RESUMO
Whether trace metals modify breast density, the strongest predictor for breast cancer, during critical developmental stages such as puberty remains understudied. Our study prospectively evaluated the association between trace metals at Tanner breast stage B1 (n = 291) and at stages both B1 and B4 (n = 253) and breast density at 2 years post-menarche among Chilean girls from the Growth and Obesity Cohort Study. Dual-energy x-ray absorptiometry assessed the volume of dense breast tissue (absolute fibroglandular volume [FGV]) and percent breast density (%FGV). Urine trace metals included arsenic, barium, cadmium, cobalt, cesium, copper, magnesium, manganese, molybdenum, nickel, lead, antimony, selenium, tin, thallium, vanadium, and zinc. At B1, a doubling of thallium concentration resulted in 13.69 cm3 increase in absolute FGV (ß: 13.69, 95% confidence interval [CI]: 2.81, 24.52), while a doubling of lead concentration resulted in a 7.76 cm3 decrease in absolute FGV (ß: -7.76, 95%CI: -14.71, -0.73). At B4, a doubling of barium concentration was associated with a 10.06 cm3 increase (ß: 10.06, 95% CI: 1.44, 18.60), copper concentration with a 12.29 cm3 increase (ß: 12.29, 95% CI: 2.78, 21.56), lead concentration with a 9.86 cm3 increase (ß: 9.86, 95% CI: 0.73, 18.98), antimony concentration with a 12.97 cm3 increase (ß: 12.97, 95% CI: 1.98, 23.79) and vanadium concentration with a 13.14 cm3 increase in absolute FGV (ß: 13.14, 95% CI: 2.73, 23.58). Trace metals may affect pubertal breast density at varying developmental stages with implications for increased susceptibility for breast cancer.
Assuntos
Absorciometria de Fóton , Densidade da Mama , Oligoelementos , Humanos , Feminino , Chile/epidemiologia , Adolescente , Densidade da Mama/efeitos dos fármacos , Oligoelementos/análise , Oligoelementos/urina , Estudos Prospectivos , Criança , Mama/efeitos dos fármacos , Mama/crescimento & desenvolvimento , Neoplasias da Mama/epidemiologiaRESUMO
It remains unclear whether manganese (Mn) exposure affects working memory (WM) in a sexually dimorphic manner. Further, no gold standard media exists to measure Mn, suggesting a combined blood and urinary Mn index may better capture the totality of exposure. We investigated the modification effect of child sex on the influence of prenatal Mn exposure on WM in school-age children, exploring two methodological frameworks to integrate exposure estimates across multiple exposure biomarkers. Leveraging the PROGRESS birth cohort in Mexico City, children (N = 559) ages 6-8 completed the between errors and strategy measures of the CANTAB Spatial Working Memory (SWM) task. Mn levels were assayed in blood and urine of mothers during the 2nd and 3rd trimesters and in umbilical cord blood from mothers and children at delivery. Weighted quantile sum regression estimated the association of a multi-media biomarker (MMB) mixture with SWM. We applied a confirmatory factor analysis to similarly quantify a latent blood Mn burden index. We then used an adjusted linear regression to estimate the Mn burden index with SWM measures. Interaction terms were used to estimate the modification effect by child sex for all models. Results showed that the between-errors-specific MMB mixture (i.e., this model demonstrates the impact of the MMB mixture on the between-error scores.) was associated (ß = 6.50, 95% CI: 0.91, 12.08) with fewer between errors for boys and more between errors for girls. The strategy-specific MMB mixture (i.e., this model demonstrates the impact of the MMB mixture on the strategy scores) was associated (ß = -1.36, 95% CI: 2.55, - 0.18) with less efficient strategy performance for boys and more efficient strategy performance for girls. A higher Mn burden index was associated (ß = 0.86, 95% CI: 0.00, 1.72) with more between errors in the overall sample. The vulnerability to prenatal Mn biomarkers on SWM differs in the directionality by child sex. An MMB mixture and composite index of body burden are stronger predictors than a single biomarker for Mn exposure on WM performance.
Assuntos
Manganês , Efeitos Tardios da Exposição Pré-Natal , Masculino , Gravidez , Feminino , Humanos , Criança , Manganês/análise , Memória de Curto Prazo , México , Desenvolvimento Infantil , Biomarcadores/análise , Efeitos Tardios da Exposição Pré-Natal/epidemiologia , Exposição Ambiental/análiseRESUMO
BACKGROUND: Lead (Pb) exposure is a global health hazard causing a wide range of adverse health outcomes. Yet, the mechanisms of Pb toxicology remain incompletely understood, especially during pregnancy. To uncover biological pathways impacted by Pb exposure, this study investigated serum metabolomic profiles during the third trimester of pregnancy that are associated with blood Pb and bone Pb. METHODS: We used data and specimens from 99 women enrolled in the Programming Research in Obesity, Growth, Environment, and Social Stressors birth cohort in Mexico City. Maternal Pb exposure was measured in whole blood samples from the third trimester of pregnancy and in the tibia and patella bones at 1 month postpartum. Third-trimester serum samples underwent metabolomic analysis; metabolites were identified based on matching to an in-house analytical standard library. A metabolome-wide association study was performed using multiple linear regression models. Class- and pathway-based enrichment analyses were also conducted. RESULTS: The median (interquartile range) blood Pb concentration was 2.9 (2.6) µg/dL. Median bone Pb, measured in the tibia and patella, were 2.5 (7.3) µg/g and 3.6 (9.5) µg/g, respectively. Of 215 total metabolites identified in serum, 31 were associated with blood Pb (p < 0.05). Class enrichment analysis identified significant overrepresentation of metabolites classified as fatty acids and conjugates, amino acids and peptides, and purines. Tibia and patella Pb were associated with 14 and 8 metabolites, respectively (p < 0.05). Comparing results from bone and blood Pb, glycochenodeoxycholic acid, glycocholic acid, and 1-arachidonoylglycerol were positively associated with blood Pb and tibia Pb, and 7-methylguanine was negatively associated with blood Pb and patella Pb. One metabolite, 5-aminopentanoic acid, was negatively associated with all three Pb measures. CONCLUSIONS: This study identified serum metabolites in pregnant women associated with Pb measured in blood and bone. These findings provide insights on the metabolic profile around Pb exposure in pregnancy and information to guide mechanistic studies of toxicological effects for mothers and children.
