The effect of confounding variables in studies of lead exposure and IQ

Risk of significant functional impairment across cancer diagnosis and care continuum

BACKGROUND

The authors examined baseline physical functional (PF) impairment among cancer outpatients in the National Cancer Institute Cancer Moonshot study Northwestern University Improving the Management of Symptoms During and Following Cancer Treatment (NU IMPACT). They hypothesized that PF impairment, measured with the Patient Reported Outcome Measurement Information System-Physical Function (PROMIS-PF) survey, would (1) be common and more prevalent for patients receiving treatment compared with no treatment and (2) differ across tumor types, independent of cancer continuum phase.

METHODS

Adults who were diagnosed with cancer in NU IMPACT (n = 2273) were sampled, and their PROMIS-PF scores were compared across tumor types and cancer continuum (curative, noncurative, or no treatment), with scores ≤40 indicating moderate-severe impairment. Multivariable logistic regression models were used to evaluate the relation among patient and cancer factors and PF scores using a 95% confidence interval.

RESULTS

Forty percent of the surveyed patients reported moderate-severe PF impairment. Patients with melanoma reported the least impairment, and those with lung cancer were 6.5 times more likely to have moderate-severe impairment (95% confidence interval, 2.393-17.769). The noncurative group was 1.5 times more likely to have moderate-severe impairment (95% confidence interval, 1.045-2.145; mean score, 43; p < .001) than the curative (mean score, 6) and no treatment (mean score, 48) groups. One-third of those who reported PF impairment also had significant pain and/or fatigue.

CONCLUSIONS

A sizeable minority experienced PF impairment across tumor types for which pain and/or fatigue co-occurred, particularly in the noncurative group. The PROMIS-PF survey effectively identified variations in physical function. Future studies will explore how screening for PF impairment can be used to refer patients for appropriate cancer rehabilitation services.

A preliminary estimate of the environmental burden of disease associated with exposure to pyrethroid insecticides and ADHD in Europe based on human biomonitoring

Human biomonitoring (HBM) data indicate that exposure to pyrethroids is widespread in Europe, with significantly higher exposure observed in children compared to adults. Epidemiological, toxicological, and mechanistic studies raise concerns for potential human health effects, particularly, behavioral effects such as attention deficit hyperactivity disorder (ADHD) in children at low levels of exposure. Based on an exposure-response function from a single European study and on available quality-assured and harmonized HBM data collected in France, Germany, Iceland, Switzerland, and Israel, a preliminary estimate of the environmental burden of disease for ADHD associated with pyrethroid exposure was made for individuals aged 0-19 years. The estimated annual number of prevalence-based disability-adjusted life years (DALYs) per million inhabitants were 27 DALYs for Israel, 21 DALYs for France, 12 DALYs for both Switzerland and Iceland, and 3 DALYs for Germany; while the annual ADHD cases per million inhabitants attributable to pyrethroids were 2189 for Israel, 1710 for France, 969 for Iceland, 944 for Switzerland, and 209 for Germany. Direct health costs related to ADHD ranged between 0.3 and 2.5 million EUR yearly per million inhabitants for the five countries. Additionally, a substantial number of ADHD cases, on average 18%, were associated with pyrethroid exposure. Yet, these figures should be interpreted with caution given the uncertainty of the estimation. A sensitivity analysis showed that by applying a different exposure-response function from outside the EU, the population attributable fraction decreased from an average of 18 to 7%. To ensure more robust disease burden estimates and adequate follow-up of policy measures, more HBM studies are needed, along with increased efforts to harmonize the design of epidemiological studies upfront to guarantee meta-analysis of exposure-response functions. This is particularly important for pyrethroids as evidence of potential adverse health effects is continuously emerging.

