Behavioral difficulties in 7-year old children in relation to developmental exposure to perfluorinated alkyl substances

Abstract

Background Perfluorinated alkyl substances (PFAS) are suspected endocrine disruptors that are highly persistent and neurotoxic in animals. Human epidemiological studies of exposure-related deviations of children’s behaviors are sparse. We assessed the associations between prenatal, 5- and 7-year PFAS exposures and behavioral problem scores in 7-year Faroese children. Methods Concentrations of perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA), perfluorooctane sulfonate (PFOS), and perfluorohexane sulfonic acid (PFHxS) were measured in maternal serum and in serum from children at ages 5 and 7 years (n=539, 508, and 491, respectively). We used multivariable regressions and structural equations models to estimate the covariate-adjusted associations between serum-PFAS concentrations and behavioral difficulties, as assessed by the strengths and difficulties questionnaire (SDQ) at age 7. Results Serum-PFOS and PFHxS concentrations declined over time, whereas PFOA, PFNA, and PFDA tended to increase. No associations were observed between prenatal PFAS concentrations and SDQ scores. However, a two-fold increase in 5-year serum-PFOA, PFNA, and PFDA concentrations was associated with increases in total SDQ scores by 1.03 (95% CI: 0.11, 1.95), 0.72 (95% CI: 0.07, 1.38) and 0.78 points (95% CI: 0.01, 1.55), respectively. For SDQ subscales, significant associations were found in regard to hyperactivity, peer relationship, and conduct problems, as well as internalizing and externalizing problems and autism screening composite scores. Cross-sectional analyses at age 7 years showed possible sex-dimorphic associations between PFAS concentrations and SDQ scores, where girls had consistently positive associations with SDQ scores whereas boys exhibited a pattern of negative or null associations. Conclusions Higher serum PFAS concentrations at ages 5- and 7-years, but not prenatally, were associated with parent-reported behavioral problems at age 7.

Determinants of serum concentrations of perfluoroalkyl acids (PFAAs) in school children and the contribution of low-level PFAA-contaminated drinking water

“…No differences were reported for <13 years old children from USA, 0-18 years old "non-adults" from China, and 5 year-old children from the Faroe Islands. 24,61,62 Similarly as in the present study, higher PFOS and PFOA concentrations in boys than in girls (1-18 years) were reported in a population with high PFOA exposure from DW in the USA, 54 and similar results were observed for PFHxS and the linear isomer of PFOS in 3-11 years old children participating in NHANES 2013-14 in the USA. 63 However, in the latter case no differences were observed for PFOA (linear isomer), PFNA and PFDA.…”

Gestational diabetes and offspring birth size at elevated environmental pollutant exposures

“…The maternal serum concentrations of PFASs are comparable to those reported in Europe and North America though the mixture profiles vary among populations (Casas et al 2015; Shapiro et al 2016; Zhang et al 2015). PFOS and PFOA have been widely used in the past 60 years in consumer products and industrial applications due to their oil and water repellent properties (Grandjean and Clapp 2014), and while PFOS exposure has decreased in the past decade, exposure to other PFASs (e.g., PFNA and PFHxS) has emerged (Kato et al 2011; Oulhote et al 2016). In regard to mercury exposure, 30% to 65% of mothers in our study have hair concentrations above the recommended safety limits of 1.0 μg/g and 0.58 μg/g, which is a lower proportion compared to Southern European countries, but higher than in most other EU regions (Bellanger et al 2013).…”

Early Life Exposure to Perfluoroalkyl Substances (PFAS) and ADHD: A Meta-Analysis of Nine European Population-Based Studies

“…Due to differences in ADHD prevalence in males and females (Polanczyk et al 2007), as well as the differential associations by sex of PFAS with behavioral problems and ADHD observed in previous studies (Oulhote et al 2016;Quaak et al 2016;Stein et al 2014), we additionally presented the estimates stratified by sex. By using pooled analyses of individual-level data, we added an interaction term for sex (cutoff for significance was p < 0:10) to evaluate possible effect-modification by sex.…”

“…Moreover, a total of four studies reported sex-specific associations, with girls having higher prevalence of ADHD than boys in association with PFASs (Lenters et al 2019;Oulhote et al 2016;Quaak et al 2016;Stein et al 2014).…”