Assuntos
Chumbo , Gestantes , Criança , Feminino , Humanos , Exposição Materna , México , Patela , GravidezRESUMO
Background: Lead is a neurotoxic metal potentially affecting the developing brain. Children are particularly susceptible since they can absorb between 50% and 100% of ingested lead. There is no safe level for lead, therefore preventing exposure is crucial. We previously reported a positive association between lead concentrations found in candy and concurrent blood lead levels in Mexican children. This first report garnered media and the general public's attention. Objective: To conduct a follow-up study to assess lead concentrations in candy brands that we previously reported with concentrations ≥0.1ppm the U.S. Food and Drug Administration's recommended maximum lead level in candy likely to be consumed frequently by small children. Methods: In 2018 we analyzed 50 additional candy samples. Lead concentrations were analyzed by an inductively coupled plasma mass spectrometer and lead content per candy unit was calculated. Findings: We found concentrations were typically low, with a marked decrease from prior levels (2008). Nevertheless two candy units had concentrations of 0.1 ppm of lead. Conclusions: Candy may have lead concentrations up to 0.1 ppm and 1.2 µg per unit. This is a concern because candies are exported and consumed in many countries worldwide potentially resulting in human exposure. Continued public health surveillance is needed to protect populations especially vulnerable to lead exposure, especially children.
Assuntos
Doces/análise , Contaminação de Alimentos/análise , Intoxicação por Chumbo/prevenção & controle , Chumbo/análise , Política Pública , Contaminação de Alimentos/legislação & jurisprudência , Contaminação de Alimentos/prevenção & controle , Humanos , México , Espectrofotometria AtômicaRESUMO
BACKGROUND: We evaluated: (1) associations of prenatal manganese (Mn) levels with child neurodevelopment at 4-6 years; (2) effect modification by maternal anemia and iron deficiency; and (3) sex-specific effects. METHODS: We measured blood Mn, hemoglobin, and serum ferritin in mothers at the second trimester, third trimester, and at birth, and in cord blood from a prospective birth cohort in Mexico City (n = 571). McCarthy Scales of Children's Abilities were measured at 4-6 years. Using linear regression, we estimated associations between prenatal Mn and neurodevelopment, examined anemia and iron deficiency as effect modifiers, and analyzed associations by child sex. RESULTS: No direct associations were observed between Mn, anemia, or iron deficiency and McCarthy Scales. Second trimester iron deficiency and third trimester anemia modified the effect of Mn on child neurodevelopment. For instance, second trimester Mn was positively associated child memory scores in mother's with normal ferritin (1.85 (0.02, 3.45)), but negatively associated in mother's with low ferritin (-2.41 (-5.28, 0.47), interaction P value = 0.01), a pattern observed across scales. No effect modification at birth or in cord blood was observed. CONCLUSIONS: Anemia/iron deficiency during pregnancy may modify Mn impacts on child neurodevelopment, particularly in boys.
Assuntos
Anemia Ferropriva/complicações , Desenvolvimento Infantil , Manganês/efeitos adversos , Sistema Nervoso/crescimento & desenvolvimento , Transtornos do Neurodesenvolvimento/etiologia , Complicações Hematológicas na Gravidez , Efeitos Tardios da Exposição Pré-Natal , Fatores Etários , Anemia Ferropriva/sangue , Anemia Ferropriva/diagnóstico , Biomarcadores/sangue , Criança , Pré-Escolar , Feminino , Ferritinas/sangue , Idade Gestacional , Hemoglobinas/metabolismo , Humanos , Masculino , Manganês/sangue , México , Transtornos do Neurodesenvolvimento/diagnóstico , Transtornos do Neurodesenvolvimento/fisiopatologia , Gravidez , Complicações Hematológicas na Gravidez/sangue , Complicações Hematológicas na Gravidez/diagnóstico , Estudos Prospectivos , Medição de Risco , Fatores de Risco , Fatores SexuaisRESUMO
BACKGROUND: Occupational studies have shown an association between elevated Mn exposure and depressive symptoms. Blood Mn (BMn) naturally rises during pregnancy due to mobilization from tissues, suggesting it could contribute to pregnancy and postpartum depressive symptoms. OBJECTIVES: To assess the association between BMn levels during pregnancy and postpartum depression (PPD), creating opportunities for possible future interventions. METHODS: We studied 561 women from the reproductive longitudinal Programming Research in Obesity, Growth, Environment, and Social Stressors (PROGRESS) cohort in Mexico City. BMn was measured at the 2nd and 3rd trimesters, as well as delivery. The Edinburgh Postnatal Depression Scale (EPDS) was used to assess PPD symptoms at 12-months postpartum. We used a generalized linear model assuming a Poisson distribution to assess the association between BMn levels and PPD, with adjustments for age, stress and depressive symptoms during pregnancy, education, socioeconomic status, and contemporaneous blood lead levels. RESULTS: The mean⯱â¯standard deviation (SD) EPDS score at 12-months postpartum was 6.51⯱â¯5.65, and 17.11% of women met the criteria for possible PPD (score ≥ 13). In adjusted models, BMn during the 3rd trimester (ß: 0.13, 95% CI: 0.04-0.21) and BMn levels averaged at the 2nd and 3rd trimester (ß: 0.14, 95% CI: 0.02-0.26) had a positive association with EPDS scores at 12 months postpartum. BMn at the 2nd trimester (ß: 0.07, 95% CI: -0.09-0.22) and delivery (ß: 0.03, 95% CI: -0.04-0.10) had a non-significant positive association with EPDS scores at 12-months postpartum. Stress and depressive symptoms during pregnancy was associated with higher EPDS scores at 12-months postpartum in all of the adjusted models but were only significant when either BMn during 3rd trimester or BMn averaged across 2nd and 3rd trimester was assessed as the exposure. DISCUSSION: Our results demonstrate that elevated BMn levels during pregnancy predict PPD symptoms and could be a potential pathway for intervention and prevention of PPD.
