Browsing by Author "Hoffman, Kate"
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Item Open Access A Comparative Analysis of the Role Race and Socioeconomic Status Play in Chemical Exposure in the United States(2019-04-26) Early, TaraEnvironmental justice concerns arise when historically underrepresented groups are disproportionately exposed to toxins in the environment. Analysis of environmental biomonitoring data provides a method to analyze chemicals for race/ethnicity and income-related disparity. Using data from the US National Health and Nutrition Examination Survey 2013-2014, biomarker concentrations of 167 chemicals were analyzed. Ten subgroups were defined on the basis of race/ethnicity and income. To examine disparity, geometric mean (GM) concentrations of chemical biomarker for each subgroup were compared to a reference group (i.e., the non-Hispanic white individuals with poverty to income ratio ≥ 2). Of the 167 compounds considered, 95 were detected in >60% of samples and were evaluated for disparity. There was evidence of an environmental justice concern for 42 compounds (GM ratios significantly > 1) in at least one of the identified subgroups. For 21 of these compounds, disparity was present only in the low-income non-Hispanic Black subpopulation. Disparity was particularly pronounced for cotinine, propyl paraben, and dichlorophenol. GM ratios were significantly <1 for 16 chemicals, indicating higher exposure among high-income non-Hispanic whites. Cumulatively, this project demonstrates disproportionate exposure to environmental contaminants by income and race/ethnicity. Results suggest that the low-income non-Hispanic Black subpopulation experiences much higher instances of disparity. Comparing with prior research, results also suggest that disparity in environmental exposure may be increasing.Item Open Access Analyzing Euthyroid & Hyperthyroid Indoor Cat Exposure to Flame Retardants(2020-04-23) Osteen, Mary-CatherineHyperthyroidism in cats has increased since its original description in the 1970s. Environmental exposures are suggested as a potential contributing factor. This research investigated pet cats’ exposure to flame retardant chemicals in the home environment and associations with hyperthyroidism. Silicone collar tags were used as indicators of exposure to two classes of flame retardants: polybrominated diphenyl ethers (PBDEs) and organophosphate esters (OPEs). Though previous studies have documented PBDE exposure among house cats, less is known about exposure to OPEs. Thus, we first evaluated silicone tags as measures of internal exposure to OPEs. Cats wore silicone collar tags for 7 days in their home environment, after which tags were analyzed for flame retardants. Urine samples were collected from 9 cats and analyzed for OPE metabolites. Tris(2-chloroisopropyl) phosphate (TCIPP), was significantly and positively correlated with its urinary metabolites (r≥0.73; p<0.05), and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) was significantly and positively correlated with its urinary metabolite (r=0.77; p<0.05). Several other OPEs from tags were correlated with their metabolites in urine, suggesting that tags capture information about cats’ internal exposure; however, correlations were not statistically significant. To evaluate exposure differences by thyroid status, 12 hyperthyroid and 12 euthyroid cats (matched by age and sex) wore tags for 7 days. Tags were analyzed for PBDEs and OPEs. Two PBDEs, BDE-47 and BDE-99, were higher on tags worn by hyperthyroid compared to euthyroid cats (p<0.05). Associations with thyroid status were not significant for OPEs; however, we caution against over-interpretation of these results given our limited sample size. Potential confounders, including diet and activity level, were evaluated; however, no significant differences were found between hyperthyroid and euthyroid cats (p>0.20), suggesting these factors are not likely to confound associations with flame retardant exposures. Cumulatively, results suggest that exposure to PBDE flame retardants is higher among hyperthyroid cats, which is in agreement with previous studies that have reported differences in serum PBDE levels of hyperthyroid and euthyroid cats.Item Open Access Antibody Responses to Vaccines and PFAS Exposure in Early Childhood(2021-04-22) Bao, NancyPer- and polyfluoroalkyl substances (PFAS), are human-made chemicals commonly incorporated into personal care products, cookware, food packaging, and other industrial uses. Previous studies have found that early life exposure to PFAS is associated with health effects in both