The CIRCA DIEM Study is a multicentre randomised controlled clinical trial led and coordinated by the Developmental Chronobiology Team at The Kids Research Institute Australia. The study involves clinical research teams from across Australia and New Zealand. The study name CIRCA DIEM comes from the title of the study: Cognitive Improvement through early Restoration of CIRCADian rhythms in very preterm Infants via Environmental Modification.
The study aims to determine whether day/night cycling of environmental light and noise improves brain development and other health outcomes in premature babies compared to standard neonatal care. The study will help us to improve the way we care for our tiniest babies here in Australia, and around the globe.
Babies randomised to the intervention group experienced a simulated day/night cycle while in hospital commencing in the first week of life. Infants wore specially designed black-out eye masks and soft silicone ear-plugs overnight to reduce exposure to light and noise. During the day, the eye masks and earplugs were removed to allow exposure to a safe level of light and normal daytime nursery sounds. Babies randomised to the control group received standard care in which light and noise levels remain relatively constant throughout the day and the night.
The expectation is that the study intervention will help premature babies to develop their own circadian rhythms during their hospitalisation rather than after discharge home, and that this earlier circadian rhythm development will promote better brain development at two years of age for children born very preterm.
The CIRCA DIEM Study successfully recruited and enrolled 869 preterm babies across recruiting centres between February 2019 and January 2026. The CIRCA DIEM Study has now closed its recruitment phase but follow-up of the study participants is continuing as the primary outcome for the study requires assessment of brain development at two years corrected age. A total of 321 children have completed their 2-year follow-up appointments as of June 2026. The two-year follow up phase of this study is expected to be completed by the end of 2028.
This study has approval from the Child and Adolescent Health Service Human Research Ethics Committee based in Western Australia, who can be contacted via CAHS.Ethics@health.wa.gov.au or by telephoning (08) 6456 0561. The study was registered prospectively on The Australian and New Zealand Clinical Trials Registry (ANZCTR) Trial Registry Number: ACTRN12618000371291
If you have any questions about the CIRCA DIEM Study, please contact us via email at circadiem@thekids.org.au.
