Environmental Health最新文献

Background: Polybrominated diphenyl ethers (PBDEs) and organophosphate esters (OPEs) are commonly used as flame retardants. Limited research exists on socioeconomic and racial/ethnic disparities in exposure to these compounds and their impact on executive functioning (EF) in early childhood. The present study examined independent and joint effects of income and race/ethnicity on flame retardant exposure in early childhood and investigated associations between flame retardant exposure and children's EF.

Methods: This cross-sectional study used data from 349 preschool children recruited in Oregon. Children wore silicone wristband samplers for seven days, with exposures to 41 flame retardant compounds analyzed by gas chromatography mass spectrometry. We focused on exposure to 6 compounds (BDE 47, BDE 99, BDE100, TCPP, TDCPP, TPP) and two composite indices (ΣPBDE, ΣOPE). Wilcoxon rank-sum tests examined exposure differences by race/ethnicity and income (low income = below federal poverty level). Multiple linear regression models, nested within classrooms, assessed the association between PBDE and OPE exposure and EF, measured by the Head-Toes-Knees-Shoulders-Revised (HTKS-R) and Dimensional Change Card Sort (DCCS) tasks.

Results: Children were 5.1 years old (SD = 0.3), 29.9% were from underserved racial/ethnic backgrounds, and 27.8% of families were low income. Compared with higher income families, children from low income families were exposed to 83.4% greater ΣPBDE exposures and 36% greater TDCPP exposures. There was no evidence of racial/ethnic disparities in PBDE or OPE exposures. Controlling for age, sex, income, race/ethnicity, and disability or cognitive delay, neither PBDE nor OPE exposures were consistently related to EF, but children from lower income families scored 28.6% lower on the HTKS-R, and children from underserved races/ethnicities scored 25.9% lower on the HTKS-R.

Conclusions: Our findings highlight persistent income disparities in PBDE exposures at a pivotal point in children's development, and reveal similar disparities in TDCPP exposures. Furthermore, socioeconomic disadvantage was more strongly associated with reduced EF than either PBDE or OPFR exposures. These findings underscore the need to address structural social inequities, and also highlight the need for greater representation of children from underserved backgrounds in research that seeks to characterize chemical and social exposures within neighborhood and preschool environments.

Introduction: Aflatoxins are environmental hazards; potent carcinogenic and immunosuppressive agents that contaminates corn and other crops. A high proportion of hepatocellular carcinoma cases are caused by exposure to dietary aflatoxins. Cervical cancer is common among Ugandan women; this malignancy is caused by persistent infection with oncogenic HPV types. An analysis was performed to examine associations between plasma aflatoxin B₁ (AFB₁) detection and oncogenic HPV detection (HPV types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68) and persistence among Ugandan women.

Methods: Ugandan women were enrolled in a prospective cohort study. Annual cervical swabs (Enrollment, Month 12 and Month 24) were tested for oncogenic HPV. Plasma AFB₁ concentration was measured (as AFB₁-lysine conjugate, or AFB₁-lys) at Enrollment and Month 12. Multivariable regression models were fitted to examine associations of plasma AFB₁-lys concentrations and oncogenic HPV controlling for demographic and behavioral characteristics.

Results: The analytical sample consisted of 114 women with a mean age of 33.2 years; 60 women were living with HIV; 59 were receiving antiretroviral therapy (ART) at enrollment. AFB₁-lysine adducts (AFB₁-lys) was detected in plasma from all 114 women. Multivariable regression models showed that plasma AFB₁-lys concentration was associated with a higher risk of detection of HPV 16 (OR = 2.64, 95% CI = 1.42-4.90, p = 0.002) and HPV 18 (OR = 2.24, 95% CI = 1.27-3.96, p = 0.005), and persistence of HPV 16 (OR = 3.16, 95% CI = 1.59-6.26, p = 0.001) and HPV 18 (OR = 2.06, 95% CI = 1.09-3.90, p = 0.025), controlling for age, marital status, years of education, home ownership, distance to health care, number of lifetime sex partners, age of first sex, and HIV status.

Conclusions: AFB₁ is an environmental hazard that is prevalent among Ugandan women. Higher plasma AFB₁-lys concentration was associated with detection and persistence of HPV 16 and HPV 18; this association was independent of HIV status. As a result, these women may be at increased risk of cervical cancer. Further studies are needed to determine the mechanisms involved.

