Changes will be made to the inclusion and exclusion criteria for the study -- which determines which children are eligible to participate -- as well as the consent form that families are given before agreeing to participate, he said.
How families are updated during the yearlong study also will be changed, he said, and there will be additional monitoring of the study by the NHLBI.
Exactly what the specific changes will be is not known, however. The monitoring board made recommendations to Pitt and its lead investigator, researcher Juan Celedon, director of the Pediatric Asthma Center at Children's.
"Dr. Celedon started making some changes (to the study) almost as soon as Dr. Davidson came to us" with his concerns this past summer, Kiley said.
Celedon, Pitt and Children's declined to answer questions about the study beyond an emailed statement from Children's spokesman Marc Lukasiak that said, in part, that the "health and safety of our trial participants is our top concern."
Reached by phone, Richard Guido, the chairman of Pitt's IRB, which ultimately will have to approve any changes to the study, said he had no comment.
Celedon began the study in 2014 with a smaller pilot of 24 children in Pittsburgh that did not use a no-dose placebo, and instead used a maintenance dose of 200 units a day. Children's has dubbed the larger study the "Vit-D-Kids" asthma study and undertaken an advertising campaign to recruit participants, which is still ongoing.
Media representatives at all three other sites that are also recruiting children for the study -- St. Louis Children's Hospital, Boston Children's Hospital and UCSF Benioff's Children's Hospital in San Francisco -- did not make their lead investigators available to answer questions and referred the Post-Gazette back to Celedon and Pitt.
That lack of transparency is nothing new to Davidson, who also was rebuffed by Pitt, Celedon and representatives from all three sites when he began raising questions about the study's format this past summer.
The fact that everyone involved but the federal government refuses to discuss the case "is wrong," Davidson said.