Venda Health Examination Of Mothers, Babies And Their Environment Research Articles

Association between prenatal exposure to indoor residual spraying insecticides and infection rates among South African children participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE)

In 2021, 53 countries conducted indoor residual spraying (IRS), the application of insecticides such as dichlorodiphenyl trichloroethane (DDT) or pyrethroids to the walls of homes to control malaria. Animal studies show that these insecticides can increase susceptibility to infections but only one human study was conducted in a population from an area where IRS is applied. The aim of the present study was thus to investigate whether maternal exposure to DDT, its breakdown product dichlorodiphenyl dichloroethylene (DDE) or pyrethroid insecticides is associated with symptoms of infection among children living in a region of South Africa were IRS is conducted annually. As part of the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) we measured maternal serum concentrations of DDT and DDE, and urinary concentrations of four pyrethroid metabolites in peripartum samples. Poisson regression models with robust variance estimates were used to investigate associations with the rates of infection symptoms between ages 3.5–5 years among 629 children as assessed based on caregiver interviews. Multiple pyrethroid metabolites were associated with infection symptoms. For instance, cis-DBCA was associated with increased rates of ear infection (Incidence Rate Ratio for a 10-fold increase (IRR10) = 1.4; 95 % Confidence Interval (CI) = 1.0, 2.1) and persistent diarrhea (IRR10 = 2.1; 95 % CI = 1.2, 3.9), trans-DCCA was associated with increased rates of colds in children (IRR10 = 1.3; 95 % CI = 1.0, 1.6) and persistent fever (IRS10 = 1.4; 95 % CI = 1.0, 2.0), and 3-PBA was associated with increased rates of persistent fever (IRR10 = 1.8; 95 % CI = 1.0, 3.0). We found limited evidence of association between maternal DDE and DDT serum concentrations and infection symptoms. Results suggest that prenatal exposure to pyrethroid insecticides may be associated with infections among children from an area where IRS is conducted.

Maternal exposure to pyrethroid insecticides during pregnancy and respiratory allergy symptoms among children participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE)

BackgroundPyrethroid insecticides use for indoor residual spraying (IRS) in malaria-endemic areas results in high levels of exposure to local populations. Pyrethroids may cause asthma and respiratory allergies but no prior study has investigated this question in an IRS area. MethodsWe measured maternal urinary concentrations of pyrethroid metabolites (cis-DBCA, cis-DCCA, trans-DCCA, 3-PBA) in samples collected at delivery from 751 mothers participating in the Venda Health Examination of Mothers, Babies, and their Environment (VHEMBE), a birth cohort study based in Limpopo, South Africa. At 3.5-year and 5-year follow-up visits, caregivers of 647 and 620 children, respectively, were queried about children's respiratory allergy symptoms based on validated instruments. We applied marginal structural models for repeated outcomes to estimate associations between biomarker concentrations and asthma diagnosis as well as respiratory allergy symptoms at ages 3.5 and 5 years. ResultsWe found that a10-fold increase in maternal urinary cis-DCCA, trans-DCCA and 3-PBA concentrations were associated with more than a doubling in the risk of doctor-diagnosed asthma (cis-DCCA: RR = 2.1, 95% CI = 1.3, 3.3; trans-DCCA: RR = 2.1, 95% CI = 1.1, 3.9; 3-PBA: RR = 2.4, 95% CI = 1.0, 5.8) and an about 80% increase in the risk of wheezing or whistling in the chest (cis-DCCA: RR = 1.8, 95% CI = 1.1, 3.0; trans-DCCA: RR = 1.7, 95% CI = 1.1, 2.6; 3-PBA: RR = 1.8, 95% CI = 1.0, 3.3) and suspected asthma (cis-DCCA: RR = 1.8, 95% CI = 1.1, 3.1; trans-DCCA: RR = 1.8, 95% CI = 1.1, 2.8). We also observed that higher concentrations of cis-DBCA and 3-PBA were related to increases in the risks of dry cough at night (RR = 3.5, 95% CI = 1.3, 9.5) and seasonal rhinoconjunctivitis (RR = 2.0, 95% CI = 1.1, 3.9), respectively. ConclusionMaternal exposure to pyrethroids may increase the risk of asthma and other respiratory allergy symptoms among preschool children from an IRS area.