Background: Exposure to high levels of vehicle traffic during childhood seems to have a negative effect on lung function. Less is known about the effects of exposure to relatively low levels during childhood. We aimed to study how exposure to vehicle traffic in childhood is associated with lung function and asthma in young adulthood in a 10-year follow-up of a population-based cohort in a municipality with relatively low levels of vehicle traffic.

Methods: The Obstructive Lung Disease in Northern Sweden (OLIN) pediatric cohort II was recruited in 2006 at age 8 years. Exposure to vehicle traffic at baseline was studied in relation to lung function at follow-up at age 19 years (n = 1056 participants). Lung function measures included FEV₁, FVC and FEV₁/FVC. Different exposure thresholds were defined based on proximity (within a 200 m radius from the home address) to a road with a minimum daily count of heavy vehicles (≥ 250 and ≥ 500) or any type of vehicle (≥ 4000 and ≥ 8000). The association between exposure to vehicle traffic at baseline and lung function at follow-up was analyzed by linear regression adjusting for potential confounders.

Results: In general, those above the exposure thresholds had lower lung function than those below, but not significantly so in all comparisons. Those exposed to ≥ 250 heavy vehicles/day had lower mean FEV₁ z-score at follow-up (-0.38) compared with those exposed to < 250 heavy vehicles/day (-0.21), p = 0.033, and this association remained after adjustment for confounders (p = 0.036). Also, those exposed to ≥ 8000 vehicles/day had lower mean FVC z-score (-0.19) than those exposed to < 8000 vehicles/day (-0.02), p = 0.047, with p = 0.032 after adjustment.

Conclusions: Exposure to vehicle traffic in childhood, in a relatively low traffic-flow environment, may be associated with a slightly lower lung function in young adulthood.

The risk assessment of microbial pesticides in the European Union (EU) is covered by a regulatory framework based on EU Regulation 1107/2009 and 546/2011 together with the data requirements in EU Regulation 283/2013 and 284/2013, Part B, respectively (all amended in 2022). Furthermore, several guidance documents specify the data requirements for the human health assessment. As in other regulatory contexts, the assessment of hazardous properties of a microbial plant protection product (PPP) can be based on in vivo data. In order to decrease the use of test animals, support high-throughput data generation with larger repetition, and to facilitate faster testing methods, New Approach Methodologies (NAMs) for this field need to be developed. Here we focus on the assessment of the potential pathogenicity/infectivity and the presence of transferable antimicrobial resistance (AMR) genes of a microorganism when utilised as the active substance (AS) in a PPP. For the purpose of risk assessment of microbial PPPs, NAMs developed in view of the Next Generation Risk Assessment (NGRA) for chemicals can be applied. However, major drawbacks in the ability to use existing NAMs in the risk assessment of microbial pesticides are the reliability of Adverse Outcome Pathway (AOP) generated data for humans and the practicability of in vitro methods to test living microorganisms. It must be emphasised that tests for risk assessment are only useful if the test interpretation is clearly defined. Without prior definition of the possible effects and their interpretation, including the possible outcome for risk assessment, the test has limited value, as the results may raise more questions than answers. Overall, the regulatory assessment of the human health effects of microbial pesticides used in PPP needs reliable and robust data. These data should ideally be presented by an applicant based on animal-free study setups together with thorough literature searches.

Background: The water supply of the Gaza Strip has been unstable and under great strain for decades, resulting in major problems with the quality, reliability, and acceptability of drinking water. Destruction of water infrastructure and concerns over the quality of piped water have resulted in a complex constellation of drinking water sources. We aim to describe the different types of drinking water sources used by households, compare water quality from drinking water samples, present different water treatments used in households and highlight different insecurities around water access in households.

Methods: We conducted a cross-sectional household survey in North Gaza, Gaza and Rafah between January and March 2023. Using an interviewer-administered survey, we collected information on drinking water sources and insecurities and obtained a drinking water sample from the tap in the household. The water samples were analyzed for microbial contamination, nitrate, sodium and mineral content.

