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Respiratory Effects of Obesity in Children

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ClinicalTrials.gov Identifier: NCT03376880
Recruitment Status : Recruiting
First Posted : December 19, 2017
Last Update Posted : April 5, 2018
Sponsor:
Information provided by (Responsible Party):
University of Texas Southwestern Medical Center

Brief Summary:
In obese children, excess fat on the thorax exerts an unfavorable burden on the respiratory system, particularly during exercise; however, it is unclear if this burden reduces exercise tolerance, provokes dyspnea on exertion, or contributes to respiratory symptoms that could be misdiagnosed as asthma, placing obese children at risk of unnecessary treatment and potentially a reluctance to exercise explaining reports of low physical activity and fitness levels, which are counterproductive to weight loss. The investigators will examine the respiratory effects of obesity in prepubescent boys and girls, including those with respiratory symptoms misdiagnosed as asthma, before and after 1) a program of weight loss and regular exercise and 2) continued weight gain as compared with prepubescent normal weight boys and girls before and after 1 year. These results will have broad and immediate clinical impact on the care of obese children, especially those with respiratory symptoms misdiagnosed as asthma, and the results could alter interventional approaches for preventing and treating childhood obesity.

Condition or disease Intervention/treatment
Childhood Obesity Other: 1 year follow-up testing

Detailed Description:

In obese children, excess fat exerts an unfavorable burden on the respiratory system, particularly during exercise, potentially reducing exercise tolerance and leading to DOE (dyspnea on exertion), which could explain reports of low physical activity and fitness levels in obese children. The investigators propose that most of the respiratory effects in obese children are the result of low lung volume breathing, i.e., a reduction in functional residual capacity (FRC) at rest, and end-expiratory lung volume (EELV) during exercise.

The overall objective of this application is to investigate the respiratory effects of obesity in prepubescent children, including obese children with respiratory symptoms misdiagnosed as asthma, before and after 1) a program of weight loss and regular exercise and 2) continued weight gain as compared with normal weight children before and after 1 yr. The investigative approach will be to examine respiratory function, exercise tolerance, and DOE in prepubescent obese boys and girls, including those misdiagnosed with asthma (i.e., asthma not confirmed by lung function tests), before and after 1) weight loss (or an equivalent reduction in BMI percentile) and regular exercise and 2) continued weight gain (or an increase in BMI percentile) as compared with prepubescent normal weight boys and girls before and after a control period of 1 yr.

Specific Aims: The following hypotheses will be tested in obese children as compared with normal weight children:

Aim 1) Obesity will decrease respiratory function but to a greater extent in obese children misdiagnosed with asthma as evidenced by altered pulmonary function and breathing mechanics at rest; Aim 2) Obesity will decrease exercise tolerance (as evidenced by peak VO2 in ml/min/kg, i.e., physical fitness), but not cardiorespiratory fitness (as evidenced by peak VO2 in % of predicted based on ideal body wt), except in obese children misdiagnosed with asthma where both may be reduced during graded cycle ergometry; Aim 3) Obesity will increase DOE but to a greater extent in obese children misdiagnosed with asthma as evidenced by increased ratings of perceived breathlessness during constant load exercise cycling; and Aim 4) Weight loss and regular exercise will improve respiratory function, exercise tolerance, and DOE in obese children, including those misdiagnosed with asthma, while continued weight gain will worsen respiratory function, exercise tolerance, and DOE in obese children, including those misdiagnosed with asthma, as compared with normal weight children before and after 1 yr.

The long-term objective is to investigate the effects of obesity on respiratory function, exercise tolerance, and DOE, examine obesity-related respiratory symptoms misdiagnosed as asthma in obese children, and provide novel results that could alter interventional approaches for preventing obesity and treating obesity in obese children. Thus, these results will have broad and immediate clinical impact on the care of obese children, especially those with respiratory symptoms misdiagnosed as asthma.