Maternal exposure to DDT, DDE, and pyrethroid insecticides for malaria vector control and hypospadias in the VHEMBE birth cohort study, Limpopo, South Africa

Hypospadias is the ectopic opening of the urethra on the penis or scrotum. Exposure to estrogenic and/or anti-androgenic chemicals in utero may play an etiologic role. DDT and the pyrethroids cypermethrin and deltamethrin, are used to control malaria. DDT is estrogenic and its breakdown product DDE is anti-androgenic; cypermethrin and deltamethrin can also disrupt androgen pathways. We examined the relationship between maternal exposure to these insecticides during pregnancy and hypospadias among boys participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) in Limpopo Province, South Africa. We measured peripartum levels of p,p'-DDT and p,p'-DDE in maternal serum and urinary pyrethroid metabolites. We conducted urogenital examination on 359 one-year-old boys. A total of 291 (81.0 %) had phimosis, which prevented full urogenital examination, leaving a final sample of 68 boys for determination of the presence of hypospadias. Diagnosis was based on concordance of two independent physicians. We identified hypospadias in 23 of the 68 boys (34 %). Maternal urinary concentrations of cis-DCCA and trans-DCCA metabolites of cypermethrin and other pyrethroids, were associated with an increased risk for hypospadias, but the other metabolite 3-PBA was not (adjusted relative risk per 10-fold increase = 1.58, 95 % CI 1.07–2.34; 1.61, 95 % CI 1.09–2.36; and 1.48, 95 % CI 0.78–2.78, respectively). No associations were found between p,p'-DDT, p,p'-DDE, 3-PBA or cis-DBCA and hypospadias. We observed a high prevalence of hypospadias among boys without phymosis. Boys with higher prenatal exposure to pyrethroid insecticides were at higher risk of hypospadias. Our findings may have global implications given that pyrethroid insecticides are widely used for malaria control, in agriculture and for home use.

In-utero exposure to DDT and pyrethroids and child behavioral and emotional problems at 2 years of age in the VHEMBE cohort, South Africa

BackgroundHalf the world's population is at risk for malaria. Indoor residual spraying (IRS) with insecticides has been effective in controlling malaria, yet the potential neurotoxicity of these insecticides is of concern, particularly for infants exposed in utero. ObjectivesTo determine the association of prenatal exposure to DDT/DDE and pyrethroid insecticides and behavioral/emotional problems in two-year-old children. MethodsThe Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) birth cohort in South Africa, measured concentrations of p,p’-DDT and p,p’-DDE in maternal serum and pyrethroid metabolites (cis-DBCA, cis-DCCA, trans-DCCA, and 3-PBA) in maternal urine collected during pregnancy. At 2 years, 683 mothers were interviewed about their children's behavior and emotional development, using the Child Behavior Checklist (CBCL). We examined associations between behavioral or emotional problems and biomarkers of prenatal insecticide exposure. ResultsMaternal serum p,p’-DDT concentrations were associated with heightened withdrawn behavior in 2-year olds, with a 0.24 increase in raw scores (95%CI = 0.00, 0.49) and a 12% increase (95%CI = 1.01, 1.23) in risk of being at or above the borderline-clinical level, per 10-fold increase in concentrations. Ten-fold increases in p,p’-DDT and p,p’-DDE were related to 30% (RR = 1.30; 95%CI = 1.01, 1.67) and 39% (RR = 1.39; 95%CI =1.01, 1.91) higher risks, respectively, for increased oppositional-defiant behavior. p,p’-DDE concentrations were also related to increased risk of ADHD-related problems (RR = 1.30; 95%CI = 0.98, 1.72). Maternal urinary concentrations of cis-DBCA and 3-PBA were associated with increased risk of externalizing behaviors (RR = 1.30; 95%CI = 1.05, 1.62; RR = 1.35, 95%CI = 1.03, 1.78 per 10-fold increase, respectively), with some evidence of an association between cis-DBCA and affective disorders (RR = 1.25; 95%CI = 0.99, 1.56). Some associations with maternal pyrethroid concentrations were stronger in girls than boys. ConclusionsPrenatal exposure to DDT and pyrethroid insecticides may be associated with maternally-reported behavioral problems in two-year-old children. Given their long history and continued use, further investigation is warranted.

