RESUMO
Purpose: The purpose of this study was to determine the association between prenatal and early life exposure to lead and the presence of molar hypomineralization (MH) in a group of Mexican children. Methods: A subset of participants of the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENTS) cohort study was examined for the presence of molar hypomineralization using European Academy of Pedi- atric Dentistry (EAPD) criteria. Prenatal lead exposure was assessed by K-ray fluorescence measurements of patella and tibia lead and by maternal blood lead levels by trimester and averaged over trimesters. Postnatal exposure was assessed by levels of maternal blood lead at delivery and child blood lead at 12 and 24 months. Results: A subset of 506 subjects from the ELEMENT cohorts (nine to 18 years old) were examined for MH; 87 subjects (17.2 percent) had MH. Maternal blood lead levels in the third trimester (odds ratio [OR] equals 1.08; 95 percent confidence interval [95% CI] equals 1.02 to 1.15) and averaged over three trimesters (OR equals 1.10; 95% CI equals 1.02 to 1.19) were significantly associated with MH status. None of the maternal bone lead or the child's blood lead parameters was significantly associated with the presence of MH (P>0.05). Conclusions: This study documents a significant association between prenatal lead exposure especially in late pregnancy and the odds of molar hypomineralization.
Assuntos
Hipomineralização Molar , Efeitos Tardios da Exposição Pré-Natal , Criança , Feminino , Humanos , Gravidez , Adolescente , Estudos de Coortes , Chumbo/efeitos adversos , Família , México , Exposição MaternaRESUMO
BACKGROUND AND AIM: An association between lead (Pb) exposure and antisocial behaviors has been documented, but findings have been inconclusive. We aimed to estimate the association between prenatal, early childhood, and preadolescent/adolescent (periadolescent) Pb exposure and aggression and conduct problems in periadolescent residents of Mexico City. METHODS: Using information from the ELEMENT cohort study, we assessed prenatal Pb exposure through maternal patella Pb (MPPb) measurement during the puerperium, early childhood (birth to 5 years of age) exposure through a cumulative blood lead index (CBLI), and periadolescent exposure through a blood Pb (BPb) measurement concurrent with the evaluation of the outcomes. Outcomes were assessed during periadolescence using the parent-reported scales of aggression and conduct problems of the Behavioral Assessment System for Children-2nd version (BASC-2). We modeled the association between Pb exposure at each stage and each outcome (defined as a T-score ≥60 in the corresponding behavioral scale) using logistic regression, adjusting for sex, maternal age at delivery, maternal education, and household socioeconomic status (SES). The differential effect by sex was assessed with an interaction term in the models. RESULTS: 743, 704, and 595 participants were respectively eligible for inclusion in final models of prenatal, early childhood, and periadolescent Pb exposure. Median Pb exposure at each stage was 9.9 µg/g for MPPb (prenatal), 5.19 µg/dl for CBLI (early childhood), and 2.62 µg/dl for concurrent BPb (periadolescence). 12 % of participants met the criterion for aggression, and 15 % for conduct problems. In adjusted models, a one interquartile range increase in MPPb increased the odds of conduct problems (OR:1.31; 95 % CI: 1.01, 1.70) and aggression (OR=1.24; 95 % CI: 0.93, 1.65) during periadolescence. Pb exposure during early childhood or periadolescence was not associated with either outcome. We found no evidence of interactions by sex. CONCLUSIONS: Exposure to Pb during the prenatal stage was associated with aggression and conduct problems during periadolescence.
Assuntos
Efeitos Tardios da Exposição Pré-Natal , Comportamento Problema , Criança , Adolescente , Gravidez , Feminino , Humanos , Pré-Escolar , Chumbo/efeitos adversos , Estudos de Coortes , Agressão , México/epidemiologia , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamenteRESUMO
Epidemiological studies assessing prenatal fluoride exposure and anthropometry at birth are scarce, inconsistent and with methodological limitations. The aim of this study was to evaluate associations between maternal urinary fluoride (MUF) at each trimester of pregnancy and birth weight and length in 536 mother-child pairs in the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) cohort study. MUF (mg/L) was measured using microdiffusion/fluoride-specific electrode from at least one trimester of pregnancy. Non-linear associations were assessed through segmented regression models (MUF and birth weight Z-score) and we used linear regression models for MUF and birth length Z-score. Models were adjusted for potential confounders including urinary creatinine concentrations as a covariate. Non-creatinine adjusted MUF levels at each trimester of pregnancy were 0.81, 0.86, and 0.82 mg/L, mean concentrations for first, second and third trimester, respectively. For birth weight, we identified a MUF breakpoint at 0.99, 0.68 and 0.58 mg/L, for first, second and third trimester of pregnancy, respectively. In the first trimester, an increase of 1 mg/L in MUF concentrations ≥0.99 mg/L was associated with an increase in weight Z-score at birth (ß = 0.79; 95% CI: 0.10, 1.48; p = 0.02). Second trimester MUF (≥0.68 mg/L) was marginally associated with birth weight decrease (ß = -0.25; 95% CI: -0.55, 0.04; p = 0.09) and third trimester MUF (≥0.58 mg/L) was significantly associated with birth weight decrease (ß = -0.33; 95% CI: -0.63, -0.03; p = 0.03). We observed a linear and significant association between MUF and Z-score of length at birth only for the first trimester of pregnancy (ß = 0.55; 95% CI: 0.07, 1.04; p < 0.02). Prenatal fluoride exposure was associated with birthweight z-score with different susceptibility windows. Our findings reinforce the hypothesis that maternal fluoride exposure may affect birth anthropometry.
