Blood Lead Levels Research Articles

Reproducibility of blood lead levels after blood stored for seven days in trumpeter swans (Cygnus buccinator) and mute swans (Cygnus olor)

Reproducibility of blood lead levels after blood stored for seven days in trumpeter swans (Cygnus buccinator) and mute swans (Cygnus olor)

Effect of Lead Exposure and Lifestyle Factors on Methylation Index Markers Among Pb-Exposed Workers.

S-Adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) and the ratio of SAM and SAH in Pb-exposed workers need to be assessed. In this study, we investigated the effects of Pb exposure on SAM, SAH, and methylation index (MI) in Pb-exposed workers with contemplation of lifestyle factors. Blood lead levels (BLLs), SAM, SAH, MI, and lifestyle factors were assessed in 338 male Pb-exposed workers. BLLs are estimated by ICP-OES method. SAM and SAH levels in serum were determined by ELISA method. The MI was calculated using SAM and SAH individual values. The lifestyle factors were collected using standard questionnaire. Levels of SAM and MI were significantly decreased with increased age, experience > 5 years, habits of tobacco chewing, smoking, alcohol consumption, and BLLs 10-30, 30-50, and > 50 µg/dL. Levels of SAH were significantly increased with increased age, habits of tobacco chewing and smoking, and BLLs 10-30, 30-50, and > 50 µg/dL. The association between BLLs and methylation index markers (SAM and MI) was reported as negative and significant. The association between BLLs and SAH was noted positive and significant. The influence of BLLs and lifestyle factors on SAM was noted at 12%, SAH at 35%, and MI at 27%, respectively. The highest percentage of influence was noted in SAH, followed by MI and SAM. In the workers exposed to Pb, lifestyle factors resulted in decreased SAM and MI and increased SAH levels. Adaptation of healthy lifestyle factors, personal hygiene practices, and use of PPE were suggested to minimize the reduction of methylation index markers.

Association between blood lead levels and socio-demographic factors among outpatient children in Ningbo, China

Association between blood lead levels and socio-demographic factors among outpatient children in Ningbo, China

Assessment of occupational exposure to lead among workers engaged in a city bus garage in Addis Ababa, Ethiopia: a comparative cross-sectional study

BackgroundLead is one of the most nonessential toxic heavy metal agents found in automotive garages. The occupational exposure of garage workers to lead commonly poses acute and chronic health risks that can be prevented. In Ethiopia, there have been limited studies on lead exposure among garage workers, who overemphasize exposure to lead. This study aimed to assess occupational blood lead levels and associated factors in garage workers using a cross-sectional comparative design.MethodsA comparative cross-sectional study design was used to compare the occupational blood lead levels of 36 randomly selected garage workers and 34 office workers who were matched by age and sex. Blood specimens were collected by trained medical laboratory experts. The collected blood samples were tested in a certified laboratory using a microwave plasma atomic emission spectrometry (MP-AES) device at a wavelength of 405.78 nm. Excel and SPSS Version 26 were used for data management and analysis, respectively.ResultsThe mean (SD) age of the exposed group was 39.0 (7.5) years, whereas the mean age of the unexposed group was 38.0 (6.1) years. The occupational mean (SD) blood-lead-level in the exposed groups was 29.7 (12.2) µg/dl, compared to 14.8 (9.9) µg/dl among the unexposed groups. The mean blood-lead level among the exposed workers was significantly different from that among the unexposed workers (P < 0.01). Of all the study participants, only 22.2% of the exposed groups had blood lead levels higher than the World Health Organization’s recommended limit of 40 µg/dl. The main significant predictors of occupational blood-lead-level exposure among workers were extra working hours, service years, and having a previous (prior) employment history in a garage. The occupations of the two groups did not significantly differ in terms of blood-lead levels (p > 0.05).ConclusionsThe BLL of the Garage workers was significantly greater than that of the Non-Garage workers. Hence, it is advised that garage management should encourage workers to use exposure prevention methods, such as washing their hands before eating and taking showers after the completion of work, by providing regular occupational safety training.

