604 - Role of Maternal Body Mass Index in the Association of Infant Appetitive Traits with Early Growth Velocity

Poster Number: 604
Publication Number: 604.2895

Background: Early pregnancy maternal body mass index (mBMI), infant appetitive traits, and rapid weight gain (RWG) in infancy predict obesity risk through the lifecourse. Yet, it is unknown whether specific growth periods during infancy are more sensitive to appetitive traits and how mBMI may modify these associations.

Objective: To determine associations of infant appetitive traits with growth trajectories during specific developmental periods in infancy and whether mBMI modifies these associations.

Design/Methods: We included 63 mother-infant dyads from a longitudinal cohort study in Boston, MA. We obtained early ( < 15 weeks) pregnancy weight and height from medical records, calculated and categorized BMI per WHO criteria. Mothers reported on their infant (1) appetitive traits during the first 3 months of life using the Baby Eating Behavior Questionnaire (BEBQ) and (2) weights and lengths from pediatrician visits, from which we derived WHO age- and sex- standardized BMIz scores. We calculated cohort-specific z-scores for each of the BEBQ subscales and categorized infants in the lowest vs. two highest tertiles. We used linear spline mixed-effects models to examine whether BMIz growth velocities and BMIz scores in early (birth-6 wks), mid (6wks-5mo), and later (5mo-13mo) infancy differed by category of eating behaviors. We then used stratified models to examine whether these associations differ by mBMI category.

Results: Cohort characteristics are presented in Table 1 . Twenty-nine (46%) mothers had BMI in the overweight/obese (OWOB) category. Infants exposed in utero to maternal OWOB (vs. normal BMI) tended to more likely have higher scores in the enjoyment of food subscale (75% vs. 56%, p=0.12). Lower satiety responsiveness was associated with greater BMIz velocity (β 0.30 SD units/month; CI: -0.01, 0.62) in mid-infancy, and lower food responsiveness with lower velocity (-0.20; -0.39, -0.02) in late infancy, resulting in higher and lower BMIz at 10 months of age, respectively (Fig.1). Lower slowness in eating scores were associated with lower BMIz velocity (-0.59; -1.17, -0.01) in early infancy. In stratified analyses, we found that these associations were driven by exposure to maternal OWOB in utero given differences in growth velocities were only observed among infants of mothers with OWOB (Table 2).

Conclusion(s): Appetitive traits are associated with growth velocities in specific developmental windows in infancy, particularly in infants of mothers with OWOB. Characterizing appetitive traits associated with RWG across key developmental periods in infancy in high-risk groups can inform targeted interventions.