Catherine M. Bulka

Arsenic in drinking water and prostate cancer in Illinois counties: An ecologic study

BACKGROUND Inorganic arsenic is a lung, bladder, and skin carcinogen. One of the major sources of exposure to arsenic is through naturally contaminated drinking water. While positive associations have been observed between arsenic in drinking water and prostate cancer, few studies have explored this association in the United States. OBJECTIVES To evaluate the association between inorganic arsenic concentrations in community water systems and prostate cancer incidence in Illinois using an ecologic study design. METHODS Illinois Environmental Protection Agency data on arsenic concentrations in drinking water from community water systems throughout the state were linked with county-level prostate cancer incidence data from 2007 to 2011 from the Illinois State Cancer Registry. Incidence rates were indirectly standardized by age to calculate standardized incidence ratios (SIRs) for each county. A Poisson regression model was used to model the association between county-level SIRs and mean arsenic tertile (0.33-0.72, 0.73-1.60, and 1.61-16.23ppb), adjusting for potential confounders. RESULTS For counties with mean arsenic levels in the second tertile, the SIR was 1.05 (95% CI: 0.96-1.16). For counties with mean arsenic levels in the third tertile, the SIR was 1.10 (95% CI: 1.03-1.19). There was a significant linear dose-response relationship observed between mean arsenic levels and prostate cancer incidence (p for trend=0.003). CONCLUSIONS In this ecologic study, counties with higher mean arsenic levels in community water systems had significantly higher prostate cancer incidence. Individual-level studies of prostate cancer incidence and low-level arsenic exposure are needed.

The unintended consequences of a gluten-free diet

To the Editor:Gluten-free diets have become immensely popular in the United States. Despite <1% of Americans having diagnosed celiac disease, an estimated 25% of American consumers reported consuming gluten-free food in 2015, a 67% increase from 2013.1,2 Gluten is a protein found in a variety of

Patients at Increased Risk of Major Adverse Events Following Operative Treatment of Distal Radius Fractures: Inpatient versus Outpatient

Purpose The purpose of this study was to compare complication rates following inpatient versus outpatient distal radius fracture ORIF and identify specific complications that occur at increased rates among inpatients. Methods Using the 2005‐2013 ACS‐NSQIP, we collected patient demographics, comorbidities, surgical characteristics, and 30‐day postoperative complications following isolated ORIF of distal radius fractures. A propensity score matched design using an 8‐to‐1 “greedy” matching algorithm in a 1:4 ratio of inpatients to outpatients was utilized. Rates of minor, major, and total complications were compared. A multinomial logistic regression model was then used to assess the odds of complications following inpatient surgery. Results Total 4,016 patients were identified, 776 (19.3%) of whom underwent inpatient surgery and 3,240 (80.3%) underwent outpatient surgery. The propensity score matching algorithm yielded a cohort of 629 inpatients who were matched with 2,516 outpatients (1:4 ratio). After propensity score matching, inpatient treatment was associated with increased rates of major and total complications but not with minor complications. There was an increased odds of major complications and total complications following inpatient surgery compared with outpatient surgery. There was no difference in odds of minor complications between groups. Conclusion Inpatient operative treatment of distal radius fractures is associated with significantly increased rates of major and total complications compared with operative treatment as an outpatient. Odds of a major complication are six times higher and odds of total complications are two and a half times higher following inpatient distal radius ORIF compared with outpatient. Quality improvement measures should be specifically targeted to patients undergoing distal radius fracture ORIF in the inpatient setting.

Arsenic and Obesity: A Comparison of Urine Dilution Adjustment Methods

Introduction: A commonly used approach to adjust for urine dilution in analyses of biomarkers is to adjust for urinary creatinine. However, creatinine is a product of muscle mass and is therefore associated with body mass. In studies of urinary analytes and obesity or obesity-related outcomes, controlling for creatinine could induce collider stratification bias. We illustrate this phenomenon with an analysis of urinary arsenic. Objective: We aimed to evaluate various approaches of adjustment for urinary dilution on the associations between urinary arsenic concentration and measures of obesity. Methods: Using data from the National Health and Nutrition Examination Survey, we regressed body mass index (BMI) and waist-to-height ratios on urinary arsenic concentrations. We compared eight approaches to account for urine dilution, including standardization by urinary creatinine, osmolality, and flow rates, and inclusion of these metrics as independent covariates. We also used a recently proposed method known as covariate-adjusted standardization. Results: Inverse associations between urinary arsenic concentration with BMI and waist-to-height ratio were observed when either creatinine or osmolality were used to standardize or as covariates. Not adjusting for dilution, standardizing or adjusting for urinary flow rate, and using covariate-adjusted standardization resulted in null associations observed between arsenic concentration in relation to BMI and waist-to-height ratio. Conclusions: Our findings suggest that arsenic exposure is not associated with obesity, and that urinary creatinine and osmolality may be colliders on the causal pathway from arsenic exposure to obesity, as common descendants of hydration and body composition. In studies of urinary biomarkers and obesity or obesity-related outcomes, alternative metrics such as urinary flow rate or analytic strategies such as covariate-adjusted standardization should be considered. https://doi.org/10.1289/EHP1202

Relations Between Residential Proximity to EPA-Designated Toxic Release Sites and Diffuse Large B-Cell Lymphoma Incidence.