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Study Type : Observational
Estimated Enrollment : 96 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Respiratory Effects of Obesity in Children
Actual Study Start Date : April 26, 2017
Estimated Primary Completion Date : June 30, 2022
Estimated Study Completion Date : June 30, 2022

Resource links provided by the National Library of Medicine


Group/Cohort Intervention/treatment
Obese Boys
Obese boys group defined by a Tanner score ≤ 3 in 8-12 yr olds with a BMI > 95th percentile, which will be expressed as a percentage above the 95th percentile < 150% of the 95th percentile.
Other: 1 year follow-up testing
The approach of the study is not in studying the effectiveness of the intervention stimulus, the dose response of diet and exercise, or the rate of weight loss but only the response to 1) weight loss and regular exercise or 2) continued weight gain.

Obese Girls
Obese girls group defined by a Tanner score ≤ 3 in 8-12 yr olds with a BMI > 95th percentile, which will be expressed as a percentage above the 95th percentile < 150% of the 95th percentile.
Other: 1 year follow-up testing
The approach of the study is not in studying the effectiveness of the intervention stimulus, the dose response of diet and exercise, or the rate of weight loss but only the response to 1) weight loss and regular exercise or 2) continued weight gain.

Normal Weight Boys
Normal weight boys group defined by a Tanner score ≤ 3 in 8-12 yr olds with a BMI between 16th and 84th percentile.
Other: 1 year follow-up testing
The approach of the study is not in studying the effectiveness of the intervention stimulus, the dose response of diet and exercise, or the rate of weight loss but only the response to 1) weight loss and regular exercise or 2) continued weight gain.

Normal Weight Girls
Normal weight girls group defined by a Tanner score ≤ 3 in 8-12 yr olds with a BMI between 16th and 84th percentile.
Other: 1 year follow-up testing
The approach of the study is not in studying the effectiveness of the intervention stimulus, the dose response of diet and exercise, or the rate of weight loss but only the response to 1) weight loss and regular exercise or 2) continued weight gain.

Obese Boys Misdiagnosed with Asthma
Obese boys group defined by a Tanner score ≤ 3 in 8-12 yr olds with a BMI > 95th percentile, which will be expressed as a percentage above the 95th percentile < 150% of the 95th percentile.This group will have a prior diagnosis of asthma without confirmation by lung function testing.The absence of asthma will be confirmed by a negative response (<10% increase in FEV1) to spirometry before and after bronchodilator (and on visit 2 by a negative bronchial challenge test [<10% decrease in FEV1]; i.e., EVH).
Other: 1 year follow-up testing
The approach of the study is not in studying the effectiveness of the intervention stimulus, the dose response of diet and exercise, or the rate of weight loss but only the response to 1) weight loss and regular exercise or 2) continued weight gain.

Obese Girls Misdiagnosed with Asthma
Obese girls group defined by a Tanner score ≤ 3 in 8-12 yr olds with a BMI > 95th percentile, which will be expressed as a percentage above the 95th percentile < 150% of the 95th percentile.This group will have a prior diagnosis of asthma without confirmation by lung function testing.The absence of asthma will be confirmed by a negative response (<10% increase in FEV1) to spirometry before and after bronchodilator (and on visit 2 by a negative bronchial challenge test [<10% decrease in FEV1]; i.e., EVH).
Other: 1 year follow-up testing
The approach of the study is not in studying the effectiveness of the intervention stimulus, the dose response of diet and exercise, or the rate of weight loss but only the response to 1) weight loss and regular exercise or 2) continued weight gain.




Primary Outcome Measures :
  1. Pulmonary Function: Lung Volumes [ Time Frame: Change from Baseline in difference between nonobese and obese children at 1 yr ]
    Pulmonary function is comprised of several physiological variables but this study will primarily measure Lung Volume: FRC (liters) and TLC (liters)

  2. Exercise Tolerance - Peak VO2 [ Time Frame: Change from Baseline differences between nonobese and obese children at 1 yr ]
    Exercise Tolerances is represented by several physiological variables but the primary variable is Maximal oxygen uptake (L/min and percent predicted)

  3. Dyspnea on Exertion [ Time Frame: Change from Baseline differences between nonobese and obese children at 1 yr ]
    Dyspnea on Exertion is represented using the Borg Scale which provides Ratings of Perceived Breathlessness (RPB) during constant load exercise cycling. The Borg Scale measures from 0-10, where 0 = no breathlessness and 10 = maximal breathlessness.


