Partial correlation analysis reveals abnormal retinotopically organized functional connectivity of visual areas in amblyopia

Amblyopia is a prevalent developmental visual disorder of childhood that typically persists in adults. Due to altered visual experience during critical periods of youth, the structure and function of adult visual cortex is abnormal. In addition to substantial deficits shown with task-based fMRI, previous studies have used resting state measures to demonstrate altered long-range connectivity in amblyopia. This is the first study in amblyopia to analyze connectivity between regions of interest that are smaller than a single cortical area and to apply partial correlation analysis to reduce network effects. We specifically assess short-range connectivity between retinotopically defined regions of interest within the occipital lobe of 8 subjects with amblyopia and 7 subjects with normal vision (aged 19–45). The representations of visual areas V1, V2, and V3 within each of the four quadrants of visual space were further subdivided into three regions based on maps of visual field eccentricity. Connectivity between pairs of all nine regions of interest in each quadrant was tested via correlation and partial correlation for both groups. Only the tests of partial correlation, i.e., correlation between time courses of two regions following the regression of time courses from all other regions, yielded significant differences between resting state functional connectivity in amblyopic and normal subjects. Subjects with amblyopia showed significantly higher partial correlation between para-foveal and more eccentric representations within V1, and this effect associated with poor acuity of the worse eye. In addition, we observed reduced correlation in amblyopic subjects between isoeccentricity regions in V1 and V2, and separately, between such regions in V2 and V3. We conclude that partial correlation-based connectivity is altered in an eccentricity-dependent pattern in visual field maps of amblyopic patients. Moreover, results are consistent with known clinical and psychophysical vision loss. More broadly, this provides evidence that abnormal cortical adaptations to disease may be better isolated with tests of partial correlation connectivity than with the regular correlation techniques that are currently widely used.

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Cortical functional connectivity abnormalities exist in amblyopia at a scale finer than previously reported.

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Connectivity changes within primary visual cortex are consistent with known loss of function.

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Connectivity changes between visual areas are consistent with concept of deafferentation.

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Partial correlation differentiates patients from controls, whereas correlation does not.

O'Connor et al. systematic review regarding animal feeding operations and public health: critical flaws may compromise conclusions

In this comment, we summarize several scientific concerns with the recently published systematic review from O'Connor and colleagues that examined the relationship between proximity to animal-feeding operations and health of individuals in nearby communities. The authors utilized a bias tool not designed for environmental health research, erroneously excluded important studies, and incorrectly interpreted others. As a result, the conclusions drawn in the review misrepresent the evidence from the published literature, limiting its value to policymakers, researchers, and the public.

Developmental PBDE Exposure and IQ/ADHD in Childhood: A Systematic Review and Meta-analysis

BACKGROUND

In the United States, one in six children are affected by neurodevelopmental disorders, and polybrominated diphenyl ethers (PBDEs) in flame-retardant chemicals are measured ubiquitously in children.

OBJECTIVE

We conducted a systematic a systematic review regarding developmental exposure to PBDEs and intelligence or Attention Deficit/Hyperactivity Disorder (ADHD) and attention-related behavioral conditions in humans.

METHODS

We searched articles published up to 26 September 2016, and included original studies that quantified exposures to PBDEs incurred any time in proximity to conception or during in utero, perinatal, or childhood time periods. We evaluated the risk of bias of individual studies and the overall quality and strength of the evidence according to the Navigation Guide systematic review methodology. We established criteria in advance to identify studies that could be combined using random effects meta-analyses (DerSimonian-Laird method).

RESULTS

Fifteen studies met the inclusion criteria; 10 studies met the criteria for intelligence and nine for attention-related problems. We rated studies generally with "low" to "probably low" risk of bias and rated the overall body of evidence as "moderate" quality with "sufficient" evidence for an association between Intelligence Quotient (IQ) and PBDEs. Our meta-analysis of four studies estimated a 10-fold increase (in other words, times 10) in PBDE exposure associated with a decrement of 3.70 IQ points (95% confidence interval: 0.83, 6.56). We concluded the body of evidence was of "moderate" quality for ADHD with "limited" evidence for an association with PBDEs, based on the heterogeneity of association estimates reported by a small number of studies and the fact that chance, bias, and confounding could not be ruled out with reasonable confidence.

CONCLUSION

We concluded there was sufficient evidence supporting an association between developmental PBDE exposure and reduced IQ. Preventing developmental exposure to PBDEs could help prevent loss of human intelligence. https://doi.org/10.1289/EHP1632.

