Infant age at egg introduction and malnutrition-related child growth in the United States

Area of Science:

• Pediatric Nutrition and Growth
• Infant Feeding Practices
• Malnutrition and Child Development

Background:

• The optimal timing for introducing allergenic foods, such as eggs, remains a key area of infant nutrition research.
• Understanding the impact of delayed egg introduction on child growth is crucial for public health guidelines.

Purpose of the Study:

• To investigate the association between the age of egg introduction in infancy and malnutrition-related growth outcomes in US children.
• To explore potential sex-based differences in these growth outcomes.

Main Methods:

• Analysis of secondary data from 1716 mother-child dyads from the Infant Feeding Practices Study II and its Year 6 Follow-Up Study.
• Growth outcomes assessed included body mass index z-score (BMIZ), weight-for-height z-score (WHZ), height-for-age z-score (HAZ), and related malnutrition indicators (obesity, wasting, stunting).
• Generalized estimating equations were used to analyze continuous and binary outcomes, adjusting for confounders and exploring interactions.

Main Results:

• Later introduction of eggs was associated with a lower mean height-for-age z-score (HAZ) and increased risk of stunting at 6 years.
• The association between egg introduction timing and growth outcomes differed by child sex at 12 months.
• Among females, later egg introduction correlated with a lower mean weight-for-height z-score (WHZ) at 12 months.

Conclusions:

• Delayed introduction of eggs during infancy may negatively impact long-term growth, specifically height and stunting risk, by age six.
• Sex-specific effects highlight that later egg introduction is associated with reduced weight-for-height in 12-month-old girls.
• Findings underscore the importance of considering infant feeding timing in relation to growth monitoring and nutritional guidance.