Early Infant Feeding and BMI Trajectories in the First 5 Years of Life

Area of Science:

• Pediatric nutrition
• Childhood obesity research
• Growth trajectory analysis

Background:

• Infant feeding practices significantly influence child development.
• Understanding the long-term impact of breastfeeding and solids introduction on body mass index (BMI) is crucial for public health.
• Existing research highlights potential links between feeding patterns and childhood BMI, but further clarification is needed.

Purpose of the Study:

• To investigate the independent effects of breastfeeding duration and the timing of solids introduction on body mass index z-score (BMIz) trajectories in early childhood.
• To analyze growth rate differences in relation to these feeding practices.
• To provide evidence-based recommendations for infant feeding guidelines.

Main Methods:

• Secondary analysis of prospective cohort data from the Melbourne Infant Feeding, Activity and Nutrition Trial (InFANT) Program (N=542).
• Data collected at birth and at 3, 9, 18, 42, and 60 months.
• Linear spline multilevel models used to assess BMIz trajectories.

Main Results:

• Longer breastfeeding duration (≥6 months) was associated with significantly lower BMIz from 3 to 60 months, with adjusted mean differences ranging from -0.13 to -0.44.
• Introduction of solids before 6 months was linked to higher BMIz at 18 and 42 months, though these differences were attenuated after adjustments.
• Differential growth rates were observed between birth-3 months and 9-18 months based on feeding practices.

Conclusions:

• Prolonged breastfeeding duration (≥6 months) is associated with sustained lower BMIz throughout early childhood up to 5 years.
• The timing of solids introduction also impacts BMIz, with later introduction (after 6 months) showing a protective effect.
• Findings support current infant feeding guidelines advocating for extended breastfeeding to promote healthy child growth and potentially reduce obesity risk.