Construction of residential histories to estimate long-term environmental exposures in the California Teachers Study cohort

Environmental epidemiologic studies using geospatial data often estimate exposure at a participant's residence upon enrollment, but mobility during the exposure period can lead to misclassification. We aimed to mitigate this issue by constructing residential histories for participants in the California Teachers Study through follow-up (1995-2018). Address records have been collected from the US Postal Service, LexisNexis, Experian, and California Cancer Registry. We identified records of the same address based on geo-coordinate distance (≤250 m) and street name similarity. We consolidated addresses, prioritizing those confirmed by participants during follow-up questionnaires, and estimating the duration lived at each address using dates associated with records (e.g., date-first-seen). During 23 years of follow-up, about half of participants moved (48%, including 14% out-of-state). We observed greater mobility among younger women, Hispanic/Latino women, and those in metropolitan and lower socioeconomic status areas. The cumulative proportion of in-state movers remaining eligible for analysis was 21%, 32%, and 41% at 5, 10, and 20 years post enrollment, respectively. Using self-reported information collected 10 years after enrollment, we correctly identified 94% of movers and 95% of non-movers as having moved or not moved from their enrollment address. This dataset provides a foundation for estimating long-term environmental exposures in diverse epidemiologic studies in this cohort. IMPACT: Our efforts in constructing residential histories for California Teachers Study participants through follow-up (1995-2018) benefit future environmental epidemiologic studies. Address availability during the exposure period can mitigate misclassification due to residential changes, especially when evaluating long-term exposures and chronic health outcomes. This can reduce differential misclassification among more mobile subgroups, including younger women and those from lower socioeconomic and urban areas. Our approach to consolidating addresses from multiple sources showed high accuracy in comparison to self-reported residential information. The residential dataset produced from this analysis provides a valuable tool for future studies, ultimately enhancing our understanding of environmental health impacts.

Method validation for (ultra)-trace element concentrations in urine for small sample volumes in large epidemiological studies: application to the population-based epidemiological multi-ethnic study of atherosclerosis (MESA)

Analysis of essential and non-essential trace elements in urine has emerged as a valuable tool for assessing occupational and environmental exposures, diagnosing nutritional status and guiding public health and health care intervention. Our study focused on the analysis of trace elements in urine samples from the Multi-Ethnic Study of Atherosclerosis (MESA), a precious resource for health research with limited sample volumes. Here we provide a comprehensive and sensitive method for the analysis of 18 elements using only 100 μL of urine. Method sensitivity, accuracy, and precision were assessed. The analysis by inductively coupled plasma mass spectrometry (ICP-MS) included the measurement of antimony (Sb), arsenic (As), barium (Ba), cadmium (Cd), cesium (Cs), cobalt (Co), copper (Cu), gadolinium (Gd), lead (Pb), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se), strontium (Sr), thallium (Tl), tungsten (W), uranium (U), and zinc (Zn). Further, we reported urinary trace element concentrations by covariates including gender, ethnicity/race, smoking and location. The results showed good accuracy and sensitivity of the ICP-MS method with the limit of detections rangings between 0.001 μg L-1 for U to 6.2 μg L-1 for Zn. Intra-day precision for MESA urine analysis varied between 1.4% for Mo and 26% for Mn (average 6.4% for all elements). The average inter-day precision for most elements was <8.5% except for Gd (20%), U (16%) and Mn (19%) due to very low urinary concentrations. Urinary mean concentrations of non-essential elements followed the order of Sr > As > Cs > Ni > Ba > Pb > Cd > Gd > Tl > W > U. The order of urinary mean concentrations for essential trace elements was Zn > Se > Mo > Cu > Co > Mn. Non-adjusted mean concentration of non-essential trace elements in urine from MESA participants follow the order Sr > As > Cs > Ni > Ba > Pb > Cd > Gd > Tl > W > U. The unadjusted urinary mean concentrations of essential trace elements decrease from Zn > Se > Mo > Cu > Co > Mn.

Urinary Metal Levels and Coronary Artery Calcification: Longitudinal Evidence in the Multi-Ethnic Study of Atherosclerosis (MESA)

Objective

Growing evidence indicates that exposure to metals are risk factors for cardiovascular disease (CVD). We hypothesized that higher urinary levels of metals with prior evidence of an association with CVD, including non-essential (cadmium , tungsten, and uranium) and essential (cobalt, copper, and zinc) metals are associated with baseline and rate of change of coronary artery calcium (CAC) progression, a subclinical marker of atherosclerotic CVD.

Methods

We analyzed data from 6,418 participants in the Multi-Ethnic Study of Atherosclerosis (MESA) with spot urinary metal levels at baseline (2000-2002) and 1-4 repeated measures of spatially weighted coronary calcium score (SWCS) over a ten-year period. SWCS is a unitless measure of CAC highly correlated to the Agatston score but with numerical values assigned to individuals with Agatston score=0. We used linear mixed effect models to assess the association of baseline urinary metal levels with baseline SWCS, annual change in SWCS, and SWCS over ten years of follow-up. Urinary metals (adjusted to μg/g creatinine) and SWCS were log transformed. Models were progressively adjusted for baseline sociodemographic factors, estimated glomerular filtration rate, lifestyle factors, and clinical factors.

Results

At baseline, the median and interquartile range (25th, 75th) of SWCS was 6.3 (0.7, 58.2). For urinary cadmium, the fully adjusted geometric mean ratio (GMR) (95%Cl) of SWCS comparing the highest to the lowest quartile was 1.51 (1.32, 1.74) at baseline and 1.75 (1.47, 2.07) at ten years of follow-up. For urinary tungsten, uranium, and cobalt the corresponding GMRs at ten years of follow-up were 1.45 (1.23, 1.71), 1.39 (1.17, 1.64), and 1.47 (1.25, 1.74), respectively. For copper and zinc, the association was attenuated with adjustment for clinical risk factors; GMRs at ten years of follow-up before and after adjustment for clinical risk factors were 1.55 (1.30, 1.84) and 1.33 (1.12, 1.58), respectively, for copper and 1.85 (1.56, 2.19) and 1.57 (1.33, 1.85) for zinc.