Assessment of lead contamination in soil and tap water in daycare facilities in Addis Ababa: implications for children's health

ABSTRACT In recent years, lead poisoning has been recognized as a serious environmental health problem throughout the world, particularly, for children in developing countries. The objective of the study was to investigate the lead level in the water and soil of daycare facilities in Addis Ababa. Graphite furnaces atomic absorption spectrometry was used to analyze the concentration of lead in soil and tap water of 28 daycare centers. The result indicated that the mean levels of lead in soil and water were 0.00237 mg/g and 8.26 μg/L, respectively, which are below the permissible values of 0.1 mg/g and 10 μg/L according to WHO standards. The blood lead levels and exposure to lead in children were calculated using the integrated exposure uptake biokinetic model as per United States Environmental Protection Agency (USEPA) guidelines. The mean blood lead level was 1.78 μg/dL, and the model also predicted that 6.497% of the children in the city may have blood lead levels above the Center for Disease Control recommended reference value of 3.5 μg/dL. Even if the values were below the reference, there is no safe blood lead level since even a small amount can have adverse effects on children.

Plomo en sangre y su relación con hemoglobina y hematocrito en niños expuestos a la contaminación minera, Apurímac 2023

Exposure to heavy metals causes a high level of lead in the blood, which causes various problems in various organs, including a deficit in the production of hemoglobin, which causes anemia. This circumstance was the impetus to carry out this research study. The objective of the research was to determine the relationship between blood lead levels and hemoglobin and hematocrit levels in children aged 0 to 11 years exposed to mining pollution in the community of the district and province of Andahuaylas in the department of Apurímac. . A non-experimental quantitative and descriptive design was used. 98 minors from 0 to 11 years of age, registered in the district and province of Andahuaylas in the department of Apurímac, participated in the "lead in blood and its relationship with hemoglobin and hematocrit" campaign from April to May 2023. The study on anemia found that fifty percent (50%) of the subjects did not have anemia. The percentages of mild (6 subjects), moderate (33 subjects), and severe (9 subjects) anemia were 6.1% to 33.7% and 9.2%, respectively. Regarding lead poisoning, 64 (65.3%) of the subjects did not show significant levels, while 34 (34.7%) of the subjects showed toxic levels. The relationship of lead levels with hemoglobin was not significantly influenced by age group, sex or area of ​​residence. Hemoglobin decreases by 0.755 for every one unit increase in blood lead level, with a p-value &lt;0.001 and a 95% confidence interval of -0.839 - 0.671. This study demonstrates a significant correlation between blood lead levels and low hemoglobin levels (corrected for height), underscoring the importance of interventions focused on prevention and health promotion in at-risk populations.

Estimating lead-attributable mortality burden by socioeconomic status in the USA.

This study aimed to estimate population-level and state-level lead-attributable mortality burdens stratified by socioeconomic status (SES) class in the USA. Based on the National Health and Nutrition Examination Survey (NHANES), we constructed individual-level SES scores from income, employment, education and insurance data. We assessed the association between the blood lead levels (BLL) and all-cause mortality by Cox regression in the NHANES cohort (n = 31 311, 4467 deaths). With estimated hazard ratios (HR) and prevalences of medium (2-5 μg/dL) and high (≥ 5 μg/dL) BLL, we computed SES-stratified population-attributable fractions (PAFs) of all-cause mortality from lead exposure across 1999-2019. We additionally conducted a systematic review to estimate the lead-attributable mortality burden at state-level. The HR for every 2-fold increase in the BLL decreased from 1.23 (1.10-1.38) for the lowest SES class to 1.05 (0.90-1.23) for the highest SES class. Across all SES quintiles, medium BLL exhibited a greater mortality burden. Individuals with lower SES had higher lead-attributable burdens, and such disparities haver persisted over the past two decades. In 2017-19, annually 67 000 (32 000-112 000) deaths in the USA were attributable to lead exposure, with 18 000 (2000-41 000) of these deaths occurring in the lowest SES class. Substantial disparities in the state-level mortality burden attributable to lead exposure were also highlighted. These findings suggested that disparities in lead-attributable mortality burden persisted within US adults, due to heterogeneities in the effect sizes of lead exposure as well as in the BLL among different SES classes.

Delta-Aminolevulinic acid dehydratase enzyme activity and susceptibility to lead toxicity in Uganda’s urban children

