Associations between serum perfluoroalkyl acid (PFAA) concentrations and health related biomarkers in firefighters.

OBJECTIVES: Firefighters who used aqueous film forming foam in the past have experienced elevated exposures to perfluoroalkyl acids (PFAAs). The objective of this study was to examine the associations between clinical chemistry endpoints and serum concentrations of perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS), perfluoroheptane sulfonate (PFHpS) and perfluorooctane sulfonate (PFOS) in firefighters. Multiple linear regression was used to assess relationships between PFAA serum concentrations and biochemical markers for cardiovascular disease, kidney-, liver- and thyroid function, in a cross-sectional survey of 783 firefighters with elevated levels of PFHxS, PFHpS and PFOS in relation to the most recently reported levels in the general Australian population. Linear logistic regression was used to assess the odds ratios for selected self-reported health outcomes. Repeated measures linear mixed models were further used to assess relationships between PFAAs and biomarkers for cardiovascular disease and kidney function longitudinally in a subset of the firefighters (n = 130) where serum measurements were available from two timepoints, five years apart. In the cross-sectional analysis, higher levels of all PFAAs were significantly associated with higher levels of biomarkers for cardiovascular disease (total-cholesterol, and LDL-cholesterol). For example, doubling in PFOS serum concentration were associated with increases in total cholesterol (ß:0.111, 95% confidence interval (95%CI): 0.026, 0.195 mmol/L) and LDL-cholesterol (ß: 0.104, 95%CI:0.03, 0.178 mmol/L). Doubling in PFOA concentration, despite not being elevated in the study population, were additionally positively associated with kidney function marker urate (e.g., ß: 0.010, 95%CI; 0.004, 0.016 mmol/L) and thyroid function marker TSH (e.g., ß: 0.087, 95%CI: 0.014, 0.161 mIU/L). PFAAs were not associated with any assessed self-reported health conditions. No significant relationships were observed in the longitudinal analysis. Findings support previous studies, particularly on the association between PFAAs and serum lipids.

Genome-wide Association Meta-analysis of Childhood and Adolescent Internalizing Symptoms.

OBJECTIVE: To investigate the genetic architecture of internalizing symptoms in childhood and adolescence. METHOD: In 22 cohorts, multiple univariate genome-wide association studies (GWASs) were performed using repeated assessments of internalizing symptoms, in a total of 64,561 children and adolescents between 3 and 18 years of age. Results were aggregated in meta-analyses that accounted for sample overlap, first using all available data, and then using subsets of measurements grouped by rater, age, and instrument. RESULTS: The meta-analysis of overall internalizing symptoms (INToverall) detected no genome-wide significant hits and showed low single nucleotide polymorphism (SNP) heritability (1.66%, 95% CI = 0.84-2.48%, neffective = 132,260). Stratified analyses indicated rater-based heterogeneity in genetic effects, with self-reported internalizing symptoms showing the highest heritability (5.63%, 95% CI = 3.08%-8.18%). The contribution of additive genetic effects on internalizing symptoms appeared to be stable over age, with overlapping estimates of SNP heritability from early childhood to adolescence. Genetic correlations were observed with adult anxiety, depression, and the well-being spectrum (|rg| > 0.70), as well as with insomnia, loneliness, attention-deficit/hyperactivity disorder, autism, and childhood aggression (range |rg| = 0.42-0.60), whereas there were no robust associations with schizophrenia, bipolar disorder, obsessive-compulsive disorder, or anorexia nervosa. CONCLUSION: Genetic correlations indicate that childhood and adolescent internalizing symptoms share substantial genetic vulnerabilities with adult internalizing disorders and other childhood psychiatric traits, which could partially explain both the persistence of internalizing symptoms over time and the high comorbidity among childhood psychiatric traits. Reducing phenotypic heterogeneity in childhood samples will be key in paving the way to future GWAS success.

Biomonitoring of per- and polyfluoroalkyl substances (PFAS) exposure in firefighters: Study design and lessons learned from stakeholder and participant engagement.

Firefighters may be occupationally exposed to per- and polyfluoroalkyl substances (PFASs) through Aqueous Film-Forming Foam (AFFF), smoke, dust and turnout gear, in addition to other background exposure sources. Epidemiological assessment of PFAS exposure in an occupational cohort of firefighting staff commenced in 2013-2014, following cessation of PFAS-based AFFF in Australian aviation. Here we present the study design and methodology of a follow-up study conducted in 2018-2019. We focus on our experiences engaging with stakeholders and participants with the establishment of an inclusive study group and highlight the key lessons learned from implementing a co-design process in the study. The study included a cross-sectional assessment of blood serum concentrations of 40 PFASs, including perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS), and 14 health-related biomarkers in 799 current and former Aviation Rescue Firefighting Services employees. A large proportion (87%) of the participants from the preliminary exposure study in 2013-2014 were re-recruited in the follow-up study. This enabled further longitudinal analyses in this subset of 130 participants. Participants included employees from different work roles and timeframes, reflecting the periods when three different firefighting foams were utilised in Australia. Establishment of a collaborative and inclusive study group (including stakeholders and participants) contributed to several components of the study design, including the expansion of robust analytical quality assurance and control measurements, and tailoring of communication and dissemination strategies. These outcomes were key factors that improved transparency of the research design, methods and results. Additionally, implementing elements of co-design helped build trust between researchers and participants, which is an important consideration for studies funded by stakeholders related to the exposure source.

Genetic association study of childhood aggression across raters, instruments, and age.

