Combined Effect of Lead Exposure and Allostatic Load on Cardiovascular Disease Mortality-A Preliminary Study

Lead exposure, glucocorticoids, and physiological stress across the life course: A systematic review

The biological pathways linking lead exposure to adverse outcomes are beginning to be understood. Rodent models suggest lead exposure induces dysfunction within the hypothalamic-pituitary-adrenal (HPA) axis and glucocorticoid regulation, a primary physiological stress response system. Over time, HPA axis and glucocorticoid dysfunction has been associated with adverse neurocognitive and cardiometabolic health, much like lead exposure. This systematic review utilized PRISMA guidelines to synthesize the literature regarding associations between lead exposure and downstream effector hormones of the HPA axis, including cortisol, a glucocorticoid, and dehydroepiandrosterone (DHEA), a glucocorticoid antagonist. We additionally determined the state of the evidence regarding lead exposure and allostatic load, a measure of cumulative body burden resultant of HPA axis and glucocorticoid dysfunction. A total of 18 articles were included in the review: 16 assessed cortisol or DHEA and 3 assessed allostatic load. Generally, the few available child studies suggest a significant association between early life lead exposure and altered cortisol, potentially suggesting the impact of developmental exposure. In adulthood, only cross sectional studies were available. These reported significant associations between lead and reduced cortisol awakening response and increased cortisol reactivity, but few associations with fasting serum cortisol. Two studies reported significant associations between increasing lead exposure and allostatic load in adults and another between early life lead exposure and adolescent allostatic load. The paucity of studies examining associations between lead exposure and allostatic load or DHEA and overall heterogeneity of allostatic load measurements limit conclusions. However, these findings cautiously suggest associations between lead and dysregulation of physiological stress pathways (i.e., glucocorticoids) as seen through cortisol measurement in children and adults. Future research would help to elucidate these associations and could further examine the physiological stress pathway as a mediator between lead exposure and detrimental health outcomes.

Associations of prenatal and childhood Pb exposure with allostatic load in adolescence: Findings from the ELEMENT cohort study

The biological pathways which link lead (Pb) and long-term outcomes are unclear, though rodent models and a few human studies suggest Pb may alter the body's stress response systems, which over time, can elicit dysregulated stress responses with cumulative impacts. This study examined associations between prenatal and early childhood Pb exposure and adolescent allostatic load, an index of an individual's body burden of stress in multiple biological systems, and further examined sex-based associations. Among 391 (51% male) participants in the ELEMENT birth cohort, we related trimester-specific maternal blood Pb, 1-month postpartum maternal tibia and patella Pb, and child blood Pb at 12-24 months to an allostatic load index in adolescence comprised of biomarkers of cardiovascular, metabolic, neuroendocrine, and immune function. The results were overall mixed, with prenatal exposure, particularly maternal bone Pb, being positively associated with allostatic load, and early childhood Pb showing mixed results for males and females. In adjusted Poisson regression models, 1 mcg/g increase in tibia Pb was associated with a 1% change in expected allostatic load (IRR = 1.01; 95%CI 0.99, 1.02). We found a significant Pb × sex interaction (IRR = 1.05; 95%CI 1.01, 1.10); where males saw an increasing percent change in allostatic load as 12 month Pb levels increased compared to females who saw a decreasing allostatic load. Further examination of allostatic load will facilitate the determination of potential mechanistic pathways between developmental toxicant exposures and later-in-life cardiometabolic outcomes.

Identifying Sources of Lead Exposure for Children in the Republic of Georgia, with Lead Isotope Ratios

In the Republic of Georgia, a 2018 national survey estimated that more than 40% of children aged 2-7 years had a blood lead concentration (BLC) of more than 5 µg/dL. The objective of this study was to document the feasibility of employing lead isotope ratios (LIRs) to identify and rank the Pb (lead) exposure sources most relevant to children across Georgia. A cross-sectional survey between November 2019 and February 2020 of 36 children previously identified as having BLCs > 5 µg/dL from seven regions of Georgia involved the collection of blood and 528 environmental samples, a questionnaire on behaviours and potential exposures. The LIRs in blood and environmental samples were analysed in individual children and across the whole group to ascertain clustering. A fitted statistical mixed-effect model to LIR data first found that the blood samples clustered with spices, tea, and paint, then, further isotopically distinct from blood were sand, dust, and soil, and lastly, milk, toys, pens, flour, and water. Analysis of the LIRs provided an indication and ranking of the importance of Pb environmental sources as explanatory factors of BLCs across the group of children. The findings support the deployment of interventions aimed at managing the priority sources of exposure in this population.

