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

BACKGROUND: Bisphenol A (BPA) has been associated with impairments in children's behavior, but few studies have investigated its relationship with cognitive function. OBJECTIVE: To investigate the association of urinary BPA concentrations with cognitive domains and intelligence quotient (IQ) in Spanish boys. METHODS: 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. RESULTS: 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 (ß = 5.47; 95%CI: 1.4, 9.4 and ß = 3.57; 95%CI: -0.4, 7.5, respectively); and boys in the third quartile showed better inhibitory control (ß = 1.6; 95%CI: -0.3, 3.5) and impulsivity (ß= -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 (ß= -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 [ORa = 1.51; 95%CI: 1.01, 2.25]. DISCUSSION: 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.

Bisphenol A and adiposity measures in peripubertal boys from the INMA-Granada cohort.

INTRODUCTION: Childhood obesity is one of the most serious public health challenges of our times. Although an important body of experimental evidence highlights the obesogenic potential of endocrine disruptors such as bisphenol A (BPA), the epidemiological evidence remains inconclusive and limited. OBJECTIVE: To assess associations between urinary BPA concentrations and several adiposity measures in peripubertal boys from the Environment and Childhood (INMA) cohort in Granada, Spain. MATERIAL AND METHODS: BPA concentrations were determined in spot urine samples from 298 boys aged 9-11, and their weight, height, waist circumference, and percentage body fat mass were measured. Overweight/obesity was defined as BMI z-score ≥85th percentile and abdominal obesity as waist-to-height ratio (WHtR) ≥0.5. Associations were assessed using multivariable linear and logistic regression models. RESULTS: In adjusted models, each natural log-unit increase in urinary BPA concentrations was associated with higher BMI z-score (ß = 0.22; 95%CI = 0.03, 0.41) and increased odds of overweight/obesity (OR = 1.46; 95%CI = 1.05, 2.05). Children with higher BPA concentrations had higher WHtR values (ß = 0.007; 95%CI = -0.001, 0.015), and BPA was associated with a greater risk of abdominal obesity (OR = 1.45; 95%CI = 1.03, 2.06). No associations were found with % body fat mass. CONCLUSIONS: BPA may exert an obesogenic effect in peripubertal boys, potentially increasing the risk of overweight/obesity, especially abdominal obesity. However, these results should be interpreted with caution given the modest sample size and the possibilities of reverse causality and residual confounding by diet and lifestyle patterns.

Air Pollution Exposure During Pregnancy and Symptoms of Attention Deficit and Hyperactivity Disorder in Children in Europe.

BACKGROUND: Exposure to air pollution during pregnancy may increase attention-deficit/hyperactivity disorder (ADHD) symptoms in children, but findings have been inconsistent. We aimed to study this association in a collaborative study of eight European population-based birth/child cohorts, including 29,127 mother-child pairs. METHODS: Air pollution concentrations (nitrogen dioxide [NO2] and particulate matter [PM]) were estimated at the birth address by land-use regression models based on monitoring campaigns performed between 2008 and 2011. We extrapolated concentrations back in time to exact pregnancy periods. Teachers or parents assessed ADHD symptoms at 3-10 years of age. We classified children as having ADHD symptoms within the borderline/clinical range and within the clinical range using validated cutoffs. We combined all adjusted area-specific effect estimates using random-effects meta-analysis and multiple imputations and applied inverse probability-weighting methods to correct for loss to follow-up. RESULTS: We classified a total of 2,801 children as having ADHD symptoms within the borderline/clinical range, and 1,590 within the clinical range. Exposure to air pollution during pregnancy was not associated with a higher odds of ADHD symptoms within the borderline/clinical range (e.g., adjusted odds ratio [OR] for ADHD symptoms of 0.95, 95% confidence interval [CI] = 0.89, 1.01 per 10 µg/m increase in NO2 and 0.98, 95% CI = 0.80, 1.19 per 5 µg/m increase in PM2.5). We observed similar associations for ADHD within the clinical range. CONCLUSIONS: There was no evidence for an increase in risk of ADHD symptoms with increasing prenatal air pollution levels in children aged 3-10 years. See video abstract at, http://links.lww.com/EDE/B379.

