BACKGROUND: Heavy metals are significant risk factors for kidney function. Numerous studies have shown that exposure to heavy metals negatively correlates with kidney function through oxidative stress pathways, and serum α-klotho is linked to oxidative stress. However, the role of α-klotho in the relationship between blood lead, mercury, and kidney function remains unclear. METHOD: This study evaluated the mediating role of alpha-klotho in the relationship between lead, mercury and renal function, using data from the 2007-2016 National Health and Nutrition Examination Survey (NHANES) in U.S. adults aged 40-79. The sample included 11,032 participants, with blood lead, mercury, α-klotho, and other relevant covariates measured. Inductively coupled plasma mass spectrometry was used to assess blood lead and mercury levels, and enzyme-linked immunosorbent assay (ELISA) was employed to measure serum α-klotho. Kidney function was evaluated using estimated glomerular filtration rate (eGFR) based on creatinine levels. Multivariable linear regression was conducted to analyze the relationships between blood lead, mercury, α-klotho, and eGFR. A mediation analysis model was used to assess whether α-klotho influenced these associations. RESULTS: We observed a significant association between blood lead and eGFR. Mediation analysis revealed that α-klotho accounted for 12.76% of the relationship between serum lead and eGFR in the NHANES population. Subgroup analysis showed that α-klotho mediated 12.43%, 6.87%, 21.50% and 5.44% of the relationship between blood lead and eGFR in women, middle-aged adults (40-59 years old), without cardiovascular disease and hypertension, respectively. However, α-klotho did not mediate the relationship between blood mercury and eGFR in terms of gender or age. This newly identified pathway may provide valuable insights for the prevention and treatment mechanisms related to kidney function impairment. CONCLUSION We found that blood lead was associated with renal function. According to the results of subgroup analysis, for blood lead, serum α-klotho mediated the association in females, middle aged 60-79 years. The relationship between blood mercury and renal function was not clinically significant, and serum α-Klotho mediated the relationship between blood mercury and renal function without significant clinical significance.
Humans ; Middle Aged ; Lead/blood* ; Female ; Klotho Proteins ; Male ; Aged ; Adult ; Mercury/blood* ; Glomerular Filtration Rate ; Nutrition Surveys ; United States ; Kidney/physiology* ; Glucuronidase/blood* ; Environmental Pollutants/blood*

BACKGROUND: Recent studies have provided compelling evidence that exposure to brominated flame retardants (BFRs) can adversely affect human health. We aim to explore the potential impact of BFRs on adiposity and central obesity. METHODS: Data from the National Health and Nutrition Examination Surveys (NHANES) cycles conducted between 2009 and 2014 was used to study the connections between variables. After filtering, we analyzed a sample of 4,110 adults aged 20 years and above. Our goal was to examine the potential association between BFRs and consequences and investigate the part played by oxidative stress and inflammatory markers as intermediaries. To achieve this, we used advanced statistical methods such as weighted quantile sum (WQS) regression, quantile-based g-computation (QGC), and the Bayesian kernel machine regression (BKMR). RESULTS: The findings showed that among the examined chemicals, exposure to PBDE85 (weight: 41%), PBDE100 (24%), and PBB153 (23%) may be the dominant contributors to general obesity risk. Upon controlling for all variables that could impact the results, it was found that the QGC outcomes indicated a positive correlation between exposure to mixtures of brominated flame retardants and the occurrence of abdominal obesity (OR = 1.187, 95% CI: 1.056-1.334, p = 0.004). Significant contributions were made by PBDE85 (52%), PBB153 (27%), and PBDE100 (21%). Mediation analysis shows that lymphatic cells (LC) and albumin (ALB) partially mediate the link between brominated flame retardants and obesity. The results of BKMR are generally consistent with those of WQS and QGC. CONCLUSION At a population level, our research has revealed a noteworthy correlation between BFRs and obesity. However, further investigation is required through prospective cohort studies and in-depth mechanistic exploratory studies.
Humans ; Flame Retardants/adverse effects* ; Oxidative Stress/drug effects* ; Adult ; Male ; Female ; Middle Aged ; Inflammation/epidemiology* ; Obesity/chemically induced* ; Biomarkers/blood* ; Nutrition Surveys ; Mediation Analysis ; Young Adult ; United States/epidemiology* ; Environmental Exposure/adverse effects* ; Aged ; Environmental Pollutants/adverse effects* ; Halogenated Diphenyl Ethers/adverse effects*