Background With rapid industrialization, urbanization, and population explosion in sub-Saharan Africa including Uganda, the population has experienced increased exposure to environmental lead subsequently causing elevated blood lead levels. Mean blood levels of 332µg/dL,120µg/dʟ, 25µg/dL,11µg/dL, and 10µg/dL in children under 18 years of age in Nigeria, DR Congo, South Africa, Sudan, and Uganda respectively. Susceptibility to lead toxicity correlates with one’s nutrition status, age, and genetics. This study expounded susceptibility to lead toxicity by relating blood lead levels, delta-aminolevulinic acid dehydratase (ALAD) enzyme activity, and genetic variations of proteins that code for ALAD in urban children of Uganda aged between 6 and 60 months. Methods A total of 198 blood samples were analyzed for blood lead levels (BLL), on an atomic absorption spectrophotometer whereas hemoglobin (Hb) levels, and ALAD enzyme activity, were analyzed on a spectrophotometer before DNA extraction, polymerase chain reaction, and restriction fragment length digestion for ALAD polymorphism. Results Geometric means of BLL (10.55µg/dL, SD = 7.4), Hb (7.85g/dL, SD = 1.3) and ALAD enzyme activity (37.15 units/L BLL, S.D = 9.7), corresponded to samples that coded for ALAD1 allele (99.05%) compared to the 0.05% that coded for ALAD2 with BLL (14.5µg/ dL, SD = 4.7), Hb (6.1 g/ dL), ALAD enzyme activity (33.8 units/L, SD=1.45). There was a significant relationship with a negative linear correlation between BLL, Hb (status, and ALAD enzyme activity in the three isozymes (ALAD1-1, ALAD1-2, and ALAD2-2) in the strength of ALAD1-1 (r = 0.42, p-value = 0.02) ˂ ALAD1-2 (r = 0.62, effective size = 0.43, p-value = ˂ 0.001) ˂ ALAD2-2 (r = 0.67, effective size = 0.86, p-value = ˂ 0.001). Conclusions Most of the study participants coded for the ALAD1 allele hence hoarded blood lead, which could result in delayed exposure and adverse effects later in their lives.

Comparison of empirical and mechanistic blood lead models for children

Childhood exposure to lead can result in increased blood lead levels, which can have detrimental health effects. Models that can predict blood lead level based on exposure to floor and window sill dust lead at varying concentrations are useful tools for informing policy decisions. We compare an empirical model relating blood lead in children to the lead content of household dust, with a mechanistic model that simulates lead exposure in children through their daily activities. The empirical model is constructed using 1999–2004 NHANES data, while the mechanistic model is validated using 2011–2016 NHANES data. The models are evaluated at dust loadings ranging from 0.18 – 43 µg/ft2 and the resulting blood leads are compared. Specific demographic variables are chosen to simulate individuals are generated with “typical,” “high end,” and “low end” exposures in the empirical model; these are directly compared with the median, 95th, and 5th percentile results from the mechanistic model. For a child with “typical” lead exposure, the 95 % confidence interval for computed blood lead values contained the median blood lead value from the mechanistic model at all dust lead exposure levels considered. Similar results hold when comparing the 95th percentile to “high end” and 5th percentile to “low end”. The blood lead level computed by the mechanistic model increases more quickly with respect to dust loading than the empirical model, particularly at higher loadings. The empirical and mechanistic models generate similar blood lead distributions across the range of dust loadings considered, particularly at low loadings. The mechanistic model may be more appropriate for higher loadings due to limitations inherit in the structure of the empirical model.

Associations of mixed metal exposure with chronic kidney disease from NHANES 2011–2018

Metals have been proved to be one of risk factors for chronic kidney disease (CKD) and diabetes, but the effect of mixed metal co-exposure and potential interaction between metals are still unclear. We assessed the urine and whole blood levels of cadmium (Cd), manganese (Mn), lead (Pb), mercury (Hg), and renal function in 3080 adults from National Health and Nutrition Survey (NHANES) (2011–2018) to explore the effect of mixed metal exposure on CKD especially in people with type 2 diabetes mellitus (T2DM). Weighted quantile sum regression model and Bayesian Kernel Machine Regression model were used to evaluate the overall exposure impact of metal mixture and potential interaction between metals. The results showed that the exposure to mixed metals was significantly associated with an increased risk of CKD in blood glucose stratification, with the risk of CKD being 1.58 (1.26,1.99) times in urine and 1.67 (1.19,2.34) times in whole blood higher in individuals exposed to high concentrations of the metal mixture compared to those exposed to low concentrations. The effect of urine metal mixture was elevated magnitude in stratified analysis. There were interactions between urine Pb and Cd, Pb and Mn, Pb and Hg, Cd and Mn, Cd and Hg, and blood Pb and Hg, Mn and Cd, Mn and Pb, Mn and Hg on the risk of CKD in patients with T2DM and no significant interaction between metals was observed in non-diabetics. In summary, mixed metal exposure increased the risk of CKD in patients with T2DM, and there were complex interactions between metals. More in-depth studies are needed to explore the mechanism and demonstrate the causal relationship.