Conclusion

Higher levels of cadmium, tungsten, uranium, cobalt, copper, and zinc, as measured in urine, were associated with subclinical CVD at baseline and at follow-up. These findings support the hypothesis that metals are pro-atherogenic factors.

A State-of-the-Science Review on Metal Biomarkers

PURPOSE OF REVIEW

Biomarkers are commonly used in epidemiological studies to assess metals and metalloid exposure and estimate internal dose, as they integrate multiple sources and routes of exposure. Researchers are increasingly using multi-metal panels and innovative statistical methods to understand how exposure to real-world metal mixtures affects human health. Metals have both common and unique sources and routes of exposure, as well as biotransformation and elimination pathways. The development of multi-element analytical technology allows researchers to examine a broad spectrum of metals in their studies; however, their interpretation is complex as they can reflect different windows of exposure and several biomarkers have critical limitations. This review elaborates on more than 500 scientific publications to discuss major sources of exposure, biotransformation and elimination, and biomarkers of exposure and internal dose for 12 metals/metalloids, including 8 non-essential elements (arsenic, barium, cadmium, lead, mercury, nickel, tin, uranium) and 4 essential elements (manganese, molybdenum, selenium, and zinc) commonly used in multi-element analyses.

RECENT FINDINGS

We conclude that not all metal biomarkers are adequate measures of exposure and that understanding the metabolic biotransformation and elimination of metals is key to metal biomarker interpretation. For example, whole blood is a good biomarker of exposure to arsenic, cadmium, lead, mercury, and tin, but it is not a good indicator for barium, nickel, and uranium. For some essential metals, the interpretation of whole blood biomarkers is unclear. Urine is the most commonly used biomarker of exposure across metals but it should not be used to assess lead exposure. Essential metals such as zinc and manganese are tightly regulated by homeostatic processes; thus, elevated levels in urine may reflect body loss and metabolic processes rather than excess exposure. Total urinary arsenic may reflect exposure to both organic and inorganic arsenic, thus, arsenic speciation and adjustment for arsebonetaine are needed in populations with dietary seafood consumption. Hair and nails primarily reflect exposure to organic mercury, except in populations exposed to high levels of inorganic mercury such as in occupational and environmental settings. When selecting biomarkers, it is also critical to consider the exposure window of interest. Most populations are chronically exposed to metals in the low-to-moderate range, yet many biomarkers reflect recent exposures. Toenails are emerging biomarkers in this regard. They are reliable biomarkers of long-term exposure for arsenic, mercury, manganese, and selenium. However, more research is needed to understand the role of nails as a biomarker of exposure to other metals. Similarly, teeth are increasingly used to assess lifelong exposures to several essential and non-essential metals such as lead, including during the prenatal window. As metals epidemiology moves towards embracing a multi-metal/mixtures approach and expanding metal panels to include less commonly studied metals, it is important for researchers to have a strong knowledge base about the metal biomarkers included in their research. This review aims to aid metals researchers in their analysis planning, facilitate sound analytical decision-making, as well as appropriate understanding and interpretation of results.

Blood and Urinary Metal Levels among Exclusive Marijuana Users in NHANES (2005-2018)

BACKGROUND

Marijuana is the third most used drug in the world.

OBJECTIVES

Because the cannabis plant is a known scavenger of metals, we hypothesized that individuals who use marijuana will have higher metal biomarker levels compared with those who do not use.

METHODS

We combined data from the National Health and Nutrition Examination Survey (2005-2018) for n = 7,254 participants, classified by use: non-marijuana/non-tobacco, exclusive marijuana, exclusive tobacco, and dual marijuana and tobacco use. Five metals were measured in blood and 16 in urine using inductively coupled plasma mass spectrometry; urinary metals were adjusted for urinary creatinine.

RESULTS

Participants reporting exclusive marijuana use compared with non-marijuana/non-tobacco use had statistically significantly higher mean cadmium levels in blood [1.22 μ g / L (95% CI: 1.11, 1.34); p < 0.001 ] and urine [1.18 μ g / g (95% CI: 1.0, 1.31); p = 0.004 ] and statistically significantly higher mean lead levels in blood [1.27 μ g / dL (95% CI: 1.07, 1.50); p = 0.006 ] and urine [1.21 μ g / g (95% CI: - 0.006 , 1.50); p = 0.058 ].

DISCUSSION

Our results suggest marijuana is a source of cadmium and lead exposure. Research regarding cannabis use and cannabis contaminants, particularly metals, should be conducted to address public health concerns related to the growing number of cannabis users. https://doi.org/10.1289/EHP12074.

Association of blood manganese, selenium with steatosis, fibrosis in the National Health and Nutrition Examination Survey, 2017-18

BACKGROUND & AIMS

Chronic liver disease is a growing health burden worldwide. Chronic metal exposures may be associated with non-alcoholic fatty liver disease (NAFLD). We aimed to evaluate the association of blood cadmium (Cd), mercury (Hg), lead (Pb), manganese (Mn), and selenium (Se) with two hallmark features of NAFLD: liver steatosis and fibrosis in the general U.S.

METHODS

We analyzed transient liver elastography data from participants of the National Health and Nutrition Examination Survey (NHANES) 2017-18, using ordinal logistic regression analyses to evaluate the cross-sectional association between blood metal concentrations and clinical stages of steatosis and fibrosis. We applied survey weights, strata, and primary sampling units and analyses were conducted using the R survey package.

RESULTS

4,154 participants were included. Median (IQR) for blood Mn and blood Se were 9.28 (7.48-11.39) and 191.08 (176.55-207.16) μg/L, respectively. Per interquartile range increase of natural log transformed blood Mn, the adjusted odds ratio (OR) (95% CI) was 1.59 (1.13-2.23) for a higher grade of steatosis and 1.16 (0.67-2.00) for liver fibrosis. The corresponding OR for steatosis was 2.00 (1.24-3.24) and 2.14 (1.04-4.42) in Black and Mexican American participants, respectively. The corresponding OR for liver fibrosis was 2.96 (1.42-6.17) for females. Per interquartile range increase of natural log transformed blood Se, the adjusted OR was 2.25 (1.30-3.89) for steatosis but 0.31 (0.13-0.72) for liver fibrosis. The inverse association of blood Se with liver fibrosis was also observed in males and White participants. Blood Cd, Hg, and Pb were not associated with liver steatosis and fibrosis in fully-adjusted models overall.