BACKGROUND: Research has demonstrated that heavy metals and cholesterol are associated with stress urinary incontinence (SUI) in women and that heavy metal exposure can cause dyslipidemia in humans. However, the potential mediating role of cholesterol in the relationship between heavy metals and female SUI remains unexplored. METHODS: The study utilized data from the National Health and Nutrition Examination Survey database from 2013-2018. Blood lead (Pb), cadmium (Cd), total mercury (Hg), manganese (Mn), selenium (Se), and methyl mercury (MeHg) were included in the study. The single and combined effects of the six metals exposure on SUI were examined using logistic analysis, restricted cubic spline (RCS) curves, weighted quantile sum (WQS) regression, and bayesian kernel machine regression (BKMR). The mediating effects of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were investigated through mediation analysis. RESULTS: The study included 2241 females, with 42.66% experiencing SUI. Initial analysis of six heavy metals revealed the associations between MeHg, Pb, Cd, total Hg, and SUI (all P < 0.05). WQS regression identified that Cd, Se, and Pb were major contributors to the mixed effect causing SUI. BKMR results indicated a positive mixed effect between six heavy metals and SUI. TC partially mediated the relationship of Pb, MeHg, and total Hg with SUI, and LDL-C partially mediated the association of Pb with SUI (all P for mediation < 0.05). CONCLUSIONS Blood heavy metal concentrations influence the development of female SUI, with blood cholesterol mediating the association between different heavy metals and SUI.
Humans ; Female ; Metals, Heavy/blood* ; Nutrition Surveys ; Middle Aged ; Adult ; United States/epidemiology* ; Urinary Incontinence, Stress/chemically induced* ; Environmental Pollutants/blood* ; Aged ; Cholesterol/blood* ; Environmental Exposure

BACKGROUND: Depression among older adults is an important public health issue, and air and noise pollution have been found to contribute to exacerbation of depressive symptoms. This study examined the association of exposure to air and noise pollutants with clinically-newly-diagnosed depressive disorder. The mediating role of individual pro-inflammatory markers was explored. METHODS: We linked National Health Insurance claim data with 2998 healthy community-dwellers aged 55 and above who participated in the Healthy Aging Longitudinal Study between 2009 and 2013. Newly diagnosed depressive disorder was identified using diagnostic codes from the medical claim data. Pollutants were estimated using nationwide land use regression, including PM_2.5 and PM₁₀, carbon monoxide, ozone, nitrogen dioxide, sulfur dioxide, and road traffic noise. Cox proportional hazard models were employed to examine the association between pollutants and newly developed depressive disorders. The mediating effect of serum pro-inflammatory biomarkers on the relationship was examined. RESULTS: Among the 2998 participants, 209 had newly diagnosed depressive disorders. In adjusted Cox proportional hazard models, one interquartile range increase in PM_2.5 (8.53 µg/m³) was associated with a 17.5% increased hazard of developing depressive disorders. Other air pollutants and road traffic noise were not linearly associated with depressive disorder incidence. Levels of serum tumor necrosis factor receptor 1 mediated the relationship between PM_2.5 and survival time to newly onset depressive disorder. CONCLUSION PM_2.5 is related to an increased risk of newly developed depressive disorder among middle-aged and older adults, and the association is partially mediated by the pro-inflammatory marker TNF-R1.
Humans ; Particulate Matter/analysis* ; Male ; Female ; Middle Aged ; Longitudinal Studies ; Aged ; Incidence ; Air Pollutants/analysis* ; Environmental Exposure/adverse effects* ; Taiwan/epidemiology* ; Receptors, Tumor Necrosis Factor, Type I/blood* ; Proportional Hazards Models ; Biomarkers/blood* ; Depression/epidemiology* ; Aged, 80 and over ; Depressive Disorder/chemically induced* ; Risk Factors ; Air Pollution/adverse effects*

