Faculty Bibliography

Context: Common environmental contaminants can disrupt normal thyroid function, which plays essential but varying roles at different ages. Objective: To evaluate the relationship of perchlorate, thiocyanate, and nitrate, three sodium-iodide symporter (NIS) inhibitors, and thyroid function in different age-sex-stratified populations. Design, Setting, Participants, and Intervention: This was a cross-sectional analysis of data from the 2009-2012 National Health and Nutrition Examination Surveys (NHANES) evaluating the exposure to perchlorate, thiocyanate, and nitrate in 3,151 participants aged 12-80. Main Outcome Measure: Blood serum free thyroxine (FT4) as both a continuous and categorical variable. We also assessed blood serum thyroid stimulating hormone (TSH). Results: Controlling for serum cotinine, BMI, total daily energy consumption, race/ethnicity, and poverty-to-income ratio, for each log unit increase in perchlorate, FT4 decreased by 0.03 ng/dL in both the general population (p=0.004) and in all women (p=0.005), and by 0.06 ng/dL in adolescent girls (p=0.029), corresponding to 4% and 8% decreases relative to median FT4, respectively. For each log unit increase thiocyanate, FT4 decreased by 0.07 ng/dL in adolescent boys (p=0.003), corresponding to a 9% decrease relative to median FT4, respectively. Conclusions: Our results indicate that adolescent boys and girls represent vulnerable subpopulations to the thyroid-blocking effects of NIS symporter inhibitors. These results suggest a valuable screening and intervention opportunity.

BACKGROUND: Socioeconomic analysis is currently used in the Europe Union as part of the regulatory process in Regulation Registration, Evaluation and Authorisation of Chemicals (REACH), with the aim of assessing and managing risks from dangerous chemicals. The political impact of the socio-economic analysis is potentially high in the authorisation and restriction procedures, however, current socio-economic analysis dossiers submitted under REACH are very heterogeneous in terms of methodology used and quality. Furthermore, the economic literature is not very helpful for regulatory purposes, as most published calculations of health costs associated with chemical exposures use epidemiological studies as input data, but such studies are rarely available for most substances. The quasi-totality of the data used in the REACH dossiers comes from toxicological studies. METHODS: This paper assesses the use of the integrated probabilistic risk assessment, based on toxicological data, for the calculation of health costs associated with endocrine disrupting effects of triclosan. The results are compared with those obtained using the population attributable fraction, based on epidemiological data. RESULTS: The results based on the integrated probabilistic risk assessment indicated that 4894 men could have reproductive deficits based on the decreased vas deferens weights observed in rats, 0 cases of changed T3 levels, and 0 cases of girls with early pubertal development. The results obtained with the Population Attributable Fraction method showed 7,199,228 cases of obesity per year, 281,923 girls per year with early pubertal development and 88,957 to 303,759 cases per year with increased total T3 hormone levels. The economic costs associated with increased BMI due to TCS exposure could be calculated. Direct health costs were estimated at euro5.8 billion per year. CONCLUSIONS: The two methods give very different results for the same effects. The choice of a toxicological-based or an epidemiological-based method in the socio-economic analysis will therefore significantly impact the estimated health costs and consequently the political risk management decision. Additional work should be done for understanding the reasons of these significant differences.

BACKGROUND: The health effects of bisphenol A (BPA) and di-(2-ethylhexyl) phthalate (DEHP) have been studied extensively in children. The impact of other chemicals in these two classes has not been investigated as fully. METHODS: We conducted a cross-sectional pilot study of 10-13 year old healthy children. We assessed descriptive, univariable and multivariable associations of urinary metabolites of bisphenols and phthalates with oxidant stress, insulin resistance, body mass, and endothelial dysfunction. Possible associations with brachial artery distensibility, pulse wave velocity (markers of vascular stiffness), and serum endothelial cell-derived microparticle levels were also assessed. RESULTS: We enrolled 41 participants, 12.1 +/- 1.0 years, most of whom were Mexican-Americans (42%) or other Hispanics (34%). Increased BPA levels were associated with increased levels of F2-isoprostane (ng/ml) (P=0.02), with a similar trend for DEHP metabolites. Each log unit increase of high molecular weight (HMW) phthalate metabolites was associated with 0.550 increase in HOMA-IR units (p=0.019) and altered circulating levels of activated endothelial cell-derived microparticles (% per ml) (P=0.026). Bisphenol S (BPS), a replacement for BPA, was associated with increased albumin (mg):creatinine (g) ratio (P=0.04). Metabolites of HMW phthalates were also associated with decreased brachial artery distensibility (P=0.047). CONCLUSIONS: Exposure to bisphenols and phthalates, including a BPA replacement, is associated with increased oxidant stress, insulin resistance, albuminuria, as well as disturbances in vascular function in healthy children.Pediatric Research (2017); doi:10.1038/pr.2017.16.

The World Trade Center (WTC) disaster released large amounts of various chemical substances into the environment, including perfluoroalkyl substances (PFASs). Yet, no studies have examined exposures in children living or attending schools near the disaster site. We measured serum PFASs in WTC Health Registry (WTCHR) respondents who were