Head circumference trajectories during the first two years of life and cognitive development, emotional, and behavior...

The associations of early-life head circumference (HC) with child neurodevelopmental and mental health among generally healthy population remain unclear. We aimed to examine the associations of early-life HC trajectories with cognitive development and emotional and behavioral problems in adolescence and to identify the HC growth-sensitive period. We conducted a prospective, community-based birth cohort study in rural western China, and 745 adolescents aged 10-14 years were followed between June and December 2016. We assessed their HC eight times during the first 2 years of life and their adolescent cognitive, emotional, and behavioral outcomes using the Wechsler Intelligence Scale for Children-IV and Youth Self-Report-2001, respectively. We applied group-based trajectory modeling to identify the HC trajectories and conditional growth to derive the HC growth-sensitive periods. We identified five distinct HC trajectories characterized as Start below average-then decrease (7.8% of the sample), Start below average-then increase (6.8%), Start average-then decrease (33%), Consistently average (38%), and Consistently above average (14%). Infants in the trajectory of consistently above average had higher cognitive scores in adolescence compared to those from suboptimal trajectories, with adjusted mean differences ranging from 2.84 to 8.99 points. The conditional gains showed that the HC growth-sensitive period was between 0 and 18 months for child cognition. We found null associations between HC measures and adolescent emotional and behavioral problem scores.

Early-life HC trajectories were associated with adolescent cognitive development. HC may serve as an inexpensive screening tool to monitor child development at risk during the first 18 months, particularly in resource-limited settings.

• Postnatal head circumference (HC) has been shown to be associated with cognitive development in infants who were born premature and/or fetal growth restriction, while inconsistent associations were reported among generally healthy populations, especially in low- and middle- income countries, challenging its utility in public health practices.

• Adolescents in the HC growth trajectory of consistently above average had higher cognitive scores compared to those with other suboptimal trajectories, while null findings were observed for adolescent emotional and behavioral health. • HC may serve as an inexpensive screening tool to monitor child development at risk during the first 18 months of life, particularly in resource-limited settings.