Persistent and Changing Food Insecurity Among Students at a Midwestern University is Associated With Behavioral and Mental Health Outcomes.

PURPOSE: To assess associations between persistent and changing food insecurity and behavioral and mental health outcomes in college students. DESIGN: Online surveys conducted November 2018 and March 2019 (freshman year), and March 2020 (sophomore year) were used to assess food insecurity, which was then used to create 4 food security transitions: persistent food insecurity, emergent food insecurity, emergent food security, and persistent food security. SETTING: Large Midwestern university. SAMPLE: 593 students completing all 3 surveys. MEASURES: Dietary intake and behavioral and mental health outcomes (eating disorders, anxiety, depression, sleep quality) were assessed using validated instruments. ANALYSIS: Associations between food security transitions and dietary intake, behavioral, and mental health outcomes were examined using generalized linear models. RESULTS: Compared to persistent food security, emergent and persistent food insecurity was associated with lower (7% and 13% respectively) intake of fruits and vegetables combined; persistent food insecurity was associated with 17% lower intake of fruits, 6% lower intake of fiber and 10% higher intake of added sugar from beverages. Compared to persistent food secure students, eating disorder symptom risk was higher for emergent food insecure (OR = 7.61, 95% CI: 3.32, 17.48), and persistent food insecure (OR = 6.60, 95% CI: 2.60, 16.72) students; emergent (OR = 2.05, 95% CI: 1.14, 3.71) and persistent (OR = 2.55, 95% CI: 1.34, 4.87) food insecure students had higher odds of poor sleep quality, and persistent food insecure, emergent food insecure, and emergent food secure students had higher odds of anxiety and depression (OR range 2.35-2.85). CONCLUSION: Food security transitions were associated with aspects of low diet quality and poorer behavioral and mental health outcomes among college students.

Environmental-, Climate-, and Health-Related Dietary Motivations Are Associated With Higher Diet Quality in a National Sample of US Adults With Lower Incomes.

BACKGROUND: Plant-based diets can have co-benefits for human and planetary health. Associations between environmental, climate, and health concerns and dietary intake in US adults are understudied, particularly in underserved populations. OBJECTIVE: The study objectives were to assess how dietary choices motivated by the environment, climate, and health vary by sociodemographic characteristics and how they relate to diet quality and intake frequency of different food groups in US adults with lower incomes. DESIGN: The study design was cross-sectional. PARTICIPANTS/SETTING: A web-based survey was fielded in December 2022 to 1,798 US adults with lower incomes (<250% of federal poverty guidelines). MAIN OUTCOME MEASURES: Environmental-, climate-, and health-related dietary motivations and diet quality and dietary food group intake frequency were assessed. STATISTICAL ANALYSES: Differences in mean dietary outcomes and dietary motivation ratings by sociodemographic characteristics were evaluated using analysis of variance and Kruskal-Wallis tests. Associations between dietary motivations and diet quality scores and dietary intake frequency were examined using generalized linear models adjusted for sociodemographic covariates. RESULTS: Younger adults, women, nonbinary people, racial and ethnic minoritized groups, and adults experiencing food insecurity reported higher environmental and climate dietary motivations; older adults, higher-income adults, and food-secure adults reported higher health motivations. Agreeing with environmental- (ß = 2.28, 95% CI 1.09 to 3.47), climate- (ß = 2.15, 95% CI 0.90 to 3.40), and health-related (ß = 5.27, 95% CI 3.98 to 6.56) dietary motivations was associated with higher diet quality scores compared with those with neutral rankings. Similarly, agreement with environmental-, climate-, and health-related dietary motivations was associated with higher intake frequency of fish, fruits and vegetables, and plant proteins, but not with red and processed meat intake frequency. Of several climate-mitigation behaviors presented, participants perceived meat reduction as least effective (P < .001). CONCLUSIONS: Environment, climate, and health were positive motivators of several healthy dietary choices in US adults with lower incomes. Such motivators did not translate to lower intake frequency of red and processed meat.

