A Case-Control Study of the Association BetweenKarenia Brevis(Red Tide) and Biliary Atresia

Objective The study objective was to evaluate the association between maternal Karenia brevis (K. brevis) exposure during pregnancy and the prevalence of biliary atresia (BA) in offspring. Study Design This was a hospital-based, case-control study in which cases were infants diagnosed with BA at Johns Hopkins All Children’s Hospital from October 2001 to December 2019. Controls were matched 4:1 by age, randomly selected from healthy infants hospitalized during the study period for common pediatric diagnoses. Infants were excluded if they had congenital anomalies and/or were non-Florida residents. Gestational K. brevis exposure levels (cells/liter) were determined from Florida Fish and Wildlife Conservation Commission exposure data at 10- and 50-mile radii from the mother’s zip code of residence. Multivariable conditional logistic regression determined adjusted odds of BA in offspring based on maternal gestational K. brevis exposure. Results Of 38 cases and 152 controls, no significant inter-group differences were observed in race/ethnicity, season of birth or coastal residence. Median gestational exposure at the 10-mile radius was 0 cells/liter in both groups. A greater proportion of cases had no K. brevis exposure (63.2%, n = 24) in comparison to controls (37.5%, n = 57; p = .04) at a 10-mile radius. At the 50-mile radius, cases had a peak median exposure at 6 months of gestation compared to controls’ peak at 9 months. After adjustment for sex, seasonality, race/ethnicity, and coastal residence, there was no significant association between BA and maximum K. brevis exposure per trimester of pregnancy at the 10-or 50-mile radius. Conclusion We observed no association between gestational K. brevis (cells/liter) exposure at a 10- and 50-mile radius from maternal zip code of residence and BA in offspring. Key points Environmental toxins may cause biliary atresia (BA) Red tide is caused by algal blooms ( Karenia brevis) Red tide is debilitating to marine wildlife Gestational exposure to K. brevis does not cause BA