animal and human studies. There are growing concerns over the potential health consequences such as immunological health associated with prenatal and early childhood PFAS exposure. Studies have found that exposure to environmental stressors during early periods of fetal growth and development may have implications for the development of later life adverse health effects. Few studies have assessed the association between PFAS exposure and waning immunity to vaccines during early childhood. Of these studies, PFAS exposure has been inversely associated with antibody responses to vaccines against infectious diseases such as diphtheria and tetanus. Antibody responses to vaccines are commonly used as biomarkers to assess immune function and development. The objective of this study was to evaluate the impacts of PFAS exposures on critical windows of immune function and maturation in early childhood. Early childhood immune function was evaluated using antibody responses to the Diphtheria-Tetanus-acellular Pertussis (DTaP) vaccine. Multiple linear regression analyses (adjusted for child’s age, biological sex of child, and maternal age) were conducted to evaluate the associations between maternal and child serum PFAS levels in a North Carolina birth cohort (n=47) and antibody responses to the DTaP vaccine in children (ages 3-6). Maternal serum PFAS were used to assess prenatal exposure. Child serum was analyzed for diphtheria and tetanus antibody titers as well as postnatal PFAS exposure. Prenatal PFAS exposure measured from maternal serum was not significantly associated with tetanus antibody titers; however, a positive and significant association (p<0.05) was observed between prenatal PFNA exposure and diphtheria antibody titers. Postnatal PFAS exposure was not significantly associated with diphtheria antibody titers. Postnatal PFOA exposure was positively associated with tetanus antibody responses (p<0.05). The results do not suggest that prenatal and early childhood exposure to PFAS is associated with declines in immune responses to vaccines. Other factors associated with environmental PFAS exposure and vaccine antibody responses should be explored to expand on these findings.Item Open Access Assessing Children's Exposure to Organophosphate Flame Retardants in the Home Environment(2017-04-28) Frenchmeyer, Meredith; Flaherty, BridgetOrganophosphate flame retardants (OPFRs) are increasingly being used in the home environment as replacements for the phased out polybrominated diphenyl ethers (PBDEs). Several studies utilizing hand wipes and dust samples in concert with urine samples have illustrated that human exposure is occurring in the home environment. While exposure has been measured across age groups and locations, few epidemiological studies have investigated the potential health effects of these individual compounds and their mixtures. Preliminary animal research indicates their potential for endocrine disruption, with a particular emphasis on thyroid hormone dysregulation. Additionally, particular OPFRs may bind with the PPARγ, a nuclear receptor involved in adipogenesis, or the formation of fat cells. The present study uses passive air and urine samples collected from a central North Carolina toddler cohort to explore, for the first time, associations between air and biomarkers of OPFR exposure (i.e. urinary metabolites). This will help to assess inhalation as a potentially important exposure pathway for OPFRs. In addition, associations between levels of OPFR metabolites measured in urine and growth measures are assessed. Few epidemiological studies have explored OPFRs and health outcomes such as weight; therefore, this study provides relevant and new information about specific metabolites and their relationship with BMI percentile. Univariate analyses revealed statistically significant differences in urinary metabolite concentrations between children whose mothers had a college degree compared to those that did not. The urinary metabolites DPHP and tbutylDPHP were significantly correlated with OPFR compounds measured in indoor air. One urinary metabolite, ip-DPHP, was found to have a statistically significant relationship with BMI percentile, suggesting exposure might be affecting growth. Limitations of the present study include the measure of exposure being limited to one time point, and the cohort being limited to the central North Carolina area.Item Embargo Characterizing the contribution of residential phthalate dust concentrations to internal phthalate dose in the US population: an updated systematic review & meta-analysis(2023-04-28) Milton, SashoyObjectives: Phthalates are prevalent chemical substances that have been linked to endocrine disruption, reproductive disorders, and other adverse health effects. Although exposure to phthalates is widespread, few studies provide information on the relative contributions of exposure sources and routes of exposure. The objective of this systematic review and meta-analysis is to quantify the contribution of phthalates and phthalate alternatives in residential dust to internal human dose in the US general population. Methods: This review updates a pre-existing systematic review and meta-analysis published in 2015. It includes 12 studies published between January 2000 and April 2022 identified from Web of Science and PubMed using a predetermined search strategy. Pooled weighted median phthalate and phthalate alternative dust concentrations were determined from the studies included in our literature review. The phthalate and phthalate alternative dust concentrations were then used to calculate daily intake rates. Separately, using a reverse dosimetry model, the daily intake rate representing total phthalate and phthalate alternative internal dose was estimated from urinary phthalate metabolite concentrations measured in the 2017-2018 National Health and Nutrition Examination Survey (NHANES). The daily intake rates predicted from the indoor dust (systematic review/meta-analysis) and the urinary metabolites (NHANES) were then compared to drive the percent contribution of phthalates and phthalate alternatives measured in residential dust to internal dose. A summary showing the potential human health hazards associated with the measured chemical substances was compiled to provide context for risk. Results: ATBC (phthalate alternative) had the highest dust concentrations (systematic review/meta-analysis) while DEHTP (phthalate alternative) had the highest internal exposure level in children and adults (NHANES). Dust had a greater contribution to the internal phthalate and phthalate alternative concentration levels of children than adults when all exposure pathways (i.e., dust ingestion (direct), inhalation (indirect), and dermal absorption from air (indirect)) were considered. It was also observed that the dust ingestion pathway contributed significantly to the overall dust intake rate for high-molecular weight (HMW) phthalates. Conversely, the inhalation and dermal absorption from air exposure pathways were more significant for low-molecular weight (LMW) phthalates. The relative contribution of dust to the overall intake of the chemical substances varied depending on the physio-chemical characteristics, with dust being a more important contributor for LMW phthalates such as DEP and BBP. Conclusion: The relative contribution of dust to overall internal exposure of individuals is greater for LMW than HMW phthalates. This is linked to the increased likelihood of LMW phthalates partitioning from dust to indoor air, which makes the indirect contribution of dust to internal phthalate exposure greater than its direct contribution.Item Open Access Exploring Associations Between Prenatal PFAS Exposure and Childhood Asthma(2021-04-28) Bogar, LanePer- and polyfluoroalkyl substances (PFAS) are a large class of man-made chemicals used extensively in consumer and industrial products, making them ubiquitous in the built and natural environment. These chemicals pose a cause for concern, as there is increasing experimental and epidemiological evidence suggesting that exposure is associated with adverse health outcomes, especially prenatal PFAS exposure during critical periods of development. This study explored the associations between prenatal PFAS exposure, measured via maternal serum levels collected during pregnancy, and childhood asthma incidence in a cohort of 155 women, and 165 of their children from North Carolina. PFAS were detected in all serum samples and levels were similar to those in the general population. Statistical analyses incorporated potential predictors and covariates, including sex, age and race. After adjusting for these factors, statistically significant associations with asthma were found. Future efforts are needed to examine prenatal PFAS exposures and respiratory outcomes in later life.Item Open Access Exposure to flame retardant chemicals and occurrence and severity of papillary thyroid cancer: A case-control study.