Water Insecurity Indicators Are Associated with Lower Diet and Beverage Quality in a National Survey of Lower-Income United States Adults.

BACKGROUND: Tap water distrust and avoidance, indicators of water insecurity, are prevalent in marginalized United States populations. As future environmental challenges stress water resources, further understanding of the scope of water insecurity and its impact on diet quality is needed, particularly in vulnerable United States populations. OBJECTIVES: To evaluate associations between 3 potential indicators of water insecurity-1) perception of tap water safety for drinking, 2) perception of tap water safety for cooking, and 3) tap water avoidance-and dietary quality and beverage intake in lower-income United States adults. METHODS: A cross-sectional, web-based survey was fielded to 1798 lower-income (<250% federal poverty guidelines) United States adults. Participants answered questions detailing tap water safety perceptions and avoidance, beverage intake, dietary intake (30-d prime diet quality score), and sociodemographic covariates. Sociodemographic differences in drinking water insecurity measures were evaluated using chi-square and Fisher-Freeman-Halton tests. Associations between water insecurity measures and dietary outcomes were assessed using generalized linear models adjusted for sociodemographic covariates, and effect modification by sociodemographic covariates was assessed. RESULTS: Over half of the adults surveyed experienced some aspect of water insecurity. Measures of water security differed significantly by sociodemographic covariates (Ps < 0.05), with higher percentages of women and gender-nonconforming persons, minoritized racial and ethnic groups, lower-income groups, and food-insecure adults reporting indicators of water insecurity. Presence of any water insecurity was associated with lower diet quality (ß = -1.07; 95% CI: -2.11, -0.03; P = 0.04), lower tap water intake (relative difference [RD] = 0.35; 95% CI: 1.28, 2.12; P < 0.0001), higher bottled water intake (RD = 1.64; 95% CI: 1.28, 2.12; P = 0.0001), and higher sugar-sweetened beverages intake frequency (frequency ratio = 1.13; 95% CI: 1.01, 1.27; P = 0.03). CONCLUSIONS: Water insecurity indicators are associated with poorer diet quality and beverage intake in a population of United States adults with lower-incomes. Addressing the intersection of water insecurity, food security, environmental impacts, and nutrition may help to improve the well-being and resiliency of vulnerable populations.

Tap water perceptions and water filter use vary with socio-demographic characteristics and are associated with water and sugar-sweetened beverage consumption in university students.

OBJECTIVE: The goal of this study is to evaluate university students' perceptions of tap water safety and water filter use and determine how these perceptions and behaviours affect water and sugar-sweetened beverage intake. DESIGN: Cross-sectional; online survey conducted in Fall 2021. SETTING: A large, public Midwestern university in the USA. PARTICIPANTS: Seven-hundred ninety-three university students. RESULTS: Students who experienced food insecurity, were on a Pell grant, were first-generation college students or were racial/ethnic minorities were less likely to trust tap water safety. Tap water filtration behaviour also varied by age and race/ethnicity. Students who did not agree with the statement 'my local tap water is safe to drink' had lower odds of consuming ≥ 3 cups of total water per day (OR = 0·45, 95 % CI: 0·32, 0·62), lower odds of consuming tap water ≥ 3 times/d (OR = 0·46, 95 % CI: 0·34, 0·64), higher odds of drinking bottled water ≥ 1 time per day (OR = 1·80, 95 % CI: 1·22, 2·66) and higher odds of drinking SSB ≥ 1 time per day (OR = 1·47, 95 % CI: 1·01, 2·14) than those who agreed. Students who always or sometimes filtered their tap water had lower odds of consuming ≥ 3 cups of total water per day (OR = 0·59, 95 % CI: 0·39, 0·90) than students who never filtered their tap water. CONCLUSIONS: Tap water perceptions and behaviours affect tap and bottled water and SSB intake among university students. Tap water perceptions and behaviours in this demographic provide important context for university programming promoting healthy beverage initiatives.

Environmental and Climate Impact Perceptions in University Students: Sustainability Motivations and Perceptions Correspond With Lower Red Meat Intake.