Assuntos
Depressão Pós-Parto/sangue , Manganês/sangue , Adulto , Estudos de Coortes , Depressão Pós-Parto/epidemiologia , Feminino , Humanos , México , Escalas de Graduação PsiquiátricaRESUMO
BACKGROUND: Among highly exposed populations, arsenic exposure in utero may be associated with decreased birth weight, however less is known about potential effects of arsenic exposure in urban communities without contaminated sources such as drinking water. OBJECTIVE: Investigate the association of blood arsenic levels with birth weight-for-gestational age categories within a prospective birth cohort study. DESIGN/METHODS: We analyzed 730 mother-infant dyads within the Programming Research in Obesity, GRowth, Environment and Social Stressors (PROGRESS) cohort in Mexico City. Total arsenic was measured in maternal blood samples from the 2nd and 3rd trimesters, at delivery, as well as from infant umbilical cord blood samples. Multivariable, multinomial logistic regression models adjusting for maternal age at enrollment, pre-pregnancy body mass index, parity, infant sex, socioeconomic position, and prenatal environmental tobacco smoke exposure were used to calculate odds ratios of small-for-gestational age (<10th percentile, SGA) and large-for-gestational age (>90th percentile, LGA) compared to appropriate-for-gestational age (AGA) per unit increase of log-transformed arsenic. RESULTS: Median (IQR) blood arsenic levels for maternal second trimester were 0.72 (0.33) µg/L, maternal third trimester 0.75 (0.41) µg/L, maternal at delivery 0.85 (0.70) µg/L, and infant cord 0.78 (0.65) µg/L. Maternal delivery and infant cord blood samples were most strongly correlated (spearman râ¯=â¯0.65, pâ¯<â¯0.0001). Maternal arsenic levels at delivery were associated with significantly higher odds of both SGA (adj. ORâ¯=â¯1.44, 95% CI: 1.08-1.93) and LGA (adj. ORâ¯=â¯2.03, 95% CI: 1.12-3.67) compared to AGA. Results were similar for cord blood. There were 130 SGA infants and 22 LGA infants. Earlier in pregnancy, there were no significant associations of arsenic and birth weight-for-gestational age. However, we observed non-significantly higher odds of LGA among women with higher arsenic levels in the 3rd trimester (adj. ORâ¯=â¯1.46, 95% CI: 0.67-3.12). CONCLUSION: We found that in a Mexico City birth cohort, higher maternal blood arsenic levels at delivery were associated with higher odds of both SGA and LGA. However, sources and species of arsenic were not known and the number of LGA infants was small, limiting the interpretation of this finding and highlighting the importance of future large studies to incorporate arsenic speciation. If our findings were confirmed in studies that addressed these limitations, determining modifiable factors that could be mitigated, such as sources of arsenic exposure, may be important for optimizing fetal growth to improve long-term health of children.
