Body composition during the first 2 years of life: an updated reference

Area of Science:

• Pediatric Nutrition
• Human Physiology
• Growth and Development

Background:

• Accurate assessment of infant body composition is vital for monitoring growth and nutritional status.
• Existing normative data may not reflect current pediatric populations with mixed feeding practices.

Purpose of the Study:

• To derive normative body composition data for children during the first two years of life.
• To present fat-free mass (FFM) and fat mass (FM) components, growth rates, and conversion constants.
• To establish age- and gender-specific references for pediatric body composition assessment.

Main Methods:

• Prospective study of 76 children from 0.5 to 24 months of age.
• Utilized a multicomponent model including total body water (TBW) via deuterium dilution, total body potassium (TBK) by whole body counting, and bone mineral content (BMC) via DXA.
• Estimated FFM and FM at multiple time points throughout the first two years.

Main Results:

• FFM was higher in boys than girls from 0.5-18 months. Percent FM increased initially then declined, with higher percentages in girls at 6 and 9 months.
• FFM components changed with age, notably increasing protein content and bone mineral percentage, while TBW decreased.
• FFM density and potassium content increased with age, providing further normative insights.

Conclusions:

• This study provides updated normative body composition data for infants and toddlers.
• These references are valuable for assessing the growth and nutritional status of diverse pediatric populations.
• The findings contribute to a better understanding of physiological changes during early childhood development.