BACKGROUND: Red meat production is a leading contributor to food-related greenhouse gas emissions. Decreasing red meat intake can mitigate climate change and lower risk of diet-related diseases. OBJECTIVE: The goal of this study is to evaluate university students' perceptions of climate-friendly behaviors and to assess how these perceptions are associated with the frequency of red meat intake. DESIGN: Cross-sectional survey SETTING: A large, public California university and a large, public Michigan university PARTICIPANTS: Undergraduate students from a California university (n = 721) and a Michigan university (n = 568) MAIN OUTCOME MEASURES: Perceptions of climate-friendly behaviors and frequency of red meat intake STATISTICAL ANALYSIS: Differences in perceptions by student characteristics were compared using t-tests and one-way analysis of variance. Associations between perceptions of climate-friendly behaviors and red meat intake frequency were examined using generalized linear models, adjusted for sociodemographic covariates. RESULTS: Across both universities, students rated reducing meat intake as less effective than other climate change mitigation behaviors such as recycling and using less plastic. However, students who reported (1) making food and beverage choices that "are good for the environment," (2) making food and beverage choices that "reduce climate change impact," or (3) agreeing that "eating less meat is an effective way to combat climate change" reported 10% to 25% lower frequency of red meat intake for each point higher on the agreement scale. In contrast, making food and beverage choices motivated by health was not associated with frequency of red meat intake. CONCLUSIONS: Sustainability motivations and perceptions of meat's climate impact were associated with lower frequency of red meat intake, despite the overall moderate rating of eating less meat as an effective climate change mitigator. This research lends support to behavioral interventions, public education campaigns, and policies aiming to reinforce sustainable dietary patterns in young adults.

Food Insecurity and Food Addiction in a Large, National Sample of Lower-Income Adults.

Background: Growing research has highlighted associations between food insecurity and eating-related problems. Food addiction is one important, clinically significant pattern of problematic eating, which is related to, but distinct from, eating disorders. To date, there is only one study examining the association between food insecurity and food addiction, to our knowledge. Additional research is needed to understand the complexities of this association. Objective: We examined the association between food insecurity and food addiction in a large, national convenience sample of lower-income adults and potential heterogeneity in this association by age, gender, race, and ethnicity. Design: A cross-sectional, web-based study was conducted among 1780 US adults (≥18 y) with household incomes <250% of the federal poverty guideline. Household food security was assessed using the Household Food Security Survey Module. Food addiction was assessed using the modified Yale Food Addiction Scale (mYFAS), version 2.0. Multivariate logistic regression models examined the associations between food insecurity and food addiction, adjusting for sociodemographic covariates. Results: The prevalence of food addiction was 7.3%, and the prevalence of food insecurity was 51%. Compared with adults with food security, adults with food insecurity endorsed each mYFAS symptom with significantly greater frequency, including failure to fulfill major role obligations (20%), continued use despite social or interpersonal problems (18%), and craving or strong desire to use (16%). After adjustment, food insecurity was associated with 3.82-fold higher odds of food addiction (95% CI 2.36, 6.19), with no significant heterogeneity by age, gender, or race and ethnicity. The most problematic foods reported by adults with food insecurity were chips, nondiet soda, chocolate, pizza, and ice cream. Conclusion: These findings provide additional support for the association between food insecurity and food addiction. Mechanistic studies are needed to explore the role of psychosocial factors, eating behaviors, and the food environment in contributing to these associations.

Urinary arsenic species, toenail arsenic, and arsenic intake estimates in a Michigan population with low levels of arsenic in drinking water.

