-8 points). Sum up all points, greater value indicates better eating behavior. | After filling in physical activity questionnaire, lasting 5 minutes. | 
| Depression | Fill in questionnaire (Mongomery-Asberg Depression Rating Scale, MADRS). This questionnaire includes 10 questions, scoring 0-6 points. Sum up all points, greater value indicates more depressed. | After filling in eating behavior questionnaire, lasting 5 minutes. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Respiratory exchange ratio, Body image, Heart rate variability