(Environ Int, 2017-10) Hoffman, Kate; Lorenzo, Amelia; Butt, Craig M; Hammel, Stephanie C; Henderson, Brittany Bohinc; Roman, Sanziana A; Scheri, Randall P; Stapleton, Heather M; Sosa, Julie AnnBACKGROUND: Thyroid cancer is the fastest increasing cancer in the U.S., and papillary thyroid cancer (PTC) accounts for >80% of incident cases. Increasing exposure to flame retardant chemicals (FRs) has raised concerns about their possible role in this 'epidemic'. The current study was designed to test the hypothesis that higher exposure to FRs is associated with increased odds of PTC. METHODS: PTC patients at the Duke Cancer Institute were approached and invited to participate. Age- and gender-matched controls were recruited from the Duke Health System and surrounding communities. Because suitable biomarkers of long-term exposure do not exist for many common FRs, and levels of FRs in dust are significantly correlated with exposure, relationships between FRs in household dust and PTC were evaluated in addition to available biomarkers. PTC status, measures of aggressiveness (e.g. tumor size) and BRAF V600E mutation were included as outcomes. RESULTS: Higher levels of some FRs, particularly decabromodiphenyl ether (BDE-209) and tris(2-chloroethyl) phosphate in dust, were associated with increased odds of PTC. Participants with dust BDE-209 concentrations above the median level were 2.29 times as likely to have PTC [95% confidence interval: 1.03, 5.08] compared to those with low BDE-209 concentrations. Associations varied based on tumor aggressiveness and mutation status; TCEP was more strongly associated with larger, more aggressive tumors and BDE-209 was associated with smaller, less aggressive tumors. CONCLUSIONS: Taken together, these results suggest exposure to FRs in the home, particularly BDE-209 and TCEP, may be associated with PTC occurrence and severity, and warrant further study.Item Open Access Geographic and Racial Disparities in Infant Hearing Loss.(Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2018-10-09) Lantos, Paul M; Maradiaga-Panayotti, Gabriela; Barber, Xavier; Raynor, Eileen; Tucci, Debara; Hoffman, Kate; Permar, Sallie R; Jackson, Pearce; Hughes, Brenna L; Kind, Amy; Swamy, Geeta KObjective Approximately 1 to 2 of every 1000 American newborns has hearing loss identified by newborn screening. This study was designed to determine if infant hearing loss is more common in socioeconomically disadvantaged communities. Study Design In this retrospective study, we analyzed electronic medical record data using geostatistical models. Setting Infants were residents of Durham County, North Carolina, born in 2 hospitals of the Duke University Health System. This county includes the city of Durham and surrounding suburban and rural communities. Subjects and Methods Subjects were hearing-screened newborns, born between 2005 and 2016, whose residential address was in Durham County, North Carolina. This was a retrospective study using medical record data. We used Bayesian regression models with smoothing of coordinate date to identify both spatial and nonspatial predictors of infant hearing loss. Results We identified 19,348 infants from Durham County, of whom 675 had failed initial hearing screening and 191 had hearing loss confirmed on follow-up. Hearing loss was significantly associated with minority race (odds ratio [OR], 2.45; 95% confidence interval, 1.97-3.06), as well as lower gestational age and maternal sexually transmitted infections. We identified significant geographic heterogeneity, with a higher probability of hearing loss in poorer urban neighborhoods (local OR range, 0.59-1.39). Neighborhood disadvantage was a significant predictor of hearing loss, as was high local seroprevalence of cytomegalovirus (CMV) among pregnant women. Conclusions Urban, low-income neighborhoods have a high prevalence of infant hearing loss compared with more affluent surrounding communities, particularly among minorities. This distribution may be attributable to congenital CMV infection.Item Open Access HOG AND POULTRY CAFOS IN NC AND GEOSPATIAL ASSOCIATIONS WITH INFANT BIRTH OUTCOMES(2020-04-24) Wang, ChengyangConcentrated animal feeding operation (CAFO) facilities can emit air- and water-borne contaminants to adjacent environments. Recently there has been increasing concern that these facilities may cause adverse health effects in nearby neighborhoods and residents. North Carolina has a large number of CAFOs, with more than 2000 swine and 4000 poultry facilities state-wide. This study sought to determine whether proximity to CAFOs within NC was associated with adverse health outcomes in families, with a particular focus on birth outcomes. Low birth weight and preterm birth are both risk factors for chronic diseases later in life. Using individual-level birth certificate data (NC Department of Vital