Prenatal exposure to insecticides and child cardiometabolic risk factors in the VHEMBE birth cohort.

Background:As part of malaria control programs, many countries spray dichlorodiphenyltrichloroethane (DDT) or pyrethroid insecticides inside dwellings in a practice called indoor residual spraying that results in high levels of exposure to local populations. Gestational exposure to these endocrine- and metabolism-disrupting chemicals may influence child cardiometabolic health.Methods:We measured the serum concentration of DDT and dichlorodiphenyldichloroethylene (DDE) and urinary concentration of pyrethroid metabolites (cis-DBCA, cis-DCCA, trans-DCCA, 3-PBA) in peripartum samples collected between August 2012 and December 2013 from 637 women participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), a birth cohort study based in Limpopo, South Africa. We applied marginal structural models to estimate the relationship between biomarker concentrations and child-size (height and weight), adiposity (body mass index [BMI], body fat percentage, waist circumference) and blood pressure at 5 years of age.Results:Maternal concentrations of all four pyrethroid metabolites were associated with lower adiposity including reduced BMI z-scores, smaller waist circumferences, and decreased body fat percentages. Reductions in BMI z-score were observed only among children of mothers with sufficient energy intake during pregnancy (βcis-DCCA, trans-DCCA=−0.4, 95% confidence interval (CI) = −0.7,−0.1; pinteraction=0.03 and 0.04, respectively) but there was no evidence of effect modification for the other measures of adiposity. Maternal p,p’-DDT concentrations were associated with a reduction in body fat percentage (β = −0.4%, 95% CI = −0.8,−0.0).Conclusions:Gestational exposure to pyrethroids may reduce adiposity in children at 5 years of age.

Prenatal exposure to insecticides and child weight trajectories in a South African birth cohort

Background: DDT or pyrethroid insecticides are sprayed inside dwellings as part of global malaria vector control programs, resulting in high levels of exposure to millions of people, including pregnant women. These chemicals are endocrine disruptors and may affect child growth. Study Design: The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) is a birth cohort study based in Limpopo, South Africa (n=752). Maternal peripartum concentrations of DDT and its breakdown product DDE were measured in serum and pyrethroid metabolites were measured in urine. Child weight was measured at birth and at 1, 2, 3.5 and 5-year follow-up visits; weight measurements were also abstracted from medical records. Methods: We modelled child weight trajectories using SuperImposition, Translation and Rotation (SITAR) to estimate child-specific weight over time and age at peak weight velocity (APWV). We then estimated associations between insecticides and SITAR parameters using multivariable linear regression. We also investigated whether child sex and maternal energy intake sufficiency during pregnancy modified these associations. Results: Maternal p,p’-DDT was associated with greater weight among girls (β=14g per 10-fold increase; 95%CI=0, 28) and children of mothers with sufficient energy intake (β=18g per 10-fold increase; 95%CI=1, 35). We also found that pyrethroids may be associated with lower weight and earlier APWV among boys, particularly for cis-DBCA, which is specific to deltamethrin (βweight= -24g per 10-fold increase; 95%CI=-52, 4; βAPWV=-2.6 days per 10-fold increase; 95% CI: -5.3, 0.1). Conclusions: Maternal DDT and pyrethroid exposure may be associated with child growth through age 5. Positive associations between p,p’-DDT and weight among girls are consistent with its estrogenic properties, and inverse associations between pyrethroids and weight and APWV among boys may be related to their androgenic properties. These findings, as well as that of effect modification by maternal energy intake, support our previous research in this population.

