Fraser W. Gaspar

Phthalate Exposure and Risk Assessment in California Child Care Facilities

Approximately 13 million U.S. children less than 6 years old spend some time in early childhood education (ECE) facilities where they may be exposed to potentially harmful chemicals during critical periods of development. We measured five phthalate esters in indoor dust (n = 39) and indoor and outdoor air (n = 40 and 14, respectively) at ECE facilities in Northern California. Dust and airborne concentrations were used to perform a probabilistic health risk assessment to compare estimated exposures with risk levels established for chemicals causing reproductive toxicity and cancer under Californias Proposition 65. Di(2-ethylhexyl) phthalate (DEHP) and butyl benzyl phthalate (BBzP) were the dominant phthalates present in floor dust (medians = 172.2 and 46.8 μg/g, respectively), and dibutyl phthalate (DBP), diethyl phthalate (DEP), and diisobutyl phthalate (DIBP) were the dominant phthalates in indoor air (medians = 0.52, 0.21, and 0.10 μg/m(3), respectively). The risk assessment results indicate that 82-89% of children in California ECE had DBP exposure estimates exceeding reproductive health benchmarks. Further, 8-11% of children less than 2 years old had DEHP exposure estimates exceeding cancer benchmarks. This is the largest study to measure phthalate exposure in U.S. ECE facilities and findings indicate wide phthalate contamination and potential risk to developing children.

Prenatal DDT and DDE exposure and child IQ in the CHAMACOS cohort.

Although banned in most countries, dichlorodiphenyl-trichloroethane (DDT) continues to be used for vector control in some malaria endemic areas. Previous findings from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort study found increased prenatal levels of DDT and its breakdown product dichlorodiphenyl-dichloroethylene (DDE) to be associated with altered neurodevelopment in children at 1 and 2years of age. In this study, we combined the measured maternal DDT/E concentrations during pregnancy obtained for the prospective birth cohort with predicted prenatal DDT and DDE levels estimated for a retrospective birth cohort. Using generalized estimating equation (GEE) and linear regression models, we evaluated the relationship of prenatal maternal DDT and DDE serum concentrations with childrens cognition at ages 7 and 10.5years as assessed using the Full Scale Intelligence Quotient (IQ) and 4 subtest scores (Working Memory, Perceptual Reasoning, Verbal Comprehension, and Processing Speed) of the Wechsler Intelligence Scale for Children (WISC). In GEE analyses incorporating both age 7 and 10.5 scores (n=619), we found prenatal DDT and DDE levels were not associated with Full Scale IQ or any of the WISC subscales (p-value>0.05). In linear regression analyses assessing each time point separately, prenatal DDT levels were inversely associated with Processing Speed at age 7years (n=316), but prenatal DDT and DDE levels were not associated with Full Scale IQ or any of the WISC subscales at age 10.5years (n=595). We found evidence for effect modification by sex. In girls, but not boys, prenatal DDE levels were inversely associated with Full Scale IQ and Processing Speed at age 7years. We conclude that prenatal DDT levels may be associated with delayed Processing Speed in children at age 7years and the relationship between prenatal DDE levels and childrens cognitive development may be modified by sex, with girls being more adversely affected.