Statistics), the NC swine CAFO permit data (NC Department of Environmental Quality), and the NC poultry CAFO locations (Environmental Working Group), this study investigated associations between CAFO size and distance to residence with birth outcomes, and specifically gestational age and infant birth weight. Two models were constructed, one using distance to the nearest CAFO and the second model using kernel density layers; both models were adjusted for potential confounding variables (e.g. maternal race, education, age, etc.) and stratified by infant sex. Results suggest that mothers living within 2 – 5 mi of a poultry CAFOs were 1.13 and 1.14 (p<0.01) times as likely to deliver preterm or low birth weight (LBW) infants, respectively, compared to those living greater than 5 mi from a CAFO. On average, infants (both sexes) born in households within 1 mi, 1 – 2 mi, and 2 – 5 mi radius from a poultry CAFO were born 0.1, 0.08, and 0.09 weeks earlier than those living farther away (p < 0.001). Models using the more sophisticated kernel density approach suggest that the number and size of adjacent hogs CAFOs may influence these outcomes. Although the magnitude of these effects was small, these findings suggest distance to poultry CAFOs may be a risk factor for preterm birth in NC, and interestingly, these effects may be sex-specific.Item Embargo Infants’ exposure to parabens: identifying factors that contribute to higher levels of exposure(2023-04-27) Zhong, YilinItem Open Access Maternal Exposure to Per- and Polyfluorinated alkyl substances (PFAS) in Drinking Water and Associations with Birth Outcomes(2020-04-24) Xiong, WanchenPer- and polyfluoroalkyl substances (PFAS), used in firefighting foam and as water and oil-repellants in nonstick cookware, fabrics and other materials, are widely detected in watersheds across the United States, and globally. Epidemiological studies have found that PFAS are associated with adverse health effects, including thyroid disease, cancer, and adverse birth outcomes. In 2017-2018, high levels of PFAS were detected in both the Haw River and Cape Fear River in North Carolina, raising concerns for potential health effects in towns which draw drinking water from these rivers. This research sought to examine associations between exposure to PFAS (using watershed as a proxy for PFAS exposure) and birth outcomes in NC, focusing specifically on birth weight and gestational age at birth. A multiple linear regression model was used to compare outcomes in eleven regions of NC, defined by their drinking water source. After adjusting for potential confounders and stratifying analyses by infant sex, the largest difference in birth weight was observed in the Headwater of the Cape Fear River (serving the population of Eastern Chatham County and Goldston-Gulf District), where male infants were born 0.26 lbs (± 0.13) lighter on average, and were born 4.72 (± 1.93) days earlier, than the reference group (Falls Lake (Raleigh); p<0.1 for birth weight and p<0.05 for gestational age). Similar patterns were observed in populations drawing water from Lake Mackintosh, Jordan Lake, and the Cape Fear River, whereas no statistically significant differences in birth weight or gestational age were observed in the population drawing water from the Haw River (i.e., the Town of Pittsboro). Overall, the research study concluded that there are spatial differences in adverse birth outcomes across NC, which may be due to exposure to contaminants in water such as PFAS; however, future studies are needed to specially examine PFAS exposures at the individual level.Item Open Access Neighborhood Disadvantage is Associated with High Cytomegalovirus Seroprevalence in Pregnancy.(J Racial Ethn Health Disparities, 2017-08-24) Lantos, Paul M; Hoffman, Kate; Permar, Sallie R; Jackson, Pearce; Hughes, Brenna L; Kind, Amy; Swamy, GeetaBACKGROUND: Cytomegalovirus (CMV) is the most common infectious cause of fetal malformations and childhood hearing loss. CMV is more common among socially disadvantaged groups, and geographically clusters in poor communities. The Area Deprivation Index (ADI) is a neighborhood-level index derived from census data that reflects material disadvantage. METHODS: We performed a geospatial analysis to determine if ADI predicts the local odds of CMV seropositivity. We analyzed a dataset of 3527 women who had been tested for CMV antibodies during pregnancy. We used generalized additive models to analyze the spatial distribution of CMV seropositivity. Adjusted models included individual-level age and race and neighborhood-level ADI. RESULTS: Our dataset included 1955 