0255 Longitudinal Trajectories of Infant Circadian Rest-Activity Patterns and Their Association with Neurodevelopment at 12 Months: The Snuggle Bug Study

Abstract Introduction Infant sleep-wake development is associated with neurodevelopmental outcomes, yet prior literature shows mixed findings that vary by age of assessment, measurement modality, number of follow-up periods, and neurodevelopmental domain. Most studies also rely on parent-reported infant sleep, limiting precision. This secondary analysis examined actigraphy-assessed circadian rest-activity (CRA) trajectories across infancy and their associations with neurodevelopmental domains at 12 months. Methods In this longitudinal, observational cohort (Snuggle Bug | Acurrucadito), singleton, full-term infants (≥37 weeks) born of normal weight were recruited from the Phoenix, AZ community. At six timepoints (3 and 8 weeks; 3, 6, 9, and 12 months), infants wore an ankle actigraph (Micro Motionlogger, Ambulatory Monitoring, Inc.) for five consecutive 24-hr periods. Minute-level data were used to derive CRA metrics: relative amplitude (RA) and interdaily stability (IS). At 12 months, mothers completed the Ages and Stages Questionnaire-3 (ASQ-3), yielding scores in infant communication, gross motor, fine motor, problem-solving, and personal-social domains, categorized using age-normative cutpoints. Latent growth curve analysis (LGCA) identified CRA trajectory classes and tested associations between CRA class membership and ASQ categories, adjusting for confounders showing significant univariate associations with ASQ categories (infant sex, gestational age, maternal education and age, breastfeeding duration). Results One hundred eighteen infants (58% female) contributed CRA and ASQ-3 data. Both RA and IS increased significantly over time in nonlinear trajectories, with the largest increases from 3 weeks to 3 months for IS and from 3 weeks to 6 months for RA. LGCA identified two latent IS classes and no classes for RA. Infants in IS latent class 2 demonstrated consistently higher IS values across infancy. Compared with class 1, class 2 membership was associated with non-normative gross motor scores; however, this association was attenuated after adjustment for gestational age (Estimate: 0.21 [SE=0.11], t=1.87, p=0.06). No associations were observed between IS and RA and other ASQ-3 domains. Conclusion CRA trajectories across the first year of life were not significantly associated with neurodevelopmental outcomes at age 1 year. The next immediate steps include evaluating additional CRA metrics, multidimensional sleep health, and longer-term developmental outcomes. Support (if any) NIH/NHLBI R01HL147931