Assuntos
Fluoretos , Exposição Materna , Peso ao Nascer , Estudos de Coortes , Feminino , Fluoretos/efeitos adversos , Humanos , Recém-Nascido , Gravidez , Segundo Trimestre da GravidezRESUMO
Dietary factors are known to influence urinary fluoride (UF) levels in nonpregnant people. Maternal UF is used as a biomarker of fluoride exposure; however, dietary influences on UF during pregnancy are unknown. We compared UF levels and assessed the associations between UF and five select dietary influences in pregnancy vs. one-year postpartum: dietary fluoride (F), calcium intake from diet (Ca-diet), calcium intake from supplements (Ca-sup), dietary acid load (AL), and table salt use (TS) in 421 women exposed to fluoridated salt in the Mexican diet. Spot UF (mg/L) was measured by microdiffusion/fluoride-specific electrode and dilution-corrected with specific gravity (SG). Dietary variables were estimated from a validated Food Frequency Questionnaire. Comparisons among UF in pregnancy vs. one-year postpartum were performed with non-parametric tests. Associations between dietary variables and UF were assessed using random effect models (for pregnancy) and linear regression (for one-year postpartum). SG-corrected UF (median, range) during pregnancy (0.77, 0.01-4.73 mg/L) did not significantly differ from one-year postpartum (0.75, 0.15-2.62 mg/L) but did increase every 10 gestational weeks, ß = 0.05 (CI: 0.00-0.10). Different dietary influences on UF were identified at each state. Although Ca-diet and AL were not associated with UF in either state, Ca-sup decreased UF only during pregnancy, ß = - 0.012 mg/L (CI: - 0.023-0.00). Reporting TS use was associated with 12% increase in UF only at one-year postpartum (p = 0.026). These results suggest different dietary influences on UF in the pregnant state, which need consideration when using UF as a biomarker of fluoride exposure.
Assuntos
Dieta , Fluoretos , Suplementos Nutricionais , Feminino , Fluoretos/análise , Humanos , México , Período Pós-Parto , GravidezRESUMO
BACKGROUND: Gestational lead (Pb) exposure can adversely affect offspring health through multiple mechanisms, including epigenomic alterations via DNA methylation (5mC) and hydroxymethylation (5hmC), an intermediate in oxidative demethylation. Most current methods do not distinguish between 5mC and 5hmC, limiting insights into their individual roles. OBJECTIVE: Our study sought to identify the association of trimester-specific (T1, T2, T3) prenatal Pb exposure with 5mC and 5hmC levels at multiple cytosine-phosphate-guanine sites within gene regions previously associated with prenatal Pb (HCN2, NINJ2, RAB5A, TPPP) in whole blood leukocytes of children ages 11-18 years of age. METHODS: Participants from the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) birth cohorts were selected (n=144) for pyrosequencing analysis following oxidative or standard sodium bisulfite treatment. This workflow directly quantifies total methylation (5mC+5hmC) and 5mC only; 5hmC is estimated by subtraction. RESULTS: Participants were 51% male, and mean maternal blood lead levels (BLL) were 6.43±5.16µg/dL in Trimester 1 (T1), 5.66±5.21µg/dL in Trimester 2 (T2), and 5.86±4.34µg/dL in Trimester 3 (T3). In addition, 5hmC levels were calculated for HCN2 (mean±standard deviation(SD), 2.08±4.18%), NINJ2 (G/C: 2.01±5.95; GG: 0.90±3.97), RAB5A (0.66±0.80%), and TPPP (1.11±6.67%). Furthermore, 5mC levels were measured in HCN2 (81.3±9.63%), NINJ2 (heterozygotes: 38.6±7.39%; GG homozygotes: 67.3±9.83%), RAB5A (1.41±1.21%), and TPPP (92.5±8.03%). Several significant associations between BLLs and 5mC/5hmC were identified: T1 BLLs with 5mC in HCN2 (ß=-0.37, p=0.03) and 5hmC in NINJ2 (ß=0.49, p=0.003); T2 BLLs with 5mC in HCN2 (ß=0.37, p=0.03) and 5hmC in NINJ2 (ß=0.27, p=0.008); and T3 BLLs with 5mC in HCN2 (ß=0.50, p=0.01) and NINJ2 (ß=-0.35, p=0.004) and 5hmC in NINJ2 (ß=0.45, p<0.001). NINJ2 5mC was negatively correlated with gene expression (Pearson r=-0.5, p-value=0.005), whereas 5hmC was positively correlated (r=0.4, p-value=0.04). DISCUSSION: These findings suggest there is variable 5hmC in human whole blood and that prenatal Pb exposure is associated with gene-specific 5mC and 5hmC levels at adolescence, providing evidence to consider 5hmC as a regulatory mechanism that is responsive to environmental exposures. https://doi.org/10.1289/EHP8507.