Building the Future of Environmental Public Health Tracking: Proceedings and Recommendations of an Expert Panel Workshop

Since 2002, the national Environmental Health Tracking Program of the Centers for Disease Control and Prevention (CDC) has provided vital support to state environmental public health efforts while simultaneously building a nationwide network of state, local, and academic partners to improve our nation’s capacity to understand and respond to environmental threats to public health. As part of program review and strategic planning, national thought leaders in environmental public health were convened to assess progress, identify gaps and challenges, and provide recommendations for enhancing the utility and impact of the Tracking Program. Several opportunities were identified. Chief among these was the need for continued and expanded CDC leadership to develop a coordinated Tracking Program agenda identifying specific scientific goals, data needs, and initiatives. Recommendations for future growth included expanded data availability and program coverage: i.e., making data available at the community scale and establishing tracking programs in all 50 states. Finally, a set of recommendations emphasizing communication to decision makers and the public was made that will be integral to the future utility and success of the Tracking Program.

A Systematic Review and Meta-Analysis of Multiple Airborne Pollutants and Autism Spectrum Disorder

BACKGROUND

Exposure to ambient air pollution is widespread and may be detrimental to human brain development and a potential risk factor for Autism Spectrum Disorder (ASD). We conducted a systematic review of the human evidence on the relationship between ASD and exposure to all airborne pollutants, including particulate matter air pollutants and others (e.g. pesticides and metals).

OBJECTIVE

To answer the question: "is developmental exposure to air pollution associated with ASD?"

METHODS

We conducted a comprehensive search of the literature, identified relevant studies using inclusion/exclusion criteria pre-specified in our protocol (registered in PROSPERO, CRD # 42015017890), evaluated the potential risk of bias for each included study and identified an appropriate subset of studies to combine in a meta-analysis. We then rated the overall quality and strength of the evidence collectively across all air pollutants.

RESULTS

Of 1,158 total references identified, 23 human studies met our inclusion criteria (17 case-control, 4 ecological, 2 cohort). Risk of bias was generally low across studies for most domains; study limitations were related to potential confounding and accuracy of exposure assessment methods. We rated the quality of the body of evidence across all air pollutants as "moderate." From our meta-analysis, we found statistically significant summary odds ratios (ORs) of 1.07 (95% CI: 1.06, 1.08) per 10-μg/m3 increase in PM10 exposure (n = 6 studies) and 2.32 (95% CI: 2.15, 2.51) per 10-μg/m3 increase in PM2.5 exposure (n = 3 studies). For pollutants not included in a meta-analysis, we collectively evaluated evidence from each study in rating the strength and quality of overall evidence considering factors such as inconsistency, imprecision, and evidence of dose-response. All included studies generally showed increased risk of ASD with increasing exposure to air pollution, although not consistently across all chemical components.

CONCLUSION

After considering strengths and limitations of the body of research, we concluded that there is "limited evidence of toxicity" for the association between early life exposure to air pollution as a whole and diagnosis of ASD. The strongest evidence was between prenatal exposure to particulate matter and ASD. However, the small number of studies in the meta-analysis and unexplained statistical heterogeneity across the individual study estimates means that the effect could be larger or smaller (including not significant) than these studies estimate. Our research supports the need for health protective public policy to reduce exposures to harmful airborne contaminants among pregnant women and children and suggests opportunities for optimizing future research.

Characteristics of Four Upward-Pointing Cosmic-Ray-like Events Observed with ANITA

We report on four radio-detected cosmic-ray (CR) or CR-like events observed with the Antarctic Impulsive Transient Antenna (ANITA), a NASA-sponsored long-duration balloon payload. Two of the four were previously identified as stratospheric CR air showers during the ANITA-I flight. A third stratospheric CR was detected during the ANITA-II flight. Here, we report on characteristics of these three unusual CR events, which develop nearly horizontally, 20-30 km above the surface of Earth. In addition, we report on a fourth steeply upward-pointing ANITA-I CR-like radio event which has characteristics consistent with a primary that emerged from the surface of the ice. This suggests a possible τ-lepton decay as the origin of this event, but such an interpretation would require significant suppression of the standard model τ-neutrino cross section.

Ambient air pollution epidemiology systematic review and meta-analysis: A review of reporting and methods practice

BACKGROUND

Systematic review and meta-analysis (SRMA) are increasingly employed in environmental health (EH) epidemiology and, provided methods and reporting are sound, contribute to translating science evidence to policy. Ambient air pollution (AAP) is both among the leading environmental causes of mortality and morbidity worldwide, and of growing policy relevance due to health co-benefits associated with greenhouse gas emissions reductions.

OBJECTIVES

We reviewed the published AAP SRMA literature (2009 to mid-2015), and evaluated the consistency of methods, reporting and evidence evaluation using a 22-point questionnaire developed from available best-practice consensus guidelines and emerging recommendations for EH. Our goal was to contribute to enhancing the utility of AAP SRMAs to EH policy.