Toxicity of Heavy Metals and Recent Advances in Their Removal: A Review

Natural and anthropogenic sources of metals in the ecosystem are perpetually increasing; consequently, heavy metal (HM) accumulation has become a major environmental concern. Human exposure to HMs has increased dramatically due to the industrial activities of the 20th century. Mercury, arsenic lead, chrome, and cadmium have been the most prevalent HMs that have caused human toxicity. Poisonings can be acute or chronic following exposure via water, air, or food. The bioaccumulation of these HMs results in a variety of toxic effects on various tissues and organs. Comparing the mechanisms of action reveals that these metals induce toxicity via similar pathways, including the production of reactive oxygen species, the inactivation of enzymes, and oxidative stress. The conventional techniques employed for the elimination of HMs are deemed inadequate when the HM concentration is less than 100 mg/L. In addition, these methods exhibit certain limitations, including the production of secondary pollutants, a high demand for energy and chemicals, and reduced cost-effectiveness. As a result, the employment of microbial bioremediation for the purpose of HM detoxification has emerged as a viable solution, given that microorganisms, including fungi and bacteria, exhibit superior biosorption and bio-accumulation capabilities. This review deals with HM uptake and toxicity mechanisms associated with HMs, and will increase our knowledge on their toxic effects on the body organs, leading to better management of metal poisoning. This review aims to enhance comprehension and offer sources for the judicious selection of microbial remediation technology for the detoxification of HMs. Microbial-based solutions that are sustainable could potentially offer crucial and cost-effective methods for reducing the toxicity of HMs.

A better cost:benefit analysis yields better and fairer results: EPA's lead and copper rule revision

When conducted on a societal level, cost-benefit analysis (CBA) can indicate policies that best allocate scarce public resources. Done incompletely, CBA can produce spurious, biased results. To estimate the potential health benefits of EPA's recent Lead and Copper Drinking Water Rule Revision (LCRR), we used EPA's exposure, compliance, and effect coefficient estimates to monetize 16 of the health endpoints EPA has determined are causally related to lead exposure. In addition, we monetized one health endpoint that EPA has used elsewhere: preterm birth. We estimated that the total annual health benefits of the LCRR greatly exceed EPA's estimated annual costs: $9 billion vs $335 million (2016$). Our benefit estimates greatly exceed EPA's benefit estimates. There are also nonhealth benefits because lead generally contaminates drinking water through the corrosion of plumbing components that contain lead. The LCRR therefore has 2 components: reducing how corrosive the water is and limited replacement of lead pipes. Reducing corrosion damage to drinking water and wastewater infrastructure and residential appliances that use water yields significant annualized material benefits also: $2-8 billion (2016$). Effectively, the health benefits are free. Finally, while actual exposure data are limited, the available data on lead-contaminated drinking water exhibits known risk patterns, disproportionately burdening low-income and minority populations and women. This economic analysis demonstrates that to maximize national benefits and improve equity, the LCRR should be as rigorous as possible.

Stress Experience, Depression and Neck Disability in Patients with Temporomandibular Disorder-Myofascial Pain with Referral

The etiology of temporomandibular disorders (TMDs) is firmly anchored in the biopsychosocial model in which a special role is attributed to the stress, depression, somatic symptoms, and anxiety. The aim of the study was to assess the level of stress, depression and neck disability in patients with temporomandibular disorder-myofascial pain with referral. The study group enrolled 50 people (37 women and 13 men) with complete natural dentition. All the patients underwent a clinical examination according to the Diagnostic Criteria for Temporomandibular Disorders and were diagnosed as individuals with myofascial pain with referral. The questionnaires were associated with stress, depression, and neck disability; Perceived Stress Scale (PSS-10), Beck Depression Inventory(BDI), and Neck Disability Index (NDI) were evaluated. Of the individuals evaluated, 78% showed elevated levels of stress, and the average value of the PSS-10 in the study group was 18 points (Me = 17). Furthermore, 30% of the subjects presented depressive symptoms, with the average value of BDI was 8.94 points (Me = 8), and 82% of the subjects showed neck disability. The multiple linear regression model revealed that BDI and NDI allowed explanations for the 53% differentiation of PSS-10. In conclusion, stress, depression, and neck disability coexist with temporomandibular disorder-myofascial pain with referral.