Assuntos
Arsênio/sangue , Peso ao Nascer , Poluentes Ambientais/sangue , Idade Gestacional , Exposição Materna/estatística & dados numéricos , Criança , Estudos de Coortes , Feminino , Humanos , Lactente , Recém-Nascido , Recém-Nascido Pequeno para a Idade Gestacional , Masculino , México , Gravidez , Estudos ProspectivosRESUMO
INTRODUCTION: Manganese (Mn) is an essential nutrient but also a toxicant at high exposures, when it can induce oxidative stress (OS). Mn uptake is inversely correlated with iron status, therefore anemic individuals may be more susceptible to Mn overload induced-OS, which can manifest as changes in mitochondrial DNA copy number (mtDNA CN). Our objectives were to: 1) determine stage-specific associations of prenatal Mn exposure with cord blood MtDNA CN; and 2) investigate effect modification by maternal anemia, ferritin, and mean corpuscular volume (MCV). MATERIALS AND METHODS: We measured whole blood Mn, hemoglobin, serum ferritin, and MCV in the 2nd and 3rd trimester, in maternal blood at birth, and in cord blood from a prospective birth cohort in Mexico City, Mexico (nâ¯=â¯485). We then extracted DNA from cord blood leukocytes to determine mtDNA CN. We used robust regression to measure associations between Mn and mtDNA CN at each trimester and at birth. Anemia (hemoglobin ≤11â¯g/dL), iron deficiency (ferritin ≤15â¯ng/mL) and MCV (stratified at median), were examined as effect modifiers. RESULTS: Mn levels increased throughout pregnancy, and Mn was inversely correlated with ferritin. We observed a positive association between Mn in the 3rd trimester and Mn in cord blood and mtDNA CN (ßâ¯=â¯0.04-0.05; 95% CIâ¯=â¯0.01, 0.08). Anemia significantly modified the association between mtDNA CN and Mn in the 2nd trimester. We found a positive association between 2nd trimester Mn and mtDNA CN in mothers with normal hemoglobin, and a negative association in those with low hemoglobin. (ßhighâ¯=â¯0.06; 95% CIâ¯=â¯0.01, 0.11; pâ¯=â¯0.01 and ßlowâ¯=â¯-0.06; 95% CIâ¯=â¯0.03, -0.13; pâ¯=â¯0.06). No associations were detected between anemia, iron deficiency and MCV and mtDNA CN. CONCLUSIONS: Maternal blood Mn in the 3rd trimester and in cord blood was positively associated with mtDNA CN, suggesting that higher late pregnancy prenatal Mn exposures can impact newborn mitochondria by promoting OS. Furthermore, 2nd trimester Mn was positively associated with mtDNA in non-anemic mother-child pairs but inversely associated in anemic individuals, indicating potential interactions between Mn and chronic anemia.
Assuntos
Anemia/sangue , DNA Mitocondrial/análise , Poluentes Ambientais/sangue , Sangue Fetal/química , Manganês/sangue , Adulto , Variações do Número de Cópias de DNA , Feminino , Humanos , Recém-Nascido , Masculino , Troca Materno-Fetal , México , Mães , Gravidez , Terceiro Trimestre da Gravidez , Adulto JovemRESUMO
INTRODUCTION: Lead (Pb) crosses the placenta and can cause oxidative stress, reduced fetal growth and neurological problems. The principal source of oxidative stress in human cells is mitochondria. Therefore, disruption of normal mitochondrial function during pregnancy may represent a primary mechanism behind the adverse effects of lead. We sought to assess the association of Pb exposure during pregnancy with mitochondrial DNA (mtDNA) content, a sensitive marker of mitochondrial function, in cord blood. MATERIALS AND METHODS: This study comprised mother-infant pairs from the Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) study, a prospective birth-cohort that enrolled 1050 pregnant women from Mexico City who were receiving prenatal care between December 2007 and July 2011. Quantitative PCR was used to calculate relative MtDNA content (mitochondrial-to-nuclear DNA ratio (mtDNA/nDNA)) in cord blood. Lead concentrations in both maternal blood (2nd and 3rd trimester and at delivery day) and in cord blood were measured by ICP-MS. Multivariable regression models adjusting for multiple confounders were fitted with 410 mother-infant pairs for whom complete data for mtDNA content, lead levels, and covariates were available. RESULTS: Maternal blood Pb measured in the second (mean 3.79⯵g/dL, SD 2.63; ßâ¯=â¯0.059, 95% CI 0.008, 0.111) and third trimester (mean 3.90⯵g/dL; SD 2.84; ßâ¯=â¯0.054, 95% CI 0.002, 0.107) during pregnancy and PB in cord blood (mean 3.50⯵g/dL, SD 2.59; ßâ¯=â¯0.050, 95% CI 0.004; 0.096) were associated with increased cord blood mtDNA content (mean 1.46, SD 0.44). In two-way interaction analyses, cord blood Pb marginally interacted with gestational age leading to an increase in mtDNA content for pre-term births (Benjamini-Hochberg False Discovery Rate correction; BH-FDRâ¯=â¯0.08). CONCLUSION: This study shows that lead exposure in pregnancy alters mtDNA content in cord blood; therefore, alteration of mtDNA content might be a mechanism underlying the toxicity of lead.
Assuntos
DNA Mitocondrial/análise , Poluentes Ambientais/metabolismo , Sangue Fetal/química , Chumbo/metabolismo , Exposição Materna , Adulto , Feminino , Humanos , Recém-Nascido , Masculino , México , Estresse Oxidativo , Gravidez , Estudos Prospectivos , Adulto JovemRESUMO
BACKGROUND: Trace metal concentrations may affect cardiometabolic risk, but the role of prenatal exposure is unclear. We examined (1) the relation between blood metal concentrations during pregnancy and child cardiometabolic risk factors; (2) overall effects of metals mixture (essential vs. nonessential); and (3) interactions between metals. METHODS: We measured 11 metals in maternal second-trimester whole blood in a prospective birth cohort in Mexico City. In children 4-6 years old, we measured body mass index (BMI), percent body fat, and blood pressure (N = 609); and plasma hemoglobin A1C (HbA1c), non-high-density lipoprotein (HDL) cholesterol, triglycerides, leptin, and adiponectin (N = 411). We constructed cardiometabolic component scores using age- and sex-adjusted z scores and averaged five scores to create a global risk score. We estimated linear associations of each metal with individual z scores and used Bayesian Kernel Machine Regression to assess metal mixtures and interactions. RESULTS: Higher total metals were associated with lower HbA1c, leptin, and systolic blood pressure, and with higher adiponectin and non-HDL cholesterol. We observed no interactions between metals. Higher selenium was associated with lower triglycerides in linear (ß = -1.01 z score units per 1 unit ln(Se), 95% CI = -1.84, -0.18) and Bayesian Kernel Machine Regression models. Manganese was associated with decreased HbA1c in linear models (ß = -0.32 and 95% CI = -0.61, -0.03). Antimony and arsenic were associated with lower leptin in Bayesian Kernel Machine Regression models. Essential metals were more strongly associated with cardiometabolic risk than were nonessential metals. CONCLUSIONS: Low essential metals during pregnancy were associated with increased cardiometabolic risk factors in childhood.
