| Bronchopulmonary dysplasia (BPD), the consequence of abnormal lung growth and healing from injury, affects 25–50% of infants born weighing <1500gm. Strong biological evidence supports poor vitamin A status as a factor in the pathogenesis of BPD but clinical findings are conflicting. A large, historical cohort study was undertaken to evaluate the association of plasma retinol status during the first postnatal month and the risk of developing BPD among very low birth weight infants (VLBW < 1250g). VLBW infants admitted to the University of Washington Hospital Neonatal Intensive Care Unit from 1993–1999 surviving for >72 hours were eligible; 352 infants (71% of eligible) had available retinol levels and caregiver's consent. The cohort was followed for evidence of BPD at day 28 (defined by clinical and radiological criteria), at 36 weeks postconception age (PCA) (based on supplemental oxygen use), and supplemental oxygen use at 6 months PCA.; Plasma retinol concentrations, assessed by high performance liquid chromatography, ranged from 31 to 760 μg/L (median 95 μg/L). One hundred and ninety two infants exhibited low retinol levels (one or more <100μg/L) during the first 28 days. Among survivors, 52% (173/331) developed BPD at day 28 and at 36 weeks PCA (147/285), with 14% (33/244) still dependent on oxygen support at 6 months PCA. Potential confounding factors, such as: carrier protein levels, gestational age, duration of parenteral nutrition, surfactant and steroid use, and other neonatal diseases, were included in multiple logistic regression analyses.; After adjusting for confounding, infants with retinol concentrations <100 μg/L during the first month of life had a 3.5 times greater odds of BPD at day 28 (95% CI 1.68, 7.23) and 1.7 times greater odds of BPD at 36 weeks PCA (95% CI 1.02, 2.73) compared to those with levels ≥100 μg/L Low retinol levels were associated with long-term respiratory disability. At 6 months PCA, the adjusted odds for oxygen use with low retinol levels was 2.6 (1.09, 6.39) in survivors and 1.2 (0.62, 2.23) for death or oxygen use. A significant dose-response relationship between retinol levels and BPD was also evident at day 28. These findings support poor vitamin A status as a contributing factor to the risk of BPD. Optimal vitamin A dose and mode of administration for VLBW infants needs to be defined. |