Potential Health Risks of Lead Exposure from Early Life through Later Life: Implications for Public Health Education

Lead (Pb) exposure has been a serious environmental and public health problem throughout the world over the years. The major sources of lead in the past were paint and gasoline before they were phased out due to its toxicity. Meanwhile, people continue to be exposed to lead from time to time through many other sources such as water, food, soil and air. Lead exposure from these sources could have detrimental effects on human health, especially in children. UNICEF reported that approximately 800 million children have blood lead levels (BLLs) at or above 5 micrograms per deciliter (µg/dL) globally. This paper reports on the potential risks of lead exposure from early life through later life. The articles used in this study were searched from databases such as Springer, Science Direct, Hindawi, MDPI, Google Scholar, PubMed and other academic databases. The levels of lead exposure in low income and middle-income countries (LMICs) and high-income countries (HICs) were reported, with the former being more affected. The intake of certain nutrients could play an essential role in reducing (e.g., calcium and iron) or increasing (e.g., high fat foods) lead absorption in children. Elevated blood lead levels may disturb the cells' biological metabolism by replacing beneficial ions in the body such as calcium, magnesium, iron and sodium. Once these ions are replaced by lead, they can lead to brain disorders, resulting in reduced IQ, learning difficulties, reduced attention span and some behavioral problems. Exposure to lead at an early age may lead to the development of more critical problems later in life. This is because exposure to this metal can be harmful even at low exposure levels and may have a lasting and irreversible effect on humans. Precautionary measures should be put in place to prevent future exposure. These will go a long way in safeguarding the health of everyone, most especially the young ones.

Sources of Lead Exposure in West Africa

This commentary is an investigation of sources of lead (Pb) exposure in West Africa. Pb is generally acknowledged as one of the most widespread environmental health hazards in West Africa, and there is heightened concern over adverse health effects at various levels of exposure (at doses once considered safe) in the West African region. A literature review for the possible health implications of Pb exposure on human health showed nervous system dysfunction, anemia, and potential cognitive diseases as the major health issues among children, while adults were found to suffer more from cardiovascular dysfunction, neurological decline, and reproductive diseases. Despite a decline in blood lead levels (BLLs), lead exposure continues to be a major public health concern as no level of Pb exposure can be considered safe. Moreover, lowering BLLs entails identifying various lead sources such as gasoline emissions, leaded paint, canned foods, and beverages, as well as plausible biological pathways of lead exposure and response. However, only countries such as Nigeria and Ghana have extensive research available regarding the different sources of Pb exposure. Further, it is not apparent which country is affected the most by Pb exposure. Therefore, this commentary was aimed to explore different literature sources to describe and list the different sources of Pb exposure in 15 West African countries. The findings indicated water, food, and occupational exposure as the major sources of Pb exposure in the region. People with occupations such as e-waste and Pb acid battery recycling, auto mechanics, fuel attending, welding, electronic repairing, farming/spraying, and mining were found to be at immediate risk. Tobacco, spices and paints constituted additional potential sources of exposure. For residents living near landfills or urban area, the major sources of Pb exposure were soil, air, and dust particles. The review revealed a vast research gap on the sources and implications of Pb exposure. Exposure to Pb could further increase due to uncontrolled traffic, urban growth, inadequate urban planning, and the inadequate enforcement of regulations. Therefore, more extensive research on the changing trends of Pb exposure among West African populations is needed.