Assuntos
Metilação de DNA , Chumbo , 5-Metilcitosina , Adolescente , Moléculas de Adesão Celular Neuronais , Criança , Citosina , Epigênese Genética , Epigenômica , Feminino , Humanos , Masculino , México , GravidezRESUMO
BACKGROUND: Exposure to environmental toxicants may play a role in the pathogenesis of Non Alcoholic Fatty Liver Disease (NAFLD). Cumulative exposure to lead (Pb) has chronic and permanent effects on liver function. Pediatric populations are vulnerable to the toxic effects of Pb, even at low exposure levels. The purpose of the study was to estimate the association between cumulative Pb exposure during childhood and hepatic steatosis biomarkers in young Mexican adults. METHODS: A subsample of 93 participants from the ELEMENT cohort were included in this study. Childhood blood samples were collected annually from ages 1-4 years and were used to calculate the Cumulative Childhood Blood Lead Levels (CCBLL). Hepatic steatosis during adulthood was defined as an excessive accumulation of hepatic triglycerides (>5%) determined using Magnetic Resonance Imaging (MRI). Liver enzymes were also measured at this time, and elevated liver enzyme levels were defined as ALT (≥30 IU/L), AST (≥30 IU/L), and GGT (≥40 IU/L). Adjusted linear regression models were fit to examine the association between CCBLL (quartiles) and the hepatic steatosis in young adulthood. RESULTS: In adulthood, the mean age was 21.4 years, 55% were male. The overall prevalence of hepatic steatosis by MRI was 19%. Elevate levels of the enzymes ALT, AST, and GGT were present in 25%, 15%, and 17% of the sample, respectively. We found a positive association between the highest quartile of CCBLL with the steatosis biomarkers of hepatic triglycerides (Q4 vs. Q1: ß = 6.07, 95% CI: 1.91-10.21), elevated ALT (Q4 vs. Q1: ß = 14.5, 95% CI: 1.39-27.61) and elevated AST (Q4 vs. Q1: ß = 7.23, 95% CI: 0.64-13.82). No significant associations were found with GGT. CONCLUSIONS: Chronic Pb exposure during early childhood is associated with a higher levels of hepatic steatosis biomarkers and hepatocellular injury in young adulthood. More actions should be taken to eliminate sources of Pb during the first years of life.
Assuntos
Chumbo , Hepatopatia Gordurosa não Alcoólica , Adulto , Alanina Transaminase , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Lactente , Chumbo/toxicidade , Masculino , México/epidemiologia , Hepatopatia Gordurosa não Alcoólica/induzido quimicamente , Hepatopatia Gordurosa não Alcoólica/epidemiologia , Adulto JovemRESUMO
OBJECTIVE: To estimate dietary fluoride intake (F) over the course of pregnancy and the overall adjusted difference in dietary F intake by pregnancy stages and levels of compliance with dietary recommendations. DESIGN: Secondary data analysis from a longitudinal pregnancy cohort study in a population exposed to fluoridated salt. Women were followed during the early, middle and late stages of their pregnancy (n 568). The dietary intake of recommended prenatal nutrients according to Mexican dietary guidelines and F intake (mg/d) was estimated with a validated FFQ. Data were summarised with descriptive statistics. Levels of F intake were compared with the USA's Institute of Medicine adequate intake (AI) of 3 mg/d for pregnancy. Adjusted differences in F intake by pregnancy stages and levels of compliance with recommendations were estimated using random effects models. SETTING: Mexico City. PARTICIPANTS: Women participating in the Early Life Exposures in Mexico to ENvironmental Toxicants (ELEMENT) project, from 2001 to 2003. RESULTS: Median dietary F intake throughout pregnancy ranged from 0·64 (interquartile range (IQR) 0·38) in the early to 0·70 (IQR 0·42) in the middle, and 0·72 (IQR 0·44) mg/d in the late stage (0·01 mg F/kg per d). Corresponding adjusted intakes of F were 0·72 (95 % CI 0·70, 0·74), 0·76 (95 % CI 0·74, 0·77) and 0·80 (95 % CI 0·78, 0·82) mg/d. Women who were moderately and highly compliant with Mexican dietary recommendations ingested, on average, 0·04 and 0·14 mg F/d more than non-compliant women (P < 0·005). CONCLUSIONS: Dietary F intake was below current AI, was greater with the progression of pregnancy and in women who were moderately and highly compliant with dietary recommendations.