CMV seropositive women, 1549 who were seronegative, and 23 with recent CMV infection based on low avidity CMV antibodies. High ADI percentiles, representing greater neighborhood poverty, were significantly associated with the nonwhite race (48 vs. 22, p < 0.001) and CMV seropositivity (39 vs. 28, p < 0.001). Our unadjusted spatial models identified clustering of high CMV odds in poor, urban neighborhoods and clustering of low CMV odds in more affluent suburbs (local odds ratio 0.41 to 1.90). Adjustment for both individual race and neighborhood ADI largely eliminated this spatial variability. ADI remained a significant predictor of local CMV seroprevalence even after adjusting for individual race. CONCLUSIONS: Neighborhood-level poverty as measured by the ADI is a race-independent predictor of local CMV seroprevalence among pregnant women.Item Open Access PHTHALATE EXPOSURE AND CONSUMER PRODUCT USE AMONG CHILDREN IN A NORTH CAROLINA COHORT(2017-04-28) Killius, AllisonPhthalates, chemicals found in plastics and personal care products, are a ubiquitous class of chemical compounds that have been associated with adverse health effects. Mothers and their toddlers were recruited from a pregnancy cohort and completed a questionnaire that included demographic information and reports of children’s product use habits. Pooled urine samples (3 over 48 hours) were collected from 180 toddlers and analyzed for five major phthalate metabolites: mEHP, mEP2, mBP, miBP, and mBzP2. Statistical analysis compared the urinary metabolite concentrations with the children’s demographic information and average product use. Maternal education was inversely associated with urinary concentrations of all metabolites. After controlling for confounding by demographic variables, plastic bag, lotion, and nail polish use were significant predictors of urinary mEP2 levels. This study suggests plastic and personal care product use in toddlers influences phthalate exposure.Item Open Access Redlining Matters: Neighborhood Differences in Vegetative Cover, Urban Heat and Heat-Related Illnesses in Durham, North Carolina(2022-04-21) Chen, RuoxueDiscriminatory, race-based housing practices, known as “redlining” resulted in refused home loans, insurance, and other essential investments such as green infrastructure beginning in the 1930s. Although redlining was abandoned in the 1960s, research suggests it continues to have implications for many communities. In this project, we evaluated environmental factors (i.e., vegetative cover and urban heat) to determine if the effects of redlining persist in Durham, North Carolina. Formerly redlined areas had less vegetation and more heat exposure. We also investigated heat-related illnesses and found the same communities had higher incidence rates of heat-related illnesses, especially among non-Hispanic Black residents. Cumulatively, our study demonstrates current health and environmental disparities related for the historical redlining policy.Item Open Access The Excess Burden of Cytomegalovirus in African American Communities: A Geospatial Analysis.(Open Forum Infect Dis, 2015-12) Lantos, Paul M; Permar, Sallie R; Hoffman, Kate; Swamy, Geeta KBackground. Cytomegalovirus (CMV) is a common cause of birth defects and hearing loss in infants and opportunistic infections in the immunocompromised. Previous studies have found higher CMV seroprevalence rates among minorities and among persons with lower socioeconomic status. No studies have investigated the geographic distribution of CMV and its relationship to age, race, and poverty in the community. Methods. We identified patients from 6 North Carolina counties who were tested in the Duke University Health System for CMV immunoglobulin G. We performed spatial statistical analyses to analyze the distributions of seropositive and seronegative individuals. Results. Of 1884 subjects, 90% were either white or African American. Cytomegalovirus seropositivity was significantly more common among African Americans (73% vs 42%; odds ratio, 3.31; 95% confidence interval, 2.7-4.1), and this disparity persisted across the life span. We identified clusters of high and low CMV odds, both of which were largely explained by race. Clusters of high CMV odds were found in communities with high proportions of African Americans. Conclusions. Cytomegalovirus seropositivity is geographically clustered, and its distribution is strongly determined by a community's racial composition. African American communities have high prevalence rates of CMV infection, and there may be a disparate burden of CMV-associated morbidity in these communities.