CONCLUSIONS

In NHANES 2017-18, higher blood Mn was positively associated with liver steatosis, and higher Se was positively associated with liver steatosis but negatively associated with liver fibrosis. Longitudinal studies are needed to examine the association of Mn and Se with fibrosis progression.

Arsenic Exposure, Blood DNA Methylation, and Cardiovascular Disease

BACKGROUND

Epigenetic dysregulation has been proposed as a key mechanism for arsenic-related cardiovascular disease (CVD). We evaluated differentially methylated positions (DMPs) as potential mediators on the association between arsenic and CVD.

METHODS

Blood DNA methylation was measured in 2321 participants (mean age 56.2, 58.6% women) of the Strong Heart Study, a prospective cohort of American Indians. Urinary arsenic species were measured using high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry. We identified DMPs that are potential mediators between arsenic and CVD. In a cross-species analysis, we compared those DMPs with differential liver DNA methylation following early-life arsenic exposure in the apoE knockout (apoE^-/-) mouse model of atherosclerosis.

RESULTS

A total of 20 and 13 DMPs were potential mediators for CVD incidence and mortality, respectively, several of them annotated to genes related to diabetes. Eleven of these DMPs were similarly associated with incident CVD in 3 diverse prospective cohorts (Framingham Heart Study, Women's Health Initiative, and Multi-Ethnic Study of Atherosclerosis). In the mouse model, differentially methylated regions in 20 of those genes and DMPs in 10 genes were associated with arsenic.

CONCLUSIONS

Differential DNA methylation might be part of the biological link between arsenic and CVD. The gene functions suggest that diabetes might represent a relevant mechanism for arsenic-related cardiovascular risk in populations with a high burden of diabetes.

An epigenome-wide study of DNA methylation profiles and lung function among American Indians in the Strong Heart Study

BACKGROUND

Epigenetic modifications, including DNA methylation (DNAm), are often related to environmental exposures, and are increasingly recognized as key processes in the pathogenesis of chronic lung disease. American Indian communities have a high burden of lung disease compared to the national average. The objective of this study was to investigate the association of DNAm and lung function in the Strong Heart Study (SHS). We conducted a cross-sectional study of American Indian adults, 45-74 years of age who participated in the SHS. DNAm was measured using the Illumina Infinium Human MethylationEPIC platform at baseline (1989-1991). Lung function was measured via spirometry, including forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC), at visit 2 (1993-1995). Airflow limitation was defined as FEV1 < 70% predicted and FEV1/FVC < 0.7, restriction was defined as FEV1/FVC > 0.7 and FVC < 80% predicted, and normal spirometry was defined as FEV1/FVC > 0.7, FEV1 > 70% predicted, FVC > 80% predicted. We used elastic-net models to select relevant CpGs for lung function and spirometry-defined lung disease. We also conducted bioinformatic analyses to evaluate the biological plausibility of the findings.

RESULTS

Among 1677 participants, 21.2% had spirometry-defined airflow limitation and 13.6% had spirometry-defined restrictive pattern lung function. Elastic-net models selected 1118 Differentially Methylated Positions (DMPs) as predictors of airflow limitation and 1385 for restrictive pattern lung function. A total of 12 DMPs overlapped between airflow limitation and restrictive pattern. EGFR, MAPK1 and PRPF8 genes were the most connected nodes in the protein-protein interaction network. Many of the DMPs targeted genes with biological roles related to lung function such as protein kinases.

CONCLUSION

We found multiple differentially methylated CpG sites associated with chronic lung disease. These signals could contribute to better understand molecular mechanisms involved in lung disease, as assessed systemically, as well as to identify patterns that could be useful for diagnostic purposes. Further experimental and longitudinal studies are needed to assess whether DNA methylation has a causal role in lung disease.

Environmental-level exposure to metals and metal-mixtures associated with spirometry-defined lung disease in American Indian adults: Evidence from the Strong Heart Study

BACKGROUND

American Indians have a higher burden of chronic lung disease compared to the US average. Several metals are known to induce chronic lung disease at high exposure levels; however, less is known about the role of environmental-level metal exposure. We investigated respiratory effects of exposure to single metals and metal-mixtures in American Indians who participated in the Strong Heart Study.

METHODS

We included 2077 participants with data on 6 metals (As, Cd, Mo, Se, W, Zn) measured from baseline urine samples (1989-1991) and who underwent spirometry testing at follow-up (1993-1995). We used generalized linear regression to assess associations of single metals with spirometry-defined measures of airflow limitation and restrictive ventilatory pattern, and continuous spirometry. We used Bayesian Kernel Machine Regression to investigate the joint effects of the metal-mixture. Sensitivity analyses included stratifying by smoking status and diabetes.

RESULTS

Participants were 40% male, with median age 55 years. 21% had spirometry-defined airflow limitation, and 14% had a restrictive ventilatory pattern. In individual metal analyses, Cd was associated with higher odds of airflow limitation and lower FEV1 and FEV1/FVC. Mo was associated with higher odds of restrictive ventilatory pattern and lower FVC. Metal-mixtures analyses confirmed these models. In smoking stratified analyses, the overall metal-mixture was linearly and positively associated with airflow limitation among non-smokers; Cd was the strongest contributor. For restrictive ventilatory pattern, the association with the overall metal-mixture was strong and linear among participants with diabetes and markedly attenuated among participants without diabetes. Among those with diabetes, Mo and Zn were the major contributors.

CONCLUSIONS

Environmental-level exposure to several metals was associated with higher odds of spirometry-defined lung disease in an American Indian population. Exposure to multiple metals, including Cd and Mo, may have an under-recognized adverse role on the respiratory system.