Exploring Blood Lead Level Determinants in Refinery Workers: A Cross-Sectional Study.

Occupational lead exposure poses a significant risk to workers in industrial settings, especially in petroleum refineries. The study aimed to examine the prevalence and determinants of high blood lead concentrations among refinery workers in Kirkuk, Iraq. It has also been aimed to provide evidence-based approaches to identify associated risk factors. A cross-sectional study was conducted among 187 workers from three departments (transportation, storage, and production) in a petroleum refinery from August 2023 to April 2024. Blood lead levels (BLLs) were measured using graphite furnace atomic absorption spectroscopy (GFAAS)(Agilent, Santa Clara, CA). The elevated BLLs were defined as lead levels in blood samples greater than 10 µg/dL. Data on demographic characteristics, such as occupations, smoking habits, and drinking milk, were collected using a researcher-developed information sheet. Statistical analyses included the Kruskal-Wallis test and Pearson Chi-Square test, and logistic regression was used to address the determinants of elevated BLLs. The corresponding associations were reported using odds ratios (OR) and adjusted OR(AOR) along with 95% confidence intervals (CIs). Eighty-five percent of the workers had high BLLs, with a median BLL of 17.11 µg/dL. The findings revealed that workers employed in outdoor settings had 4.25 times higher AOR(95% CI: 1.24-14.48) of experiencing high BLLs compared to those working indoors, after adjusting for other factors. This was especially true for workers who spent nine to 16 hours outdoors. Additionally, age and smoking were also found to be associated with an increased risk of high BLLs. On the other hand, the analysis indicated that drinking milk had a protective effect against high BLLs. The high prevalence of elevated BLLs among refinery workers in Kirkuk underscores the urgency for immediate interventions. Regular monitoring of BLLs, improved training, dietary adjustments (e.g., consuming calcium and phosphate-rich milk, which can help lower BLLs), and smoking cessation programs are recommended to reduce lead exposure and safeguard workers' health. Furthermore, the results suggest that drinking milk could potentially reduce BLLs among petroleum refinery workers. Additional research is necessary to evaluate the effectiveness of these interventions and to continue monitoring exposure levels.

Lead exposure and source attribution for a mammalian scavenger before and after a culling program

Lead-based ammunition is a significant source of environmental lead and threatens species that scavenge lead-shot carcasses, particularly in areas with intensive shooting. With the impacts of lead on avian scavengers well established, there is increasing focus on the effects of lead on mammalian scavengers. We investigated lead exposure in a morphologically specialized mammalian scavenger, the Tasmanian devil (Sarcophilus harrisii), by analyzing their blood lead levels (BLLs) before and after a marsupial culling program using linear mixed effects models. We compared lead isotope signatures in devil blood to those in the culling ammunition to inform potential source attributions. We sampled 23 devils before culling and 15 after culling, finding no significant difference in mean BLLs pre and post-culling. However, devils captured closer to forestry coupes where culling had occurred had higher BLLs, and a greater proportion of devils displayed elevated BLLs post-culling (33 % compared to 18 % pre-culling). The highest BLL (7.93 μg/dL) was found in a devil post-culling and this individual had lead isotope signatures that matched the ammunition samples analyzed, suggesting the individual was exposed to lead from scavenging on culled carcasses. While 18 % of the devil blood lead samples had isotope signatures consistent with the ammunition samples, most were measurably different, indicating other sources of lead in the landscape. BLLs in our study landscape were similar to published BLLs for wild devils across Tasmania. That said, lead isotope signatures in the blood of individual devils sampled both before and after culling shifted closer to those of ammunition samples post-culling. Our results indicate that while some individual devils may have been exposed to lead from culling, most devils in the landscape did not show evidence of recent exposure. However, even low lead levels can adversely impact wildlife health and immunity, a particular concern for devils, a species endangered by disease.