Assuntos
Dieta , Fluoretos , Estudos de Coortes , Feminino , Humanos , México , Política Nutricional , GravidezRESUMO
To examine the association of dietary fluoride intake, total carbohydrate consumption and other key dietary variables with dental caries experience among adolescents, a cross-sectional analysis was conducted in a sample of 402 participants from the Early Life Exposures in Mexico to Environmental Toxicants cohort. The presence and severity of dental caries were assessed using the International Caries Detection and Assessment System (ICDAS) to calculate the number of decayed, missing, and filled teeth or surfaces (D1MFT/D4MFT). The dietary intake of fluoride, energy, carbohydrates, and food groups was estimated using a validated food frequency questionnaire (FFQ). Multivariate zero-inflated negative binomial regression models and negative binomial regression models were run to estimate the association of fluoride intake (mg/day) and total carbohydrate intake (g/day) with the D1MFT/D4MFT index. We found that 80% of the adolescents experienced dental caries (D1MFT >0), with 30% presenting cavitated lesions (D4MFT >0). The mean scores for D1MFT and D4MFT were 6.2 (SD 5.3) and 0.67 (SD 1.3), respectively. The median intake of fluoride estimated by the FFQ was 0.015 mg/kg/day. This intake was statistically higher in participants with a D4MFT = 0 compared to those with a D4MFT >0 (0.90 vs. 0.82 mg/day; 0.016 vs. 0.014 mg/kg/day; p < 0.05). For D1MFT, D1MFS, D4MFT, and D4MFS scores, a higher fluoride consumption (mg/day) from foods and beverages was associated with a statistically significant reduction in the number of lesions. The reported frequency of consumption of sugary foods in a whole day was statistically higher in those with D1MFT >0 than in those with D1MFT = 0 (p < 0.05). The total carbohydrate intake (g/day) was positively associated with dental caries experience. We conclude that a higher fluoride intake through foods and beverages is associated with a lower dental caries experience among adolescents; this effect was seen even when the dietary intake of fluoride was 0.015 mg/kg/day, which is lower than the average intake recommendation. In contrast, a higher total carbohydrate intake and the frequency of intake of sugary foods were associated with a higher dental caries experience, with no apparent threshold for the effects.
Assuntos
Cárie Dentária , Fluoretos , Adolescente , Estudos de Coortes , Estudos Transversais , Índice CPO , Cárie Dentária/epidemiologia , Cárie Dentária/etiologia , Dieta , Fluoretos/efeitos adversos , Humanos , MéxicoRESUMO
OBJECTIVES: The purpose of this study was to determine whether there is an association between lead exposure within the ages of 1-4 years and dental caries in the permanent dentition between ages 9-17 among Mexican youth. METHODS: Data were collected for the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) cohort from a group of 490 children born and reared in Mexico City. Among ages 1-4 years, blood lead levels were measured in micrograms of lead per deciliter of blood (µg/dL) and the presence of caries in adolescence was determined using the International Caries and Detection and Assessment System (ICDAS). The relationship between blood levels of lead and decayed, missing, or filled surfaces (DMFS) was examined using negative binomial regression. Covariates were selected based on previous studies and included age, gender, socioeconomic status, oral hygiene, body mass index, and diet. The nonlinear relationship between lead and DMFS was examined using smoothing splines. RESULTS: The mean overall blood lead level (BLL) was 4.83 µg/dL (S.D. of 2.2). The mean overall caries level (DMFS) was 4.1. No statistically significant association was found between early childhood blood lead levels and dental caries in adolescence. CONCLUSION: This study shows a lack of association between exposure to lead between the ages of 1-4 years of age and dental caries in permanent dentition later in life. Other covariates, such as age and sugar consumption, appeared to play a more prominent role in caries development.
Assuntos
Cárie Dentária , Chumbo , Adolescente , Criança , Pré-Escolar , Índice CPO , Cárie Dentária/epidemiologia , Dentição Permanente , Humanos , Lactente , México/epidemiologia , Higiene BucalAssuntos
Fluoretos , Fórmulas Infantis , Canadá , Criança , Ingestão de Alimentos , Fluoretos/análise , Humanos , Lactente , ÁguaRESUMO
During pregnancy, maternal lead from earlier exposures mobilizes and crosses placental barriers, placing the developing fetus at risk for lead exposure and neurodevelopmental deficits. Some neuronal circuits known to be affected in neurodevelopment disorders can be probed with simple physiological behavioral paradigms. One such neural biomarker is Pre-Pulse Inhibition (PPI), an indicator of adequate sensorimotor gating processing. In clinical studies, deficits in PPI have been associated with neurodevelopmental disorders in human subjects. To our knowledge, no studies have examined the use of PPI as a biomarker of toxicant effects on the brain in epidemiological studies. We aimed to estimate the causal effect of prenatal lead exposure, assessed by maternal cortical bone lead concentrations, on PPI in 279 children from Mexico City. in vivo maternal cortical bone lead measurements were taken at four weeks postpartum at the mid-tibia shaft using a K-Shell X-ray fluorescence instrument. PPI recording occurred in an isolated clinical setting and eye blink responses were measured using electromyography. We assessed if the conditions for causal inference held in our study and used the results of our assessment to estimate the causal effect of prenatal lead exposure on PPI using an ordinary least squares regression model, a marginal structural model, and the parametric g-formula. Results were consistent across the three modeling approaches. For the parametric g-formula, a one standard deviation (10.0⯵g/g) increase in prenatal lead significantly reduced PPI by approximately 19.0 % (95 % CI: 5.4 %, 34.3 %). This decrease is similar in magnitude to clinical studies on schizophrenia, which have observed PPI impairments in patients with schizophrenia as compared to controls. Our results are consistent with findings from other studies establishing an association between lead exposure and neurodevelopmental disorders in children and suggest that PPI may be useful as an objective biomarker of toxicant effects on the brain.