The large disparity between arsenic concentrations in drinking water and urine remains unexplained. This study aims to evaluate predictors of urinary arsenic in a population exposed to low concentrations (≤50 µg/l) of arsenic in drinking water. Urine and drinking water samples were collected from a subsample (n=343) of a population enrolled in a bladder cancer case-control study in southeastern Michigan. Total arsenic in water and arsenic species in urine were determined using ICP-MS: arsenobetaine (AsB), arsenite (As[III]), arsenate (As[V]), methylarsenic acid (MMA[V]), and dimethylarsenic acid (DMA[V]). The sum of As[III], As[V], MMA[V], and DMA[V] was denoted as SumAs. Dietary information was obtained through a self-reported food intake questionnaire. Log(10)-transformed drinking water arsenic concentration at home was a significant (P<0.0001) predictor of SumAs (R(2)=0.18). Associations improved (R(2)=0.29, P<0.0001) when individuals with less than 1 µg/l of arsenic in drinking water were removed and further improved when analyses were applied to individuals who consumed amounts of home drinking water above the median volume (R(2)=0.40, P<0.0001). A separate analysis indicated that AsB and DMA[V] were significantly correlated with fish and shellfish consumption, which may suggest that seafood intake influences DMA[V] excretion. The Spearman correlation between arsenic concentration in toenails and SumAs was 0.36 and between arsenic concentration in toenails and arsenic concentration in water was 0.42. Results show that arsenic exposure from drinking water consumption is an important determinant of urinary arsenic concentrations, even in a population exposed to relatively low levels of arsenic in drinking water, and suggest that seafood intake may influence urinary DMA[V] concentrations.

Accuracy of commercially available residential histories for epidemiologic studies.

A key problem facing epidemiologists who wish to account for residential mobility in their analyses is the cost and difficulty of obtaining residential histories. Commercial residential history data of acceptable accuracy, cost, and coverage would be of great value. The present research evaluated the accuracy of residential histories from LexisNexis, Inc. The authors chose LexisNexis because the Michigan Cancer Registry has considered using their data, they have excellent procedures for privacy protection, and they make available residential histories at 25 cents per person. Only first and last name and address at last-known residence are required to access the residential history. The authors compared lifetime residential histories collected through the use of written surveys in a case-control study of bladder cancer in Michigan to the 3 residential addresses routinely available in the address history from LexisNexis. The LexisNexis address matches, as a whole, accounted for 71.5% of participants' lifetime addresses. These results provided a level of accuracy that indicates routine use of residential histories from commercial vendors is feasible. More detailed residential histories are available at a higher cost but were not analyzed in this study. Although higher accuracy is desirable, LexisNexis data are a vast improvement over the assumption of immobile individuals currently used in many spatial and spatiotemporal studies.

Lifetime exposure to arsenic in drinking water and bladder cancer: a population-based case-control study in Michigan, USA.

OBJECTIVE: Arsenic in drinking water has been linked with the risk of urinary bladder cancer, but the dose-response relationships for arsenic exposures below 100 microg/L remain equivocal. We conducted a population-based case-control study in southeastern Michigan, USA, where approximately 230,000 people were exposed to arsenic concentrations between 10 and 100 microg/L. METHODS: This study included 411 bladder cancer cases diagnosed between 2000 and 2004, and 566 controls recruited during the same period. Individual lifetime exposure profiles were reconstructed, and residential water source histories, water consumption practices, and water arsenic measurements or modeled estimates were determined at all residences. Arsenic exposure was estimated for 99% of participants' person-years. RESULTS: Overall, an increase in bladder cancer risk was not found for time-weighted average lifetime arsenic exposure >10 microg/L when compared with a reference group exposed to <1 microg/L (odds ratio (OR) = 1.10; 95% confidence interval (CI): 0.65, 1.86). Among ever-smokers, risks from arsenic exposure >10 microg/L were similarly not elevated when compared to the reference group (OR = 0.94; 95% CI: 0.50, 1.78). CONCLUSIONS: We did not find persuasive evidence of an association between low-level arsenic exposure and bladder cancer. Selecting the appropriate exposure metric needs to be thoughtfully considered when investigating risk from low-level arsenic exposure.

Influence of groundwater recharge and well characteristics on dissolved arsenic concentrations in southeastern Michigan groundwater.