Results: We collected data from 905 households. Only 3% had access to a single water source, 87% had access to two sources and 96% had access to piped water from the municipality. Piped municipal water was mainly used for hygiene and bathing, while the three most used sources for drinking were tanker trucks (82%), public taps (10%) and piped water from the municipalities (3.7%). Fecal coliform was present in 20% of water samples, 1% had high nitrate levels and nearly all samples had low mineral content. While around 15-19% of the households were sometimes or often water insecure, over 90% reported never drinking from undesirable sources, drinking unsafe water, or going to sleep thirsty. Households using municipal piped water tended to be most water secure.

Conclusions: The water quality and insecurity about accessibility and quality of water pose a health threat and need to be addressed at system level. Rebuilding the water infrastructure will be a key element during the reconstruction after the current war. It is crucial that the shortcomings of the pre-war water system are not rebuilt, and lessons are learnt from pre-war data to establish a health-promoting water system in the Gaza Strip.

Clinical trial number: Not applicable.

Background: This study is a long-term follow-up of individuals exposed to polybrominated biphenyls (PBBs). Widespread contamination of PBBs began in 1973 in Michigan when PBBs entered the food chain. PBBs are synthetic chemicals that were once used in industrial products. Their production in the United States ended following this incident. PBBs and other brominated flame retardants belong to a class of persistent organic pollutants that have been shown to affect human health. We conducted this study to investigate whether PBB exposure was associated with all-cause or cause-specific mortality risk.

Methods: We included cohort data from 1976 (when the study began) and linked to National Death Index data obtained through the early release of 2021. Serum PBB concentrations were measured at enrollment in the study. We used survival analysis to estimate sex-specific hazard ratios (HR) and 95% confidence intervals (CI), adjusting for age and other important risk factors. The mortality study included 3,954 individuals.

Results: In age-stratified analyses, higher PBB exposure was not associated with all-cause mortality risk in males or females. In cause-specific analyses conducted in the 16 or older group, we found no association between PBB exposure and circulatory system disease mortality. For all-cancer mortality, we found higher PBB exposure associated with increased risk of mortality in females (HR: 1.50, 95% CI: 1.02-2.22), which was inversed in males (HR: 0.68, 95% CI: 0.46-1.01). BMI appeared to modify the association between PBB exposure and all-cause mortality risk in males and all-cancer mortality risk in males and females.

Conclusions: This comprehensive study found that the association between PBB exposure and cancer mortality risk varied by sex. Further research is needed to understand these sex-specific differences.

Background: Open-air burning was a prevalent waste management method at many U.S. military bases during the wars in Afghanistan and Iraq. Past studies of the health impacts of burn pit exposure have relied on exposure assessments that did not account for waste segregation practices introduced in the later years of the wars, such as removing hazardous and medical waste before open burning and the use of incinerators.

Objective: We developed a refined exposure assessment that accounts for waste management practices on military bases and evaluated the impact of waste segregation and incineration on cardiovascular and respiratory health outcomes among veterans deployed during these conflicts.

Methods: The study cohort consisted of 459,381 Army and Air Force veterans who were deployed between 2005 and 2011 and received health care through the Veterans Health Administration (VHA) after deployment. The 109 most populated military bases in Afghanistan and Iraq were classified into four waste disposal categories by year: unsegregated, segregated, incineration, and no burning or incineration. Individual exposure was defined as the total number of days spent at bases based on the Department of Defense deployment histories. Health outcomes were determined through VHA healthcare records, from the end of deployment through the end of follow-up in 2020. Logistic regression was performed to investigate the association between deployment to bases with varying waste management practices and the risk of respiratory and cardiovascular diseases.

Results: Deployment to bases using burn pits with unsegregated waste was associated with elevated risks of hypertension and asthma, whereas deployment to bases that segregated waste or used incinerators was not. Prolonged deployment (highest duration tertile of > 240 days) to bases with unsegregated waste burning was associated with a 16% higher risk of hypertension (aOR 1.16, 95% CI 1.13-1.19) compared to those never stationed at such bases. There was a clear deployment duration-response association for hypertension, but this was not observed for asthma.

Conclusions: The observed increased risk of hypertension and asthma among military veterans deployed to bases that used open burning of unsegregated waste - but not among those deployed to bases that segregated waste or used incinerators - highlights the importance of considering waste management methods in future studies examining the health effects of burn pit exposures among military veterans.

