ABSTRACT
The notion that maternal personality characteristics influence cognitive development in their children has been grounded in stress moderation theory. Maternal personality traits, such as self-esteem, may buffer maternal stressors or lead to improved maternal-child interactions that directly impact neurodevelopment. This can be extended to suggest that maternal personality may serve to attenuate or exacerbate the effects of other neurotoxicants, although this has not been studied directly. We examined whether mothers' self-esteem had a direct or main effect on their children's cognitive outcomes. We also explored the modifying effects of maternal self-esteem on the association between exposure to lead and neurodevelopment in these children. Study participants included 379 mother-child pairs from Mexico City. Data included the Coopersmith Self-Esteem Scale in mothers, children's Bayley's Scale of Infant Development (BSID) scores, and sociodemographic information. Linear regression was used to model the relationship between maternal self-esteem and the Bayley's Mental Development Index (MDI) and Psychomotor Development Index (PDI) scores at age 24 months using models stratified by levels of maternal self-esteem. In adjusted models, each point increase in maternal self-esteem was associated with children having 0.2 higher score on the Bayley's MDI (p=0.04). Similar results were observed using the PDI outcome. Moreover, there was evidence that maternal self-esteem attenuated the negative effects of lead exposure, although the interaction fell short of conventional levels of statistical significance.
Subject(s)
Child Development , Environmental Pollutants/adverse effects , Lead/adverse effects , Mothers/psychology , Nervous System/drug effects , Self Concept , Adolescent , Adult , Child, Preschool , Cognition/drug effects , Cohort Studies , Environmental Pollutants/blood , Female , Humans , Lead/blood , Linear Models , Male , Mexico , Models, Biological , Models, Psychological , Mother-Child Relations , Nervous System/growth & development , Neuropsychological Tests , Parenting , Psychomotor Performance/drug effectsABSTRACT
OBJECTIVE: Low-level postnatal lead exposure is associated with poor intellectual development in children, although effects of prenatal exposure are less well studied. We hypothesized that prenatal lead exposure would have a more powerful and lasting impact on child development than postnatal exposure. DESIGN: We used generalized linear mixed models with random intercept and slope to analyze the pattern of lead effect of the cohort from pregnancy through 10 years of age on child IQ from 6 to 10 years. We statistically evaluated dose-response nonlinearity. PARTICIPANTS: A cohort of 175 children, 150 of whom had complete data for all included covariates, attended the National Institute of Perinatology in Mexico City from 1987 through 2002. EVALUATIONS/MEASUREMENTS: We used the Wechsler Intelligence Scale for Children-Revised, Spanish version, to measure IQ. Blood lead (BPb) was measured by a reference laboratory of the Centers for Disease Control and Prevention (CDC) quality assurance program for BPb. RESULTS: Geometric mean BPb during pregnancy was 8.0 microg/dL (range, 1-33 microg/dL), from 1 through 5 years was 9.8 microg/dL (2.8-36.4 microg/dL), and from 6 through 10 years was 6.2 microg/dL (2.2-18.6 microg/dL). IQ at 6-10 years decreased significantly only with increasing natural-log third-trimester BPb (beta=-3.90; 95% confidence interval, -6.45 to -1.36), controlling for other BPb and covariates. The dose-response BPb-IQ function was log-linear, not linear-linear. CONCLUSIONS: Lead exposure around 28 weeks gestation is a critical period for later child intellectual development, with lasting and possibly permanent effects. There was no evidence of a threshold; the strongest lead effects on IQ occurred within the first few micrograms of BPb. RELEVANCE TO CLINICAL PRACTICE: Current CDC action limits for children applied to pregnant women permit most lead-associated child IQ decreases measured over the studied BPb range.
Subject(s)
Intelligence/drug effects , Lead/toxicity , Prenatal Exposure Delayed Effects , Child , Cohort Studies , Female , Humans , Male , PregnancyABSTRACT
We determined the secular trend in blood lead levels in a cohort of 321 children born in Mexico City between 1987 and 1992. Blood lead level was measured every 6 months during a 10-year period. We modeled the effect of yearly air lead concentration nested within the calendar year in which the child was born, family use of lead-glazed pottery, socioeconomic status, year in which the child was born, age of the child at the time of blood lead measurement, place of residence, and an indicator variable for subjects with complete or incomplete blood lead values. The yearly mean of air lead of the Valley of Mexico decreased from its highest level of 2.80 microg/m3 in 1987 to 0.07 microg/m3 in 2002. The contribution of air lead to blood lead according to year of birth was strongest for subjects born in 1987 and fell to nearly zero for children born in 1992. The geometric mean of the entire cohort rose from 8.4 microg/dL in the first year of life to 10.1 microg/dL in the second and decreased thereafter until it reached 6.4 microg/dL at 10 years of age. Children of families who used lead-glazed ceramics had blood lead levels 18.5% higher than did children of nonusing families. Children who belonged to the lowest socioeconomic levels had blood lead levels 32.2% higher than did those of highest socioeconomic levels. Children who lived in the northeast part of the city had blood lead levels 10.9% higher compared with those who lived in the southwest.