Exposure study on susceptible people - SPES: An integrative biomonitoring approach

BACKGROUND

The evaluation of environmental exposure risk requires a global analysis of pollution phenomena, including biological effects and potentially correlated clinical outcomes in susceptible populations. Although human biomonitoring plays a fundamental role in assessing the degree of contamination, it is not effective alone in identifying a direct link between exposure, biomolecular effects and outcomes on target organisms. While toxicogenomics and epidemiology are mainly focused on the investigation of molecular reactions and clinical outcomes, the monitoring of environmental matrices works independently to characterize the territorial distribution of toxic compounds, without proving any correlated health risk for residents.

OBJECTIVES

We propose a new biomonitoring model based on a whole systemic analytical evaluation of environmental context. The paradigm of the method consists of identifying the sources of pollution, the migration pathways of those pollutants and their effects on target organisms. By means of this innovative, holistic epidemiological approach, we included healthy human subjects in a cohort to identify potential risks of exposure and predict possible correlated clinical outcomes. 4205 residents of the Campania region were enrolled in the "SPES" biomonitoring study, which especially focused on the areas dubbed "Land of Fires" in the recent decades.

DISCUSSION

The analysis of environmental exposure risk suffers the lack of data integration from various science fields, and this comes down to a limited point of view and a limited knowledge of phenomena. In implementing our model, we first constructed an analytical picture of the Real-world situation. We next conducted a comparative risk assessment, in order to identify possible correlations between pollution and health within a holistic view.

CONCLUSION

This type of research activities aims to support the implementation of public health interventions and to become a reference model in the evaluation of the risk of exposure to environmental pollutants.

An atlas of metallome and metabolome interactions and associations with incident diabetes in the Strong Heart Family Study

BACKGROUND

Chronic exposure to certain metals plays a role in disease development. Integrating untargeted metabolomics with urinary metallome data may contribute to better understanding the pathophysiology of diseases and complex molecular interactions related to environmental metal exposures. To discover novel associations between urinary metal biomarkers and metabolism networks, we conducted an integrative metallome-metabolome analysis using a panel of urinary metals and untargeted blood metabolomic data from the Strong Heart Family Study (SHFS).

METHODS

The SHFS is a prospective family-based cohort study comprised of American Indian men and women recruited in 2001-2003. This nested case-control analysis of 145 participants of which 50 developed incident diabetes at follow up in 2006-2009, included participants with urinary metal and untargeted metabolomic data. Concentrations of 8 creatinine-adjusted urine metals/metalloids [antimony (Sb), cadmium (Cd), lead (Pb), molybdenum (Mo), selenium (Se), tungsten (W), uranium (U) and zinc (Zn)], and 4 arsenic species [inorganic arsenic (iAs), monomethylarsonate (MMA), dimethylarsinate (DMA), and arsenobetaine (AsB)] were measured. Global metabolomics was performed on plasma samples using high-resolution Orbitrap mass spectrometry. We performed an integrative network analysis using xMWAS and a metabolic pathway analysis using Mummichog.

RESULTS

8,810 metabolic features and 12 metal species were included in the integrative network analysis. Most metal species were associated with distinct subsets of metabolites, forming single-metal-multiple-metabolite clusters (|r|>0.28, p-value < 0.001). DMA (clustering with W), iAs (clustering with U), together with Mo and Se showed modest interactions through associations with common metabolites. Pathway enrichment analysis of associated metabolites (|r|>0.17, p-value < 0.1) showed effects in amino acid metabolism (AsB, Sb, Se and U), fatty acid and lipid metabolism (iAs, Mo, W, Sb, Pb, Cd and Zn). In stratified analyses among participants who went on to develop diabetes, iAs and U clustered together through shared metabolites, and both were associated with the phosphatidylinositol phosphate metabolism pathway; metals were also associated with metabolites in energy metabolism (iAs, MMA, DMA, U, W) and xenobiotic degradation and metabolism (DMA, Pb) pathways.

CONCLUSION

In this integrative analysis of multiple metals and untargeted metabolomics, results show common associations with fatty acid, energy and amino acid metabolism pathways. Results for individual metabolite associations differed for different metals, indicating that larger populations will be needed to confirm the metal-metal interactions detected here, such as the strong interaction of uranium and inorganic arsenic. Understanding the biochemical networks underlying metabolic homeostasis and their association with exposure to multiple metals may help identify novel biomarkers, pathways of disease, potential signatures of environmental metal exposure.

Spatial relationship between well water arsenic and uranium in Northern Plains native lands

Arsenic and uranium in unregulated private wells affect many rural populations across the US. The distribution of these contaminants in the private wells of most American Indian communities is poorly characterized, and seldom studied together. Here, we evaluate the association between drinking water arsenic and uranium levels in wells (n = 441) from three tribal regions in North Dakota and South Dakota participating in the Strong Heart Water Study. Groundwater contamination was extensive; 29% and 7% of wells exceeded maximum contaminant levels for arsenic and uranium respectively. 81% of wells had both arsenic and uranium concentrations at one-tenth of their human-health benchmark (arsenic, 1 μg/L; uranium 3 μg/L). Well arsenic and uranium concentrations were uncorrelated (rs = 0.06); however, there appeared to be a spatial correlation of wells co-contaminated by arsenic and uranium associated with flow along a geologic contact. These findings indicate the importance of measuring multiple metals in well water, and to understand underlying hydrogeological conditions. The underlying mechanisms for the prevalence of arsenic and uranium across Northern Plains Tribal Lands in the US, and in particular the occurrence of both elevated arsenic and uranium in drinking water wells in this region, demands further study.

Urinary arsenic and heart disease mortality in NHANES 2003-2014

BACKGROUND

Evidence evaluating the prospective association between low-to moderate-inorganic arsenic (iAs) exposure and cardiovascular disease in the general US population is limited. We evaluated the association between urinary arsenic concentrations in National Health and Nutrition Examination Survey (NHANES) 2003-2014 and heart disease mortality linked from the National Death Index through 2015.

METHODS

We modeled iAs exposure as urinary total arsenic and dimethylarsinate among participants with low seafood intake, based on low arsenobetaine levels (N = 4990). We estimated multivariable adjusted hazard ratios (HRs) for heart disease mortality per interquartile range (IQR) increase in urinary arsenic levels using survey-weighted, Cox proportional hazards models, and evaluated flexible dose-response analyses using restricted quadratic spline models. We updated a previously published relative risk of coronary heart disease mortality from a dose-response meta-analysis per a doubling of water iAs (e.g., from 10 to 20 μg/L) with our results from NHANES 2003-2014, assuming all iAs exposure came from drinking water.

