Background. β-carotene is one of the few carotenoids that can be endogenously converted to vitamin A, a nutrient essential for inner ear development. While previous studies have identified a protective effect of carotenoids on hearing in adults, the impact of β-carotene on hearing outcomes in neonates is not well understood. The purpose of this study is to investigate the relationship between maternal β-carotene intake, maternal plasma, and umbilical cord plasma β-carotene levels and abnormal Newborn Hearing Screen (NHS) results.
Significance of Problem. The prenatal period is critical for auditory development; thus, effectors of auditory development may significantly impact long-term hearing ability. Because maternal nutrition is modifiable, an improved understanding of the relationship between β-carotene levels and hearing outcomes may be relevant for prenatal care recommendations.
Hypothesis. We hypothesize that higher levels of β-carotene will be associated with decreased risk of abnormal NHS results.
Experimental Design. An IRB-approved study enrolled mother-infant pairs (n=541) at the time of delivery. β-carotene plasma levels were analyzed with HPLC. Maternal intake of β-carotene over the past year was quantified using the validated Harvard Food Frequency Questionnaire. NHS results were obtained from the Electronic Medical Record. Statistical analysis was done using the Mann-Whitney U and logistic regression tests, with p\u3c0.05 considered statistically significant.
Results. Of the 541 participants, 8.5% of infants had abnormal NHS results. Higher median maternal β-carotene intake was observed in infants who failed their NHS compared to those who passed (5924 vs. 4722 mcg/day, p=0.019). Higher median maternal plasma levels of both trans- (206 vs. 149 mcg/L, p=0.021) and cis-β-carotene (15.9 vs. 11.2 mcg/L, p=0.015) were observed in infants who failed their NHS. Higher median cord plasma trans β-carotene was observed in infants who failed their NHS (15.5 vs. 8.0 mcg/L, p=0.04). Associations between failed NHS and log-transformed β-carotene intake and serum levels remained in a logistic regression model after adjustment for NICU admission, race/ethnicity, smoking status, maternal age, corrected gestational age, infant sex, and log transformed maternal caloric intake.
Conclusion. The observed relationship between higher β-carotene levels and abnormal NHS was unexpected. While other studies suggest both deficient and excessive levels of vitamin A can impact inner ear development, β-carotene levels in our study were not exceptionally high. One possible explanation is that higher maternal β-carotene levels may be indicative of impaired transfer of β-carotene to the fetus. Further study is warranted to better understand the relationship between β-carotene and NHS results.https://digitalcommons.unmc.edu/chri_forum/1063/thumbnail.jp