Assuntos
Chumbo/efeitos adversos , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Efeitos Tardios da Exposição Pré-Natal/psicologia , Inibição Pré-Pulso , Adolescente , Exposição Ambiental/efeitos adversos , Feminino , Humanos , Chumbo/sangue , Exposição Materna/efeitos adversos , México , Gravidez , Efeitos Tardios da Exposição Pré-Natal/sangueRESUMO
CONTEXT: Several cross-sectional studies have assessed the association of lead exposure with type 2 diabetes and cardiometabolic risk factors in adults; however, studies of such associations in childhood are rare. OBJECTIVE: We assessed the prospective associations of prenatal exposure to lead with type 2 diabetes and cardiometabolic risk factors in children. DESIGN: The Early Life Exposure in Mexico to Environmental Toxicants is a birth cohort study of pregnant women and their offspring. SETTING: Public hospitals in Mexico City. PATIENTS OR OTHER PARTICIPANTS: Women were recruited during pregnancy; their offspring were recruited for a follow-up visit at age 10 to 18 years (n = 369). MAIN OUTCOME MEASURES: We measured fasting serum markers of type 2 diabetes and cardiometabolic risk factors in children, including fasting glucose, insulin, and lipids. The index of insulin resistance was calculated. RESULTS: The geometric mean of maternal blood lead levels (BLLs) during pregnancy was 4.3 µg/dL (95% confidence interval [CI]): 4.0-4.6 µg/dL) in the entire sample. In boys, those with maternal BLLs ≥ 5 µg/dL (compared with those with BLLs < 5 µg/dL) had significantly lower z scores for total cholesterol (ß = -0.41, 95% CI: -0.71, -0.12), high-density lipoprotein cholesterol (ß = -0.32, 95% CI: -0.59, -0.05), and low-density lipoprotein cholesterol (ß = -0.52, 95% CI: -0.81, -0.22), adjusting for covariates. No associations were detected in girls. CONCLUSIONS: In our study, we found that higher prenatal exposure to lead was associated with lower levels of cholesterol in children following a sex-specific pattern. Further studies with a larger sample size that examine whether sex is a potential modifier are needed to confirm our findings.
Assuntos
Doenças Cardiovasculares/etiologia , Filho de Pais com Deficiência , Diabetes Mellitus Tipo 2 , Intoxicação por Chumbo , Doenças Metabólicas/etiologia , Gravidez em Diabéticas , Efeitos Tardios da Exposição Pré-Natal/epidemiologia , Adolescente , Adulto , Doenças Cardiovasculares/epidemiologia , Criança , Filho de Pais com Deficiência/estatística & dados numéricos , Estudos de Coortes , Estudos Transversais , Feminino , Seguimentos , Humanos , Recém-Nascido , Chumbo/análise , Chumbo/sangue , Chumbo/toxicidade , Masculino , Doenças Metabólicas/epidemiologia , México/epidemiologia , Gravidez , Efeitos Tardios da Exposição Pré-Natal/sangue , Fatores de Risco , Adulto JovemRESUMO
BACKGROUND: Several animal studies have suggested that fluoride exposure may increase the levels of cardiometabolic risk factors, but little is known about whether fluoride exposure is associated with such risk in humans. OBJECTIVES: We examined the cross-sectional association between peripubertal exposure to fluoride and markers of cardiometabolic risk in 280 girls and 256 boys at age 10-18â¯years living in Mexico City. METHODS: We measured plasma fluoride concentration using a microdiffusion method. We collected data on anthropometry including BMI, waist circumference (WC) and trunk fat percentage. We measured serum markers of cardiometabolic risk, including fasting glucose, insulin and lipids. All the indicators of outcome were converted to age- and sex-specific z-scores. We also calculated a summary cardiometabolic risk score for each participant. Multivariable linear regression models were used to examine these associations. RESULTS: The geometric mean (95% confidence interval (CI)) of plasma fluoride was 0.21⯵mol/L (0.20, 0.23⯵mol/L) in the total sample. In girls, plasma fluoride concentrations were associated with higher z-scores for all the individual markers (except for lipids) and for the combined cardiometabolic risk score (risk score: ßâ¯=â¯1.28, 95% CI: 0.57-2.00, p-sex interactionâ¯=â¯0.02)), adjusting for covariates. No associations were found in boys. CONCLUSIONS: We found that higher peripubertal fluoride exposure at the levels observed in this study population was significantly associated with increased levels of cardiometabolic risk factors in Mexican girls but not boys. Future studies with a longitudinal design are needed to confirm our findings and further elucidate the role of fluoride in cardiometabolic risk.
