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

Systemic injuries are important drivers for TWC in miners in terms of median compensation and TTD.

Occupation is an important predictor of OLD in the mining industry.

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We observed a significant relationship between mining tenure and emphysema severity among South African miners in PATHAUT between 1975 and 2014. This relationship was evident in multi-variable analyses adjusted for smoking among white miners. Hazards from long term exposure to inhaled mineral dust leading to lung damage (silicosis, fibrosis, COPD) is evident and warrants further improvement of working conditions and prevention measures in South African mines especially for black workers. Further research is needed to determine if there is an effect of TB and HIV co-infection on the development of emphysema.

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Introduction: Arsenic is ubiquitous in the environment as an element of the earth’s crust. Human exposure predominantly occurs through ingestion of contaminated drinking water and arsenic-rich foods such as seafood and rice. Chronic exposure to inorganic arsenic has been associated with certain cancers, and more recently with cardiovascular disease and diabetes that are common among the obese. However, little is known about the specific relationship between inorganic arsenic exposure and obesity. Hypothesis: We assessed the hypothesis that inorganic arsenic exposure was correlated with obesity in the general population of the United States. Methods: We analyzed a representative sample of 4,105 adults from the U.S. population using data from the 2007-2010 National Health and Nutrition Examination Survey (NHANES). Arsenobetaine and arsenocholine concentrations, which are forms of organic arsenic, were subtracted from total urinary arsenic concentrations to estimate the amount of inorganic arsenic in urine as a biomarker of exposure. These values were standardized by urinary creatinine to control for hydration status. Obesity was assessed using measured body mass index (BMI) in kg/m 2 and waist circumference in cm. Crude and adjusted survey-weighted linear regression models were performed. Results: Creatinine-adjusted urinary inorganic arsenic concentrations were inversely associated with log-transformed BMI (p for trend = 0.0003) and log-transformed waist circumference (p for trend = 0.0001). The highest quintile of inorganic arsenic concentration (>10.4 to 483.3 μg/L) was associated with a 5% (95% CI: 3 to 8%) lower BMI and a 4% (95% CI: 2 to 6%) smaller waist circumference compared to the lowest quintile (0 to 2.3 μg/L). Adjustments for age, gender, race, thyroid problems, diabetes, smoking status, seafood consumption, rice consumption, red blood cell folate, serum folate, socioeconomic status, and survey cycle did not appreciably alter these results. There was no evidence of effect modification between urinary inorganic arsenic concentrations and covariates on obesity. Conclusions: While inorganic arsenic exposure has generally been positively associated with obesity-related diseases, we observed a negative association between urinary inorganic arsenic concentrations and obesity in this representative cross-sectional analysis. It is unclear if this is a true association in which inorganic arsenic exposure is protective against obesity, or if this finding reflects differential arsenic absorption, metabolism, or storage by adiposity level.

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