Assuntos
Doenças Cardiovasculares/epidemiologia , Metais/sangue , Adiponectina/sangue , Tecido Adiposo , Adolescente , Adulto , Teorema de Bayes , Pressão Sanguínea , Índice de Massa Corporal , Criança , Pré-Escolar , Colesterol/sangue , Feminino , Hemoglobinas Glicadas/análise , Humanos , Leptina/sangue , Metais/classificação , México/epidemiologia , Gravidez , Segundo Trimestre da Gravidez/sangue , Estudos Prospectivos , Fatores de Risco , Triglicerídeos/sangue , Adulto JovemRESUMO
BACKGROUND: High blood pressure (BP) in childhood is frequently renal in origin and a risk factor for adult hypertension and cardiovascular disease. Shorter gestations are a known risk factor for increased BP in adults and children, due in part to a nephron deficit in children born preterm. As nephrogenesis is incomplete until 36â¯weeks gestation, prenatal lead exposure occurring during a susceptible period of renal development may contribute to programming for later life renal disease. The relationship between shorter gestation and children's BP has not yet been explored to identify i) critical windows using nonlinear piecewise models or ii) combined with other early life risk factors such as prenatal lead exposure. OBJECTIVES: (1) To evaluate the nonlinear relationship between lower gestational age and childhood BP measured at 4-6â¯years of age, and (2) to investigate modification by prenatal lead exposure. METHODS: In a prospective longitudinal birth cohort, we assessed 565 children between 4 and 6â¯years of age (mean: 4.8â¯years) in the PROGRESS cohort in Mexico City, Mexico. Gestational age at delivery was calculated using maternal report of last menstrual period (LMP) and confirmed with Capurro physical examination at birth. We measured pregnant women's blood lead levels (BLLs) in the second trimester via inductively coupled plasma-mass spectrometry and children's BP using an automated device. We performed both linear and nonlinear piecewise regression analyses to examine associations of gestational age with children's BP adjusting for children's age, sex, height, prenatal exposure to smoke, and maternal socioeconomic status. We stratified to assess modification by prenatal lead exposure, and used a data-adaptive approach to identify a lead cutpoint. RESULTS: Maternal second trimester BLLs ranged from 0.7 to 17.8⯵g/dL with 112 (20%) women above the CDC guideline level of 5⯵g/dL. In adjusted linear regression models, a one week reduction in gestational age was associated with a 0.5â¯mmâ¯Hg (95%CI: 0.2, 0.8) increase in SBP and a 0.4â¯mmâ¯Hg (95%CI 0.1, 0.6) increase in DBP. Our nonlinear models suggested evidence for different magnitude estimates on either side of an estimated join-point at 35.9â¯weeks' gestation, but did not reach statistical significance. However, when stratified by prenatal lead exposure, we identified a cutpoint lead level of concern of 2.5⯵g/dL that suggested an interaction between gestational age and blood lead. Specifically, for BLLsâ¯≥â¯2.5⯵g/dL, SBP was 1.6 (95%CI: 0.3, 2.9) mmâ¯Hg higher per each week reduction in gestational age among children born before 37.0â¯weeks; and among children born after 37.0â¯weeks, this relationship was attenuated yet remained significant [ß: 0.9, 95%CI (0.2, 1.6)]. At BLLs below 2.5⯵g/dL, there was no appreciable association between lower gestational age and SBP. CONCLUSIONS: Our findings suggest that shorter gestation combined with higher prenatal lead exposure contributes to a higher risk of increased SBP at 4-6â¯years of age, particularly among infants born <37â¯weeks gestation. Our results underscore the importance of preventing prenatal lead exposure - even levels as low as 2.5⯵g/dL - especially among pregnant women at risk for preterm birth. Given that high BP in childhood is a risk factor for adult hypertension and cardiovascular disease later in life, these results may have implications that extend across the life span.
Assuntos
Poluentes Ambientais/efeitos adversos , Idade Gestacional , Hipertensão/epidemiologia , Chumbo/efeitos adversos , Efeitos Tardios da Exposição Pré-Natal , Adolescente , Adulto , Pressão Sanguínea/efeitos dos fármacos , Criança , Pré-Escolar , Estudos de Coortes , Poluentes Ambientais/sangue , Feminino , Humanos , Recém-Nascido , Chumbo/sangue , Masculino , Troca Materno-Fetal , México/epidemiologia , Gravidez , Estudos Prospectivos , Adulto JovemRESUMO
BACKGROUND: As population lead levels decrease, the toxic effects of lead may be distributed to more sensitive populations, such as infants with poor fetal growth. OBJECTIVES: To determine the association of prenatal lead exposure and fetal growth; and to evaluate whether infants with poor fetal growth are more susceptible to lead toxicity than those with normal fetal growth. METHODS: We examined the association of second trimester maternal blood lead levels (BLL) with birthweight-for-gestational age (BWGA) z-score in 944 mother-infant participants of the PROGRESS cohort. We determined the association between maternal BLL and BWGA z-score by using both linear and quantile regression. We estimated odds ratios for small-for-gestational age (SGA) infants between maternal BLL quartiles using logistic regression. Maternal age, body mass index, socioeconomic status, parity, household smoking exposure, hemoglobin levels, and infant sex were included as confounders. RESULTS: While linear regression showed a negative association between maternal BLL and BWGA z-score (ß=-0.06 z-score units per log2 BLL increase; 95% CI: -0.13, 0.003; P=0.06), quantile regression revealed larger magnitudes of this association in the <30th percentiles of BWGA z-score (ß range [-0.08, -0.13] z-score units per log2 BLL increase; all P values<0.05). Mothers in the highest BLL quartile had an odds ratio of 1.62 (95% CI: 0.99-2.65) for having a SGA infant compared to the lowest BLL quartile. CONCLUSIONS: While both linear and quantile regression showed a negative association between prenatal lead exposure and birthweight, quantile regression revealed that smaller infants may represent a more susceptible subpopulation.