Levels and Determinants of DDT and DDE Exposure in the VHEMBE Cohort

Background: Although indoor residual spraying (IRS) is an effective tool for malaria control, its use contributes to high insecticide exposure in sprayed communities and raises concerns about possible unintended health effects. Objective: The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) is a birth cohort study initiated in 2012 to characterize prenatal exposure to IRS insecticides and exposures’ impacts on child health and development in rural South Africa. Methods: In this report, we describe the VHEMBE cohort and dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) serum concentrations measured in VHEMBE mothers when they presented for delivery. In addition, we applied a causal inference framework to estimate the potential reduction in population-level p,p′-DDT and p,p′-DDE serum concentrations under five hypothetical interventions. A total of 751 mothers were enrolled. Results: Serum concentrations of p,p′ isomers of DDT and DDE were above the limit of detection (LOD) in ≥98% of the samples, whereas the o,p′ isomers were above the LOD in at least 80% of the samples. Median (interquartile range) p,p′-DDT and p,p′-DDE serum concentrations for VHEMBE cohort participants were 55.3 (19.0–259.3) and 242.2 (91.8–878.7) ng/g-lipid, respectively. Mothers reporting to have lived in a home sprayed with DDT for malaria control had ∼5–7 times higher p,p′-DDT and p,p′-DDE serum concentrations than those who never lived in a home sprayed with DDT. Of the five potential interventions tested, we found increasing access to water significantly reduced p,p′-DDT exposure and increasing the frequency of household wet mopping significantly reduced p,p′-DDT and p,p′-DDE exposure. Conclusion: Our findings suggest that several intervention approaches may reduce DDT/DDE exposure in pregnant women living in IRS communities. https://doi.org/10.1289/EHP353

Exposure to DDT and hypertensive disorders of pregnancy among South African women from an indoor residual spraying region: The VHEMBE study

Abstract Indoor Residual Spraying (IRS), the use of insecticides inside residences for malaria control, may cause elevated exposure to insecticides such as dichlorodiphenyl trichloroethane (DDT). Evidence suggests that DDT exposure may increase blood pressure but no study has investigated associations with hypertensive disorders of pregnancy (HDP) in an IRS area. We measured the serum concentration of DDT and its breakdown product dichlorodiphenyl trichloroethylene (DDE) at the time of delivery among 733 rural South African women participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE). We also collected data on HDP diagnosis through questionnaires administered to participants and medical record abstraction. We used multiple logistic regression models to examine the relation between DDT/E and HDP. p,p′‐DDT and p,p′‐DDE serum concentrations were associated with HDP based on self‐report (OR = 1.50; 95%CI = 1.10, 2.03 for p,p′‐DDT and OR = 1.58; 95%CI = 1.09, 2.28 for p,p′‐DDE) and medical records (OR = 1.32; 95%CI = 0.99, 1.75 for p,p′‐DDT and OR = 1.47; 95%CI = 1.03, 2.09 for p,p′‐DDE). p,p′‐DDE was also associated with gestational hypertension (OR = 1.44; 95% CI = 1.00, 2.07). Exposure to DDT and DDE may be associated with elevated risks of HDP in South African women residing in an area sprayed for malaria control. HighlightsDDT is used in 10 countries to control malaria.Prior studies suggest associations between DDT and essential hypertension.No study of hypertensive disorders of pregnancy have been conducted in countries currently using DDT.In this study, DDT and DDE are associated with elevated odds of hypertensive disorders of pregnancy.Further studies are needed to confirm this finding.

Rates and predictors of recurrent work disability due to common mental health disorders in the United States

Context Despite the high prevalence of work disability due to common mental disorders (CMD), no information exists on the rates and predictors of recurrence in a United States population. Objective To estimate recurrent work disability statistics and evaluate factors associated with recurrence due to CMDs including adjustment, anxiety, bipolar, and depressive disorders. Methods Recurrent work disability statistics were calculated using a nationwide database of disability claims. For the CMDs, univariate and multiple variable analyses were used to examine demographic factors and comorbidities associated with the time to recurrence. Results Of the CMDs, cases with bipolar (n = 3,017) and depressive disorders (n = 20,058) had the highest recurrence densities, 98.7 and 70.9 per 1000 person-years, respectively. These rates were more than three times higher than recurrence rates for other chronic disorders (e.g., diabetes, asthma; n = 105,558) and non-chronic disorders (e.g., injury, acute illnesses; n = 153,786). Individuals with CMD were also more likely to have a subsequent disability distinct from their mental health condition. Risk factors for recurrent CMD disability included being younger, being an hourly employee, living in a geographic area with more college graduates, having more previous psychiatric visits, having a previous work leave, and the type of work industry. Conclusions Results indicate that CMD patients may benefit from additional care and disability management both during and after their work absence to help prevent subsequent CMD and non-CMD related leaves.