Exposure sources, intake pathways and accumulation of lead in human blood

Lead (Pb) is a toxic heavy metal and its long-term accumulation in human bodies can lead to serious diseases. Investigation on Pb exposure provides an effective intervention opportunity to reduce the blood lead levels (BLLs) of the populations. Although the phase-out of the gasoline has been conducted in many developing countries (e.g., China), the BLLs of these populations are still higher than the alert BLL (5.0 μg/dL) set by World Health Organization (WHO) and Centers for Disease Control and Prevention of USA (CDC). Here, we reviewed the BLLs of the populations in different countries and summarized the sources and intake pathways of blood Pb which were associated with dietary Pb intake and non-dietary Pb intake. Extensive progress has been made in the studies of soil biogeochemistry and the plant biological processes, including the effects of soil pH, redox potential, Fe/Mn oxides, and organic matter on the availability of soil Pb, as well as the mechanisms regulating the Pb absorption by plant root and transport from root to shoot. The oral-nasal respiration and skin infiltration pathways have been specifically identified as the main causes of the increased BLLs of the populations exposed to different Pb sources. In the developing countries, complex dietary and non-dietary Pb intakes increase the BLLs, making intervention strategies to reduce BLLs difficult. This review provides a systematic understanding in the processes and mechanisms of Pb intake from environment to human blood and helps to guide safe strategies to reduce the BLLs and enhance human health.

Blood Lead Levels in the Population Living in Algeria: A Cross-Sectional National Study.

Lead poisoning, is currently recognized as a real public health problem, The WHO classifies lead as one of 10 chemicals of serious public health concern. In Algeria and North Africa, to date, no study on the evaluation of lead impregnation has been carried out at the national level. The main objective of this work is to assess the exposure of the general Algerian population to lead. A cross-sectional study was carried out over the entire Algerian national territory, on a population aged between 3 and 74years old. The survey lasted three years, A questionnaire, a clinical examination and a blood sample were carried out for each individual. Generalized linear regression models were used to determine the factors influencing lead levels measured in blood samples. The study population, spread over 39 wilayas and 121 districts, consists of 3674 individuals. The mean lead levels were 28.27μg/L, the median was 22.22μg/L, and the 95th percentile was 73.83μg/L, Blood lead levels were influenced differently by age, gender, wilaya of residence, dietary habits such as consumption of canned food and the way in which water is conserved for daily consumption. The use of kohl has been confirmed as a potential source of lead exposure. In Algeria, a blood lead value of 75µg/L serves as the Reference Exposure Value, guiding public health responses and risk management strategies, Recommendations have been issued to reduce the blood lead levels of the general population in Algeria in terms of limitation of lead in the sources of exposure, installation of an effective health monitoring system.

House Sparrows as Sentinels of Childhood Lead Exposure.

Our understanding of connections between human and animal health has advanced substantially since the canary was introduced as a sentinel of toxic conditions in coal mines. Nonetheless, the development of wildlife sentinels for monitoring human exposure to toxins has been limited. Here, we capitalized on a three-decade long child blood lead monitoring program to demonstrate that the globally ubiquitous and human commensal house sparrow (Passer domesticus) can be used as a sentinel of human health risks in urban environments impacted by lead mining. We showed that sparrows are a viable proxy for the measurement of blood lead levels in children at a neighborhood scale (0.28 km2). In support of the generalizability of this approach, the blood lead relationship established in our focal mining city enabled us to accurately predict elevated blood lead levels in children from another mining city using only sparrows from the second location. Using lead concentrations and lead isotopic compositions from environmental and biological matrices, we identified shared sources and pathways of lead exposure in sparrows and children, with strong links to contamination from local mining emissions. Our findings showed how human commensal species can be used to identify and predict human health risks over time and space.

Effectiveness of soil remediation intervention in abandoned used lead acid battery (ULAB) recycling sites to reduce lead exposure among the children

Lead (Pb) is a neurotoxin, and children are vulnerable due to their evolving physiology and high-risk behaviours. Soil remediation interventions have proven effective in reducing Pb exposure. The primary objective is to measure the effectiveness of soil remediation at abandoned used lead acid battery (ULAB) recycling sites, nearby household cleaning, and community awareness in reducing blood lead levels (BLLs) in children. Additionally, this study aims to examine associations of Pb exposure with hematological, cardiovascular, renal, immunological, and endocrinological parameters in children aged 0–12 years. This study employs a quasi-experimental design, with abandoned ULAB sites as intervention sites and two control sites in Bangladesh. The intervention includes soil remediation coupled with community education. Data will be collected prior to the intervention and at a 12-month follow-up, including a comprehensive Pb exposure survey and collect environmental, turmeric samples, and blood from the child. Pb concentrations in environmental samples and turmeric samples will be determined using XRF analyser. Child BLL will be measured using Graphite Furnace Atomic Absorption Spectrometry (GF-AAS) and proposed biochemical parameters will be analysed using routine laboratory methods. This study could provide valuable insights for designing targeted interventions in similar settings and mitigating exposure to Pb.

