Dietary intake and urinary metals among pregnant women in the Pacific Northwest

Food groups consumption and urinary metal mixtures in women from Northern Mexico

OBJECTIVE

We aimed to evaluate the association between food groups and mixtures of urinary metal concentrations in a sample of women; as well as identify the most important metals within each mixture.

METHODS

This is a cross-sectional analysis between food groups consumption and mixtures of various metals in urine from 439 women, ≥18 years old, from Northen Mexico. We estimated the dietary intake of 20 food groups through a validated semi-quantitative food frequency questionnaire. Urinary metal concentration of aluminum, antimony, arsenic, barium, cadmium, cesium, chromium, cobalt, copper, lead, manganese, magnesium, molybdenum, nickel, selenium, thallium, tin, vanadium, and zinc, were measured by inductively coupled plasma triple quad. We used weighted quantile sum (WQS) regression with binomial family specification to assess the association of food groups and metal mixtures, as well as to identify the most important ones.

RESULTS

We identified tin, lead, and antimony as the most important metals, in the metal mixtures that were positively associated with the consumption of eggs, non-starchy vegetables, fruits, seafood, corn, oil seeds, chicken, soda, legumes, red and/or processed meats, as well as negatively with the consumption of alliums, corn tortillas and/or vegetable oils.

CONCLUSION

Our findings suggest that food consumption is related to more than one metal in the study sample, and highlights the presence of some of them. Further research is required to identify the possible sources of metals in food, as well as the chronic adverse health effects attributed to their simultaneous presence.

Mollusc and crustacean consumption in the first 1000 days: a scoping review

Mollusc and crustacean consumption in the first 1000 d may improve maternal and child health by providing essential nutrients. However, in some contexts, molluscs and crustaceans have been associated with allergies and environmental contamination, potentially leading to adverse health and development outcomes. It is unclear whether the health benefits of consuming molluscs and crustaceans, collectively classified as shellfish in nutrition, are outweighed by the potential risks to pregnant women and children. We conducted a scoping review (PROSPERO: CRD42022320454) in PubMed, Scopus and EBSCO Global Health of articles published between January 2000 and March 2022 that assessed shellfish consumption during pregnancy, lactation or childhood (0-2 years) in relation to maternal health, child health or child development. A total of forty-six articles were included in this review. Overall, shellfish consumption was associated with higher biomarkers of environmental contaminants, with mercury being the most studied and having the strongest evidence base. The limited research on nutritional biomarker status shows an association between shellfish consumption and iodine status. Preterm birth was not associated with shellfish consumption, but newborn anthropometry showed mixed results, with several studies reporting lower birth weight with higher shellfish consumption. The few studies that examined child development and maternal health outcomes reported no significant associations. This review revealed trade-off health risks and benefits with inclusion of molluscs and crustaceans in the dietary patterns of mothers and young children. More research is needed to understand how these aquatic animal-source foods may be safely consumed and leveraged for improving human nutrition.

Correlates of whole blood metal concentrations among reproductive-aged Black women

BACKGROUND

Metals may influence reproductive health, but few studies have investigated correlates of metal body burden among reproductive-aged women outside of pregnancy. Furthermore, while there is evidence of racial disparities in exposure to metals among U.S. women, there is limited research about correlates of metal body burden among Black women.

OBJECTIVE

To identify correlates of whole blood metal concentrations among reproductive-aged Black women.

METHODS

We analyzed cross-sectional data from a cohort of 1664 Black women aged 23-35 years in Detroit, Michigan, 2010-2012. We collected blood samples and questionnaire data. We measured concentrations of 17 metals in whole blood using inductively-coupled plasma-mass spectrometer-triple quadrupole and total mercury using Direct Mercury Analyzer-80. We used multivariable linear regression models to identify sociodemographic, environmental, reproductive, and dietary correlates of individual metal concentrations.

RESULTS

In adjusted models, age was positively associated with multiple metals, including arsenic, cadmium, and mercury. Education and income were inversely associated with cadmium and lead. Current smoking was strongly, positively associated with cadmium and lead. Alcohol intake in the past year was positively associated with arsenic, barium, copper, lead, mercury, vanadium, and zinc. Having pumped gasoline in the past 24 h was positively associated with cadmium, chromium, and molybdenum. Having lived in an urban area for the majority of residence in Michigan was positively associated with arsenic, lead, and nickel. Higher water intake in the past year was positively associated with several metals, including lead. Fish intake in the past year was positively associated with arsenic, cesium, and mercury. We also observed associations with body mass index, season, and other environmental, reproductive, and dietary factors.

