Metabolic Effects of Differential Organ Growth Rates

Completed

• Conditions: Resting Energy Expenditure

• Registration Number: NCT03219229
• Lead Sponsor: Columbia University

Brief Summary

Young children have a high resting energy expenditure (REE) relative to their body weight and metabolically active compartment, fat-free mass (FFM). Both body weight and FFM are, however, metabolically heterogeneous and include organs and tissues varying widely in specific metabolic rate (i.e., organ REE/kg/d). One prevailing hypothesis is that most, if not all, of the higher REE observed in young animals and children compared to adults can be accounted for by a larger proportion of high metabolic rate components such as brain, liver, and heart..

Detailed Description

FFM was the traditional and only means of adjusting REE for between-individual differences in metabolically active tissue components. The investigators seek to improve the understanding of variation in REE by developing new and improved rapid magnetic resonance imaging (MRI) methods of quantifying some of the major heat producing organs and tissues in children and adults. The long-term aim is to provide an improved understanding of human energy requirements. Specifically, the investigators propose to test whether: 1) a portion of the elevated daily REE adjusted for FFM observed in young children (Tanner Stage 1) could be accounted for by the relative fractions of body mass as high metabolic activity tissues (heart, liver, kidney, brain) and low metabolic activity tissues (skeletal muscle, adipose tissue), 2) a portion of the age-related decline in daily REE adjusted for FFM observed in children could be accounted for by changes in the relative fractions of body mass as high and low metabolic rate tissues during growth.

Study Timeline

• Study Start: 2004-02-14
• Primary Completion: 2007-02-20
• Study Completion: 2007-02-20
• Status Verified: 2017-07
• Study First Submitted: 2017-07-11
• Study First Submitted QC: 2017-07-13
• Last Update Submitted: 2017-07-14
• Study First Posted: 2017-07-17
• Last Update Posted: 2017-07-18

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 49

Inclusion Criteria

• Healthy
• Aged from 7-11 years
• Pre-pubertal (based on Tanner staging)
• Africa-American, Asian, and Caucasian (by self-report of all 4 grandparents of same race group)

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Exclusion Criteria

• Actively involved in a weight management program
• Have co-morbidities of obesity (Blounts disease, hypertension, diabetes; sleep apnea)
• Have entered puberty
• Precocious puberty
• Have known metabolic abnormalities
• Were born prematurely, or were small or large for gestational age
• Lean individuals who have a family history (parents or siblings) of obesity or Type 2 diabetes
• Current or previous significant use of any medication known to affect any of the variables being measured

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Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Weight in kilograms	Day 1	Measured using a calibrated scale
Heart in kilogram	Day 1	Left ventricular mass measured by cardiac gated MRI
Spleen in kilograms	Day 1	Total volume measured by MRI
Liver in kilograms	Day 1	Total volume measured by MRI
Resting energy expenditure in kilocalories	Day 1	REE is measured by indirect calorimetry over a 30 minute period and extrapolated to a 24 hour period
Fat mass in kilograms	Day 1	Measured from a whole-body dual energy X-ray absorptiometry (DXA) scan
Fat-free mass in kilograms	Day 1	Measured from a whole-body dual energy X-ray absorptiometry (DXA) scan
Trunk high metabolic rate organs in kilograms	Day 1	The sum of liver, kidneys, spleen, and heart
Residual fat-free mass in kilograms	Day 1	Fat-free mass minus the sum of kidneys, liver, spleen, heart, and skeletal muscle
Height in meters	Day 1	Measured using a stadiometer
Kidneys in kilogram	Day 1	Total volume measured by MRI
Skeletal muscle mass in kilograms	Day 1	Skeletal muscle volume measured by MRI
Variability in resting energy expenditure	Day 1	The collected measures will be aggregated to statistically test the following question: How much of the variability in resting energy expenditure can be accounted for by the mass of the measured organs (liver, kidneys, spleen, heart) and tissues (fat, skeletal muscle, brain) and is the explained variance greater than the variance explained when predicting resting energy explained from a model using fat and fat-free mass alone.
Total body adipose tissue mass in kilogram	Day 1	Represents the sum of visceral, subcutaneous, and intermuscular adipose tissue by MRI
Brain mass in kilogram	Day 1	Total volume measured by MRI
Body mass index in kg/m2	Day 1	Weight and height will be combined to report BMI

Secondary Outcome Measures

Name	Time	Method
Change in resting energy expenditure in relation to changes in body composition and organ mass.	From baseline measure to follow-up, approximately 2 years	A portion of age-related decline (2-years) in daily REE adjusted for FFM observed in children is explainable in part by changes in the relative fractions of body mass as high (brain, heart, liver, kidney) and low (skeletal muscle, adipose tissue) metabolic activity tissues with growth and pubertal progress

Trial Locations

Locations (1)

Dympna Gallagher; 🇺🇸 New York, New York, United States