Assuntos
Doenças Cardiovasculares/epidemiologia , Fluoretos/efeitos adversos , Adiposidade , Adolescente , Índice de Massa Corporal , Criança , Estudos Transversais , Feminino , Fluoretos/sangue , Humanos , Masculino , México/epidemiologia , Fatores de Risco , Fatores Sexuais , Circunferência da CinturaRESUMO
STUDY OBJECTIVES: Lead exposure has been linked to adverse cognitive outcomes among children, and sleep disturbances could potentially mediate these relationships. As a first step, whether childhood lead levels are linked to sleep disturbances must be ascertained. Prior studies of lead and sleep are scarce and rely on parent-reported sleep data. METHODS: The study population included 395 participants from the Early Life Exposure in Mexico to Environmental Toxicants project, a group of sequentially enrolled birth cohorts from Mexico City. Blood lead levels measured from ages 1 to 4 years were used to calculate a cumulative measure of early childhood lead levels. Average sleep duration, sleep fragmentation, and movement index were assessed once between the ages of 9 and 18 years with wrist actigraphs worn for a continuous 7-day interval. Linear regression models were fit with average sleep duration, fragmentation, or movement as the outcome and cumulative lead levels divided into quartiles as the exposure, adjusted for age, sex, and maternal education. RESULTS: Mean (standard deviation) age at follow-up was 13.8 (1.9) years, and 48% of participants were boys. Median (interquartile range) cumulative childhood lead level was 13.7 (10.8, 18.0) µg/dL. Patients in the highest quartile of the cumulative childhood lead group had on average 23 minutes less sleep than those in the first quartile in adolescence (95% confidence interval [7, 39]; P, trend = .02). Higher cumulative lead level was associated with higher sleep fragmentation in younger adolescents (younger than 14 years) only (P, interaction = .02). CONCLUSIONS: Shorter sleep duration may represent an as-yet unrecognized adverse consequence of lead exposure in youth.
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Chumbo/sangue , Privação do Sono/sangue , Actigrafia , Adolescente , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Seguimentos , Humanos , Lactente , Chumbo/efeitos adversos , Estudos Longitudinais , Masculino , México , Privação do Sono/induzido quimicamente , Privação do Sono/fisiopatologia , Fatores de TempoRESUMO
PURPOSE: The Early Life Exposure in Mexico to ENvironmental Toxicants (ELEMENT) Project is a mother-child pregnancy and birth cohort originally initiated in the mid-1990s to explore: (1) whether enhanced mobilisation of lead from maternal bone stores during pregnancy poses a risk to fetal and subsequent offspring neurodevelopment; and (2) whether maternal calcium supplementation during pregnancy and lactation can suppress bone lead mobilisation and mitigate the adverse effects of lead exposure on offspring health and development. Through utilisation of carefully archived biospecimens to measure other prenatal exposures, banking of DNA and rigorous measurement of a diverse array of outcomes, ELEMENT has since evolved into a major resource for research on early life exposures and developmental outcomes. PARTICIPANTS: n=1643 mother-child pairs sequentially recruited (between 1994 and 2003) during pregnancy or at delivery from maternity hospitals in Mexico City, Mexico. FINDINGS TO DATE: Maternal bone (eg, patella, tibia) is an endogenous source for fetal lead exposure due to mobilisation of stored lead into circulation during pregnancy and lactation, leading to increased risk of miscarriage, low birth weight and smaller head circumference, and transfer of lead into breastmilk. Daily supplementation with 1200 mg of elemental calcium during pregnancy and lactation reduces lead resorption from maternal bone and thereby, levels of circulating lead. Beyond perinatal outcomes, early life exposure to lead is associated with neurocognitive deficits, behavioural disorders, higher blood pressure and lower weight in offspring during childhood. Some of these relationships were modified by dietary factors; genetic polymorphisms specific for iron, folate and lipid metabolism; and timing of exposure. Research has also expanded to include findings published on other toxicants such as those associated with personal care products and plastics (eg, phthalates, bisphenol A), other metals (eg, mercury, manganese, cadmium), pesticides (organophosphates) and fluoride; other biomarkers (eg, toxicant levels in plasma, hair and teeth); other outcomes (eg, sexual maturation, metabolic syndrome, dental caries); and identification of novel mechanisms via epigenetic and metabolomics profiling. FUTURE PLANS: As the ELEMENT mothers and children age, we plan to (1) continue studying the long-term consequences of toxicant exposure during the perinatal period on adolescent and young adult outcomes as well as outcomes related to the original ELEMENT mothers, such as their metabolic and bone health during perimenopause; and (2) follow the third generation of participants (children of the children) to study intergenerational effects of in utero exposures. TRIAL REGISTRATION NUMBER: NCT00558623.