SIGNIFICANCE

We identified potential sources of exposure to metals among reproductive-aged Black women. Our findings improve understanding of exposures to metals among non-pregnant reproductive-aged women, and can inform policies in support of reducing disparities in exposures.

IMPACT STATEMENT

There are racial disparities in exposures to metals. We analyzed correlates of blood metal concentrations among reproductive-aged Black women in the Detroit, Michigan metropolitan area. We identified sociodemographic, anthropometric, lifestyle, environmental, reproductive, and dietary correlates of metal body burden. Age was positively associated with several metals. Education and income were inversely associated with cadmium and lead, indicating socioeconomic disparities. We identified potential exposure sources of metals among reproductive-aged Black women, including smoking, environmental tobacco smoke, pumping gasoline, living in an urban area, and intake of alcohol, water, fish, and rice.

Association between mediterranean diet and metal(loid) exposure in 4-5-year-old children living in Spain

Even relatively low levels of metals exposure may impact health, particularly among vulnerable populations such as infants and young children. However, little is known about the interplay between simultaneous metal exposures, common in real-life scenarios, and their association with specific dietary patterns. In this study, we have evaluated the association between adherence to Mediterranean diet (MD) and urinary metal concentrations individually and as an exposure mixture in 713 children aged 4-5-years from the INMA cohort study. We used a validated food frequency questionnaire to calculate two MD indexes scores: aMED and rMED. These indexes gather information on various food groups within the MD and score differently. To measure urinary concentrations of cobalt, copper, zinc, molybdenum, selenium, lead, and cadmium as exposure biomarkers, we used inductively coupled plasma mass spectrometry (ICP-MS), coupled with an ion chromatography (IC) equipment for arsenic speciation analysis. We applied linear regression and quantile g-computation, adjusted for confounders, to analyse the association between MD adherence and exposure to the metal mixture. High adherence to MD such as the quintile (Q) 5 MD was associated with higher urinary arsenobetaine (AsB) levels than Q1, with β values of 0.55 (confidence interval - CI 95% 0.01; 1.09) for aMED and 0.73 (CI 95% 0.13; 1.33) for rMED. Consumption of fish was associated with increased urinary AsB but reduced inorganic arsenic concentrations. In contrast, the aMED vegetables consumption increased urinary inorganic arsenic content. A moderate level of adherence to MD (Q2 and Q3) was associated with lower copper urinary concentrations than Q1, with β values of -0.42 (CI 95% -0.72; -0.11) for Q2 and -0.33 (CI 95% -0.63; -0.02) for Q3, but only with aMED. Our study, conducted in Spain, revealed that adhering to the MD reduces exposure to certain metals while increasing exposure to others. Specifically, we observed increase in exposure to non-toxic AsB, highlighting the significance of consuming fish/seafood. However, it is crucial to emphasize the necessity for additional efforts in reducing early-life exposure to toxic metals, even when adhering to certain food components of the MD.

Association between prenatal exposure to trace elements mixture and visual acuity in infants: A prospective birth cohort study

BACKGROUND

Prenatal environmental factors may affect the development of the offspring and can bring long lasting consequences to the offspring's health. To date, only few studies have reported inconclusive association between prenatal single trace element exposure and visual acuity, and no studies have investigated the association between prenatal exposure to trace elements mixture and visual acuity in infants.

METHODS

In the prospective cohort study, grating acuity in infants (12 ± 1 months) was measured by Teller Acuity Cards II. Concentrations of 20 trace elements in maternal urine samples collected in early-trimester were measured by Inductively Coupled Plasma Mass Spectrometry. Elastic net regression (ENET) was applied to select important trace elements. Nonlinear associations of the trace elements levels with abnormal grating were explored using the restricted cubic spline (RCS) method. The associations between selected individual elements and abnormal grating acuity were further appraised using the logistic regression model. Then Bayesian Kernel Machine Regression (BKMR) was used to estimate the joint effects of mixture and interactions between trace elements combining with NLinteraction.