BACKGROUND: The objective of this study was to investigate the potential link between myopia in adolescents and exposure to per- and polyfluoroalkyl substances (PFASs). METHODS: This investigation included 1971 subjects with accessible PFAS level data, myopia status, and associated variables from four cycles of the National Health and Nutritional Examination Survey (NHANES). The investigation focused on specific PFAS compounds found in the serum, including perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS), chosen for their frequent detection. Owing to the skewed nature of the PFAS level data, the PFAS levels were log-transformed (Ln-PFAS) prior to analysis. Logistic regression, restricted cubic spline modeling, subgroup analysis, and sensitivity analysis were used to examine the associations between exposure to PFASs and the onset of myopia. RESULTS: PFOA levels were significantly associated with myopia risk (OR: 1.33; 95% CI: 1.05-1.69; P = 0.019). More specifically, with respect to the first quartile, the second quartile (OR_Q2: 1.69; 95% CI: 1.16-2.46; P = 0.007), third quartile (OR_Q3: 1.45; 95% CI: 1.03-2.03; P = 0.035), and highest quartile (OR_Q4: 1.58; 95% CI: 1.12-2.21; P = 0.010) of participants presented with increased myopia risk. Mediation analysis revealed that PFOA and myopia risk were partially mediated by serum albumin (ALB), with a mediation percentage of 22.48% (P = 0.008). A nonlinear inverted U-shaped relationship was identified between the level of PFOA and myopia risk (P for nonlinearity = 0.005). CONCLUSION Our findings suggest a potential link between exposure to PFOA and the likelihood of myopia development in young individuals and a mediating effect of serum ALB on this relationship. Notably, PFOA was identified as a key PFAS significantly contributing to the observed link between PFAS exposure and myopia risk. The potential threat of PFOA to myopia should be examined further.
Humans ; Fluorocarbons/adverse effects* ; Myopia/blood* ; Adolescent ; Male ; Female ; Prevalence ; Environmental Exposure/adverse effects* ; Nutrition Surveys ; Environmental Pollutants/adverse effects* ; United States/epidemiology* ; Alkanesulfonic Acids/blood* ; Caprylates/blood* ; Serum Albumin/metabolism* ; Child ; Sulfonic Acids

BACKGROUND: Dental caries is a chronic childhood disease and one of the most prevalent public health problems worldwide. Lead is a heavy metal that is taken up by the teeth and bones. However, the association between lead exposure during pregnancy, when the tooth germs are formed, and the prevalence of dental caries in the primary dentition remains unclear. This study aimed to examine the association between maternal blood lead levels and the prevalence of dental caries in the primary dentition of children. METHODS: This cross-sectional study was conducted as an Adjunct Study to the Japan Environment and Children's Study (JECS), which is an ongoing nationwide birth-cohort study. Among children participating in the JECS at the University of Occupational and Environmental Health Sub-Regional Center, those aged 7-8 years underwent oral examination and questionnaire administration. The dft (i.e., sum of the number of decayed and filled primary teeth) was then determined. The dft numerically expresses the dental caries prevalence in the primary dentition (larger value indicates more prevalent dental caries). Poisson regression analyses with robust standard errors were performed to evaluate the association between maternal blood lead levels during pregnancy, measured using frozen samples, and the dft. RESULTS: The study included 139 children, of whom 54.7% were girls, and 89.2% were 7 years old. The median maternal blood lead level was 6.1 ng/g (25-75 percentile, 5.0-7.3). The median dft was 0 (25-75 percentile, 0-4). After adjusting for covariates including age, sex, and oral health status and behavior, maternal blood lead levels were significantly associated with increased dft (prevalence ratio, 1.6; 95% confidence interval, 1.3-1.8; per one standard deviation increase in natural log-transformed maternal blood lead levels). CONCLUSIONS This study found an association between maternal blood lead levels and the prevalence of dental caries in the primary dentition of children aged 7-8 years. Maternal exposure to lead during mid- to late-term pregnancy may affect the caries susceptibility of children after birth.
Humans ; Lead/blood* ; Female ; Dental Caries/epidemiology* ; Prevalence ; Tooth, Deciduous ; Male ; Japan/epidemiology* ; Child ; Cross-Sectional Studies ; Pregnancy ; Adult ; Maternal Exposure/adverse effects* ; Environmental Pollutants/blood* ; Prenatal Exposure Delayed Effects/epidemiology*

