Gestational age, birth weight and neurocognitive development in adolescents in Tanzania.

Objectives To investigate the association between gestational age (GA), birthweight, and birthweight adjusted for GA, with domains of neurocognitive development and behavioral problems in adolescents in Tanzania. Study design Data from a long-term follow-up of adolescents aged 11 to 15 years born to women previously enrolled in a randomized controlled trial of prenatal multiple micronutrient supplementation in Dar es Salaam, Tanzania, were used. A battery of neurodevelopmental tests were administered to measure adolescent general intelligence, executive function, and behavioral problems. The INTERGROWTH-21st newborn anthropometric standards were used to derive birthweight-for-GA z-scores (BWGAz). We assessed the shape of relationships using restricted cubic splines and estimated the associations of GA, birthweight, and BWGAZ with adolescent development using multivariable linear regressions. Results Among adolescents studied (n=421), higher GA (per week), birthweight (per 100 grams), and BWGAz (per SD) were linearly associated with higher intelligence score (adjusted standardized mean difference (aSMD): 0.05 SD (95%CI: 0.01, 0.09), 0.04 SD (95%CI: 0.02, 0.06), and 0.09 SD (95%CI: 0.01, 0.17), respectively). Birthweight and BWGAz, but not GA, were also associated with improved executive function. Low birthweight ( Conclusion Duration of gestation and birthweight were positively associated with adolescent neurodevelopment in Tanzania. These findings suggest that interventions to improve birth outcomes may also benefit adolescent cognitive function.