Arsenic concentrations exceeding 10 microg/l, the United States maximum contaminant level and the World Health Organization guideline value, are frequently reported in groundwater from bedrock and unconsolidated aquifers of southeastern Michigan. Although arsenic-bearing minerals (including arsenian pyrite and oxide/hydroxide phases) have been identified in Marshall Sandstone bedrock of the Mississippian aquifer system and in tills of the unconsolidated aquifer system, mechanisms responsible for arsenic mobilization and subsequent transport in groundwater are equivocal. Recent evidence has begun to suggest that groundwater recharge and characteristics of well construction may affect arsenic mobilization and transport. Therefore, we investigated the relationship between dissolved arsenic concentrations, reported groundwater recharge rates, well construction characteristics, and geology in unconsolidated and bedrock aquifers. Results of multiple linear regression analyses indicate that arsenic contamination is more prevalent in bedrock wells that are cased in proximity to the bedrock-unconsolidated interface; no other factors were associated with arsenic contamination in water drawn from bedrock or unconsolidated aquifers. Conditions appropriate for arsenic mobilization may be found along the bedrock-unconsolidated interface, including changes in reduction/oxidation potential and enhanced biogeochemical activity because of differences between geologic strata. These results are valuable for understanding arsenic mobilization and guiding well construction practices in southeastern Michigan, and may also provide insights for other regions faced with groundwater arsenic contamination.

Effects of nutritional measures on toenail arsenic concentration as a biomarker of arsenic exposure.

Correlations between drinking water and toenail arsenic concentrations have been demonstrated in previous studies, yet factors that may modify the exposure-biomarker association have not been adequately assessed. Using data from 500 controls enrolled in a bladder cancer study underway in Michigan, USA, the effects of demographic characteristics and nutritional measures on the biomarker response were evaluated. Drinking water and toenail samples were collected during a home visit and analyzed for arsenic and other elements. Participants reported dietary supplement intake habits and provided demographic data. Arsenic concentrations of drinking water and toenail samples were positively correlated. Of the nutritional measures evaluated, toenail iron concentration was a significant modifier of the exposure-biomarker association. No demographic characteristics or general measures of dietary intake affected the biomarker response. The results presented herein are critical for biomarker validation and prove promising for sound application of the arsenic toenail biomarker to future epidemiological investigations.

Intra-individual variability in toenail arsenic concentrations in a Michigan population, USA.

Arsenic concentration in toenail clippings is used as a biomarker of exposure in epidemiological studies, often under the assumption that a single measurement represents long-term exposure. For this assumption to hold, the measured arsenic concentrations must be stable over time, yet temporal variability has not been adequately assessed. This study aims to evaluate temporal variability in multiple toenail samples collected from a population exposed to drinking water arsenic levels <100 microg/l. Our objectives are to investigate factors responsible for biomarker variability and to assess the suitability of single versus multiple measurements for determining exposure in epidemiological studies. Multiple toenail and drinking water samples were collected from 254 participants enrolled in a case-control study of arsenic exposure and bladder cancer in Michigan, USA; participants also answered questions on water consumption. Toenail samples collected an average of 14 months apart were positively correlated, although a substantial amount of variability was detected (r=0.43, P<0.0001, n=236). Arsenic concentration in drinking water was stable and small changes in drinking water arsenic concentration did not explain variability in toenail arsenic concentration. Change in drinking water consumption, however, was significant in predicting differences in toenail arsenic concentration. Stronger correlations between drinking water arsenic concentration and intake and toenail arsenic concentration were observed when two toenail samples were averaged, suggesting that multiple measurements may more accurately reflect exposure. When exposure was categorized into tertiles and other pre-determined categories, 25-40% of exposures were differentially classified. Only a small percentage (<4%), however, were classified as having low exposure using a single measurement and high exposure when an average of two measurements was used. These results suggest that the use of multiple measurements is unlikely to affect exposure classification of individuals into high- or low-exposure groups; however, collection of multiple samples may be advantageous for more refined exposure classification.

Validity of spatial models of arsenic concentrations in private well water.