Bisphenol A and reproductive hormones and cortisol in peripubertal boys: The INMA-Granada cohort.

INTRODUCTION: Bisphenol A (BPA) is a well-known endocrine disrupting compound. Although several studies have investigated the effect of BPA exposure and reproductive hormones in humans, results have been inconsistent. OBJECTIVE: To explore the cross-sectional relationship between bisphenol A (BPA) exposure and reproductive hormones/cortisol among peripubertal boys. MATERIAL AND METHODS: Urinary BPA and serum hormones were assessed in 172 boys belonging to the INMA "Environment and Childhood" Granada birth cohort in their follow-up at 9-11years of age. BPA concentrations were quantified by liquid chromatography-mass spectrometry, and levels of serum total testosterone (TT), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and cortisol were measured by electrochemiluminescence immunoassay. RESULT(S): After adjustment for confounders, linear regression models showed that each natural-log unit increase in urinary BPA concentrations was associated with a 19% increase in geometric mean (GM) serum TT levels, and a 16% decrease in GM serum cortisol levels. When urinary BPA concentrations were categorized in tertiles, boys in the 3rd tertile showed 49% higher TT levels and 23% lower cortisol concentrations compared to boys in the 1st tertile. Additionally, urinary BPA concentrations were also significantly associated with higher TT:LH and TT:cortisol ratios, but not with serum LH or FSH levels. CONCLUSION(S): Our results suggest the possible endocrine disrupting potential of BPA during this important period of development. Although action at the testis or pituitary cannot be ruled out, our findings are compatible with a possible involvement of BPA at the adrenal gland, resulting in a differential production of androgens/cortisol. However, given the cross-sectional design of our study, the heterogeneous results reported in the literature, and the scant experimental research on BPA effects at the adrenal gland, the present findings should be interpreted with caution.

Does exposure to environmental radiofrequency electromagnetic fields cause cognitive and behavioral effects in 10-year-old boys?

The relationship between exposure to electromagnetic fields from non-ionizing radiation and adverse human health effects remains controversial. We aimed to explore the association of environmental radiofrequency-electromagnetic fields (RF-EMFs) exposure with neurobehavioral function of children. A subsample of 123 boys belonging to the Environment and Childhood cohort from Granada (Spain), recruited at birth from 2000 through 2002, were evaluated at the age of 9-11 years. Spot electric field measurements within the 100 kHz to 6 GHz frequency range, expressed as both root mean-square (S(RMS) and maximum power density (S(MAX)) magnitudes, were performed in the immediate surrounds of childrens dwellings. Neurocognitive and behavioral functions were assessed with a comprehensive battery of tests. Multivariate linear and logistic regression models were used, adjusting for potential confounders. All measurements were lower than reference guideline limits, with median S(RMS) and S(MAX) values of 285.94 and 2759.68 µW/m(2), respectively. Most of the cognitive and behavioral parameters did not show any effect, but children living in higher RF exposure areas (above median S(RMS) levels) had lower scores for verbal expression/comprehension and higher scores for internalizing and total problems, and obsessive-compulsive and post-traumatic stress disorders, in comparison to those living in areas with lower exposure. These associations were stronger when S(MAX) values were considered. Although some of our results may suggest that low-level environmental RF-EMF exposure has a negative impact on cognitive and/or behavior development in children; given limitations in the study design and that the majority of neurobehavioral functioning tasks were not affected, definitive conclusions cannot be drawn.

Bisphenol A: Human exposure and neurobehavior.