RESULTS

A total of 77 fatal heart disease events occurred (median follow-up time 75 months). The adjusted HRs (95% CI) of heart disease mortality for an increase in urinary total arsenic and DMA corresponding to the interquartile range were 1.20 (0.83, 1.74) and 1.18 (0.68, 2.05), respectively. Restricted quadratic splines indicate a significant association between increasing urinary total arsenic and the HR of fatal heart disease for all participants at the lowest exposure levels <4.5 μg/L. The updated pooled relative risk of coronary heart disease mortality per doubling of water iAs (μg/L) was 1.16 (95% CI 1.07, 1.25).

CONCLUSIONS

Despite a small number of events, relatively short follow-up time, and high analytical limits of detection for urinary arsenic species, iAs exposure at low-to moderate-levels is consistent with increased heart disease mortality in NHANES 2003-2014 although the associations were only significant in flexible dose-response models.

Association between rice consumption and risk of cancer incidence in the California Teachers Study

PURPOSE

We evaluated the contribution of rice intake, a source of dietary arsenic, to cancer risk in a population of women with likely low arsenic exposure from drinking water and variable rice intake who participated in the California Teachers Study.

METHODS

Rice consumption was categorized into quartiles (< 9.6, 9.7-15.6, 15.7-42.7, and ≥ 42.8 g/day). Multivariable-adjusted hazard ratios and 95% confidence intervals (95% CI) for incident cancer were estimated comparing rice consumption categories with bladder, breast, kidney, lung, and pancreatic cancer, with progressive adjustment for age, total calories, BMI, race, smoking status, physical activity, and cancer-specific covariates.

RESULTS

The number of breast, lung, pancreatic, bladder, and kidney cancer cases was 7,351; 1,100; 411; 344; and 238, respectively. The adjusted hazard ratios (95% CI) comparing the highest versus lowest rice intake quartiles were 1.07 (1.00-1.15); 0.87 (0.72-1.04); 0.95 (0.66-1.37); 1.11 (0.81-1.52) and 1.07 (0.72-1.59) for breast, lung, pancreatic, bladder, and kidney cancers, respectively. Results were consistent when rice was modeled as a continuous variable and in analyses stratified by smoking status.

CONCLUSION

Rice consumption was not associated with risk of kidney, lung or pancreatic cancer, except maybe a small excess risk for breast cancer and a small non-significant excess risk for bladder cancer, comparing the highest versus lowest quartile of rice intake. Due to lower consumption patterns in this cohort, future studies should involve populations for which rice is a staple food and use of an arsenic biomarker.

Electronic Cigarette Use and Blood Pressure Endpoints: a Systematic Review

PURPOSE OF REVIEW

E-cigarettes (e-cigs) release toxic chemicals known to increase blood pressure (BP) levels. The effects of e-cigs on BP, however, remain unknown. Studying BP may help characterize potential cardiovascular risks of short- and long-term e-cig use. We summarized published studies on the association of e-cig use with BP endpoints.

RECENT FINDINGS

Thirteen e-cig trials (12 cross-over designs) and 1 observational study evaluated systolic and diastolic blood pressure (SBP and DBP). All trials included at least one e-cig arm with nicotine, 6 a no-nicotine e-cig arm, and 3 a placebo arm. SBP/DBP increased in most nicotine e-cig arms, in some non-nicotine e-cig arms, and in none of the placebo arms. The observational study followed e-cig users and nonsmokers for 3.5 years with inconsistent findings. The use of e-cigs with and without nicotine may result in short-term elevations of both SBP and DBP. Prospective studies that investigate the long-term cardiovascular impact of e-cig use are needed.

Correction to: Low-moderate arsenic exposure and respiratory health in American Indian communities in the Strong Heart Study

The original version of this article [1], published on 28 November 2019, contained incorrect title. In this Correction the affected part of the article is shown.

Rice Intake, Arsenic Exposure, and Subclinical Cardiovascular Disease Among US Adults in MESA

Background Arsenic-related cardiovascular effects at exposure levels below the US Environmental Protection Agency's standard of 10 μg/L are unclear. For these populations, food, especially rice, is a major source of exposure. We investigated associations of rice intake, a marker of arsenic exposure, with subclinical cardiovascular disease (CVD) markers in a multiethnic population. Methods and Results Between 2000 and 2002, MESA (Multi-Ethnic Study of Atherosclerosis) enrolled 6814 adults without clinical CVD. We included 5050 participants with baseline data on rice intake and markers of 3 CVD domains: inflammation (hsCRP [high-sensitivity C-reactive protein], interleukin-6, and fibrinogen), vascular function (aortic distensibility, carotid distensibility, and brachial flow-mediated dilation), and subclinical atherosclerosis at 3 vascular sites (carotid intima-media thickness, coronary artery calcification, and ankle-brachial index). We also evaluated endothelial-related biomarkers previously associated with arsenic. Rice intake was assessed by food frequency questionnaire. Urinary arsenic was measured in 310 participants. A total of 13% of participants consumed ≥1 serving of rice/day. Compared with individuals consuming <1 serving of rice/week, ≥1 serving of rice/day was not associated with subclinical markers after demographic, lifestyle, and CVD risk factor adjustment (eg, geometric mean ratio [95% CI] for hsCRP, 0.98 [0.86-1.11]; aortic distensibility, 0.99 [0.91-1.07]; and carotid intima-media thickness, 0.98 [0.91-1.06]). Associations with urinary arsenic were similar to those for rice intake. Conclusions Rice intake was not associated with subclinical CVD markers in a multiethnic US population. Research using urinary arsenic is needed to assess potential CVD effects of low-level arsenic exposure. Understanding the role of low-level arsenic as it relates to subclinical CVD may contribute to CVD prevention and control.