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Osso e Ossos/metabolismo , Exposição Ambiental/efeitos adversos , Poluentes Ambientais/efeitos adversos , Chumbo/efeitos adversos , Chumbo/metabolismo , Efeitos Tardios da Exposição Pré-Natal/etiologia , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Adulto , Fatores Etários , Feminino , Humanos , Recém-Nascido , Masculino , México , Gravidez , Adulto JovemRESUMO
BACKGROUND: Sources of fluoride exposure for Mexicans include foods, beverages, fluoridated salt, and naturally fluoridated water. There are no available data describing fluoride content of foods and beverages consumed in Mexico. OBJECTIVE: To measure the content of fluoride in foods and beverages typically consumed and to compare their content to that of those from the United States and the United Kingdom. METHODS: Foods and beverages reported as part of the Mexican Health and Nutrition Survey (n = 182) were purchased in the largest supermarket chains and local markets in Mexico City. Samples were analyzed for fluoride, at least in duplicate, using a modification of the hexamethyldisiloxane microdiffusion method. Value contents were compared to those from the US Department of Agriculture and UK fluoride content tables. RESULTS: The food groups with the lowest and highest fluoride content were eggs (2.32 µg/100 g) and seafood (371 µg/100 g), respectively. When estimating the amount of fluoride per portion size, the lowest content corresponded to eggs and the highest to fast foods. Meats and sausages, cereals, fast food, sweets and cakes, fruits, dairy products, legumes, and seafood from Mexico presented higher fluoride contents than similar foods from the United States or the United Kingdom. Drinks and eggs from the United States exhibited the highest contents, while this was the case for pasta, soups, and vegetables from the United Kingdom. CONCLUSION: The majority of items analyzed contained higher fluoride contents than their US and UK counterparts. Data generated provide the first and largest table on fluoride content, which will be useful for future comparisons and estimations.
Assuntos
Bebidas/análise , Comércio/estatística & dados numéricos , Fluoretos/análise , Análise de Alimentos/estatística & dados numéricos , Humanos , México , Inquéritos Nutricionais , Reino Unido , Estados UnidosRESUMO
BACKGROUND: Prenatal and early childhood lead exposures have been associated with reduced weight in infants and young children, while studies that have examined such associations in children during peripubescence are rare. OBJECTIVES: We investigated the associations of prenatal and early-life exposure to lead with indices of adiposity in peripubertal children living in Mexico City. METHODS: Maternal bone lead (as a proxy for cumulative fetal exposure) was assessed at 1 month postpartum. Blood samples were obtained from children annually from 1 to 4 years. Multivariable linear regression models were used to examine the association between each lead biomarker and BMI z-score, waist circumference, sum of skinfolds and body fat percentage in 248 children aged 8-16 years. RESULTS: After adjusting for covariates, maternal patella lead was associated with lower child BMI z-score (ßâ¯=â¯-0.02, 95% CI: 0.03, -0.01, pâ¯=â¯0.004), waist circumference (ßâ¯=â¯-0.12â¯cm, 95% CI: 0.22, -0.03, pâ¯=â¯0.01), sum of skinfolds (ßâ¯=â¯-0.29â¯mm, 95% CI: 0.50, -0.08, pâ¯=â¯0.007) and body fat percentage (ßâ¯=â¯-0.09%, 95% CI: 0.17, -0.01, pâ¯=â¯0.03). No significant associations were detected from the postnatal exposure period. CONCLUSIONS: We observed a significant and inverse association of prenatal lead exposure with body composition in Mexican children, suggesting the potential role of early lead exposure in the fetal programming of child growth. Further research on the biological mechanisms underlying these associations is needed.
Assuntos
Adiposidade , Poluentes Ambientais/análise , Chumbo/análise , Exposição Materna , Efeitos Tardios da Exposição Pré-Natal , Adolescente , Adulto , Monitoramento Biológico , Criança , Cidades , Feminino , Humanos , Masculino , Troca Materno-Fetal , México , Patela/química , Gravidez , Tíbia/química , Adulto JovemRESUMO
Prepulse inhibition (PPI) is a sensorimotor gating mechanism that reduces interfering influences to the neural processing of incoming stimuli, and is associated with several neurodevelopmental disorders. To date, research on PPI and neurodevelopmental disorders has primarily been in cross-sectional, clinical settings. In this prospective, epidemiologic study, we used a data-driven prediction model to identify socio-demographic predictors of PPI in children and adolescents from Mexico City to inform future etiologic studies evaluating PPI. We conducted variable selection and validation using a modified version of the multiple imputation random lasso (MIRL) variable selection algorithm. MIRL identified six predictors of PPI at a stimulus onset asynchrony of 120 ms or 240 ms. Of those six predictors, maternal education, birthweight, and total breastfeeding months were highlighted as previously unstudied variables associated with enhanced PPI. Our findings highlight the potential value of PPI as an adjunct screening tool for identifying children at risk for neurodevelopmental disorders and underscore the relevance for validation research on this topic.