Associations between prenatal exposure to DDT and DDE and allergy symptoms and diagnoses in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), South Africa

Dichlorodiphenyl trichloroethane (DDT) is an organochlorine insecticide that is banned internationally except for use as part of Indoor Residual Spraying (IRS) programs to control malaria. Although animal studies show that DDT and its breakdown product dichlorodiphenyl dichloroethylene (DDE) affect the immune system and may cause allergies, no studies have examined this question in populations where IRS is conducted. The aim of our study was to investigate whether prenatal exposure to DDT and DDE is associated with allergy symptoms and diagnose among South African children living in an area where IRS is conducted. To accomplish this aim, we used data from the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), an ongoing birth cohort study of 752 children born between 2012 and 2013 in the rural Vhembe district of Limpopo, South Africa. We measured maternal peripartum serum concentrations of DDT and DDE, and administered a questionnaire to the caregivers of 658 children aged 3.5 years to collect information on allergy symptoms and diagnoses as well as potential confounders using validated instruments. Using multiple logistic regression models, we found positive associations between DDT and DDE serum concentrations and most of the allergy symptoms and diagnoses. Maternal DDT (Odds Ratio [OR] = 1.5 per 10-fold increase, 95% Confidence interval, CI = 1.0, 2.3) and DDE (OR = 1.4, 95% CI = 0.8, 2.4) serum concentrations were most strongly associated with caregiver report of wheezing or whistling in the chest. Concentrations of DDT and/or DDE were also associated with increased odds of children's chests sounding wheezy during or after exercise, itchy rashes coming and going for at least six months, diagnosis of food allergy, and diagnosis of dust or dust mites allergy but confidence intervals crossed the null. Results suggest that prenatal exposure to DDT, and possibly DDE, is associated with elevated odds of wheezing among children from an IRS area.

Exposure to lead and vaccine-specific IgG titers in South African children participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE): A longitudinal study

BackgroundWhile successes have been achieved in reducing global exposure to lead, few studies have investigated the potential health effects of low-level exposure (e.g. blood lead levels [BLLs] below the CDC reference level of 5 μg/dL), particularly among children from low- and middle-income countries. In addition, lead is immunotoxic in animals but human data on immune response to vaccines is limited. Our aim was to determine whether low-level exposure to lead is associated with humoral response to vaccines among rural South African children. MethodsWe used data from the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), a birth cohort study conducted in Limpopo, South Africa. BLLs were measured in whole blood collected at age 1 year and IgG titers for measles, tetanus and Haemophilus influenzae type B (Hib) were determined at age 3.5 years among 425 fully-vaccinated children. ResultsBLLs were low (median = 1.90 μg/dL) and 94% of children had a BLL below 5 μg/dL. Overall, BLLs were associated with higher risks of having IgG titers below the protective limit for tetanus (RR = 1.88 per 10-fold increase; 95%CI = 1.08, 3.24) but not measles (RR = 1.02; 95%CI = 0.26, 3.95) or Hib (RR = 0.96; 95%CI = 0.54, 1.71). BLLs were also associated with low Hib IgG titers among children exposed to HIV in utero and with low measles IgG titers among females. In contrast, the association with measles IgG titers was positive among males. ConclusionLow-level exposure to lead may compromise the humoral response to vaccines. Children exposed to HIV in utero and females may be particularly susceptible.