RESULTS

Of 932 mother-infant pairs, 70 infants had abnormal grating acuity. The ENET model produced 8 trace elements with non-zero coefficients, including cadmium, manganese, molybdenum, nickel, rubidium, antimony, tin and titanium. RCS analyses identified no nonlinear associations of the 8 elements with abnormal grating acuity. The single-exposure analyses using logistic regression revealed that prenatal molybdenum exposure possessed a significantly positive association with abnormal grating acuity (odds ratio [OR]: 1.44 per IQR increase, 95% confidence interval [CI]: 1.05, 1.96; P = 0.023), while prenatal nickel exposure presented with a significantly inverse association with abnormal grating acuity (OR: 0.64 per IQR increase, 95% CI: 0.45, 0.89; P = 0.009). Similar effects were also observed in BKMR models. Moreover, the BKMR models and NLinteraction method identified potential interaction between molybdenum and nickel.

CONCLUSIONS

We established that prenatal exposure to high concentration of molybdenum and low concentration of nickel was associated with the increased risk of abnormal visual acuity. Potential interaction may exist between molybdenum and nickel on abnormal visual acuity.

Association of Selenium Levels with Preeclampsia: A Systematic Review and Meta-analysis

Several observational studies have shown inconclusive findings on the association between selenium levels and preeclampsia. This systematic review and meta-analysis was conducted to clarify the association between selenium levels and preeclampsia. The databases PubMed, Google Scholar, ScienceDirect, and the Cochrane Library were searched for studies which investigated selenium levels with preeclampsia and which were published up to April 2022. The overall standardized mean differences (SMD) of selenium levels between cases and controls were measured. Sensitivity analysis, reporting bias, subgroup analysis, and meta-regression were performed for the estimate. The meta-analysis was calculated using the "meta" package in the open-source software R. A total of 26 studies with 1855 preeclampsia cases compared with 3728 healthy pregnant controls were included. The level of selenium was significantly lower in cases of preeclampsia compared with the controls [SMD =  - 0.85; 95% confidence interval (CI): (- 1.46, - 0.25); P =  < 0.01). As there was significant heterogeneity [I² = 96%, Cochran's Q = 620.47; P =  < 0.01], the random effects model was used. A stratified meta-analysis revealed that selenium levels were significantly lower in the cases compared with the controls among pregnant women from the African continent [SMD =  - 1.15 (- 1.65, - 0.65); P =  < 0.01]. Likewise, the same pattern was observed among women from middle- and low-income countries [SMD =  - 1.32 (- 2.22, - 0.42); P =  < 0.01]. None of the investigated factors (Modified Newcastle-Ottawa Scale quality score, year of publication, and sample size) showed significant association with the selenium SMD. The level of certainty of this evidence is "low certainty," as calculated by the GRADEpro GDT online tool. This meta-analysis with low level of evidence certainty revealed that low selenium level is associated significantly with preeclampsia. This pattern is also observed in women from the African continent and women from low- or middle-income countries. Further studies with different prospective designs and detailed patient characteristics are needed to consolidate this evidence.

Placental levels of essential and non-essential trace element in relation to neonatal weight in Northwestern Spain: application of generalized additive models

Adequate gestational progression depends to a great extent on placental development, which can modify maternal and neonatal outcomes. Any environmental toxicant, including metals, with the capacity to affect the placenta can alter the development of the pregnancy and its outcome. The objective of this study was to correlate the placenta levels of 14 essential and non-essential elements with neonatal weight. We examined relationships between placental concentrations of arsenic, cadmium, cobalt, copper, mercury, lithium, manganese, molybdenum, nickel, lead, rubidium, selenium, strontium, and zinc from 79 low obstetric risk pregnant women in Ourense (Northwestern Spain, 42°20'12.1″N 7°51.844'O) with neonatal weight. We tested associations between placental metal concentrations and neonatal weight by conducting multivariable linear regressions using generalized linear models (GLM) and generalized additive models (GAM). While placental Co (p = 0.03) and Sr (p = 0.048) concentrations were associated with higher neonatal weight, concentrations of Li (p = 0.027), Mo (p = 0.049), and Se (p = 0.02) in the placenta were associated with lower newborn weight. Our findings suggest that the concentration of some metals in the placenta may affect fetal growth.

