Associations of gestational maternal urinary concentrations of individual and mixtures of parabens with cognition in 7.5-month-old infants.

Abstract

Background: Few studies have assessed the impact of gestational paraben exposure on neurodevelopment. We evaluated associations of gestational exposure to three parabens with infant cognition at 7.5 months using a visual recognition memory task.

Methods: Parabens were quantified in urine samples pooled from five time-point collections across pregnancy. Cognition was measured using infrared eye-tracking. Infants (n = 310) were shown two identical faces (familiarization), followed by the familiar face paired with a novel face (test trials). Covariate-adjusted generalized linear regression assessed associations of each individual paraben with four cognitive outcomes. Quantile g-computation assessed associations of the paraben mixture with the outcomes. Stratified models assessed the moderation by infant sex.

Results: Mothers were mostly white and college-educated with incomes >$50,000/year. Ethylparaben was associated with changes in attention with shorter familiarization time in females (per interquartile range [IQR] increase β = -0.015; 95% confidence interval [CI] = -0.034, 0.000), but longer familiarization time in males (per IQR increase β = 0.010; 95% CI = 0.000, 0.015), as well as longer run duration (slower information processing) in females (per IQR increase β = 0.015; 95% CI = 0.000, 0.029). Propylparaben was associated with a lower shift rate, also indicating slower information processing (per IQR increase β = -0.016; 95% CI = -0.032, 0.027) in females. In contrast, the paraben mixture was associated with longer run duration (per IQR increase β = 0.317; 95% CI = -0.020, 0.654), but higher novelty preference (improved memory) (per IQR increase β = 0.029, 95% CI = 0.002, 0.056) and higher shift rate (faster processing) (per IQR increase β = 0.027; 95% CI = 0.000, 0.054) in males.

Conclusion: Parabens were associated with changes in infant cognition, with patterns of association differing by sex and cognitive domain, and when parabens were considered individually versus as a mixture.