Low-moderate arsenic exposure and respiratory in American Indian communities in the Strong Heart Study

BACKGROUND

Arsenic exposure through drinking water is an established lung carcinogen. Evidence on non-malignant lung outcomes is less conclusive and suggests arsenic is associated with lower lung function. Studies examining low-moderate arsenic (< 50 μg/L), the level relevant for most populations, are limited. We evaluated the association of arsenic exposure with respiratory health in American Indians from the Northern Plains, the Southern Plains and the Southwest United States, communities with environmental exposure to inorganic arsenic through drinking water.

METHODS

The Strong Heart Study is a prospective study of American Indian adults. This analysis used urinary arsenic measurements at baseline (1989-1991) and spirometry at Visit 2 (1993-1995) from 2132 participants to evaluate associations of arsenic exposure with airflow obstruction, restrictive pattern, self-reported respiratory disease, and symptoms.

RESULTS

Airflow obstruction was present in 21.5% and restrictive pattern was present in 14.4%. The odds ratio (95% confidence interval) for obstruction and restrictive patterns, based on the fixed ratio definition, comparing the 75th to 25th percentile of arsenic, was 1.17 (0.99, 1.38) and 1.27 (1.01, 1.60), respectively, after adjustments, and 1.28 (1.02, 1.60) and 1.33 (0.90, 1.50), respectively, based on the lower limit of normal definition. Arsenic was associated with lower percent predicted FEV1 and FVC, self-reported emphysema and stopping for breath.

CONCLUSION

Low-moderate arsenic exposure was positively associated with restrictive pattern, airflow obstruction, lower lung function, self-reported emphysema and stopping for breath, independent of smoking and other lung disease risk factors. Findings suggest that low-moderate arsenic exposure may contribute to restrictive lung disease.

Rice Consumption and Subclinical Lung Disease in US Adults: Observational Evidence From the Multi-Ethnic Study of Atherosclerosis

Rice accumulates arsenic, an established lung toxicant. Little is known about the association of rice consumption with arsenic-related health effects, particularly interstitial lung disease. Between 2000 and 2002, 6,814 white, black, Hispanic, and Chinese adults from 6 US cities were enrolled in the Multi-Ethnic Study of Atherosclerosis. We included 2,250 participants who had spirometry data, 2,557 with full-lung computed tomography (CT) scans, and 5,710 with cardiac CT scans. Rice consumption and 310 participants with urinary arsenic were assessed at baseline. Spirometry and full-lung CT-derived measures of total lung capacity and high attenuation area (HAA), and interstitial lung abnormalities were measured at examination 5. Cardiac CT-derived HAA was measured at 1-3 visits. Twelve percent of participants reported eating at least 1 serving of rice daily. Comparing data between that group with those who ate less than 1 serving weekly, the mean difference for forced vital capacity was -102 (95% confidence interval (CI): -198, -7) mL, and for forced expiratory volume in 1 second was -90 (95% CI: -170, -11) mL after adjustment for demographics, anthropometrics, dietary factors, and smoking. The cross-sectional adjusted percent difference for total lung capacity was -1.33% (95% CI: -4.29, 1.72) and for cardiac-based HAA was 3.66% (95% CI: 1.22, 6.15). Sensitivity analyses for urinary arsenic were consistent with rice findings. Daily rice consumption was associated with reduced lung function and greater cardiac-based HAA.

A Meta-analysis of Arsenic Exposure and Lung Function: Is There Evidence of Restrictive or Obstructive Lung Disease?

PURPOSE OF REVIEW

Hundreds of millions of people worldwide are exposed to arsenic via contaminated water. The goal of this study was to identify whether arsenic-associated lung function deficits resemble obstructive- or restrictive-like lung disease, in order to help illuminate a mechanistic pathway and identify at-risk populations.

RECENT FINDINGS

We recently published a qualitative systematic review outlining the body of research on arsenic and non-malignant respiratory outcomes. Evidence from several populations, at different life stages, and at different levels of exposure showed consistent associations of arsenic exposure with chronic lung disease mortality, respiratory symptoms, and lower lung function levels. The published review, however, only conducted a broad qualitative description of the published studies without considering specific spirometry patterns, without conducting a meta-analysis, and without evaluating the dose-response relationship. We searched PubMed and Embase for studies on environmental arsenic exposure and lung function. We performed a meta-analysis using inverse-variance-weighted random effects models to summarize adjusted effect estimates for arsenic and forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC ratio. Across nine studies, median water arsenic levels ranged from 23 to 860 μg/L. The pooled estimated mean difference (MD) comparing the highest category of arsenic exposure (ranging from > 11 to > 800 μg/L) versus the lowest (ranging from < 10 to < 100 μg/L) for each study for FEV₁ was - 42 mL (95% confidence interval (CI) - 70, - 16) and for FVC was - 50 mL (95% CI - 63, - 37). Three studies reported effect estimates for FEV₁/FVC, for which there was no evidence of an association; the pooled estimated MD was 0.01 (95% CI - 0.005, 0.024). This review supports that arsenic is associated with restrictive impairments based on inverse associations between arsenic and FEV₁ and FVC, but not with FEV₁/FVC. Future studies should confirm whether low-level arsenic exposure is a restrictive lung disease risk factor in order to identify at-risk populations in the USA.

Ethnic, geographic and dietary differences in arsenic exposure in the multi-ethnic study of atherosclerosis (MESA)

Differences in residential location as well as race/ethnicity and dietary habits may result in differences in inorganic arsenic (iAs) exposure. We investigated the association of exposure to iAs with race/ethnicity, geography, and dietary intake in a random sample of 310 White, Black, Hispanic, and Chinese adults in the Multi-Ethnic Study of Atherosclerosis from 6 US cities with inorganic and methylated arsenic (ΣAs) measured in urine. Dietary intake was assessed by food-frequency questionnaire. Chinese and Hispanic race/ethnicity was associated with 82% (95% CI: 46%, 126%) and 37% (95% CI: 10%, 70%) higher urine arsenic concentrations, respectively, compared to White participants. No differences were observed for Black participants compared to Whites. Urine arsenic concentrations were higher for participants in Los Angeles, Chicago, and New York compared to other sites. Participants that ate rice ≥2 times/week had 31% higher urine arsenic compared to those that rarely/never consumed rice. Participants that drank wine ≥2 times/week had 23% higher urine arsenic compared to rare/never wine drinkers. Intake of poultry or non-rice grains was not associated with urinary arsenic concentrations. At the low-moderate levels typical of the US population, exposure to iAs differed by race/ethnicity, geographic location, and frequency of rice and wine intake.