OBJECTIVE: Arsenic is a pervasive contaminant in underground aquifers worldwide, yet documentation of health effects associated with low-to-moderate concentrations (<100microg/L) has been stymied by uncertainties in assessing long-term exposure. A critical component of assessing exposure to arsenic in drinking water is the development of models for predicting arsenic concentrations in private well water in the past; however, these models are seldom validated. The objective of this paper is to validate alternative spatial models of arsenic concentrations in private well water in southeastern Michigan. METHODS: From 1993 to 2002, the Michigan Department of Environmental Quality analyzed arsenic concentrations in water from 6050 private wells. This dataset was used to develop several spatial models of arsenic concentrations in well water: proxy wells based on nearest-neighbor relationships, averages across geographic regions, and geostatistically derived estimates based on spatial correlation and geologic factors. Output from these models was validated using arsenic concentrations measured in 371 private wells from 2003 to 2006. RESULTS: The geostatisical model and nearest-neighbor approach outperformed the models based on geographic averages. The geostatistical model produced the highest degree of correlation using continuous data (Pearson's r=0.61; Spearman's rank rho=0.46) while the nearest-neighbor approach produced the strongest correlation (kappa(weighted)=0.58) using an a priori categorization of arsenic concentrations (<5, 5-9.99, 10-19.99, > or = 20microg/L). When the maximum contaminant level was used as a cut-off in a two-category classification (<10, > or =10microg/L), the nearest-neighbor approach and geostatistical model had similar values for sensitivity (0.62-0.63), specificity (0.80), negative predictive value (0.85), positive predictive value (0.53), and percent agreement (75%). DISCUSSION: This validation study reveals that geostatistical modeling and nearest-neighbor approaches are effective spatial models for predicting arsenic concentrations in private well water. Further validation analyses in other regions are necessary to indicate how widely these findings may be generalized.

Toenails as a biomarker of inorganic arsenic intake from drinking water and foods.

Toenails were used recently in epidemiological and environmental health studies as a means of assessing exposure to arsenic from drinking water. While positive correlations between toenail and drinking-water arsenic concentrations were reported in the literature, a significant percentage of the variation in toenail arsenic concentration remains unexplained by drinking-water concentration alone. Here, the influence of water consumption at home and work, food intake, and drinking-water concentration on toenail arsenic concentration was investigated using data from a case-control study being conducted in 11 counties of Michigan. The results from 440 controls are presented. Log-transformed drinking-water arsenic concentration at home was a significant predictor (p < .05) of toenail arsenic concentration (R2 = .32). When arsenic intake from consumption of tap water and beverages made from tap water (microg/L arsenic x L/d = microg/d) was used as a predictor variable, the correlation was markedly increased for individuals with >1 microg/L arsenic (R2 = .48). Increased intake of seafood and intake of arsenic from water at work were independently and significantly associated with increased toenail arsenic concentration. However, when added to intake at home, work drinking-water exposure and food intake had little influence on the overall correlation. These results suggest that arsenic exposure from drinking-water consumption is an important determinant of toenail arsenic concentration, and therefore should be considered when validating and applying toenails as a biomarker of arsenic exposure.

Individual lifetime exposure to inorganic arsenic using a space-time information system.

OBJECTIVES: A space-time information system (STIS) based method is introduced for calculating individual-level estimates of inorganic arsenic exposure over the adult life-course. STIS enables visualization and analysis of space-time data, overcoming some of the constraints inherent to spatial-only Geographic Information System software. The power of this new methodology is demonstrated using data from southeastern Michigan where 8% of the population is exposed to arsenic >10 microg/l (the World Health Organization guideline) in home drinking water. METHODS: Participants (N=440) are members of a control group in a population-based bladder cancer case-control study in southeastern Michigan and were recruited by phone using random digit dialing. Water samples were collected and analyzed for arsenic at current residence and participants were required to answer questions concerning lifetime mobility history and dietary habits. Inorganic arsenic concentrations were estimated at past residences and workplaces, and in select foods. Fluid and food consumption data were integrated with mobility histories and arsenic concentrations to calculate continuous estimates of inorganic arsenic intake over the adult life-course. RESULTS: Estimates of continuous arsenic exposure are displayed, making use of both participant age and calendar year as measures of time. Results illustrate considerable temporal variability in individual-level exposure, with 26% of the participants experiencing a change in drinking water arsenic concentration of at least +/-10 microg/l over their adult lives. The average cumulative intake over the adult life-course ranges from 2.53 x 10(4)-1.30 x 10(5) microg, depending on the selected exposure metric. CONCLUSIONS: The STIS-based exposure assessment method allows for flexible inclusion of different parameters or alternative formulations of those parameters, thus enabling the calculation of different exposure metrics. This flexibility is particularly useful when additional exposure routes are considered, input datasets are updated, or when a scientific consensus does not exist regarding the proper formulation of the exposure metric. These results demonstrate the potential of STIS as a useful tool for calculating continuous estimates of adult lifetime exposure to arsenic or other environmental contaminants for application in exposure and risk assessment.