Prenatal exposure to DDT and pyrethroids and humoral response to vaccines among South African children from an area sprayed for malaria control

OPS 60: Social factors and environmental health across the world, Room 210, Floor 2, August 27, 2019, 1:30 PM - 3:00 PM Background/Aim: Animals studies strongly suggest that exposure to insecticides such as DDT and pyrethroids may inhibit immune response to vaccines. However, few human studies have investigated this question and none have done so in communities where insecticides are used to control malaria as part of Indoor Residual Spraying programs. These communities experience high exposure to insecticides and may be particularly susceptible to their toxic effects due to poverty, malnutrition and poor health. Our objective was thus to evaluate whether prenatal exposure to DDT and pyrethroids was associated with reduced immune response to vaccines at age 3.5 and 5 years among South African children participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) birth cohort study. Methods: Between August 2012 and December 2013, we enrolled 752 women when they presented for delivery at Tshilidzini hospital in the city of Thohoyandou. We collected urine and blood samples at delivery for the measurement of pyrethroid metabolites and DDT via gas chromatography-mass spectrometry, respectively. At age 3.5 and 5 years, we measured measles, tetanus and Haemophilus influenzae b (Hib)-specific antibody titers in serum via enzyme-linked immunosorbent assay (ELISA). Results: Percentages of fully-vaccinated children with antibody titers below protective levels were 5.6% for measles, 31.1% for tetanus and 29.1% for Hib. Prenatal exposure to pyrethroids was associated with elevated risks of low measles (but not tetanus and Hib) antibody titers at 3.5 years. Each 10-fold increase in maternal urinary concentrations of 3-PBA, trans-DCCA and cis-DCCA was associated with relative risks of 1.85 (95%CI=0.98, 3.49), 1.84 (95%CI=1.09, 3.09) and 2.43 (95%CI=1.38, 4.29), respectively. No associations were found with DDT and DDE. Associations with antibody titers at age 5 will also be presented. Conclusion: Results suggest that prenatal exposure to pyrethroids may inhibit immune response to vaccines among South African children.

Seasonality of antenatal care attendance, maternal dietary intake, and fetal growth in the VHEMBE birth cohort, South Africa.

BackgroundSeasonality of food availability, physical activity, and infections commonly occurs within rural communities in low and middle-income countries with distinct rainy seasons. To better understand the implications of these regularly occurring environmental stressors for maternal and child health, this study examined seasonal variation in nutrition and health care access of pregnant women and infants in rural South Africa.MethodsWe analyzed data from the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) birth cohort study of 752 mother-infant pairs recruited at delivery from August 2012 to December 2013 in the Vhembe District of Limpopo Province, the northernmost region of South Africa. We used truncated Fourier series regression to assess seasonality of antenatal care (ANC) attendance, dietary intake, and birth size. We additionally regressed ANC attendance on daily rainfall values. Models included adjustment for sociodemographic characteristics.ResultsMaternal ANC attendance, dietary composition, and infant birth size exhibited significant seasonal variation in both unadjusted and adjusted analyses. Adequate frequency of ANC attendance during pregnancy (≥ 4 visits) was highest among women delivering during the gardening season and lowest during the lean (rainy) season. High rainfall during the third trimester was also negatively associated with adequate ANC attendance (adjusted OR = 0.59, 95% CI: 0.40, 0.86). Carbohydrate intake declined during the harvest season and increased during the vegetable gardening and lean seasons, while fat intake followed the opposite trend. Infant birth weight, length, and head circumference z-scores peaked following the gardening season and were lowest after the harvest season. Maternal protein intake and ANC ≤ 12 weeks did not significantly vary by season or rainfall.ConclusionsSeasonal patterns were apparent in ANC utilization, dietary intake, and fetal growth in rural South Africa. Interventions to promote maternal and child health in similar settings should consider seasonal factors.