Childhood aggressive behavior (AGG) has a substantial heritability of around 50%. Here we present a genome-wide association meta-analysis (GWAMA) of childhood AGG, in which all phenotype measures across childhood ages from multiple assessors were included. We analyzed phenotype assessments for a total of 328 935 observations from 87 485 children aged between 1.5 and 18 years, while accounting for sample overlap. We also meta-analyzed within subsets of the data, i.e., within rater, instrument and age. SNP-heritability for the overall meta-analysis (AGGoverall) was 3.31% (SE = 0.0038). We found no genome-wide significant SNPs for AGGoverall. The gene-based analysis returned three significant genes: ST3GAL3 (P = 1.6E-06), PCDH7 (P = 2.0E-06), and IPO13 (P = 2.5E-06). All three genes have previously been associated with educational traits. Polygenic scores based on our GWAMA significantly predicted aggression in a holdout sample of children (variance explained = 0.44%) and in retrospectively assessed childhood aggression (variance explained = 0.20%). Genetic correlations (rg) among rater-specific assessment of AGG ranged from rg = 0.46 between self- and teacher-assessment to rg = 0.81 between mother- and teacher-assessment. We obtained moderate-to-strong rgs with selected phenotypes from multiple domains, but hardly with any of the classical biomarkers thought to be associated with AGG. Significant genetic correlations were observed with most psychiatric and psychological traits (range [Formula: see text]: 0.19-1.00), except for obsessive-compulsive disorder. Aggression had a negative genetic correlation (rg = ~-0.5) with cognitive traits and age at first birth. Aggression was strongly genetically correlated with smoking phenotypes (range [Formula: see text]: 0.46-0.60). The genetic correlations between aggression and psychiatric disorders were weaker for teacher-reported AGG than for mother- and self-reported AGG. The current GWAMA of childhood aggression provides a powerful tool to interrogate the rater-specific genetic etiology of AGG.

Maternal anxiety and attention problems in children at 5 and 14 years.

OBJECTIVE: This study examines the association between maternal anxiety from pregnancy to 5 years and child attention problems at 5 and 14 years. METHOD: Birth cohort of 3,982 individuals born in Brisbane between 1981 and 1983 are assessed. Self-reported measures of maternal anxiety are assessed at four time points. Maternal reports of child attention problems using Achenbach's Child Behavior Checklist are assessed at 5 and 14 years. RESULTS: Children of mothers experiencing anxiety during or after pregnancy are at greater risk of experiencing attention problems at 5 and 14 years. After adjusting for maternal age and child's gender, antenatal anxiety is strongly associated with persistent attention problems (OR = 3.65, 95% CI = 2.19, 6.07). Children with chronically anxious mothers are 5.67 (95% CI = 3.56, 9.03) times more likely to have persistent attention problems. These associations remain consistent after adjusting for potential confounders. CONCLUSIONS: Maternal anxiety appears to increase the rate of child attention problems and identifies a need for treatment programs to have a dual focus-the mother and her child.

A comparison of the hazard perception ability of matched groups of healthy drivers aged 35 to 55, 65 to 74, and 75 to 84 years.

We examined differences in response latencies obtained during a validated video-based hazard perception driving test between three healthy, community-dwelling groups: 22 mid-aged (35-55 years), 34 young-old (65-74 years), and 23 old-old (75-84 years) current drivers, matched for gender, education level, and vocabulary. We found no significant difference in performance between mid-aged and young-old groups, but the old-old group was significantly slower than the other two groups. The differences between the old-old group and the other groups combined were independently mediated by useful field of view (UFOV), contrast sensitivity, and simple reaction time measures. Given that hazard perception latency has been linked with increased crash risk, these results are consistent with the idea that increased crash risk in older adults could be a function of poorer hazard perception, though this decline does not appear to manifest until age 75+ in healthy drivers.

The effect of simulated cataracts on drivers' hazard perception ability.

PURPOSE: We investigated the extent to which simulated cataracts slow a driver's ability to anticipate potential traffic hazards, a skill that has been found to correlate with crash risk. In previous studies, we found a significant correlation between contrast sensitivity and hazard perception in a sample of older drivers. The present study allowed us to determine the causal direction of this relationship. This is important as it provides a better understanding of the mechanisms underlying the higher crash risk of drivers with cataracts. METHODS: One hundred eighty-six drivers with normal vision completed a validated video-based hazard perception driving test, designed to measure hazard anticipation response times in dynamic scenes. They also completed a change detection task based on traffic hazards, which was designed to measure object detection times in static scenes. Participants undertook the tasks wearing either mild or moderate cataract simulation goggles, or wearing goggle frames without lenses. RESULTS: Participants wearing moderate simulated cataract goggles were slower than the control group in both the hazard perception test, t(98.50) = -3.71, p < 0.001, and the hazard change detection task, t(124) = -13.86, p < 0.001. Participants with the mild simulated cataract goggles were slower than the control group in the hazard change detection task, t(114) = -4.04, p < 0.001, but not the hazard perception test, t(114) = -1.33, p = 0.19. CONCLUSIONS: Moderate levels of simulated cataract slowed drivers' ability to detect and anticipate traffic hazards enough to warrant road safety concerns, despite the fact that the vision of participants wearing the cataract goggles still complied with the minimum legal standard required for driving.

The hazard perception ability of older drivers.

We investigated the hazard perception ability of older drivers. A sample of 118 older drivers (65 years and older) completed a video-based hazard perception test and an assessment battery designed to measure aspects of cognitive ability, vision, and simple reaction time that might plausibly be linked to hazard perception ability. We found that hazard perception response times increased significantly with age but that this age-related increase could be accounted for by measures of contrast sensitivity and useful field of view. We found that contrast sensitivity, useful field of view, and simple reaction time could account for the variance in hazard perception, independent of one another and of individual differences in age.