RESULTS AND DISCUSSION

We identified 43 studies that used both SR and MA techniques to examine associations between the AAPs PM2.5, PM10, NO2, SO2, CO and O3, and various health outcomes. On average AAP SRMAs partially or thoroughly addressed 16 of 22 questions (range 10-21), and thoroughly addressed 13 of 22 (range 5-19). We found evidence of an improving trend over the period. However, we observed some weaknesses, particularly infrequent formal reviews of underlying study quality and risk-of-bias that correlated with lower frequency of thorough evaluation for key study quality parameters. Several other areas for enhanced reporting are highlighted.

CONCLUSIONS

The AAP SRMA literature, in particular more recent studies, indicate broad concordance with current and emerging best practice guidance. Development of an EH-specific SRMA consensus statement including a risk-of-bias evaluation tool, would be a contribution to enhanced reliability and robustness as well as policy utility.

Implementing systematic review techniques in chemical risk assessment: Challenges, opportunities and recommendations

Systematic review (SR) is a rigorous, protocol-driven approach designed to minimise error and bias when summarising the body of research evidence relevant to a specific scientific question. Taking as a comparator the use of SR in synthesising research in healthcare, we argue that SR methods could also pave the way for a "step change" in the transparency, objectivity and communication of chemical risk assessments (CRA) in Europe and elsewhere. We suggest that current controversies around the safety of certain chemicals are partly due to limitations in current CRA procedures which have contributed to ambiguity about the health risks posed by these substances. We present an overview of how SR methods can be applied to the assessment of risks from chemicals, and indicate how challenges in adapting SR methods from healthcare research to the CRA context might be overcome. Regarding the latter, we report the outcomes from a workshop exploring how to increase uptake of SR methods, attended by experts representing a wide range of fields related to chemical toxicology, risk analysis and SR. Priorities which were identified include: the conduct of CRA-focused prototype SRs; the development of a recognised standard of reporting and conduct for SRs in toxicology and CRA; and establishing a network to facilitate research, communication and training in SR methods. We see this paper as a milestone in the creation of a research climate that fosters communication between experts in CRA and SR and facilitates wider uptake of SR methods into CRA.

How credible are the study results? Evaluating and applying internal validity tools to literature-based assessments of environmental health hazards

Environmental health hazard assessments are routinely relied upon for public health decision-making. The evidence base used in these assessments is typically developed from a collection of diverse sources of information of varying quality. It is critical that literature-based evaluations consider the credibility of individual studies used to reach conclusions through consistent, transparent and accepted methods. Systematic review procedures address study credibility by assessing internal validity or "risk of bias" - the assessment of whether the design and conduct of a study compromised the credibility of the link between exposure/intervention and outcome. This paper describes the commonalities and differences in risk-of-bias methods developed or used by five groups that conduct or provide methodological input for performing environmental health hazard assessments: the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group, the Navigation Guide, the National Toxicology Program's (NTP) Office of Health Assessment and Translation (OHAT) and Office of the Report on Carcinogens (ORoC), and the Integrated Risk Information System of the U.S. Environmental Protection Agency (EPA-IRIS). Each of these groups have been developing and applying rigorous assessment methods for integrating across a heterogeneous collection of human and animal studies to inform conclusions on potential environmental health hazards. There is substantial consistency across the groups in the consideration of risk-of-bias issues or "domains" for assessing observational human studies. There is a similar overlap in terms of domains addressed for animal studies; however, the groups differ in the relative emphasis placed on different aspects of risk of bias. Future directions for the continued harmonization and improvement of these methods are also discussed.

Meeting the public health challenge of protecting private wells: Proceedings and recommendations from an expert panel workshop

Private wells serving fewer than 25 people are federally unregulated, and their users may be exposed to naturally occurring agents of concern such as arsenic and radionuclides, as well as anthropogenic contaminants. The Centers for Disease Control and Prevention's Clean Water for Health Program works to protect private wells and prevent adverse health outcomes for the roughly 15% of Americans who rely on them. To understand current and emerging challenges to the private drinking water supply, an interdisciplinary expert panel workshop on "Future and Emerging Issues for Private Wells" was organized to inform strategic planning for the Clean Water for Health Program. The panel assessed current conditions of ground water as a source for private wells, identified emerging threats, critical gaps in knowledge, and public health needs, and recommended strategies to guide future activities to ensure the safety of private drinking water wells. These strategies addressed topics of broad interest to the environmental public health community including: development of new methods to support citizen science; addressing contaminant mixtures; expanding capacity for well testing; evaluating treatment technologies; building an evidence base on best practices on well owner outreach and stewardship; and research and data needs.