Sex and poverty modify associations between maternal peripartum concentrations of DDT/E and pyrethroid metabolites and thyroid hormone levels in neonates participating in the VHEMBE study, South Africa

Indoor Residual Spraying (IRS), the application of insecticides on the inside walls of dwellings, is used by 84 countries for malaria control. Although effective in preventing malaria, this practice results in elevated insecticide exposure to >100 million people, most of whom are Africans. Pyrethroid insecticides and dichlorodiphenyl trichloroethane (DDT) are currently used for IRS. Animal and in vitro studies suggest that pyrethroids and DDT interfere with thyroid hormone homeostasis but human studies are inconsistent and no prior study has investigated this question in a population residing in an area where IRS is conducted. Our objective was thus to evaluate whether prenatal exposure to pyrethroids, DDT or DDT's breakdown product dichlorodiphenyl dichloroethylene (DDE) is associated with altered thyroid hormone levels among neonates from Limpopo, South Africa, where pyrethroids and DDT are used annually to control malaria. We measured serum DDT/E and urinary pyrethroid metabolite concentrations in maternal peripartum samples from 717 women participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), a birth cohort study conducted in Limpopo's Vhembe district. We measured total thyroxine (T4) and thyroid-stimulating hormone (TSH) in dried blood spots collected via heel stick. We found that all pyrethroid metabolites were positively associated with TSH; trans-DCCA and 3-PBA showed the strongest associations with a 12.3% (95%CI = 3.0, 22.3) and 14.0% (95%CI = 0.5, 30.2) change for each 10-fold increase in biomarker concentration, respectively. These associations were substantially stronger among children from households below the South African food poverty line. DDT and DDE were associated with lower total T4 among boys only (β = −0.27 μg/dL per 10-fold increase; 95%CI = −0.47, −0.04). Results suggest that prenatal exposure to DDT, DDE and pyrethroid insecticides is associated with changes in neonatal thyroid hormones consistent with hypothyroidism/hypothyroxinemia and that sex and poverty modify associations. Further research is needed to confirm these findings and examine whether they have implications for child development.

Determinants of Exposure to Pyrethroid Insecticides in the VHEMBE Cohort, South Africa.

Exposure to pyrethroid insecticides has been linked to adverse health effects, and can originate from several sources, including indoor residual spraying (IRS) for malaria control, home pest control, food contamination, and occupational exposure. We aimed to explore the determinants of urinary pyrethroid metabolite concentrations in a rural population with high pesticide use. The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) is a birth cohort of 752 mother-child pairs in Limpopo, South Africa. We measured pyrethroid metabolites in maternal urine and collected information on several factors possibly related to pesticide exposure, including IRS, home pesticide use, and maternal factors (e.g., dietary habits and body composition). We performed statistical analysis using both conventional bivariate regressions and Bayesian variable selection methods. Urinary pyrethroid metabolites are consistently associated with pesticide factors around homes, including pesticide application in yards and food stocks, and IRS in the home during pregnancy, while more distant factors such as village spraying are not. High fat intake is associated with higher metabolite concentrations, and women from homes drawing water from wells or springs had marginally higher levels. Home pesticide use is the most consistent correlate of pyrethroid metabolite concentrations, but IRS, dietary habits, and household water source may also be important exposure determinants.

Early-life exposure to p,p′-DDT and p,p′-DDE in South African children participating in the VHEMBE study: An assessment using repeated serum measurements and pharmacokinetic modeling

