Small for gestational age and higher birth weight predict childhood obesity in preterm infants

Area of Science:

• Pediatrics
• Neonatology
• Public Health

Background:

• Childhood obesity is a significant public health concern, particularly among preterm infants who face unique developmental challenges.
• Prenatal exposure to substances and factors like small for gestational age (SGA) may influence long-term metabolic health and obesity risk.
• Understanding the interplay between early life factors and later obesity is crucial for targeted interventions in high-risk populations.

Purpose of the Study:

• To investigate the association between small for gestational age (SGA), birth weight, and childhood obesity in preterm children exposed to polysubstances.
• To identify key growth-related factors, including growth velocity and physical activity, associated with obesity and overweight in this cohort.
• To determine if prenatal substance exposure modifies the relationship between early life factors and subsequent obesity.

Main Methods:

• A cohort of 312 preterm children from the Maternal Lifestyle Study with 11-year body mass index (BMI) data was analyzed.
• Multinomial regression models were used to assess associations between 11-year obesity (OBE) and overweight (OW) and SGA, birth weight, growth velocity, diet, and physical activity.
• Adjusted analyses controlled for potential confounders, and the impact of prenatal cocaine and tobacco exposure was examined.

Main Results:

• Overall, 24% of children were obese (BMI for age ≥95th percentile) and 16.7% were overweight (BMI ≥85th and <95th percentiles).
• Small for gestational age (SGA) was significantly associated with overweight (OR=3.4), while higher birth weight correlated with both obesity (OR=1.8) and overweight (OR=1.4).
• Increased first-year growth velocity (OR=2.7 for OBE, OR=1.6 for OW) and low physical activity (OR=2.1 for OBE, OR=2.1 for OW) were also linked to higher obesity and overweight risk. Prenatal substance exposure did not significantly affect obesity outcomes.

Conclusions:

• A substantial proportion (41%) of these high-risk preterm children were obese or overweight by age 11.
• Fetal programming, indicated by SGA, and postnatal growth trajectories play significant roles in the development of obesity in preterm children.
• Interventions focusing on optimizing early growth and promoting physical activity may be critical for preventing obesity in preterm populations, irrespective of prenatal substance exposure.