Feasibility of a Food Delivery Intervention during Pregnancy in a Rural US Population: The PEAPOD Pilot Study

Pregnancy nutrition is important for maternal and child health and may affect the development of the infant gut microbiome. Our objective was to assess the feasibility of implementing a food-based intervention designed to increase fiber intake among pregnant women in a rural setting. Participants were enrolled (N = 27) mid-pregnancy from a prenatal care clinic in rural Michigan, randomized to intervention (N = 13) or usual care (N = 14), and followed to 6 weeks postpartum. The intervention was designed to be easily replicable and scalable by partnering with hospital foodservices and included non-perishable high fiber foods and recipes, as well as weekly delivery of salads, soup, and fresh fruit. Surveys, maternal blood, urine, and stool were collected at 24- and 36-weeks gestation and at 6 weeks postpartum. Infant stool was collected at 6 weeks. Participants were 100% White (7% Hispanic White, 7% Native American and White); 55% with education < 4-year college degree. Data on dietary intake and urinary trace elements are presented as evidence of feasibility of outcome measurement. Retention was high at 93%; 85% reported high satisfaction. The intervention described here can be replicated and used in larger, longer studies designed to assess the effects of pregnancy diet on the establishment of the infant gut microbiome and related health outcomes.

Environmental and dietary determinants of metal exposure in four-year-old children from a cohort located in an industrial area (Asturias, Northern Spain)

Urine samples from four-year-old children located in a heavily industrialized zone in Asturias (Spain) were collected between 2009 and 2012 (n = 334). Vanadium (V; median 54 μg/g creatinine), cobalt (Co; 1.0 μg/g c.), nickel (Ni; 3.8 μg/g c.), copper (Cu; 22 μg/g c.), zinc (Zn; 590 μg/g c.), arsenic (As; 64 μg/g c.), selenium (Se; 49 μg/g c.), molybdenum (Mo; 110 μg/g c.), cadmium (Cd; 0.27 μg/g c.), antimony (Sb; 1.0 μg/g c.), cesium (Cs; 14 μg/g c.), barium (Ba; 2.6 μg/g c.), thallium (Tl; 0.55 μg/g c.) and lead (Pb; 1.9 μg/g c.) were analysed. Comparison with children from other sites showed that this Asturias cohort was characterized by high levels of V, As, Sb, Cs and Tl. The concentrations of Co, Ni, Zn, Cu, Mo, Se, Cd, Ba and Pb were within the range of other cohorts. Terrestrial dietary items were most strongly related to increased urinary concentrations of metals in children, e.g., red meat with Ba and Ni, pasta/cereal with Ni and Zn, sweets with Zn, Co, and Cu, eggs with Mo, Cd, and Cs, and dairy products with Co and Sb. Seafood was the second group of dietary items significantly related to increased metals, e.g., shellfish with Ba, Cs, Pb, and V, fatty fish with As, and lean fish with As and Se. In contrast, higher fruit intake was significantly associated with decreased Cu and Sb, and higher legume intake with decreased Cu, Se and Cs. Higher intakes of other dietary items also led to significant decreases in some metals, such as vegetables and lower concentrations of Se and Mo, and dairy products with decreases in Cu and As. These negative correlations implied very low concentrations of the mentioned metals in these foods. Higher exposure to traffic was associated with higher concentrations of Ba, present in brake components. Children living outside urban areas had higher concentrations of Se. No association of metals with smoking in the family was found.

The Influence of Sociodemographic Factors, Lifestyle, and Risk Perception on Dietary Patterns in Pregnant Women Living in Highly Contaminated Areas: Data from the NEHO Birth Cohort

During pregnancy, maternal nutrition and lifestyle play a critical role in influencing fetal development and newborn health outcomes. The aim of this study is to investigate the factors influencing the adherence to dietary patterns in pregnant women living in highly contaminated areas, and whether women with higher environmental risk perception manifest different nutritional behaviors during pregnancy. Food consumption data on 816 pregnant women from the Neonatal Environment and Health Outcomes (NEHO) residential birth cohort were analyzed. Dietary patterns were computed by principal component analysis. A multinomial logistic regression was also applied to identify sociodemographic, lifestyle, and pregnancy-related determinants of adherence to dietary patterns during pregnancy. Three patterns of food consumption—explaining 24.9% of the total variance—were identified as “prudent”, “high energy”, and “vegetarian” patterns. Results suggest that food choices during pregnancy follow a social gradient and align with other health behaviors during pregnancy: older, better educated, and physically active women with higher risk perception are more likely to follow healthier dietary patterns. Knowledge about what is eaten can contribute to dietary choices. Interventions to improve the prenatal nutrition knowledge of pregnant women are needed, especially concerning younger mothers and those with lower educational levels.

