Association of Insulin-like Growth Factor I and Insulin-like Growth Factor–Binding Protein-3 With Intelligence Quotient Among 8- to 9-Year-Old Children in the Avon Longitudinal Study of Parents and Children

This study provides some preliminary evidence that IGF-I is associated with brain development in childhood. Additional longitudinal research is required to clarify the role of IGF-I in neurodevelopment. Because IGF-I levels are modifiable through diet and other environmental exposures, this may be one pathway through which the childhood environment may influence neurodevelopment.