Other Outcome Measures:
  1. Pulmonary Function: Spirometry [ Time Frame: Change from Baseline differences between nonobese and obese children at 1 yr ]
    Spirometry includes: FVC (liters), FEV1 (liters), FEV1/FVC (% ratio), and peak flow (liters/sec)

  2. Pulmonary Function: Diffusing Capacity [ Time Frame: Change from Baseline differences between nonobese and obese children at 1 yr ]
    Diffusing Capacity: DLco (ml/mmHg/min)

  3. Exercise Tolerance: Work Rate [ Time Frame: Change from Baseline differences between nonobese and obese children at 1 yr ]
    Associated variables such as work rate (W)

  4. Exercise Tolerance: Minute Ventilation [ Time Frame: Change from Baseline differences between nonobese and obese children at 1 yr ]
    Associated variables such as pulmonary ventilation (L/min)

  5. Exercise Tolerance: Operational Lung Volumes [ Time Frame: Change from Baseline differences between nonobese and obese children at 1 yr ]
    Associated variables such as operational lung volumes (EELV and EILV as a % of TLC)



Information from the National Library of Medicine

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Ages Eligible for Study:   8 Years to 12 Years   (Child)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Participants included in the study will be prepubescent boys and girls aged 8-12 yr old of all racial and ethnic origins with a Tanner Pubertal Stage of ≤ 3, and the ability to perform pulmonary function and exercise test accurately.
Criteria

Inclusion Criteria:

  • Otherwise healthy with normal lung function; prepubescent (Tanner equal to or less than 3); age and gender specific BMI > 95th percentile, but less than 150% of the 95th percentile based on the CDC standards or age and gender specific BMI between the 16th and 84th percentile based on the CDC standards; and ability to perform pulmonary and exercise test accurately.

Exclusion Criteria:

  • Children with significant diseases other than obesity or shortness of breath on exertion will be excluded. Subjects participating in regular conditioning-type vigorous exercise two times or more per week will be excluded (i.e., sports training). Children who are non-English speaking will be excluded from the study because the tests performed are very effort dependent, detailed, and require technical communication between the staff and the child.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03376880


Contacts
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Contact: Jamie Research Nurse 214-345-6574 IEEMLung@TexasHealth.org
Contact: Daniel Wilhite, Ph.D. 214-345-6501 IEEMLung@TexasHealth.org

Locations
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United States, Texas
Institute for Exercise and Environmental Medicine, UT Southwestern and Texas Health Presbyterian Hospital Dallas Recruiting
Dallas, Texas, United States, 75231
Contact: Jamie Research Nurse    214-345-6574    IEEMLung@TexasHealth.org   
Contact: Daniel Wilhite, Ph.D.    2143456501    IEEMLung@TexasHealth.org   
Principal Investigator: Tony G Babb, Ph.D.         
Sponsors and Collaborators
University of Texas Southwestern Medical Center
Investigators
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Principal Investigator: Tony G Babb, Ph.D. UT Southwestern Medical Center
  Study Documents (Full-Text)

Documents provided by University of Texas Southwestern Medical Center:
Informed Consent Form  [PDF] November 22, 2017


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Responsible Party: University of Texas Southwestern Medical Center
ClinicalTrials.gov Identifier: NCT03376880     History of Changes
Other Study ID Numbers: UTexasSouthwestern-Babb
First Posted: December 19, 2017    Key Record Dates
Last Update Posted: April 5, 2018
Last Verified: April 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No

Additional relevant MeSH terms:
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Obesity
Pediatric Obesity
Overnutrition
Nutrition Disorders
Overweight
Body Weight
Signs and Symptoms