In utero exposure to ionizing radiation and metabolic regulation: perspectives for future multi- and trans-generation effects studies

PURPOSE

The radiation protection community has been particularly attentive to the risks of delayed effects on offspring from low dose or low dose-rate exposures to ionizing radiation. Despite this, the current epidemiologic studies and scientific data are still insufficient to provide the necessary evidence for improving risk assessment guidelines. This literature review aims to inform future studies on multigenerational and transgenerational effects. It primarily focuses on animal studies involving in utero exposure and discusses crucial elements for interpreting the results. These elements include in utero exposure scenarios relative to the developmental stages of the embryo/fetus, and the primary biological mechanisms responsible for transmitting heritable or hereditary effects to future generations. The review addresses several issues within the contexts of both multigenerational and transgenerational effects, with a focus on hereditary perspectives.

CONCLUSIONS

Knowledge consolidation in the field of Developmental Origins of Health and Disease (DOHaD) has led us to propose a new study strategy. This strategy aims to address the transgenerational effects of in utero exposure to low dose and low dose-rate radiation. Within this concept, there is a possibility that disruption of epigenetic programming in embryonic and fetal cells may occur. This disruption could lead to metabolic dysfunction, which in turn may cause abnormal responses to future environmental challenges, consequently increasing disease risk. Lastly, we discuss methodological limitations in our studies. These limitations are related to cohort size, follow-up time, model radiosensitivity, and analytical techniques. We propose scientific and analytical strategies for future research in this field.

A case study of neurodevelopmental risks from combined exposures to lead, methyl-mercury, inorganic arsenic, polychlorinated biphenyls, polybrominated diphenyl ethers and fluoride

We performed a mixture risk assessment (MRA) case study of dietary exposure to the food contaminants lead, methylmercury, inorganic arsenic (iAs), fluoride, non-dioxin-like polychlorinated biphenyls (NDL-PCBs) and polybrominated diphenyl ethers (PBDEs), all substances associated with declines in cognitive abilities measured as IQ loss. Most of these chemicals are frequently measured in human biomonitoring studies. A component-based, personalised modified reference point index (mRPI) approach, in which we expressed the exposures and potencies of our chosen substances as lead equivalent values, was applied to perform a MRA for dietary exposures. We conducted the assessment for four different age groups (toddlers, children, adolescents, and women aged 18-45 years) in nine European countries. Populations in all countries considered exceeded combined tolerable levels at median exposure levels. NDL-PCBs in fish, other seafood and dairy, lead in grains and fruits, methylmercury in fish and other seafoods, and fluoride in water contributed most to the combined exposure. We identified uncertainties for the likelihood of co-exposure, assessment group membership, endpoint-specific reference values (ESRVs) based on epidemiological (lead, methylmercury, iAs, fluoride and NDL-PCBs) and animal data (PBDE), and exposure data. Those uncertainties lead to a complex pattern of under- and overestimations, which would require probabilistic modelling based on expert knowledge elicitation for integration of the identified uncertainties into an overall uncertainty estimate. In addition, the identified uncertainties could be used to refine future MRA for cognitive decline.

Lead Industry Influence in the 21st Century: An Old Playbook for a "Modern Metal"

In recent years, lead poisoning has received increasing attention as lead production continues to grow and the industry shifts the most polluting processes (e.g., smelting ore and recycling batteries) to low- and middle-income countries. The hazards associated with lead exposures have been well known for centuries while the industry actively promoted lead products. Less well known is how the industry continues to promote the "safe and responsible" use of lead and support research to question the underlying science and avoid regulation. Here I explore the historical context for recent actions that the industry has taken to ensure its longevity. Lead industry associations continue to employ some of the same themes that have proven successful in the past. Efforts to forestall regulatory initiatives to reduce emissions and restrict lead applications continue. Large battery manufacturers and recyclers and their associations place blame on informal-sector recycling to draw focus away from their own emissions. They have sought the cooperation of hired scientific experts and have funded United Nations organizations and nongovernmental organizations to deflect attention from their own contributions to global lead poisoning. (Am J Public Health. 2022;112(S7):S723-S729. https://doi.org/10.2105/AJPH.2022.306960).