Levels of lead in blood and water in occupationally exposed and unexposed population of the Guntur district, Andhra Pradesh: baseline analysis of a prospective cohort study

Levels of lead in blood and water in occupationally exposed and unexposed population of the Guntur district, Andhra Pradesh: baseline analysis of a prospective cohort study

The association between childhood blood lead levels and proximity to airports in Colorado

BackgroundIn October 2023, the U.S. Environmental Protection Agency announced a final endangerment finding that leaded aviation gasoline (avgas) contributes to air pollution that is harmful to public health. This study evaluates the evidence for a link between living in proximity to airports and children’s blood lead levels in Colorado.MethodsWe analyzed the association between childhood blood lead levels (BLLs) and proximity to airport point locations in children tested for lead in Colorado over a 10-year study period (2011–2020) using a correlated random effects model with bootstrapped standard errors (N = 56,002 observations, 47,322 individuals). Along with distance from airport point locations, we identified the number of days sampled children lived downwind of their nearest airport during the 60 days prior to their test date. We also adjusted the model for age, sex, detection limit, test type, sample order, seasonality, time, proximity to lead-releasing facilities, estimated monthly aircraft traffic, and demographic characteristics of the surrounding neighborhood.ResultsOur primary model estimates that living one mile (1.6 km) further from airport point locations decreases mean blood lead levels by 0.068 µg/dL. Additional analysis estimates that living one mile further from airport point locations decreases the odds of having a blood lead level ≥ 3.5 µg/dL by 13.2%.ConclusionOur results suggest that lead emissions from aircraft using leaded avgas have a small but statistically significant effect on the BLLs of children living near airport point locations in Colorado. While the risk from proximity to airports is likely less than the risks associated with deteriorating lead paint and dust, our findings highlight the value of lead testing in children who may be at risk of exposure from all sources, including those who live near airports.

Measurement of lead, mercury, and cadmium in blood donors in Canada.

Fetal and neonatal exposure to lead is associated with irreversible adverse effects on neural development. There is no reliable threshold for lead effect, so limiting exposure is recommended. A significant correlation has been reported between post-transfusion blood lead level (BLL) in infants and lead levels in transfused RBC units. We measured levels of lead, mercury, and cadmium, in Canadian donor blood to investigate if concerning levels for neonatal transfusion exist. Whole blood samples from blood donors (n = 2529) were shipped cold within 7 days of donation. All permanent blood donation clinics across Canada were sampled. Twelve of these permanent clinics and 8 mobile clinics with a greater potential for having higher lead or mercury levels were oversampled. Heavy metals were measured by inductively coupled plasma mass spectrometry. Of all donations, 2.2% (lead) and 0.4% (mercury) had levels higher than the recommended thresholds for safe neonatal transfusion. BLLs were higher in males but there was no significant difference in the blood mercury levels of males versus females. Cadmium levels were higher in females. There was a positive correlation between donor age and levels of heavy metals, with lead having the strongest correlation (r = 0.47, p < .0001). Three clinics in close proximity to two lead-producing mines were among the clinics with the highest BLLs. Significantly higher blood mercury levels were observed in coastal clinics. Our data on donor blood heavy metal levels supports considering blood transfusion as an exposure source to heavy metals and encourages informed selection of blood units for transfusion to vulnerable groups.

Associations among global long interspersed nuclear element-1 DNA methylation, metal exposure, and chronic kidney disease.

Long interspersed nuclear element-1 (LINE-1) methylation serves as an indicator of global DNA methylation. This study explored the correlation between LINE-1 methylation and chronic kidney disease (CKD). We also evaluated whether LINE-1 methylation could modify the association between CKD and metal exposure. A total of 213 patients with clinically defined CKD, without hemodialysis and 416 age and sex matched controls were recruited. Levels of LINE-1 methylation, total urinary arsenic, blood lead, blood cadmium, and plasma selenium were assessed. The results reveal a positive association between LINE-1 methylation and CKD, with an odds ratio (OR) of 5.30 (95% confidence interval: 2.81 to 9.99). Total urinary arsenic and blood cadmium concentrations were positively related with LINE-1 methylation. This study was the first to observe that low plasma selenium, high blood cadmium, and high blood lead levels significantly and additively interact with increased LINE-1 methylation to increase the OR of CKD. Additionally, high LINE-1 methylation interacted multiplicatively with low plasma selenium to increase the OR of CKD (p < 0.001). This study highlighted the significant association between LINE-1 hypermethylation and CKD. Furthermore, the results demonstrate that LINE-1 methylation can interact with high blood cadmium or low plasma selenium to affect CKD risk.