Accelerator Measurements of Magnetically Induced Radio Emission from Particle Cascades with Applications to Cosmic-Ray Air Showers

For 50 years, cosmic-ray air showers have been detected by their radio emission. We present the first laboratory measurements that validate electrodynamics simulations used in air shower modeling. An experiment at SLAC provides a beam test of radio-frequency (rf) radiation from charged particle cascades in the presence of a magnetic field, a model system of a cosmic-ray air shower. This experiment provides a suite of controlled laboratory measurements to compare to particle-level simulations of rf emission, which are relied upon in ultrahigh-energy cosmic-ray air shower detection. We compare simulations to data for intensity, linearity with magnetic field, angular distribution, polarization, and spectral content. In particular, we confirm modern predictions that the magnetically induced emission in a dielectric forms a cone that peaks at the Cherenkov angle and show that the simulations reproduce the data within systematic uncertainties.

A cross-sectional analysis of the relationships of FAM components and their effects on quality of life in Chinese patients with chronic musculoskeletal pain

Introduction

A body of evidence has accrued supporting the Fear-Avoidance Model (FAM) of chronic pain which postulated the mediating role of pain-related fear in the relationships between pain catastrophizing and pain anxiety in affecting pain-related outcomes. Yet, relatively little data points to the extent to which the FAM be extended to understand chronic pain in Chinese population and its impact on quality of life (QoL).

Objective

This study explored the relationships between FAM components and their effects on QoL in a Chinese sample.

Methods

A total of 401 Chinese patients with chronic musculoskeletal pain completed measures of three core FAM components (pain catastrophizing, pain-related fear, and pain anxiety) and QoL. Cross-sectional structural equation modeling (SEM) assessed the goodness of fit of the FAM for two QoL outcomes, Physical (Model 1) and Mental (Model 2). In both models, pain catastrophizing was hypothesized to underpin pain-related fear, thereby influencing pain anxiety and subsequently QoL outcomes.

Results

Results of SEM evidenced adequate data-model fit (CFI30.90) for the two models tested (Model 1: CFI = 0.93; Model 2: CFI = 0.94). Specifically, pain catastrophizing significantly predicted pain-related fear (Model 1: stdb = 0.90; Model 2: stdb = 0.91), which in turn significantly predicted pain anxiety (Model 1: stdb = 0.92; Model 2: stdb = 0.929) and QoL outcomes in a negative direction (Model 1: stdb = −0.391; Model 2: stdb = −0.651) (all P < 0.001) (Table 1, Fig. 1).

Conclusion

Our data substantiated the existing FAM literature and offered evidence for the cross-cultural validity of the FAM in the Chinese population with chronic pain.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

The net suppression effect of pain catastrophic cognition on anxiety sensitivity

Introduction

The existing literature on chronic pain points to the effects anxiety sensitivity, pain hypervigilance, and pain catastrophizing on pain-related fear; however, the nature of the relationships remains unclear. The three dispositional factors may affect one another in the prediction of pain adjustment outcomes. The addition of one disposition may increase the association between another disposition and outcomes, a consequence known as suppressor effects in statistical terms.

Objective

This study examined the possible statistical suppressor effects of anxiety sensitivity, pain hypervigilance and pain catastrophizing in predicting pain-related fear and adjustment outcomes (disability and depression).

Methods

Chinese patients with chronic musculoskeletal pain (n = 401) completed a battery of assessments on pain intensity, depression, anxiety sensitivity, pain vigilance, pain catastrophizing, and pain-related fear. Multiple regression analyses assessed the mediating/moderating role of pain hypervigilance. Structural equation modeling (SEM) was used to evaluate suppression effects.

Results

Our results evidenced pain hypervigilance mediated the effects of anxiety sensitivity (Model 1: Sobel z = 4.86) and pain catastrophizing (Model 3: Sobel z = 5.08) on pain-related fear. Net suppression effect of pain catastrophizing on anxiety sensitivity was found in SEM where both anxiety sensitivity and pain catastrophizing were included in the same full model to predict disability (Model 9: CFI = 0.95) and depression (Model 10: CFI = 0.93) (all P < 0.001) (see Figs. 3 and 4, Figs. 1 and 2).

Conclusions

Our findings evidenced that pain hypervigilance mediated the relationship of two dispositional factors, pain catastrophic cognition and anxiety sensitivity, with pain-related fear. The net suppression effects of pain catastrophizing suggest that anxiety sensitivity enhanced the effect of pain catastrophic cognition on pain hypervigilance.

Disclosure of interest

The authors have not supplied their declaration of competing interest.