Centile reference chart for resting metabolic rate through the life course.

Area of Science:

• Metabolic Physiology
• Growth Assessment
• Endocrinology

Background:

• Reference centile charts are crucial for growth assessment, evolving from simple height and weight to include body composition.
• Resting energy expenditure (REE) is a key metabolic indicator, but its assessment relative to lean mass across the life course is less established.

Purpose of the Study:

• To develop and present reference centile charts for a resting energy expenditure (REE) index, adjusted for lean mass and age.
• To evaluate the clinical utility of these charts in a patient with resistance to thyroid hormone alpha (RTHα).

Main Methods:

• Indirect calorimetry was used to measure REE in 411 healthy children and adults (aged 6-64 years).
• Dual-energy X-ray absorptiometry assessed body composition.
• Serial measurements were taken in a patient with RTHα during hormone therapy.

Main Results:

• The centile charts reveal significant variability in the REE index across age groups.
• At age 6 years, the REE index ranged from 0.41 to 0.59 (2nd-98th centile); at age 25 years, it ranged from 0.28 to 0.40.
• The RTHα patient's REE index varied with lean mass and treatment adherence, demonstrating clinical applicability.

Conclusions:

• Reference centile charts for the lean mass-adjusted REE index in children and adults have been successfully developed.
• These charts provide a valuable tool for assessing resting metabolic rate and its response to therapy in endocrine disorders during life transitions.