Free Cortisol Mediates Associations of Maternal Urinary Heavy Metals with Neonatal Anthropometric Measures: A Cross-Sectional Study

Prenatal exposure to heavy metals is known to be associated with adverse birth outcomes and oxidative stress biomarkers. In this study, we examined whether maternal free cortisol or 8-Hydroxy-2-Deoxyguanosine (8-OHdG) could mediate associations between maternal heavy metal exposure and birth outcomes. A total of 182 healthy pregnant women were recruited. Heavy metals (including Pb, Hg, and Cd), free-cortisol, and 8-OHdG were analyzed in urine at delivery. Birth outcomes including birth weight, length, Ponderal index, and head circumference were measured. To examine associations of maternal urinary heavy metals with biomarkers and birth outcomes, generalized linear models were employed. Birth length was positively associated with Pb (β = 0.78, 95% CI: 0.09−1.46) and Hg (β = 0.84, 95% CI: 0.23−1.45) (both p < 0.05). The Ponderal index, a measure of a newborn’s leanness, was negatively associated with maternal urinary Pb (β = −0.23, 95% CI: −0.46−−0.07) and Hg (β = −0.26, 95% CI: −0.44−−0.08) (both p < 0.05). No association between maternal Cd and birth outcomes was observed. Most heavy metals showed positive associations with free cortisol and 8-OHdG. Free cortisol was identified as a mediator underlying the observed relationship between Hg and birth length or Ponderal index. This study observed adverse birth outcomes from maternal exposures to Pb and Hg. Increased free cortisol related to Hg exposure was suggested as a possible causal pathway from Hg exposure to birth outcomes such as the Ponderal index.

Exposure to metals and metalloids among pregnant women from Spain: Levels and associated factors

BACKGROUND

Humans are regularly exposed to metals and metalloids present in air, water, food, soil and domestic materials. Most of them can cross the placental barrier and cause adverse impacts on the developing foetus.

OBJECTIVES

To describe the prenatal concentrations of metals and metalloids and to study the associated sociodemographic, environmental and dietary factors in pregnant Spanish women.

METHODS

Subjects were 1346 pregnant women of the INMA Project, for whom the following metals arsenic (As), cadmium (Cd), cobalt (Co), copper (Cu), molybdenum (Mo), nickel (Ni), lead (Pb), antimony (Sb), selenium (Se), thallium (Tl) and zinc (Zn) were determined in urine, at both the first and the third trimesters of gestation. Sociodemographic, dietary and environmental information was collected through questionnaires during pregnancy. Multiple linear mixed models were built in order to study the association between each metal and metalloid concentrations and the sociodemographic, environmental and dietary factors.

RESULTS

The most detected compounds were As, Co, Mo, Sb, Se and Zn at both trimesters. Zn was the element found in the highest concentrations at both trimesters and Tl was detected in the lowest concentrations. We observed significant associations between As, Cd, Cu, Sb, Tl and Zn concentrations and working situation, social class and age. Seafood, meat, fruits, nuts, vegetables and alcohol intake affected the levels of all the metals but Cd and Cu. Proximity to industrial areas, fields and air pollution were related to all metals except Cd, Sb and Se.

CONCLUSIONS

This is the first large prospective longitudinal study on the exposure to metals and metalloids during pregnancy and associated factors to include several cohorts in Spain. The present study shows that some modifiable lifestyles, food intakes and environmental factors could be associated with prenatal exposure to metal(loid)s, which may be considered in further studies to assess their relationship with neonatal health outcomes.

Exposure and Risk Assessment of Hg, Cd, As, Tl, Se, and Mo in Women of Reproductive Age Using Urinary Biomonitoring