Effects of time and point-of-use devices on arsenic levels in Southeastern Michigan drinking water, USA.

Health effects associated with chronic, low-level exposures to arsenic in drinking water (<100 microg/L) remain unclear, in part due to uncertainties in assessing exposure. Drinking water concentrations have been used to assess past exposure to arsenic in epidemiological studies, under the assumption that a single measurement can be used to estimate historical exposure. This study aims to better understand (1) temporal variability in arsenic concentrations in drinking water and (2) the impact of point-of-use (POU) treatment devices on arsenic exposure measurements, and on reliability of the exposure measurement for population-level studies. Multiple drinking water samples were collected at two points in time (an average of fourteen months apart) for 261 individuals enrolled in a case-control study of arsenic exposure and bladder cancer in Michigan. Sources of drinking water included private wells (n = 221), public water supplies (n = 33), and bottled water (n = 7); mean arsenic concentration was highest in private wells (7.28 microg/L) and lowest in bottled water samples (0.28 microg/L). Arsenic concentrations in primary drinking water samples were highly correlated (r = 0.88, p < 0.0001, n = 196), with 3% of the water sources exceeding the United States Environmental Protection Agency's Maximum Contaminant Level (MCL) in one sample but not in the other sample. Measurement reproducibility did not vary by type of POU device (e.g., softener, filter, reverse osmosis system). Arsenic concentrations did differ, however, between samples treated with POU devices and untreated samples taken on the same day. Substantial differences in arsenic concentrations were consistently observed for reverse osmosis systems; other POU devices had variable effects on arsenic concentrations. These results indicate that while a single residential arsenic measurement may be used to represent exposure in this region, researchers must obtain information on changes in water source and POU treatment devices to better characterize population exposures over time.

Major contributors to inorganic arsenic intake in southeastern Michigan.

Accurate estimates of inorganic arsenic intake are critical for evaluating potential health risks. Intake estimates have not been critically examined in regions of the United States where people are at risk from arsenic concentrations in drinking water exceeding the maximum contaminant limit of 10 microg/l. In southeastern Michigan, approximately 8% of the population is exposed to arsenic in drinking water >10 microg/l. Four hundred and forty participants of a control group in this region, frequency matched to cases in a population-based bladder cancer case-control study, answered a questionnaire about water and food consumption and smoking history. Water samples were collected from participants' current residences and analyzed for arsenic. Water arsenic data were combined with questionnaire data and published data of inorganic arsenic concentrations in select foods and cigarettes to examine the influence of arsenic in water at home, at work, and at other places, as well as inorganic arsenic intake from food and cigarettes. Monte Carlo simulations and analyses of individual-level intake estimates were conducted to quantify the variability attributed to different parameters in this primarily elderly white male population of southeastern Michigan. The 95th percentile of total inorganic arsenic intake ranges from 11 to 24 microg/day, depending on the intake metric selected. Results indicate that arsenic in home drinking water is the largest source of inorganic arsenic, accounting for 55.1% of the variance in the intake estimates. Food intake explains 37.3% of the variance, with rice being the largest contributor. In the upper decile of intake, consumption of plain water and beverages made with water at home, and ingestion of arsenic in water at work, also contribute to intake estimates. Water used for cooking and arsenic from smoking, however, only minimally alter the intake estimates. This is due to a relatively small volume of water absorbed into cooked foods and low concentrations of arsenic in cigarettes. Results from this study will assist investigators in better characterizing exposure to inorganic arsenic.