BackgroundThe World Health Organization recommends indoor residual spraying (IRS) of insecticides (including dichlorodiphenyltrichloroethane [DDT]) to fight malaria vectors in endemic countries. There is limited information on children's exposure to DDT in sprayed areas, and tools to estimate early-life exposure have not been thoroughly evaluated in this context. ObjectivesTo document serum p,p′-DDT/E levels in 47 mothers and children participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), a study conducted in an area where IRS insecticides are used annually, and to evaluate the precision and accuracy of a published pharmacokinetic model for the estimation of children's p,p′-DDT/E levels. Methodsp,p′-DDT/E levels were measured in maternal serum at delivery, and in children's serum at 12 and 24 months of age. A pharmacokinetic model of gestational and lactational exposure was used to estimate children's p,p′-DDT/E levels during pregnancy and the first two years of life, and estimated levels were compared to measured levels. ResultsThe geometric means of children's serum p,p′-DDT/E levels at 12 and 24 months were higher than those of maternal serum levels. Regression models of measured children's p,p′-DDT/E levels vs. levels estimated with the pharmacokinetic model (which only accounted for children's exposure through placental transfer and breastfeeding) had coefficients of determination (R2) ranging from 0.75 to 0.82. Estimated p,p′-DDE levels were not significantly different from measured levels, whereas p,p′-DDT levels were overestimated by 36% at 12 months, and 51% at 24 months. ConclusionResults indicate that children living in a sprayed area have serum p,p′-DDT/E levels exceeding their mothers' during the first two years of life. The pharmacokinetic model may be useful to estimate children's levels in the VHEMBE population.

Associations of Maternal Exposure to Dichlorodiphenyltrichloroethane and Pyrethroids With Birth Outcomes Among Participants in the Venda Health Examination of Mothers, Babies and Their Environment Residing in an Area Sprayed for Malaria Control.

Although effective in controlling malaria, indoor residual spraying results in elevated exposure to insecticides such as dichlorodiphenyltrichloroethane (DDT) and pyrethroids. These chemicals cross the placenta, but no studies have examined their associations with birth outcomes in populations residing in indoor residual spraying areas. We investigated this question in the Venda Health Examination of Mothers, Babies and Their Environment (VHEMBE), a birth cohort study of 751 South African children born between 2012 and 2013. We measured maternal peripartum serum DDT and urine pyrethroid metabolite concentrations and collected data on birth weight, length, head circumference, and duration of gestation. We analyzed the data using marginal structural models with inverse-probability-of-treatment weights, generalized propensity scores, and standard conditional linear regression. Using all 3 analytical methods, p,p'-DDT, o,p'-DDT, and to a lesser extent p,p'-dichlorodiphenyldichloroethylene were related to elevated birth weight, birth length, and head circumference among girls. Changes in gestational duration did not mediate this relationship, suggesting that these exposures accelerate fetal growth, which is consistent with the known estrogenic properties of o,p'-DDT and p,p'-DDT. No associations with pyrethroid metabolites were found. Results suggest that prenatal exposure to DDT is related to elevated birth size. Further studies are needed to elucidate the implications of these findings.

Prenatal Exposure to DDT and Pyrethroids for Malaria Control and Child Neurodevelopment: The VHEMBE Cohort, South Africa.

Background:Although indoor residual spraying (IRS) with dichlorodiphenyltrichloroethane (DDT) and pyrethroids effectively controls malaria, it potentially increases human exposure to these insecticides. Previous studies suggest that prenatal exposure to these insecticides may impact human neurodevelopment.Objectives:We aimed to estimate the effects of maternal insecticide exposure and neurodevelopment of toddlers living in a malaria-endemic region currently using IRS.Methods:The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) is a birth cohort of 752 mother–child pairs in Limpopo, South Africa. We measured maternal exposure to DDT and its breakdown product, dichlorodiphenyldichloroethylene (DDE), in maternal serum, and measured pyrethroid metabolites in maternal urine. We assessed children’s neurodevelopment at 1 and 2 y of age using the Bayley Scales of Infant Development, third edition (BSID-III), and examined associations with maternal exposure.Results:DDT and DDE were not associated with significantly lower scores for any BSID-III scale. In contrast, each 10-fold increase in cis-DCCA, trans-DCCA, and 3-phenoxybenzoic acid were associated, respectively, with a (95% CI: , ), (95% CI: , ), and (, ) decrement in Social-Emotional scores at 1 y of age. In addition, each 10-fold increase in maternal cis-DBCA levels was associated with significant decrements at 2 y of age in Language Composite scores and Expressive Communication scores [ (95% CI: , ) and (95% CI: , ), respectively, for a 10-fold increase]. Significant differences by sex were estimated for pyrethroid metabolites and motor function scores at 2 y of age, with higher scores for boys and lower scores for girls.Conclusions:Prenatal exposure to pyrethroids may be associated at 1 y of age with poorer social-emotional development. At 2 y of age, poorer language development was observed with higher prenatal pyrethroid levels. Considering the widespread use of pyrethroids, these findings deserve further investigation. https://doi.org/10.1289/EHP2129

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

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.

