Bisphenol A and cognitive function in school-age boys: Is BPA predominantly related to behavior?

Bisphenol A (BPA) has been associated with impairments in children's behavior, but few studies have investigated its relationship with cognitive function.

To investigate the association of urinary BPA concentrations with cognitive domains and intelligence quotient (IQ) in Spanish boys.

BPA levels were quantified by liquid chromatography-tandem mass spectrometry (LC-MS-MS) in one spot urine sample from 269 boys of the INMA-Granada cohort, in their follow-up at 9-11 years of age. Cognitive function was evaluated by a trained psychologist using a comprehensive neuropsychological test battery (including general intelligence, language skills, working memory, attention, impulsivity, visual-motor coordination, processing speed and executive function, among others). Cross-sectional associations between BPA levels and neuropsychological standardized scores were analyzed by adjusted linear and logistic regression models.

Median (P25, P75) BPA concentrations were 4.76 (2.77, 9.03) μg/L and 4.75 (2.75, 10.2) μg/g of creatinine (Cr). Boys in the third and fourth quartile of volume-based BPA concentrations showed better processing speed scores than boys in the first quartile (β = 5.47; 95%CI: 1.4, 9.4 and β = 3.57; 95%CI: -0.4, 7.5, respectively); and boys in the third quartile showed better inhibitory control (β = 1.6; 95%CI: -0.3, 3.5) and impulsivity (β= -4.2; 95%CI: -9.0, 0.0). In contrast, boys in the fourth quartile showed poorer working memory scores than those in the first quartile (β= -1.0; 95%CI: -2.1, -0.1). All these associations were attenuated when Cr-standardized BPA concentrations were considered. Cr-based BPA concentrations were also associated with a higher risk of being below the 20th percentile of working memory scores [OR_a = 1.51; 95%CI: 1.01, 2.25].

Our findings do not support an association between urinary BPA concentrations and cognitive function or IQ among boys, except for working memory. BPA was previously found to be associated with behavior problems in the same study population, suggesting that BPA may predominantly affect the behavior of children rather than their cognitive function, in line with previous epidemiologic studies.