Author(s): RAINE, L., THOMAS, A., WARD, K., BRAUN, B., CORRIGAN-HOAGLIN, K., GABARD-DURNAM, L., ZIMMERMAN, E., Institution: NORTHEASTERN UNIVERSITY, Country: UNITED STATES, Abstract-ID: 1095

Introduction: Infancy reflects a critical period, with large adaptations in cognitive, behavioral, and motor development occurring alongside significant physical growth. Significant weight fluctuations during the first two years of life have been associated with poor neurodevelopmental outcomes. Specifically, changes in fat mass (FM) vs fat-free mass (FFM) in early life may impact cognitive and motor development. However, minimal research exists investigating the differential role of FM vs FFM on cognitive and motor development in early life. This study investigated body composition (BMI, FM, and FFM), motor development, and cognition in the first three years of life in typically developing children.
Methods: Cognitive, fine motor, and gross motor portions of The Bayley Scales of Infant and Toddler Development – 3rd Edition were administered to participants (N = 35; age 11.86 ± 8.47 months, 54% female) to assess development. Infant length or height and weight were taken, and BMI z-scores were determined using the WHO Anthropometric Software. Body Composition measures were measured using the COSMED PEA POD or BOD POD pediatric option to estimate FM and FFM. An infant’s percent FM (%FM) was calculated as their FM divided by their total mass, and percent FFM (%FFM) as their FFM divided by their total mass. Partial correlations controlling for demographic features (age, sex, mother’s education, BMI-z, and birthweight) were conducted to understand the relationship between %FM and %FFM with cognitive and motor development.
Results: Correlations on the full sample of 40 infants (11.62 ± 8.77 months, 20 males) revealed that infant BMI-z score was positively correlated with all three Bayley scores (cognition, r = 0.40, p = 0.02; fine motor, r = 0.40, p = 0.02; gross motor, r = 0.44, p = 0.01). However, in a smaller sample of 21 infants (62% female), the following partial correlations were observed for Bayley scores with %FM and %FFM, controlling for infant age, sex, mothers’ education, BMI-z score, and birthweight:
Higher FFM% was positively associated with fine motor (r = 0.47, p = 0.038) and cognitive scores (r = 0.46, p = 0.039), while higher FM% was negatively associated with fine motor (r = −0.47, p = 0.038) and cognitive outcomes (r = −0.46, p = 0.039)
Discussion: These findings highlight the role that different tissue types have in relation to cognitive/motor development. Specifically, fat free mass appears to be advantageous in terms of cognitive and motor development in infants. Furthermore, these preliminary findings highlight the importance of obtaining detailed, specific measures of infant physical growth and development to better understand associations between physical development and cognitive/motor development.