RESUMEN
Fluoride, which may be toxic to the developing brain, is added to salt in Mexico and drinking water in Canada to prevent dental caries. We compared childhood urinary fluoride (CUF) concentrations in Mexico City and Canada to characterize patterns of fluoride exposure in these two populations. We also examined associations of CUF with dietary and water fluoride levels in Mexico City and Canada respectively. We included 561 children (ages 46; mean age 4.8 years) from the Programming Research in Obesity, Growth, Environment, and Social Stress (PROGRESS) cohort in Mexico City, and 645 children (ages 26; mean age 3.7 years) from the MaternalInfant Research on Environmental Chemicals (MIREC) cohort in Canada. We applied Spearman correlations, T-tests, ANOVA or covariate-adjusted linear regression to examine associations of CUF (mg/L; adjusted for specific gravity) with demographics and dietary or water fluoride concentrations. We used Welch equivalence testing to compare means across cohorts. Mean (SD) CUF was equivalent (t = 4.26, p < 0.001) in PROGRESS: 0.74 (0.42) and fluoridated Canadian communities: 0.66 (0.47), but lower in non-fluoridated Canadian communities: 0.42 (0.31) (t = −6.37, p < 0.001). Water fluoride concentrations were significantly associated with CUF after covariate adjustment for age and sex in MIREC (B = 0.44, 95% CI: 0.30, 0.59, p < 0.001). In contrast, daily food and beverage fluoride intake was not associated with CUF in PROGRESS (p = 0.82). We found that CUF levels are comparable among children in Mexico City and fluoridated Canadian communities, despite distinct sources of exposure. Community water fluoridation is a major source of fluoride exposure for Canadian children.
RESUMEN
Pesticides are commonly used in tropical regions such as the Caribbean for both household and agricultural purposes. Of particular concern is exposure during pregnancy, as these compounds can cross the placental barrier and interfere with fetal development. The objective of this study was to evaluate exposure of pregnant women residing in 10 Caribbean countries to the following commonly used classes of pesticides in the Caribbean: organophosphates (OPs), carbamates, phenoxy acids, and chlorophenols. Out of 438 urine samples collected, 15 samples were randomly selected from each Caribbean country giving a total of 150 samples. Samples were analyzed for the following metabolites: six OP dialkylphosphate metabolites [dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate (DMDTP), diethylphosphate (DEP), diethylthiophosphate (DETP) and diethyldithiophosphate (DEDTP)]; two carbamate metabolites [2-isopropoxyphenol (2-IPP) and carbofuranphenol]; one phenoxy acid 2,4-dichlorophenoxyacetic acid (2,4-D); and five chlorophenols [2,4-dichlorophenol (DCP), 2,5-dichlorophenol (2,5-DCP), 2,4,5-trichlorophenol (TCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP)]. OP metabolites were consistently detected in ≥60% of the samples from Antigua and Barbuda, Bermuda, and Jamaica. Of the carbamate metabolites, 2-IPP was detected in seven of the 10 Caribbean countries with a detection frequency around 30%, whereas carbofuranphenol was detected in only one sample. The detection frequency for the phenoxy acid 2,4-D ranged from 20% in Grenada to a maximum of 67% in Belize. Evidence of exposure to chlorophenol pesticides was also established with 2,4-DCP by geometric means ranging from 0.52 µg L(-1) in St Lucia to a maximum of 1.68 µg L(-1) in Bermuda. Several extreme concentrations of 2,5-DCP were detected in four Caribbean countries-Belize (1100 µg L(-1)), Bermuda (870 µg L(-1)), Jamaica (1300 µg L(-1)), and St Kitts and Nevis (1400 µg L(-1)). 2,4,5-TCP, 2,4,6-TCP, and pentachlorophenol were rarely detected. This biomonitoring study underscores the need for Caribbean public health authorities to encourage their populations, and in particular pregnant women, to become more aware of the potential routes of exposure to pesticides and to utilize these chemicals more cautiously given the possible adverse effects such exposures can have on their unborn children and infants.
Asunto(s)
Carbamatos/orina , Clorofenoles/orina , Contaminantes Ambientales/orina , Exposición Materna/estadística & datos numéricos , Compuestos Organofosforados/orina , Plaguicidas/orina , Adulto , Región del Caribe , Monitoreo del Ambiente , Femenino , Humanos , EmbarazoRESUMEN
OBJECTIVE: To assess the long-term effect on visual development of omega-3 polyunsaturated fatty acid (n-3 PUFA) intake during gestation. STUDY DESIGN: Using visual evoked potentials (VEPs), the long-term effects on visual development were evaluated in 136 school-age Inuit children exposed to high levels of n-3 PUFAs during gestation. VEP protocols using color and motion stimuli were used to assess parvocellular and magnocellular responses. Concentrations of the two major n-3 PUFAs (docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA]) were measured in umbilical cord and child plasma phospholipids, reflecting prenatal and postnatal exposure, respectively. RESULTS: After adjustment for confounders, cord plasma DHA level was found to be associated with shorter latencies of the N1 and P1 components of the color VEPs. No effects were found for current n-3 PUFA body burden or motion-onset VEPs. CONCLUSION: This study demonstrates beneficial effects of DHA intake during gestation on visual system function at school age. DHA is particularly important for the early development and long-term function of the visual parvocellular pathway.