Assuntos
Peso ao Nascer/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Desenvolvimento Fetal/efeitos dos fármacos , Chumbo/toxicidade , Exposição Materna , Adulto , Feminino , Idade Gestacional , Humanos , Recém-Nascido Pequeno para a Idade Gestacional , Masculino , México , Gravidez , Segundo Trimestre da Gravidez , Estudos Prospectivos , Risco , Adulto JovemRESUMO
Lead exposure during pregnancy remains a public health problem with potential lifelong impacts on children's growth and development. Mexico is unique in that stunting and obesity are both major public health concerns in children. This situation might be exacerbated by lead exposure which remains more common in Mexico than in the United States due in part to the use of lead glazed pottery in food preparation and storage. Our objective is to determine how lead exposure during pregnancy is associated with children's growth parameters, including height, weight, body mass index and percentage body fat measured between ages 4-6 years old in a Mexico City pregnancy cohort. Blood lead was collected in the 2nd and 3rd trimester of pregnancy as well as at delivery. Bone lead was assessed in mothers as a long term exposure biomarker. We performed multivariable linear regression analyses to assess the association between each of these lead exposure biomarkers and child anthropometry. We found a significant negative association between maternal 3rd trimester blood lead concentration and offspring height for age (ß-0.10; 95% CI -0.19, -0.01), and a negative association between maternal 3rd trimester blood lead concentration and weight for age (ß-0.11; 95% CI -0.22,-0.003). Our results in this Mexican population add to previous findings of an association of lead and decreased stature and weight in early childhood. Ongoing follow-up and longitudinal analyses may help elucidate how this impacts growth trajectory and other children's health outcomes.
Assuntos
Antropometria , Poluentes Ambientais/metabolismo , Chumbo/metabolismo , Exposição Materna , Adulto , Biomarcadores/análise , Biomarcadores/sangue , Criança , Pré-Escolar , Estudos de Coortes , Poluentes Ambientais/sangue , Feminino , Humanos , Chumbo/sangue , México , Gravidez , Adulto JovemRESUMO
BACKGROUND: Temperament is a psychological construct that reflects both personality and an infant's reaction to social stimuli. It can be assessed early in life and is stable over time Temperament predicts many later life behaviors and illnesses, including impulsivity, emotional regulation and obesity. Early life exposure to neurotoxicants often results in developmental deficits in attention, social function, and IQ, but environmental predictors of infant temperament are largely unknown. We propose that prenatal exposure to both chemical and non-chemical environmental toxicants impacts the development of temperament, which can itself be used as a marker of risk for maladaptive neurobehavior in later life. In this study, we assessed associations among prenatal and early life exposure to lead, mercury, poverty, maternal depression and toddler temperament. METHODS: A prospective cohort of women living in the Mexico City area were followed longitudinally beginning in the second trimester of pregnancy. Prenatal exposure to lead (blood, bone), mercury, and maternal depression were assessed repeatedly and the Toddler Temperament Scale (TTS) was completed when the child was 24 months old. The association between each measure of prenatal exposure and performance on individual TTS subscales was evaluated by multivariable linear regression. Latent profile analysis was used to classify subjects by TTS performance. Multinomial regression models were used to estimate the prospective association between prenatal exposures and TTS performance. RESULTS: 500 mother-child pairs completed the TTS and had complete data on exposures and covariates. Three latent profiles were identified and categorized as predominantly difficult, intermediate, or easy temperament. Prenatal exposure to maternal depression predicted increasing probability of difficult toddler temperament. Maternal bone lead, a marker of cumulative exposure, also predicted difficult temperament. Prenatal lead exposure modified this association, suggesting that joint exposure in pregnancy to both was most toxic. CONCLUSIONS: Maternal depression predicts difficult temperament and concurrent prenatal exposure to maternal depression and lead predicts a more difficult temperament phenotype in 2 year olds. The role of temperament as an intermediate variable in the path from prenatal exposures to neurobehavioral deficits and other health effects deserves further study.