Background: In 1962, a chloralkali plant began discharging mercury (Hg) into the Wabigoon-English River system, contaminating the territorial waters of Grassy Narrows First Nation, whose traditions, livelihood and diet centered on fish. Data from 1970 to 1997 government Hg biomonitoring programs were repatriated by Grassy Narrows. Our researcher-community partnership carried out secondary analyses to examine the association between childhood Hg exposure (between 5 and 15y) and survival to July 1, 2024.

Methods: Information from the governmental biomonitoring programs and from Grassy Narrows Registry of Band members were used to create a retrospective year-based equivalent hair Hg (HHg) database, with dates of birth, sampling and death (N = 317). Apparent cause of death was reported by community members. Different approaches were used to minimize potential unmeasured confounders in examining the relation between Hg exposure and early death: (i) matched pairs (deceased/alive; same sex, year of birth (± 1) (n = 81) pairs for dissymmetry analysis, Kaplan-Meier survival analysis and Cox proportional hazards regression models (ii) Longitudinal Mixed Effects Models (LMEM) with individuals who had at least 7 year-based HHg measurements (n = 35), and (iii) trajectory techniques modelling exposure.

Results: HHg measurements (n = 1031) were available for 167 boys and 150 girls. Mean age at sampling was 10.5 y (SD: 2.9); 44.2% had HHg ≥ 4 µg/g at least once. By July 1, 2024, 97 individuals (30.6%) had died (median age: 39 years (IQR: 24-49)). The Cox Hazard Ratio for HHg ≥ 4 µg/g at least once was 1.96 [1.18-3.28]. LMEM showed that HHg was 1.46 µg/g higher over the sampling period for the deceased compared to the living. Significant associations (p ≤ 0.001) were also observed for early death with respect to HHg trajectory summary scores (OR: 1.14 to 1.24; SE ≤ 0.78). Reported suicide, liver disease and cardiovascular/metabolic conditions made up 60% of all deaths.

Conclusions: Early mortality in Grassy Narrows First Nation is higher than other First Nations and the non-Indigenous populations in Canada. Convergent findings from different approaches and statistical techniques support an association between childhood Hg exposure and early death. Morbidity and mortality in this community require follow-up.

Background: Environmental exposure to per- and polyfluoroalkyl substances (PFAS) has been related to some adverse health effects. An increasing number of people are suffering from nodular goiter (NG) and papillary thyroid carcinoma (PTC), the specific types of thyroid tumors with the highest prevalence. In vivo and in vitro studies have indicated that exposure to PFAS can disrupt thyroid homeostasis and exhibit apparent endocrine-disrupting toxicity, including the decreased thyroid hormone levels and abnormal expression of thyroid-related genes. However, epidemiological evidence supporting the cause-effect relationship between PFAS exposure and the risk of NG and PTC is still lacking.

Methods: We enrolled 290 participants to explore the relationship between PFAS exposure and NG/PTC risk. 21 urinary PFAS were detected by ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS). Logistic regression, restricted cubic spline (RCS), Bayesian Kernel Machine Regression (BKMR) and quantile g-computation (qgcomp) models were adopted to examine effects of single and mixed PFAS exposure on NG/PTC risk.

Results: Our data showed that perfluoroheptane sulfonate (PFHpS) (P = 0.033) and perfluorohexane sulfonate (PFHxS) (P = 0.003) levels in NG cases and perfluoroheptanoic acid (PFHpA) (P = 0.008) levels in PTC cases were significantly higher than those in the controls. After adjustment for confounders, PFHxS was significantly related to higher NG/PTC risk (all P for trend < 0.05). A remarkable non-linear association was found between PFHpA exposure and PTC risk (P-overall < 0.001, P-non-linear = 0.001). The BKMR model indicated that PFAS mixtures significantly increased NG risk, with PFHxS contributing the most (groupPIP: 0.886, condPIP: 0.658). In stratified analyses, PFAS mixtures were positively associated with NG/PTC risk in females and normal-weight subjects.

Conclusion: Our results suggest that environmental exposure to PFAS mixtures may be associated with increased NG/PTC risk, and each PFAS may contribute to NG/PTC risk in very different ways. To the best of our knowledge, this is the first epidemiological study to examine effects of PFAS exposure on NG/PTC risk.