Methods
BPD
The original N3RO trial and its 5-year follow-up were approved by the Human Research Ethics Committee at each participating hospital (lead hospital, Women’s and Children’s Health Network [WHCN]). Written informed consent was obtained from guardians prior to randomization and before the appointment at 5 years in the N3RO trial. This cohort study’s mediation analysis was also approved by the WCHN Human Research Ethics Committee as the lead hospital with a waiver of consent based on a public interest case (noting that aims were closely related to the original trial aims of determining effects of DHA on BPD and IQ). This study followed the A Guideline for Reporting Mediation Analyses (AGReMA) statement for reporting mediation analyses of randomized trials and observational studies.