2.1. Study Design and Participants
This study was conducted as a post hoc analysis of data from a follow-up study of a randomized clinical trial funded by the Thrasher Research Fund investigating the effects of vitamin D supplementation during pregnancy on child neurodevelopment. Both the pregnancy and follow-up studies were conducted at the Medical University of South Carolina in Charleston, SC. Both studies were conducted in accordance with the Declaration of Helsinki and approved by the institutional review board at the Medical University of South Carolina. The CONSORT flow diagram outlining study procedures is shown in 