Toxicoepigenetics and Environmental Health: Challenges and Opportunities

The rapidly growing field of toxicoepigenetics seeks to understand how toxicant exposures interact with the epigenome to influence disease risk. Toxicoepigenetics is a promising field of environmental health research, as integrating epigenetics into the field of toxicology will enable a more thorough evaluation of toxicant-induced disease mechanisms as well as the elucidation of the role of the epigenome as a biomarker of exposure and disease and possible mediator of exposure effects. Likewise, toxicoepigenetics will enhance our knowledge of how environmental exposures, lifestyle factors, and diet interact to influence health. Ultimately, an understanding of how the environment impacts the epigenome to cause disease may inform risk assessment, permit noninvasive biomonitoring, and provide potential opportunities for therapeutic intervention. However, the translation of research from this exciting field into benefits for human and animal health presents several challenges and opportunities. Here, we describe four significant areas in which we see opportunity to transform the field and improve human health by reducing the disease burden caused by environmental exposures. These include (1) research into the mechanistic role for epigenetic change in environment-induced disease, (2) understanding key factors influencing vulnerability to the adverse effects of environmental exposures, (3) identifying appropriate biomarkers of environmental exposures and their associated diseases, and (4) determining whether the adverse effects of environment on the epigenome and human health are reversible through pharmacologic, dietary, or behavioral interventions. We then highlight several initiatives currently underway to address these challenges.

Allostatic load in the context of disasters

Environmental disasters, pandemics, and other major traumatic events such as the Covid-19 pandemic or war contribute to psychosocial stress which manifests in a wide range of mental and physical consequences. The increasing frequency and severity of such events suggest that the adverse effects of toxic stress are likely to become more widespread and pervasive in the future. The allostatic load (AL) model has important elements that lend themselves well for identifying adverse health effects of disasters. Here we examine several articulations of AL from the standpoint of using AL to gauge short- and long-term health effects of disasters and to provide predictive capacity that would enable mitigation or prevention of some disaster-related health consequences. We developed a transdisciplinary framework combining indices of psychosocial AL and physiological AL to produce a robust estimate of overall AL in people affected by disasters and other traumatic events. In conclusion, we urge researchers to consider the potential of using AL as a component in a proposed disaster-oriented human health observing system.

The Association between Multiple Per- and Polyfluoroalkyl Substances' Serum Levels and Allostatic Load

Background/Objective: This study aimed to explore the association between allostatic load (AL), an index of chronic stress, with nine per- and polyfluoroalkyl substances (PFASs), a group of organic compounds used in commercial and industrial applications. The PFASs explored were perfluorohexane sulfonic acid (PFHS), perfluorodecanoic acid (PFDE), perfluorobutane sulfonic acid (PFBS), perfluoroheptanoic acid (PFHP), perflurododecanoic acid (PFDO), perfluorononanoic acid (PFNA), perfluoroundecanoic acid (PFUA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS). This study was performed to better understand the association between PFASs and AL, which may be a mediator of several diseases. Methods: This study was performed on adults aged 20 and older, using the National Health and Nutrition Examination Survey (NHANES) 2007−2014 data. AL was calculated as a cumulative index of ten biomarkers from the cardiovascular, inflammatory, and metabolic system, which was dichotomized into high risk (assigned a value of 1) or low risk (assigned a value 0) depending on if the index value was ≥3 (chronic physiological stress) or <3 (less stressed). In this study, PFASs and covariates such as age, gender, ethnicity, alcohol consumption, smoking, and physical activity were explored using descriptive statistics and logistic regression modeling. Results: The results indicated that in adults, AL was more elevated in men as compared to women, in those aged ≥60 years, and varied by ethnicity. For instance, non-Hispanic Blacks had higher AL levels (mean of 3.92) compared to other ethnicities. A significant number of the participants tested for PFBS, PFHP, PFDO were below the LOD and thus these PFASs were excluded from the analysis. Our analysis demonstrated multicollinearities between variables such as PFNA, PFOS, and PFOA with variance inflation factor (VIF) values of 6.197, 6.212, and 5.139, respectively. Thus, PFASs were analyzed individually and adjusted for age, gender, ethnicity, physical activity, smoking, and alcohol consumption. The results indicated a statistically significant positive association between AL and most of the PFASs, except PFUA which was not statistically significant with a p value of 0.531. Conclusions: The findings of this study suggest that exposure to PFDE, PFNA, PFOS, PFOA, and PFHS are associated with AL when adjusted for age, gender, ethnicity, alcohol consumption, smoking, and physical activity. Future studies looking to model the effects of these factors together must consider their relationship with each other and choose different analytical approaches.