Assuntos
Transtornos do Neurodesenvolvimento/epidemiologia , Inibição Pré-Pulso , Adolescente , Algoritmos , Criança , Demografia , Feminino , Humanos , Masculino , México/epidemiologia , Transtornos do Neurodesenvolvimento/etiologia , Transtornos do Neurodesenvolvimento/fisiopatologia , Estudos Prospectivos , Medição de Risco , Fatores de Risco , Filtro SensorialRESUMO
BACKGROUND: Dental caries is an important public health problem in Mexico, a country also faced with high exposure to toxicants including lead (Pb). METHODS: Participants were 386 children living in Mexico City. Prenatal (trimester 1-3), early-childhood (12, 24, 36, and 48â¯months of age) and peri-pubertal (10-18â¯years of age) blood Pb levels were quantified using graphite-furnace atomic-absorption spectroscopy. Maternal patella and tibia bone Pb at 1â¯month postpartum were quantified with K X-ray fluorescence instrument. Dental caries presence was evaluated using decayed, missing, and filled teeth (DMFT) scores. Peri-pubertal sugar sweetened beverage (SSB) intake was estimated using a 116-item, interview-administered semi-quantitative food frequency questionnaire (FFQ). Total energy adjusted daily SSB intake was generated using the residual approach. Zero inflated negative binomial (ZINB) Poisson regression models were used to examine the associations between Pb with D1MFT and D4MFT at adolescence. RESULTS: Maternal second and third trimester and cumulative early childhood Pb exposure were positively associated with peri-pubertal D1MFT scores in unadjusted ZINB models (2nd trimester: RRâ¯=â¯1.17 (1.00, 1.37); 3rd trimester: RRâ¯=â¯1.20 (1.03, 1.40); early childhood: RRâ¯=â¯1.22 (1.02, 1.48)). These effect sizes were attenuated and no longer statistically significant after adjusting for covariates. When stratified by high/low SSB intake, a one unit increase of log-transformed 2nd trimester Pb exposure was associated with a 1.41 times (1.06, 1.86) higher D1MFT count, and 3rd trimester Pb exposure was associated with a 1.50 times (1.18, 1.90) higher D1MFT count among those with higher than median peri-pubertal SSB. Associations among those with lower SSB intake were roughly half those of the higher group and not statistically significant. CONCLUSIONS: Pb exposure during sensitive developmental periods was not statistically significantly associated with caries risk after accounting for confounders among our cohort. However, evidence from stratified analysis suggested a Pb-caries association among children with high SSB intake.
Assuntos
Cárie Dentária/epidemiologia , Exposição Ambiental/estatística & dados numéricos , Poluentes Ambientais/metabolismo , Chumbo/metabolismo , Adolescente , Bebidas , Criança , Pré-Escolar , Estudos de Coortes , Exposição Ambiental/análise , Poluentes Ambientais/toxicidade , Humanos , Lactente , Recém-Nascido , Chumbo/toxicidade , México/epidemiologia , Fatores de Risco , EdulcorantesRESUMO
BACKGROUND: Previous animal and ecological studies have provided evidence for an earlier sexual maturation in females in relation to fluoride exposure; however, no epidemiological studies have examined the association between fluoride exposure and pubertal development in both boys and girls using individual-level biomarkers of fluoride. Capitalizing on an ongoing Mexican birth cohort study, we examined the association between concurrent urinary fluoride levels and physical markers of pubertal development in children. METHODS: We conducted a cross-sectional study of 157 boys and 176 girls at age 10-17 years living in Mexico City. We used ion-selective electrode-based diffusion methods to assess fluoride levels in urine, adjusting for urinary specific gravity. Pubertal stages were evaluated by a trained physician. Associations of fluoride with pubertal stages and age at menarche were studied using ordinal regression and Cox proportional-hazard regression, respectively. RESULTS: In the entire sample, the geometric mean and interquartile range (IQR) of urinary fluoride (specific gravity adjusted) were 0.59 mg/L and 0.31 mg/L, respectively. In boys, our analysis showed that a one-IQR increase in urinary fluoride was associated with later pubic hair growth (OR = 0.71, 95% CI: 0.51-0.98, p = 0.03) and genital development (OR = 0.71, 95% CI: 0.53-0.95, p = 0.02). No significant associations were found in girls, although the direction was negative. CONCLUSIONS: Childhood fluoride exposure, at the levels observed in our study, was associated with later pubertal development among Mexican boys at age 10-17 years. Further research is needed to confirm these findings.