Asunto(s)
Ácidos Grasos Omega-3/farmacología , Atención Prenatal , Visión Ocular/fisiología , Niño , Desarrollo Infantil/efectos de los fármacos , Ácidos Grasos Omega-3/administración & dosificación , Humanos , Análisis de Regresión , Factores de TiempoRESUMEN
OBJECTIVES: To examine the relation of cord plasma docosahexaenoic acid (DHA) concentration to gestation length, birth size, growth, and infant visual acuity, cognitive, and motor development and the effects on growth and development associated with DHA intake from breast-feeding. STUDY DESIGN: DHA, other polyunsaturated fatty acids, and 3 environmental contaminants (polychlorinated biphenyls, mercury, and lead) were assessed in cord plasma and maternal plasma and milk in 109 Inuit infants in Arctic Quebec. Multiple regression was used to examine the relation of cord DHA and DHA from breast-feeding on growth and development at 6 and 11 months, after controlling for contaminant exposure and other potential confounders. RESULTS: Higher cord DHA concentration was associated with longer gestation, better visual acuity and novelty preference on the Fagan Test at 6 months, and better Bayley Scale mental and psychomotor performance at 11 months. By contrast, DHA from breast-feeding was not related to any indicator of cognitive or motor development in this full-term sample. CONCLUSIONS: The association of higher cord DHA concentration with more optimal visual, cognitive, and motor development is consistent with the need for substantial increases in this critically important fatty acid during the third trimester spurt of synaptogenesis in brain and photoreceptor development.
Asunto(s)
Desarrollo Infantil/fisiología , Ácidos Docosahexaenoicos/sangre , Ácidos Grasos Insaturados/sangre , Sangre Fetal/química , Leche Humana/química , Biomarcadores/sangre , Peso al Nacer , Cognición/fisiología , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Edad Gestacional , Humanos , Lactante , Recién Nacido , Inuk , Masculino , Destreza Motora/fisiología , Análisis Multivariante , Embarazo , Probabilidad , Quebec , Análisis de Regresión , Sensibilidad y Especificidad , Factores de Tiempo , Agudeza Visual/fisiologíaRESUMEN
In response to mounting concerns about the endocrine-disrupting influence of environmental chemicals on human health, this epidemiological study was initiated to test the hypothesis that nonoccupational exposure to the estrogenic pesticide 1,1,1-trichloro-2,2-bis(chlorodiphenyl)ethane (DDT) affects male reproductive parameters. One hundred and sixteen men aged 27 years (SD = 8.2) living in malaria endemic-areas in Chiapas (Mexico), where DDT was sprayed until 2000, participated in a cross-sectional study. Semen analyses were conducted according to World Health Organization methods and a quality control program was followed. DDT exposure was defined as the level of blood plasma p,p'-dichlorodiphenyl dichloroethylene (DDE), the major metabolite of DDT. The p,p'-DDE concentration adjusted for total lipids was 100 times higher than that reported for nonexposed populations at 45 plus or minus 32 mug/g (mean +/- SD). Crude regression analysis showed that several sperm motion parameters, including the percentage of motile sperm, decreased with higher p,p'-DDE concentrations (beta = -8.38; P = .05 for squared motility), and the percentage of sperm with morphological tail defects increased with higher plasma p,p'-DDE concentration (beta = 0.003; P = .017). Insufficient sperm chromatin condensation was observed in 46.6% of participants, and the most severe category of incomplete DNA condensation was also positively correlated with p,p'-DDE concentration (r = .223; P = .044). Therefore, nonoccupational exposure to DDT, as assessed by plasma p,p'-DDE concentrations, is associated with poorer semen parameters in men, indicating adverse effects on testicular function and/or the regulation of reproductive hormones. Previously, a causal role of environmental toxicants in human male infertility has been lacking because observed effects have been the result of unusually high exposures, either occupationally or as a result of industrial accidents, resulting in unprecedented controversy (reviewed by Cheek & McLachlan, Environmental hormones and the male reproductive system. J Androl. 1998;19:5). This is the first epidemiological study demonstrating effects after nonoccupational exposures to DDT. Based on these findings, the effect of DDT on male reproductive health should not be ignored.
Asunto(s)
DDT/toxicidad , Diclorodifenil Dicloroetileno/toxicidad , Exposición a Riesgos Ambientales , Semen/efectos de los fármacos , Adolescente , Adulto , Estudios Transversales , Disruptores Endocrinos/toxicidad , Humanos , Masculino , MéxicoRESUMEN
A cross-sectional study was conducted to evaluate nonoccupational biological exposure to 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) compounds and to identify the main factors associated with such exposure in a malaria endemic region in Mexico. Capillary gas column chromatography was used to determine levels of p,p'-DDT and its metabolites in plasma. The mean age of the 144 male participants was 28 yr. Mean p,p'-DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) and p,p'-DDT levels were 203.5 microg/l and 67.4 microg/l, respectively. Those whose houses had been sprayed for malaria control had much higher p,p'-DDE levels (p < 0.001). High levels of chlorinated pesticides were found despite being banned in Mexico for agricultural and public health use. Findings demonstrate the role of antimalarial campaigns as a major contributing factor for high DDT plasma levels.