OBJECTIVE: To investigate the associations between eight serum per- and polyfluoroalkyl substances (PFASs) and regional fat depots, we analyzed the data from the National Health and Nutrition Examination Survey (NHANES) 2011-2018 cycles. METHODS: Multiple linear regression models were developed to explore the associations between serum PFAS concentrations and six fat compositions along with a fat distribution score created by summing the concentrations of the six fat compositions. The associations between structurally grouped PFASs and fat distribution were assessed, and a prediction model was developed to estimate the ability of PFAS exposure to predict obesity risk. RESULTS: Among females aged 39-59 years, trunk fat mass was positively associated with perfluorooctane sulfonate (PFOS). Higher concentrations of PFOS, perfluorohexane sulfonate (PFHxS), perfluorodecanoate (PFDeA), perfluorononanoate (PFNA), and n-perfluorooctanoate (n-PFOA) were linked to greater visceral adipose tissue in this group. In men, exposure to total perfluoroalkane sulfonates (PFSAs) and long-chain PFSAs was associated with reductions in abdominal fat, while higher abdominal fat in women aged 39-59 years was associated with short-chain PFSAs. The prediction model demonstrated high accuracy, with an area under the curve (AUC) of 0.9925 for predicting obesity risk. CONCLUSION PFAS exposure is associated with regional fat distribution, with varying effects based on age, sex, and PFAS structure. The findings highlight the potential role of PFAS exposure in influencing fat depots and obesity risk, with significant implications for public health. The prediction model provides a highly accurate tool for assessing obesity risk related to PFAS exposure.
Humans ; Fluorocarbons/blood* ; Female ; Adult ; Middle Aged ; Male ; Environmental Pollutants/blood* ; Abdominal Fat ; Nutrition Surveys ; Alkanesulfonic Acids/blood* ; Obesity ; Environmental Exposure

OBJECTIVE: To examine the mechanistic of organochlorine-associated changes in lung function. METHODS: This study investigated 76 healthy older adults in Jinan, Shandong Province, over a five-month period. Personal exposure to organochlorines was quantified using wearable passive samplers, while inflammatory factors and thyroid hormones were analyzed from blood samples. Participants' lung function was evaluated. After stratifying participants according to their thyroid hormone levels, we analyzed the differential effects of organochlorine exposure on lung function and inflammatory factors across the low and high thyroid hormone groups. Mediation analysis was further conducted to elucidate the relationships among organochlorine exposures, inflammatory factors, and lung function. RESULTS: Bis (2-chloro-1-methylethyl) ether (BCIE), was negatively associated with forced vital capacity (FVC, -2.05%, 95% CI: -3.11% to -0.97%), and associated with changes in inflammatory factors such as interleukin (IL)-2, IL-7, IL-8, and IL-13 in the low thyroid hormone group. The mediation analysis indicated a mediating effect of IL-2 (15.63%, 95% CI: 0.91% to 44.64%) and IL-13 (13.94%, 95% CI: 0.52% to 41.07%) in the association between BCIE exposure and FVC. CONCLUSION Lung function and inflammatory factors exhibited an increased sensitivity to organochlorine exposure at lower thyroid hormone levels, with inflammatory factors potentially mediating the adverse effects of organochlorines on lung function.
Environmental Exposure ; Hydrocarbons, Chlorinated/metabolism* ; China ; Ethyl Ethers/metabolism* ; Environmental Monitoring ; Thyroid Hormones/blood* ; Lung/physiology* ; Inhalation Exposure/statistics & numerical data* ; Air Pollution/statistics & numerical data* ; Air Pollutants/metabolism* ; Humans ; Male ; Female ; Middle Aged ; Aged