Assuntos
Depressão/epidemiologia , Poluentes Ambientais/sangue , Chumbo/sangue , Exposição Materna , Efeitos Tardios da Exposição Pré-Natal , Temperamento , Adulto , Comportamento Infantil , Desenvolvimento Infantil , Pré-Escolar , Feminino , Humanos , Lactente , Mercúrio/análise , México/epidemiologia , Mães , Unhas/química , Patela/química , Gravidez , Tíbia/química , Adulto JovemRESUMO
BACKGROUND: Recent studies have shown that lead exposure continues to pose a health risk in Mexico. Children are a vulnerable population for lead effects and Mexican candy has been found to be a source of exposure in children. There are no previous studies that estimates lead concentrations in candy that children living in Mexico City consume and its association with their blood lead level. OBJECTIVES: To evaluate whether there is an association between reported recent consumption of candies identified to have lead, and blood lead levels among children in Mexico City. METHODS: A subsample of 171 children ages 2-6 years old, from the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) cohort study was assessed between June 2006 and July 2007. The candy reported most frequently were analyzed for lead using ICP-MS. The total weekly intake of lead through the consumption of candy in the previous week was calculated. Capillary blood lead levels (BLL) were measured using LeadCare (anodic stripping voltammetry). RESULTS: Lead concentrations ≥0.1ppm, the FDA permitted level (range: 0.13-0.7ppm) were found in 6 samples out of 138 samples from 44 different brands of candy. Median BLL in children was 4.5µg/dl. After adjusting for child's sex, age, BMI, maternal education & occupation, milk consumption, sucking the candy wrapper, use of lead-glazed pottery, child exposure behavior, living near a lead exposure site and use of folk remedies, an increase of 1µg of lead ingested through candy per week was associated with 3% change (95% CI: 0.1%, 5.2%) in BLL. CONCLUSIONS: Although lead concentrations in candy were mostly below the FDA permitted level, high lead concentrations were detected in 4% of the candy samples and 12% of brands analyzed. Although candy intake was modestly associated with children's BLL, lead should not be found in consumer products, especially in candy that children can consume due to the well documented long-lasting effect of lead exposure.
Assuntos
Doces/análise , Chumbo/sangue , Criança , Pré-Escolar , Feminino , Humanos , Masculino , MéxicoRESUMO
BACKGROUND: Disrupted maternal prenatal cortisol production influences offspring development. Factors influencing the hypothalamic-pituitary-adrenal axis include social (e.g., stressful life events) and physical/chemical (e.g., toxic metals) pollutants. Mercury (Hg) is a common contaminant of fish and exposure is widespread in the US. No prior study has examined the joint associations of stress and mercury with maternal cortisol profiles in pregnancy. OBJECTIVES: To investigate potential synergistic influences of prenatal stress and Hg exposures on diurnal cortisol in pregnant women. METHODS: Analyses included 732 women (aged 27.4 ± 5.6 years) from a Mexico City pregnancy cohort. Participants collected saliva samples on two consecutive days (mean 19.52 ± 3.00 weeks gestation) and reported life stressors over the past 6 months. Hg was assessed in toe nail clippings collected during pregnancy. RESULTS: There were no main effects of Hg or psychosocial stress exposure on diurnal cortisol (ps > .20) but strong evidence of interaction effects on cortisol slope (interaction B = .006, SE = .003, p = .034) and cortisol at times 1 and 2 (interaction B = -.071, SE = .028, p = .013; B = -.078, SE = .032, p = .014). Women above the median for Hg and psychosocial stress exposure experienced a blunted morning cortisol response compared to women exposed to higher stress but lower Hg levels. CONCLUSIONS: Social and physical environmental factors interact to alter aspects of maternal diurnal cortisol during pregnancy. Research focusing solely on either domain may miss synergistic influences with potentially important consequences to the offspring.
Assuntos
Exposição Ambiental , Hidrocortisona/metabolismo , Mercúrio/metabolismo , Estresse Psicológico/epidemiologia , Adulto , Ritmo Circadiano , Estudos de Coortes , Feminino , Humanos , México/epidemiologia , Unhas/química , Gravidez , Saliva/química , Estresse Psicológico/etiologia , Adulto JovemRESUMO
BACKGROUND: Recent evidence suggests that low-level environmental exposure to manganese adversely affects child growth and neurodevelopment. Previous studies have addressed the effects of prenatal exposure, but little is known about developmental effects of early postnatal exposure. METHODS: We studied 448 children born in Mexico City from 1997 through 2000, using a longitudinal study to investigate neurotoxic effects of early-life manganese exposure. Archived blood samples, collected from children at 12 and 24 months of age, were analyzed for manganese levels using inductively coupled plasma mass spectrometry. Mental and psychomotor development were scored using Bayley Scales of Infant Development at 6-month intervals between 12 and 36 months of age. RESULTS: At 12 months of age, the mean (SD) blood manganese level was 24.3 (4.5)microg/L and the median was 23.7 microg/L; at 24 months, these values were 21.1 (6.2) microg/L and 20.3 microg/L, respectively. Twelve- and 24-month manganese concentrations were correlated (Spearman correlation = 0.55) and levels declined over time ([beta] = -5.7 [95% CI = -6.2 to -5.1]). We observed an inverted U-shaped association between 12-month blood manganese and concurrent mental development scores (compared with the middle 3 manganese quintiles, for the lowest manganese quintile, [beta] = -3.3 [-6.0 to -0.7] and for the highest manganese quintile, [beta] = -2.8 [-5.5 to -0.2]). This 12-month manganese effect was apparent but diminished with mental development scores at later ages. The 24-month manganese levels were not associated with neurodevelopment. CONCLUSIONS: These results suggest a possible biphasic dose-response relationship between early-life manganese exposure at lower exposure levels and infant neurodevelopment. The data are consistent with manganese as both an essential nutrient and a toxicant.