Interaction of Per- and Polyfluoroalkyl Substances and Allostatic Load among Adults in Various Occupations

Objective: This study sought to assess the associations between occupation, serum concentrations of selected of Per- and Polyfluoroalkyl Substances (PFAS), and chronic physiological stress, as operationalized by Allostatic Load (AL), among adults aged ≥20 years. Methods: To explore the interactions of occupation with PFAS levels and AL, data from the National Health and Nutrition Examination Survey (NHANES) 2007−2014 were used. We performed Poisson regression modeling to evaluate AL’s relationships with PFAS concentrations and occupations on weighted data. Results: The results demonstrated that increased AL was positively associated with different occupation groups such as a) Public Administration and b) Arts, Entertainment, and Recreation (p-values 0.018 and 0.002, respectively), and with certain PFAS concentrations (Perfluorooctanoic acid, PFOA, p-value = 0.002). Finally, AL had a strong association with the interaction of some PFAS such as Perfluorobutane sulfonic acid (PFBS) and occupation (AL: PFBS: occupation, p-value < 0.0001), with different association measures existing across varying occupations. Conclusions: Occupation and PFOA seem to be associated with AL. This suggests the need of implementing further strategies to limit the exposure to stressors and PFAS in the work environment to promote longevity among the workforce in the U.S. Finally, policymakers must do more to clearly define standards and regulations in the work environment related to PFAS exposure.

Investigation of Differences in Allostatic Load among Black Men by Level of Educational Attainment: High School Graduates Experience the Highest Levels of Stress

Allostatic load (AL)—the biological assessment of long-term exposure to stress—may explain mortality-rate disparities among non-Hispanic Black (Black) men. We aimed to investigate AL among Black men with equivalent education status after controlling for income. A cross-sectional study was employed to investigate AL among 4113 Black men who participated in the National Health and Nutrition Examination Survey between 1999–2018. A summation of 8 biomarker factors were used to compute AL, differences in socio-demographic characteristics by education status were evaluated, and health behaviors that may influence AL were examined. To determine the high-risk thresholds for each AL component, we examined each component’s distribution among NHB men for whom complete biomarker data were available in the NHANES sample. High-risk thresholds were determined as either (1) above the 75th percentile for body mass index (BMI), diastolic blood pressure (DBP), glycated hemoglobin, systolic blood pressure (SBP), total cholesterol, and serum triglycerides; or (2) below the 25th percentile for serum albumin and serum creatinine. Modified Poisson regression models were used to estimate prevalence ratios and their associated 95% confidence intervals for high AL risk while adjusting for potential confounders. Black men with a high school diploma/GED had a greater prevalence of high AL compared with Black men who had other levels of education, and a slightly higher prevalence of high AL compared with Black men who had less than a high school education. Black men with college degrees had a lower prevalence of high AL than Black men with the lowest levels of educational attainment. Researchers must further examine the hidden costs stemming from the interplay between discrimination associated with being Black in America and systemic racism in the educational system—which may be preventing Black men from achieving optimal health.

OUP accepted manuscript

Healthy soil is foundational to human health. Healthy soil is needed to grow crops, provides food, and sustains populations. It supports diverse ecosystems and critical ecological services such as pollination. It stores water and prevents floods. It captures carbon and slows global climate change. Soil pollution is a great and growing threat to human health. Soil may be polluted by heavy metals, organic chemicals such as pesticides, biological pathogens, and micro/nanoplastic particles. Pollution reduces soil's ability to yield food. It results in food crop contamination and disease. Soil pollutants wash into rivers causing water pollution. Deforestation causes soil erosion, liberates sequestered pollutants, and generates airborne dust. Pollution of air, water, and soil is responsible for at least 9 million deaths each year. More than 60% of pollution-related disease and death is due to cardiovascular disease. Recognizing the importance of pollution to human health, the European Commission and the EU Action Plan for 2050: A Healthy Planet for All, have determined that air, water, and soil pollution must be reduced to levels that cause no harm to human or ecosystem health. We are thus required to create a toxic-free environment, respect the concept of a safe operating space for humanity, and sustain the health of our planet for future generations. This review article summarizes current knowledge of the links between soil health and human health and discusses the more important soil pollutants and their health effects.