Urinary metals and metal mixtures in Bangladesh: Exploring environmental sources in the Health Effects of Arsenic Longitudinal Study (HEALS)

INTRODUCTION

Environmental exposure to toxic metals and metalloids is pervasive and occurs from multiple sources. The Health Effects of Arsenic Longitudinal Study (HEALS) is an ongoing prospective study predominantly focused on understanding health effects associated with arsenic exposure from drinking water. The goal of this project was to measure a suite of elements in urine to better understand potential exposure patterns and to identify common environmental sources of exposure among this semi-rural Bangladeshi population.

METHODS

In a random sample of 199 adult HEALS participants (50% female), the concentrations of 15 urinary elements (As, Ba, Cd, Co, Cs, Cu, Mn, Mo, Ni, Pb, Se, Sr, Tl, W, Zn) were assessed by Inductively-Coupled Plasma Mass Spectrometry (ICP-MS) to assess commonalities with sociodemographic characteristics and potential sources of exposure. We used principal component analysis (PCA) with varimax normalized rotations, and hierarchical cluster analysis (CA), using Ward's method with Euclidean distances, to evaluate these relationships.

RESULTS

PCA and CA showed similar patterns, suggesting 6 principal components (PC) and 5 clusters: 1)PC: Sr-Ni-Cs/ CA: Sr-Ni-Co; 2) Pb-Tl/Pb-Tl-Se-Cs; 3) As-Mo-W/As-Mo-W; 4) Ba-Mn/Ba-Mn; 5) Cu-Zn/Cu-Zn-Cd; and 6) Cd. There was a strong significant association between the As-Mo-W PC/cluster and water arsenic levels (p < 0.001) and between the Cd PC and betel nut use (p = 0.003). The Sr-Ni-Cs PC was not related to any of the socio-demographic characteristics investigated, including smoking status and occupation. The first PC, Sr-Ni-Cs, explained 21% of the variability; the third PC, As-Mo-W, explained 12.5% of the variability; and the sixth PC, Cd, explained 10% of the variability. Day laborers appeared to have the highest exposure.

CONCLUSIONS

Groundwater and betel nut use are likely important sources of metal and metalloid exposure in this population. These findings will guide future exposure assessment research in Bangladesh and future epidemiologic research investigating the degree to which metal mixtures play a role in disease development.

The effect of the Environmental Protection Agency maximum contaminant level on arsenic exposure in the USA from 2003 to 2014: an analysis of the National Health and Nutrition Examination Survey (NHANES)

Background

The current US Environmental Protection Agency (EPA) maximum contaminant level (MCL) for arsenic in public water systems (10 µg/L) took effect in 2006. Arsenic is not federally regulated in private wells. The impact of the 2006 MCL on arsenic exposure in the US, as confirmed through biomarkers, is presently unknown. We evaluated national trends in water arsenic exposure in the US, hypothesizing that urinary arsenic levels would decrease over time among participants using public water systems but not among those using well water. We further estimated the expected number of avoided lung, bladder, and skin cancer cases.

Methods

We evaluated 14,127 participants in the National Health and Nutrition Examination Survey (NHANES) 2003–2014 with urinary dimethylarsinate (DMA) and total arsenic available. To isolate water exposure, we expanded a residual-based method to remove tobacco and dietary contributions of arsenic. We applied EPA risk assessment approaches to estimate the expected annual number of avoided cancer cases comparing arsenic exposure in 2013–2014 vs. 2003–2004.

Findings

Among public water users, fully adjusted geometric means (GMs) of DMA decreased from 3.01 µg/L in 2003–2004 to 2.49 µg/L in 2013–2014 (17% reduction; 95% confidence interval 10%, 24%; p-trend<0.01); no change was observed among well water users (p-trend= 0.35). Assuming these estimated exposure reductions will remain similar across a lifetime, we estimate a reduction of 200 to 900 lung and bladder cancer cases per year depending on the approach used.

Interpretation

The decline in urinary arsenic among public water but not private well users in NHANES 2003–2014 indicates that the implementation of the current MCL has reduced arsenic exposure in the US population. Our study supports prior work showing that well water users are inadequately protected against drinking water arsenic, and confirms the critical role of federal drinking water regulations in reducing toxic exposures and protecting human health.

Funding

This work was supported by the National Institute of Environmental Health Sciences (1R01ES025216, R01ES021367, 5P30ES009089 and P42ES010349). A. E. Nigra was supported by 5T32ES007322.

Provision of well-water treatment units to 600 households in Bangladesh: A longitudinal analysis of urinary arsenic indicates fading utility

BACKGROUND

Millions of villagers in Bangladesh remain exposed to high levels of arsenic (As) from drinking untreated well-water even though the scale of the problem was recognized 15years ago. Water treatment at the household-level has been promoted as a viable complement but few longitudinal studies of their efficacy using an objective measure of exposure have been conducted. Participants (N=622) of a nutrition trial in Araihazar, Bangladesh were each provided with READ-F filters at the beginning of the study and encouraged to use them over the 6month duration of the intervention. Well-water As, treated water As, and urinary As were monitored periodically during the trial and measured again one year after the trial ended.

RESULTS

The READ-F filters were initially well received and median urinary As levels for participants declined from 117μg/L to 51μg/L within a single week. However, median urinary As levels gradually rose back to 126μg/L by the end of the trial. Fifty filters were replaced over the course of the trial because of insufficient As removal or reduced flow. With these exceptions, most of the treated water met the WHO guideline for As in drinking water of 10μg/L. One year after the nutritional trial ended, 95% of participants had abandoned their filter citing inconvenience as the primary reason. At that time, median urinary As levels for 10 participants who had switched to a nearby low-As well had declined to 63μg/L.

CONCLUSIONS

Participants were probably no longer using the READ-F filter long before the 6month nutritional intervention ended despite claiming that they were using them. Household-level treatment is likely to continue to play a minor role in the effort to reduce As exposure in Bangladesh. Understanding the limitations of such expensive interventions is important for future policy regarding As mitigation.