Assuntos
Desenvolvimento Infantil , Manganês/sangue , Pré-Escolar , Exposição Ambiental/efeitos adversos , Feminino , Humanos , Lactente , Modelos Lineares , Estudos Longitudinais , Masculino , Manganês/efeitos adversos , Espectrometria de Massas , México , Testes Neuropsicológicos , Desempenho Psicomotor , Análise de RegressãoRESUMO
The authors studied 367 women who were breastfeeding their infants in Mexico City, Mexico, between 1994 and 1995 to evaluate the effect of cumulative lead exposure, breastfeeding practices, and calcium intake on breast milk lead levels over the course of lactation. Maternal blood and breast milk lead levels were measured at 1, 4, and 7 months postpartum. Bone lead measurements were obtained at 1 month postpartum. At 1, 4, and 7 months postpartum, respectively, the mean breast milk lead levels were 1.4 (standard deviation (SD), 1.1), 1.2 (SD, 1.0), and 0.9 (SD, 0.8) microg/liter and showed a significant decreasing trend over the course of lactation (p < 0.00001). The relations of bone lead and blood lead to breast milk lead were modified by breastfeeding practice, with the highest breast milk lead levels among women with a high level of patella lead who were exclusively breastfeeding. Dietary calcium supplementation increased the rate of decline in breast milk lead by 5-10%, in comparison with a placebo, over the course of lactation, suggesting that calcium supplementation may constitute an important intervention strategy, albeit with a modest effect, for reducing lead in breast milk and thus the potential for exposure by infants.
Assuntos
Osso e Ossos/efeitos dos fármacos , Cálcio da Dieta/farmacologia , Lactação/efeitos dos fármacos , Intoxicação por Chumbo/etiologia , Chumbo/sangue , Exposição Materna/efeitos adversos , Leite Humano/efeitos dos fármacos , Adulto , Suplementos Nutricionais , Feminino , Humanos , Lactente , Recém-Nascido , México , Período Pós-Parto , Gravidez , Estudos ProspectivosRESUMO
Lead (Pb) in blood, bone, and semen was measured in 162 to 186 environmentally exposed men from Mexico City, aged 19- 48. Semen Pb was measured by inductively coupled plasma mass spectrometry, blood Pb by atomic absorption spectrometry and bone Pb by K X-ray fluorescence. Mean Pb levels in blood, semen, tibia (cortical) and patella (trabecular) bone were 12 microg/dl, 2.7 microg/l, 13 microg/g, and 20 microg/g, respectively. Semen Pb was determined by blood Pb and patella Pb. Determinants of higher tibia Pb were age, living near industry in which Pb is used, and a high occupational Pb exposure index. Higher patella Pb was predicted by age, higher traffic density near home, a high index of occupational exposure to Pb and a greater number of cigarettes smoked per day in the year prior to the study. Blood and bone Pb results are consistent with findings in other populations. Semen results provide new information on the semen-bone Pb relationship. Bone, especially trabecular one, proved to be a significant endogenous lead source for blood and semen burdens in reproductive aged men.
Assuntos
Poluentes Ambientais/análise , Poluentes Ambientais/sangue , Chumbo/análise , Chumbo/sangue , Exposição Ocupacional , Adulto , Carga Corporal (Radioterapia) , Osso e Ossos/química , Humanos , Masculino , México , Pessoa de Meia-Idade , Sêmen/química , Fumar/efeitos adversosRESUMO
Nursing infants may be exposed to lead from breast milk, but relatively few data exist with which to evaluate and quantify this relationship. This route of exposure constitutes a potential infant hazard from mothers with current ongoing exposure to lead as well as from mothers who have been exposed previously due to the redistribution of cumulative maternal bone lead stores. We studied the relationship between maternal breast milk lead and infant blood lead levels among 255 mother-infant pairs exclusively or partially breast-feeding through 1 month of age in Mexico City. A rigorous, well-validated technique was used to collect, prepare, and analyze the samples of breast milk to minimize the potential for environmental contamination and maximize the percent recovery of lead. Umbilical cord and maternal blood lead were measured at delivery; 1 month after delivery (+/- 5 days) maternal blood, bone, and breast milk and infant blood lead levels were obtained. Levels of lead at 1 month postpartum were, for breast milk, 0.3-8.0 microg/L (mean +/- SD, 1.5 +/- 1.2); maternal blood lead, 2.9-29.9 microg/dL (mean +/- SD, 9.4 +/- 4.5); and infant blood lead, 1.0-23.1 microg/dL (mean +/- SD, 5.5 +/- 3.0). Infant blood lead at 1 month postpartum was significantly correlated with umbilical cord (Spearman correlation coefficient rS = 0.40, p < 0.0001) and maternal (rS= 0.42, p < 0.0001) blood lead at delivery and with maternal blood (rS= 0.67, p < 0.0001), patella rS = 0.19, p = 0.004), and breast milk (rS = 0.32, p < 0.0001) lead at 1 month postpartum. Adjusting for cord blood lead, infant weight change, and reported breast-feeding status, a difference of approximately 2 microg/L (ppb; from the midpoint of the lowest quartile to the midpoint of the highest quartile) breast milk lead was associated with a 0.82 microg/dL increase in blood lead for breast-feeding infants at 1 month of age. Breast milk lead accounted for 12% of the variance of infant blood lead levels, whereas maternal blood lead accounted for 30%. Although these levels of lead in breast milk were low, they clearly have a strong influence on infant blood lead levels over and above the influence of maternal blood lead. Additional information on the lead content of dietary alternatives and interactions with other nutritional factors should be considered. However, because human milk is the best and most complete nutritional source for young infants, breast-feeding should be encouraged because the absolute values of the effects are small within this range of lead concentrations.