OBJECTIVE: The study aim was to investigate the effects of exposure to multiple environmental organic pollutants on cardiopulmonary health with a focus on the potential mediating role of oxidative stress. METHODS: A repeated-measures randomized crossover study involving healthy college students in Beijing was conducted. Biological samples, including morning urine and venous blood, were collected to measure concentrations of 29 typical organic pollutants, including hydroxy polycyclic aromatic hydrocarbons (OH-PAHs), bisphenol A and its substitutes, phthalates and their metabolites, parabens, and five biomarkers of oxidative stress. Health assessments included blood pressure measurements and lung function indicators. RESULTS: Urinary concentrations of 2-hydroxyphenanthrene (2-OH-PHE) ( β = 4.35% [95% confidence interval ( CI): 0.85%, 7.97%]), 3-hydroxyphenanthrene ( β = 3.44% [95% CI: 0.19%, 6.79%]), and 4-hydroxyphenanthrene (4-OH-PHE) ( β = 5.78% [95% CI: 1.27%, 10.5%]) were significantly and positively associated with systolic blood pressure. Exposures to 1-hydroxypyrene (1-OH-PYR) ( β = 3.05% [95% CI: -4.66%, -1.41%]), 2-OH-PHE ( β = 2.68% [95% CI: -4%, -1.34%]), and 4-OH-PHE ( β = 3% [95% CI: -4.68%, -1.29%]) were negatively associated with the ratio of forced expiratory volume in the first second to forced vital capacity. These findings highlight the adverse effects of exposure to multiple pollutants on cardiopulmonary health. Biomarkers of oxidative stress, including 8-hydroxy-2'-deoxyguanosine and extracellular superoxide dismutase, mediated the effects of multiple OH-PAHs on blood pressure and lung function. CONCLUSION Exposure to multiple organic pollutants can adversely affect cardiopulmonary health. Oxidative stress is a key mediator of the effects of OH-PAHs on blood pressure and lung function.
Humans ; Oxidative Stress/drug effects* ; Male ; Cross-Over Studies ; Female ; Young Adult ; Environmental Pollutants/toxicity* ; Environmental Exposure/adverse effects* ; Biomarkers/blood* ; Adult ; Blood Pressure/drug effects* ; Polycyclic Aromatic Hydrocarbons/urine* ; Beijing

Ambient air pollution is increasingly being recognized as a risk factor for heart failure; however, its effects on cardiac biomarkers remain unclear. This scoping review assessed the existing evidence on the association between air pollution and cardiac biomarkers in heart failure, described the key concepts, synthesized data, and identified research gaps. Following the PRISMA-ScR guidelines, PubMed, Embase, Web of Science, and CNKI databases were searched for studies on air pollution, heart failure, and biomarkers. A total of 765 records were screened, and 81 full texts were assessed for eligibility, resulting in 15 studies. The results showed that the exposure to particulate matter was associated with elevated N-terminal pro-B-type natriuretic peptide and troponin levels. Several studies have linked particulate matter exposure to a higher cardiovascular risk and heart failure biomarkers. Inflammatory and oxidative stress markers were consistently elevated across studies, supporting the biological relevance of these associations. However, few studies have focused specifically on populations with heart failure or clinically relevant biomarkers, and the evidence for gaseous pollutants remains inconclusive. These findings highlight the need to integrate environmental risk assessment into heart failure care and inform policy efforts to reduce the pollution-related cardiovascular burden. Further research should address these gaps through improved exposure assessments and the integration of mechanistic evidence.
Heart Failure/epidemiology* ; Biomarkers/metabolism* ; Humans ; Air Pollution/adverse effects* ; Air Pollutants/adverse effects* ; Particulate Matter/adverse effects* ; Environmental Exposure ; Natriuretic Peptide, Brain/blood* ; Oxidative Stress ; Troponin/blood*