Vitamin D insufficiency in Indigenous infants and the risk of hospitalisation for acute lower respiratory infection

1 in 5 Indigenous infants are hospitalised with ALRI in their first year of life. Recent international studies suggest an association between vitamin D deficiency and ALRI despite adequate sun exposure. This study will be the first to characterise vitamin D levels in Indigenous children and will investigate the association between vitamin D deficiency and ALRI in this population. The results of this work could have implications for prevention strategies involving vitamin D supplementation for ALRIs.

Primary aim
1. To determine if vitamin D insufficiency in cord blood is associated with a higher risk of hospitalisation for ALRI during the first year of life.
Secondary aims
2. To examine the association between vitamin D insufficiency in cord blood and pathogen density in the nasopharynx at 1 month of age.
3. To examine the association between vitamin D insufficiency in cord blood and the infant response to childhood pneumococcal conjugate vaccination (PCV) assessed at 7 months of age.
4. To examine (i) the association between maternal and infant serum vitamin D levels at birth and (ii) the influence of vitamin D levels in breast milk on vitamin D levels in infant serum at 7 months post partum.

Study design
We will conduct a prospective cohort study embedded within an existing randomised controlled trial of maternal pneumococcal immunisation – the PneuMum study (NHMRC 350499). The recruitment, follow-up and specimen collection of 196 Indigenous mother-infant pairs is complete, however the exposure of interest (vitamin D insufficiency at birth) will be measured prior to the occurrence of the primary outcome (ALRI hospitalisation < 12 months). Consent for review of hospital records is available to determine ALRI status.

Investigators and groups
Chief Investigator Michael Binks has been awarded NHMRC and Douglas and Lola Douglas scholarship support for this project. Co-investigators Associate Professor Ross Andrews, Professor Anne Chang and Dr Heidi Smith-Vaughan contribute extensive experience in Indigenous respiratory health and infectious diseases research

Funding and in-kind support
Funding for this project is being provided by the Channel 7 – Children’s Research Foundation