The present study analyzed the exposure and risk assessment of 4 toxic (Hg, Cd, As, Tl) and 2 essential (Se, Mo) elements in 119 Spanish women of reproductive age. The focus was on the elements for which risk-based benchmark, biomonitoring equivalents, or health-related human biomonitoring values have already been established. All elements presented frequencies of detection of 100% (greater than the limit of detection), except for Cd (99%). The 95th percentile concentrations were, for the toxic metals, 358.37 µg/L (total As), 1.10 µg/L (Cd), 0.41 µg/L (Tl), and 3.03 µg/L (total Hg) and, for the essential elements, 68.95 µg/L (total Se) and 154.67 (Mo). We examined sociodemographic factors and dietary habits of women as predictors of urinary metal concentrations. Arsenic was positively associated with fish, shellfish, and canned fish consumption, whereas Mo was found to be associated with the consumption of cereals and pastry products. Maternal urine levels of As were negatively correlated with gestational age. In a risk-assessment context, hazard quotients (HQs) using the 95th percentile ranged from 0.08 (Tl) to 15.1 (urinary speciated As), with Cd presenting an HQ of 1.1 (95th percentile). None of the essential metals presented concentrations higher than their upper intake level; however, 3% of the mothers showed lower levels of Se than the estimated average requirement (EAR) biomonitoring equivalent, and 20% of the mothers were found to have lower levels of Mo than the EAR biomonitoring equivalent, suggesting a nutritionally inadequate diet. Environ Toxicol Chem 2021;40:1477-1490. © 2021 SETAC.

Demographic predictors of urinary arsenic in a low-income predominantly Hispanic pregnancy cohort in Los Angeles

BACKGROUND

Arsenic (As) is a contaminant of top public health concern, due to its range of detrimental health effects. Arsenic exposure has not been well-characterized among the US Hispanic populations and has been particularly understudied in this population during pregnancy.

METHODS

As part of the MADRES ongoing pregnancy cohort of predominantly lower-income, Hispanic women in Los Angeles, CA, we examined levels of maternal first trimester urinary As, including total As and As metabolites (inorganic (iAs), monomethylated (MMA) and dimethylated As (DMA)), in relation to participant demographics, lifestyle characteristics, and rice/seafood consumption, to identify factors that may influence As exposure and its metabolites during pregnancy (N = 241).

RESULTS

Total As concentrations ranged from low to high (0.8-506.2 μg/L, mean: 9.0 μg/L, SD: 32.9) in our study population. Foreign-born Hispanic women had 8.6% higher %DMA (95% CI: 3.3%, 13.9%) and -7.7% lower %iAs (95% CI: -12.6%, -2.9%) than non-Hispanic women. A similar trend was observed for US-born Hispanic women. In addition, maternal age was associated with 0.4% higher %iAs (95% CI: 0.1%, 0.6%) and 0.4% lower %DMA (95% CI: -0.7%, -0.1%) per year, which may indicate poor As methylation capacity.

CONCLUSION

Individual factors may predict As exposure and metabolism in pregnancy, and in turn, greater risk of adverse health effects.

Prenatal metal mixtures and child blood pressure in the Rhea mother-child cohort in Greece

BACKGROUND

Child blood pressure (BP) is predictive of future cardiovascular risk. Prenatal exposure to metals has been associated with higher BP in childhood, but most studies have evaluated elements individually and measured BP at a single time point. We investigated impacts of prenatal metal mixture exposures on longitudinal changes in BP during childhood and elevated BP at 11 years of age.

METHODS

The current study included 176 mother-child pairs from the Rhea Study in Heraklion, Greece and focused on eight elements (antimony, arsenic, cadmium, cobalt, lead, magnesium, molybdenum, selenium) measured in maternal urine samples collected during pregnancy (median gestational age at collection: 12 weeks). BP was measured at approximately 4, 6, and 11 years of age. Covariate-adjusted Bayesian Varying Coefficient Kernel Machine Regression and Bayesian Kernel Machine Regression (BKMR) were used to evaluate metal mixture impacts on baseline and longitudinal changes in BP (from ages 4 to 11) and the development of elevated BP at age 11, respectively. BKMR results were compared using static versus percentile-based cutoffs to define elevated BP.

RESULTS

Molybdenum and lead were the mixture components most consistently associated with BP. J-shaped relationships were observed between molybdenum and both systolic and diastolic BP at age 4. Similar associations were identified for both molybdenum and lead in relation to elevated BP at age 11. For molybdenum concentrations above the inflection points (~ 40-80 μg/L), positive associations with BP at age 4 were stronger at high levels of lead. Lead was positively associated with BP measures at age 4, but only at high levels of molybdenum. Potential interactions between molybdenum and lead were also identified for BP at age 11, but were sensitive to the cutoffs used to define elevated BP.

CONCLUSIONS

Prenatal exposure to high levels of molybdenum and lead, particularly in combination, may contribute to higher BP at age 4. These early effects appear to persist throughout childhood, contributing to elevated BP in adolescence. Future studies are needed to identify the major sources of molybdenum and lead in this population.