Objectives Examining the spatial patterns of diffuse large B-cell lymphoma (DLBCL) incidence and residential proximity to toxic release locations may provide insight regarding environmental and sociodemographic risk factors. Methods We linked and geocoded cancer incidence data for the period 1999–2008 from the Georgia Comprehensive Cancer Registry with population data from the US Census and the Environmental Protection Agency’s Toxics Release Inventory. We conducted cluster analyses and constructed Poisson regression models to assess DLBCL incidence as a function of mean distance to the toxic release sites. Results In total, 3851 incident DLBCL cases occurred among adults residing in Georgia between 1999 and 2008. Significant focal clustering was observed around 57% of ethylene oxide sites, 5% of benzene sites, 9% of tetrachloroethylene sites, 7% of styrene sites, 10% of formaldehyde sites, 5% of trichloroethylene sites, and 10% of all release sites. Mean distance to sites was significantly associated with DLBCL risk for all chemicals. Conclusions Proximity to Toxics Release Inventory sites can be linked to increased DLBCL risk as assessed through focal clustering and Poisson regression, and confirmatory studies using geospatial mapping can aid in further specifying risk factors for DLBCL.

Multiple Metal Exposures and Metabolic Syndrome: A Cross-Sectional Analysis of the National Health and Nutrition Examination Survey 2011–2014

Background: Epidemiologic studies suggest toxic metals are linked with diabetes and cardiovascular disease, while experimental studies indicate nutritionally essential metals are involved in the metabolism of macronutrients and defense against oxidative stress. Objectives: We sought to evaluate how essential and toxic metals are cross‐sectionally related to metabolic syndrome, a clustering of cardiometabolic conditions. Methods: Using data from the 2011–2014 National Health and Nutrition Examination Survey (n = 1088), we characterized metal concentrations as measured in spot urine (arsenic, cadmium, and inorganic/elemental mercury), whole blood (manganese, lead, methylmercury, and selenium), and serum (copper and zinc) samples. Principal component analysis was performed to derive patterns of exposures. Metabolic syndrome was defined according to the 2009 Joint Scientific Statement as the presence of ≥ 3 of the following conditions: high blood pressure, high triglycerides, low HDL cholesterol, high fasting glucose, and abdominal obesity. Results: After adjustment for potential confounders, prevalence ratios for metabolic syndrome comparing the highest to the lowest quartiles were 1.41 (95% CI: 1.18–1.67) for the arsenic‐inorganic/elemental mercury pattern, 0.95 (0.78–1.16) for the methylmercury‐manganese pattern, 0.73 (0.57–0.94) for the cadmium‐lead pattern, 0.91 (0.76–1.10) for the copper pattern, and 1.36 (1.13–1.63) for the selenium‐zinc pattern. The positive associations observed for the arsenic‐inorganic/elemental mercury pattern were due to an elevated prevalence of high blood pressure, low HDL cholesterol, and high triglycerides among those with greater exposures. Associations for the selenium‐zinc pattern were driven by a positive relationship with high triglycerides. Greater lead‐cadmium co‐exposures were related to a lower prevalence of dyslipidemia and abdominal obesity. Conclusions: These cross‐sectional findings suggest both toxic and essential metal exposures may contribute to cardiometabolic health, but need to be confirmed with prospective data.

Occupational Exposures and Metabolic Syndrome Among Hispanics/Latinos

Objective: We assessed the cross-sectional relationships of self-reported current occupational exposures to solvents, metals, and pesticides with metabolic syndrome and its components among 7127 participants in the Hispanic Community Health Study/Study of Latinos. Methods: Metabolic syndrome was defined as a clustering of abdominal obesity, high triglycerides, low high-density lipoprotein cholesterol, high blood pressure, and/or high fasting glucose. Regression models that incorporated inverse probability of exposure weighting were used to estimate prevalence ratios. Results: Solvent exposure was associated with a 32% higher prevalence of high blood pressure (95% confidence interval: 1.09 to 1.60) than participants not reporting exposure. No associations were observed for occupational exposures with abdominal obesity, high triglycerides, low high-density lipoprotein, or metabolic syndrome. Conclusion: Our findings suggest that solvent exposure may be an important occupational risk factor for high blood pressure among Hispanics/Latinos in the United States.