Reaction Times among Batik Workers: The Influence of Gender and Occupational Lead Exposure

(1) Background: Neglected occupational health and safety aspects in batik industries cause their workers to have an increased risk of lead exposure. The effect of occupational lead exposure on neurocognitive performance is inconclusive. Therefore, we conducted an observational study to examine the difference in simple reaction time between lead-exposed batik workers and non-exposed referents. (2) Methods: This cross-sectional study was conducted in seven batik enterprises in Lendah District, Indonesia, excluding workers with medical conditions impairing reaction time. Simple reaction time tests were conducted using an online tool. Two-way model ANCOVAs examined interactions between gender and job types on the mean differences in reaction time. (3) Results: After controlling for age and body mass index, we observed longer reaction times among lead-exposed batik workers than non-exposed referents with an adjusted mean difference of 0.19 (95% CI: 0.016–0.368) seconds. A more prominent detrimental effect of lead exposure on reaction time among female workers than among male workers was observed. (4) Conclusions: Our results suggest that occupational lead exposure could contribute to longer reaction time, notably among female workers. Thus, occupational health and safety precautions are vital to protect batik workers and preserve their important contributions to cultural heritage.

Reduction in Blood Lead Concentration in Children across the Republic of Georgia following Interventions to Address Widespread Exceedance of Reference Value in 2019

In recent years, reports of lead contamination have dramatically increased in Georgia. Given concerns about the exposure of children to lead (Pb), the National Multiple Indicator Cluster Survey (MICS-2018) included a blood sampling component. The results showed that 41% of the children that participated had blood Pb levels (BLL) ≥ 5 µg/dL and that BLL in children living in Western Georgia were higher than those in Eastern regions. In response to these findings, NCDC implemented written and verbal advice to the families of children who participated in the MICS-2018 on how to reduce Pb exposure. From August 2019 onwards, the state program of clinical follow-up was implemented. The design of this study was a longitudinal study. The intervention of interest was the public health advice and medical follow-up, and the outcome was defined as the difference in BLL between the MICS-2018 survey and the state program follow-up. We observed a significant overall reduction in median BLL between MICS-2018 and state program follow-up in both August 2019 and the latest results (until December 2019). However, we did not observe any significant further reduction between August and the most recent BLL results. In the Georgian setting, written and verbal communication targeting individual households, alongside home visits to the most exposed, effectively reduced BLL in children.

Higher Blood Lead Level Is Associated With Increased Likelihood of Abdominal Aortic Calcification

Aims: This study aimed to evaluate the association between blood lead level (BLL) and abdominal aortic calcification (AAC) in US adults aged ≥40 years.

Methods: We obtained data from 2013 to 2014 National Health and Nutrition Examination Survey (NHANES). Participants missing the data of BLL and AAC scores were excluded. BLL was measured using inductively coupled plasma mass spectrometry directly. AAC scores were quantified by Kauppila score system, and severe AAC was defined as AAC score >6. Weighted multivariable regression analysis and subgroup analysis were conducted to explore the independent relationship between BLL with AAC score and severe AAC.

Results: A total of 1,530 participants were included with the mean BLL of 1.45 ± 1.31 ng/dl and mean AAC score of 1.40 ± 3.13. The prevalence of severe AAC was 7.98% overall, and participants in higher BLL quartile showed higher prevalence of severe AAC (Quartile 1: 3.55%, Quartile 2: 7.28%, Quartile 3: 9.88%, Quartile 4: 12.58%, P < 0.0001). BLL was positively associated with higher AAC score (β = 0.15, 95% CI: 0.02, 0.27, P = 0.021) and increased risk of severe AAC (OR = 1.11; 95% CI: 1.00–1.22; P = 0.047). Subgroup analysis and interaction test indicated that the association between BLL and AAC was similar in different population settings.

Conclusions: Higher BLL was associated with higher AAC score and increased risk of severe AAC. Lead burden should be considered for people with AAC in clinical settings.