Balancing the risks and benefits of insecticide use for vector control: The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) Study.

Balancing the risks and benefits of insecticide use for vector control: The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) Study.

Balancing the risks and benefits of insecticide use for vector control: The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) Study

Balancing the risks and benefits of insecticide use for vector control: The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) Study

Dichlorodiphenyltrichloroethane exposure and anogenital distance in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) birth cohort study, South Africa.

Dichlorodiphenyltrichloroethane (DDT) is used for malaria control by 10 countries, nine of which are in Africa. Technical DDT contains various isomers with 65-80% insecticidal p,p'-DDT and 15-21% o,p'-DDT, an estrogenic chemical, while the persistent metabolite of p,p'-DDT, dichlorodiphenyldichloroethylene (p,p'-DDE), is an antiandrogen. In utero antiandrogenic exposure reduces anogenital distance in animal models and the anal position index in a single study. This study examined the associations between mother's serum DDT and DDE levels at delivery and anogenital distance in their children at birth and age 1year. Data were collected as part of the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), a birth cohort study located in rural South Africa. DDT and DDE concentrations were measured in blood samples collected from 752 mothers at delivery. Anogenital distance measurements, taken at birth (n=671) and age 1year (n=674), included anofourchette and anoclitoral distances in girls, and anoscrotal and anopenile lengths in boys. We also measured anococcygeal and coccyx-fourchette distances in girls, while in boys, we measured anococcygeal and coccyx-scrotal distances as well as penile length and penile width. The anal position index is calculated for both sexes as anoscrotal/coccyx-scrotal in boys and anofourchette/coccyx-fourchette in girls. We found no associations between p,p'-DDT/-DDE or o,p'-DDT and anogenital distance measurements at birth in either boys or girls. At 1year, o,p'-DDE was negatively associated with anofourchette in girls (β=-1.32mm, 95% confidence interval (CI)=-2.27, -0.38) and positively associated with penile width in boys (β=0.30mm, 95% CI=0.00, 0.60). The results do not suggest an overt antiandrogenic or estrogenic effect on anogenital distance after long-term DDT exposure. These weak associations may be due to chance.

Exposure To Ddt Following Indoor Residual Spraying And Hypertensive Disorders Of Pregnancy In South African Women Participating In The Vhembe Study

Introduction: Indoor Residual Spraying (IRS) for malaria control exposes 120 million people to high levels of insecticides such as DDT (dichlorodiphenyltrichloroethane). Evidence suggests DDT exposure may increase blood pressure (BP) but no study has investigated associations with hypertensive disorders of pregnancy (HDP) in an IRS area. Methods: We used data from the NIEHS-funded Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), a birth cohort study of 751 mother-infant pairs in South Africa. Serum concentrations of DDT and its breakdown product, DDE, and proteinuria were measured in pregnant women at delivery. HDP diagnostic (preeclampsia, eclampsia or gestational hypertension) was collected by questionnaire and gestational BP was abstracted from medical records. We used multiple logistic and linear regression models to examine the relation between DDT, DDE and HDP. Results: Geometric mean (GM) concentrations of DDT and DDE in maternal serum were 76.32 ng/g lipid [geometric standard deviation (GSD): 6.02] and 91.66 ng/g lipid (GSD: 4.71), respectively. Current Canadian concentrations measured in an adult population are lower for DDT (GM