Validity of human nails as a biomarker of arsenic and selenium exposure: A review.

Human nail clippings have been used in recent epidemiological studies as a routine bioindicator of arsenic and selenium exposure. To ensure sound application of this biomarker, however, it is important to consider properties and scientific knowledge pertaining to validation of this particular tool. In this review, the use of human nails to measure exposure to arsenic and selenium is discussed in the context of the biomarker validation framework. Literature related to both analytical procedures and intrinsic characteristics of the biomarker is reviewed. Specifically, the followings are addressed: sample collection and preparation methods, establishment of the exposure-biomarker relationship, intraindividual variability and reproducibility of measurements, and biomarker-disease investigations. Drawing from a rapidly growing body of literature, current knowledge of these biomarker validation steps is assessed. Therefore, this review brings attention to the important issue of biomarker validation, laying the framework for future studies measuring elemental composition of nails.

Profiles of trace elements in toenails of Arab-Americans in the Detroit area, Michigan.

Exposure to environmental contaminants is complicated by factors related to socioeconomic status, diet, and other culturally conditioned risk behaviors. Determination of a trace element profile in toenails can be used as a tool in biomonitoring the exposure history or assessing the deficiency of a particular element in a study population, which can lead to a better understanding of environmental and disease risks. Toenail clippings from 259 Arab Americans (163 adults, 96 children) residing in a highly industrialized area were analyzed for Al, V, Cr, Mn, Co, Ni, Cu, As, Se, Mo, Cd, Ba, Tl, and Pb using an inductively coupled plasma-mass spectrometer. Mean concentrations were compared with published values, and the influence of age, gender, and other demographic factors were explored. Elevated levels of Ni in this population warrant further investigation. Significant differences in the mean concentration of Al, V, Cr, Mn, Cd, Pb, and Se exist between toenails of adults and children. Pearson correlation coefficients reveal strong significant associations among Cd, Cr, and Tl (p<0.05), in addition to other elements. These investigations provide insight into exposures and factors influencing exposures in this population while adding to the growing fund of knowledge surrounding use of toenails as a marker of exposure.

Visualization and exploratory analysis of epidemiologic data using a novel space time information system.

BACKGROUND: Recent years have seen an expansion in the use of Geographic Information Systems (GIS) in environmental health research. In this field GIS can be used to detect disease clustering, to analyze access to hospital emergency care, to predict environmental outbreaks, and to estimate exposure to toxic compounds. Despite these advances the inability of GIS to properly handle temporal information is increasingly recognised as a significant constraint. The effective representation and visualization of both spatial and temporal dimensions therefore is expected to significantly enhance our ability to undertake environmental health research using time-referenced geospatial data. Especially for diseases with long latency periods (such as cancer) the ability to represent, quantify and model individual exposure through time is a critical component of risk estimation. In response to this need a STIS - a Space Time Information System has been developed to visualize and analyze objects simultaneously through space and time. RESULTS: In this paper we present a "first use" of a STIS in a case-control study of the relationship between arsenic exposure and bladder cancer in south eastern Michigan. Individual arsenic exposure is reconstructed by incorporating spatiotemporal data including residential mobility and drinking water habits. The unique contribution of the STIS is its ability to visualize and analyze residential histories over different temporal scales. Participant information is viewed and statistically analyzed using dynamic views in which values of an attribute change through time. These views include tables, graphs (such as histograms and scatterplots), and maps. In addition, these views can be linked and synchronized for complex data exploration using cartographic brushing, statistical brushing, and animation. CONCLUSION: The STIS provides new and powerful ways to visualize and analyze how individual exposure and associated environmental variables change through time. We expect to see innovative space-time methods being utilized in future environmental health research now that the successful "first use" of a STIS in exposure reconstruction has been accomplished.