The effect of bisphenol A (BPA) exposure on human brain and behavior is a relatively new issue, and particular concerns have been raised about its potential impact on children. The primary objective of this review was to analyze the current state of knowledge on the association of environmental BPA exposure during pregnancy and/or childhood with child cognitive and/or behavior outcomes. All scientific publications until March 2015 that include examination of this relationship have been reviewed using the MEDLINE/PubMed database. Although research on this issue has not been abundant, an association with altered neurobehavior was reported by eight out of the twelve available articles, including aggressive behavior, attention deficit, hyperactivity disorder, depression and anxiety impairments, mostly in children exposed in utero, indicating disruption of the brain during this critical window of development. Despite the reduced number of studies and their heterogeneity, the results suggest that prenatal BPA exposure may have a negative impact on neurobehavioral functioning in children and that the effects may be sex-dependent. It is therefore necessary to be vigilant towards the potential adverse effects of ubiquitous low-level BPA exposure, although more studies in humans are required to convincingly confirm or rule out the association between BPA exposure and health. Meanwhile, it is desirable to inform women planning or undergoing pregnancy about measures to reduce or avoid exposure to BPA. We discuss some key aspects of the relationship between exposure and neurobehavioral outcomes.

Trends in children's exposure to second-hand smoke in the INMA-Granada cohort: an evaluation of the Spanish anti-smoking law.

The smoke-free legislation implemented in Spain in 2006 imposed a partial ban on smoking in public and work places, but the result did not meet expectations. Therefore, a more restrictive anti-smoking law was passed five years later in 2011 prohibiting smoking in all public places, on public transport, and the workplace. With the objective of assessing the impact of the latter anti-smoking legislation on children's exposure to second-hand smoke (SHS), we assessed parent's smoking habits and children's urine cotinine (UC) concentrations in 118 boys before (2005-2006) and after (2011-2012) the introduction of this law. Repeated cross-sectional follow-ups of the "Environment and Childhood Research Network" (INMA-Granada), a Spanish population-based birth cohort study, at 4-5 years old (2005-2006) and 10-11 years old (2011-2012), were designed. Data were gathered by ad-hoc questionnaire, and median UC levels recorded as an objective indicator of overall SHS exposure. Multivariable logistic regression was used to examine the association between parent's smoking habits at home and SHS exposure, among other potential predictors. An increase was observed in the prevalence of families with at least one smoker (39.0% vs. 50.8%) and in the prevalence of smoking mothers (20.3% vs. 29.7%) and fathers (33.9% vs. 39.0%). Median UC concentration was 8.0ng/mL (interquartile range [IQR]: 2.0-21.8) before legislation onset and 8.7ng/mL (IQR: 2.0-24.3) afterwards. In the multivariable analysis, the smoking status of parents and smoking habits at home were statistically associated with the risk of SHS exposure and with UC concentrations in children. These findings indicate that the recent prohibition of smoking in enclosed public and workplaces in Spain has not been accompanied by a decline in the exposure to SHS among children, who continue to be adversely affected. There is a need to target smoking at home in order to avoid future adverse health effects in a population that has no choice in the acceptance or not of SHS exposure-derived risk.

Characterization of indoor extremely low frequency and low frequency electromagnetic fields in the INMA-Granada cohort.

OBJECTIVE: To characterize the exposure to electric fields and magnetic fields of non-ionizing radiation in the electromagnetic spectrum (15 Hz to 100 kHz) in the dwellings of children from the Spanish Environment and Childhood-"INMA" population-based birth cohort. METHODOLOGY: The study sample was drawn from the INMA-Granada cohort. Out of 300 boys participating in the 9-10 year follow-up, 123 families agreed to the exposure assessment at home and completed a specific ad hoc questionnaire gathering information on sources of non-ionizing radiation electric and magnetic fields inside the homes and on patterns of use. Long-term indoor measurements were carried out in the living room and bedroom. RESULTS: Survey data showed a low exposure in the children's homes according to reference levels of the International Commission on Non-Ionizing Radiation Protection but with large differences among homes in mean and maximum values. Daytime electrostatic and magnetic fields were below the quantification limit in 78.6% (92 dwellings) and 92.3% (108 dwellings) of houses, with an arithmetic mean value (± standard deviation) of 7.31±9.32 V/m and 162.30±91.16 nT, respectively. Mean magnetic field values were 1.6 lower during the night than the day. Nocturnal electrostatic values were not measured. Exposure levels were influenced by the area of residence (higher values in urban/semi-urban versus rural areas), type of dwelling, age of dwelling, floor of the dwelling, and season. CONCLUSION: Given the greater sensitivity to extremely low-frequency electromagnetic fields of children and following the precautionary principle, preventive measures are warranted to reduce their exposure.