Inorganic arsenic and respiratory health, from early life exposure to sex-specific effects: A systematic review

This systematic review synthesizes the diverse body of epidemiologic research accrued on inorganic arsenic exposure and respiratory health effects. Twenty-nine articles were identified that examined the relationship between inorganic arsenic exposure and respiratory outcomes (i.e. lung function, symptoms, acute respiratory infections, chronic non-malignant lung diseases, and non-malignant lung disease mortality). There was strong evidence of a general association between arsenic and non-malignant respiratory illness, including consistent evidence on lung function impairment, acute respiratory tract infections, respiratory symptoms, and non-malignant lung disease mortality. Overall, early life exposure (i.e. in utero and/or early-childhood) had a marked effect throughout the lifespan. This review also identified some research gaps, including limited evidence at lower levels of exposure (water arsenic <100μg/L), mixed evidence of sex differences, and some uncertainty on arsenic and any single non-malignant respiratory disease or pathological process. Common limitations, including potential publication bias; non-comparability of outcome measures across included articles; incomplete exposure histories; and limited confounder control attenuated the cumulative strength of the evidence as it relates to US populations. This systematic review provides a comprehensive assessment of the epidemiologic evidence and should be used to guide future research on arsenic's detrimental effects on respiratory health.

Folic Acid and Creatine as Therapeutic Approaches to Lower Blood Arsenic: A Randomized Controlled Trial

BACKGROUND

The World Health Organization estimates that > 140 million people worldwide are exposed to arsenic (As)-contaminated drinking water. As undergoes biologic methylation, which facilitates renal As elimination. In folate-deficient individuals, this process is augmented by folic acid (FA) supplementation, thereby lowering blood As (bAs). Creatinine concentrations in urine are a robust predictor of As methylation patterns. Although the reasons for this are unclear, creatine synthesis is a major consumer of methyl donors, and this synthesis is down-regulated by dietary/supplemental creatine.

OBJECTIVES

Our aim was to determine whether 400 or 800 μg FA and/or creatine supplementation lowers bAs in an As-exposed Bangladeshi population.

METHODS

We conducted a clinical trial in which 622 participants were randomized to receive 400 μg FA, 800 μg FA, 3 g creatine, 3 g creatine+400 μg FA, or placebo daily. All participants received an As-removal filter on enrollment, and were followed for 24 weeks. After the 12th week, half of the two FA groups were switched to placebo to evaluate post-treatment bAs patterns.

RESULTS

Linear models with repeated measures indicated that the decline in ln(bAs) from baseline in the 800-μg FA group exceeded that of the placebo group (weeks 1-12: β= -0.09, 95% CI: -0.18, -0.01; weeks 13-24: FA continued: β= -0.12, 95% CI: -0.24, -0.00; FA switched to placebo: β= -0.14, 95% CI: -0.26, -0.02). There was no rebound in bAs related to cessation of FA supplementation. Declines in bAs observed in the remaining treatment arms were not significantly different from those of the placebo group.

CONCLUSIONS

In this mixed folate-deficient/replete study population, 12- and 24-week treatment with 800 μg (but not 400 μg) FA lowered bAs to a greater extent than placebo; this was sustained 12 weeks after FA cessation. In future studies, we will evaluate whether FA and/or creatine altered As methylation profiles.

A cross-sectional study of exhaled carbon monoxide as a biomarker of recent household air pollution exposure

RATIONALE

Household air pollution causes 3.5 million deaths annually. Personal exposure assessments required for examining health associations are expensive and require technical expertize, limiting the quality of research in resource-poor settings

OBJECTIVES

To assess the feasibility of exhaled carbon monoxide and its relationship to continuous personal carbon monoxide monitoring and markers of respiratory health in female cooks primarily cooking with biomass fuels in Araihazar, Bangladesh METHODS AND MEASURE: For a 24-h period, exhaled carboxyhemoglobin (eCOHb) % saturation was measured before and after each cooking episode while simultaneous 24-h personal carbon monoxide monitoring was conducted. The Coburn-Forester-Kane (CFK) equation was used to convert continuous personal CO exposures to predicted COHb % saturation. Respiratory symptoms were assessed by St. George's Respiratory Questionnaire, airway inflammation measured by exhaled breath condensate pH, and lung function determined by spirometry. Spearman's correlation was used to examine the relationship between eCOHb and CKF-derived COHb, EBC pH, and lung function variables. eCOHb % saturation was dichotomized around the median and odds ratios calculated for each respiratory symptom

MAIN RESULTS

Measurement of eCOHb % saturation is feasible in a resource-poor setting. eCOHb % saturation responds to cooking episodes and demonstrates consistency when measured at the same time point 24-h later, suggesting that eCOHb may be a sensitive biomarker of recent HAP exposures.

The delivery of culturally sensitive health care to Native Americans

Cultural factors significantly influence the Native American's perspectives of traditional professional health care practices. To most effectively deal with Native American clients, health care providers must understand, respect, and demonstrate sensitivity to the values and implications of the Native American culture. A basic understanding of a group's cultural beliefs, values, and practices will enable the holistic nurse to appreciate the importance of appropriate interactions and techniques and, therefore, make health care more readily accepted. This article reviews the health and illness beliefs, the traditional remedies, the critical need for holistic health care, and the Five Great Values that guide Native American behavior. Familiarization with these cultural components will facilitate the provision of quality, holistic health care through improved interactions with Native American clients.

Cultural aspects of caring for Navajo Indian clients

Cultural factors significantly influence the Navajo's interactive processes as well as perceptions of health and illness. Unfortunately, very limited published information is available about the problems that may occur when health care practitioners ignore the influence of culture. The interactive processes are made even more complex when health care providers have cultural expectations that are different from those held by their patients. The article reviews some of the complex factors (i.e., family structure, health/illness beliefs, traditional remedies, and cultural practitioners) that influence the Navajo's decision to seek, accept, or reject the assistance of professional health care providers. In addition, some implications, strategies, and suggestions are included that may assist the nurse in improving the quality of care provided to the Navajo patient.