Subject(s)
Child Welfare , Lead Poisoning/epidemiology , Lead/blood , Child , Child, Preschool , Cohort Studies , Female , Humans , Infant , Infant, Newborn , Male , Mexico/epidemiology , Social Class , Urban PopulationABSTRACT
OBJECTIVE: To evaluate the validity of a food-frequency questionnaire (FFQ) for assessment of the dietary intakes of polyunsaturated fatty acids (PUFAs) against a biochemical marker of fat intake, erythrocyte cell membrane phospholipid levels, during pregnancy. DESIGN: Cross-sectional analysis. SETTING: Developmental Neurobiology Department, National Institute of Perinatology, Mexico City. SUBJECTS: One hundred forty-six healthy pregnant women during the last trimester of pregnancy. Among women enrolled, the first 35 pregnant women (24%) had their erythrocytes analysed for fatty acid status. METHODS: We administered an FFQ and compared intakes of PUFAs against their erythrocyte cell membrane concentrations, processed by gas chromatography. RESULTS: Pearson correlation coefficients among alpha-linolenic acid (ALN), docosahexaenoic acid (DHA) and eicosapentaenoic acid in erythrocyte cell membranes against their crude dietary counterparts were 0.32, 0.35 and 0.36 (each P < 0.05). In a simple linear regression, erythrocyte DHA and arachidonic acid (AA) were significantly related to their respective dietary intakes (beta = 0.30, 95% confidence interval (CI): 0.007-0.60, P=0.045 for DHA; beta = 0.49, 95% CI: 0.010-0.98, P=0.044 for AA). Erythrocyte cell membrane ALN concentration (%/total) was only marginally related to ALN dietary intake (mg day-1) (beta = 0.52, 95% CI: -0.020-1.10, P=0.061). However, after adjustment for long-chain n-3 PUFA/AA, this association reached significance (beta = 0.44, 95% CI: 0.026-0.825, P=0.038). Main dietary sources for n-3 PUFAs were canned tuna fish and fresh catfish; for n-6 these were eggs and cow's milk. The use of this FFQ in these pregnant Mexican women provided estimates of average long-term intakes of PUFAs and correlated reasonably well with their erythrocyte cell membrane phospholipid status. However, we need to consider that, during pregnancy, there is a faster turnover of PUFAs from fat storage that may modify the profile of erythrocyte PUFAs and lower the correlation between dietary intake and erythrocyte PUFAs.
Subject(s)
Erythrocyte Membrane/metabolism , Fatty Acids, Unsaturated/metabolism , Phospholipids/metabolism , Adult , Cross-Sectional Studies , Diet Surveys , Fatty Acids, Unsaturated/administration & dosage , Fatty Acids, Unsaturated/blood , Female , Humans , Mexico , PregnancyABSTRACT
Objetivo. Determinar la relación que existe entre las concentraciones de plomo en sangre prenatales y postnatales y el desarrollo intelectual del niño, evaluado a los 42 meses de edad a través del Indice General Cognitivo (IGC) de la Escala de habilidades Infantiles de McCarthy. Material y métodos. Se realizó un análisis transversal de 157 niños de 42 meses de edad, pertenecientes al Estudio Prospectivo de Plomo en la Ciudad de México, que contaban con la evaluación de McCarthy a los 42 meses de edad. Resultados. Se encontró una asociación negativa significativa entre las concentraciones de plomo en sangre postnatales determinadas a los 24, 30, 36 y 42 meses de edad y el IGC evaluado a los 42 meses. Las variables significativas que explican mejor la varianza en el IGC a los 42 meses de edad fueron: el coeficiente intelectual materno, el sexo del niño y las concentraciones de plomo a los 36 meses de vida. Conclusiones. Los resultados sugieren que la exposición temprana al plomo se asocia a un menor desarrollo intelectual del niño. Es importante valorar si estas deficiencias en el desarrollo persisten a lo largo de la vida de los niños, o si existen algunos factores que se asocien a su reversibilidad, con el objeto de apoyar iniciativas de salud pública
Subject(s)
Humans , Male , Female , Infant, Newborn , Infant , Cognition , Maternal Exposure/adverse effects , Intelligence , Lead/adverse effects , Lead/blood , Prenatal Exposure Delayed Effects , Risk AssessmentABSTRACT
Objetivo. Determinar la relación que existe entre la exposición prenatal al plomo (intervalo de plomo en sangre de 1-33 µg/dL) y el crecimiento físico del niño evaluado a través de su talla a los 3 años de edad. Material y métodos. Se realiza un análisis transversal en 124 niños de 36 meses de edad, pertenecientes al Estudio Prospectivo de Plomo en México, que contaban con información sobre concentraciones de plomo en sangre materna en el último trimestre de embarazo y talla del niño a los 36 meses de edad. Resultados. Se encontró una asociación negativa significativa entre las concentraciones maternas de plomo en la semana 36 de embarazo y la talla del niño a los 36 meses de edad
Subject(s)
Humans , Male , Female , Child, Preschool , Child , Cross-Sectional Studies , Maternal Exposure/adverse effects , Growth/physiology , Lead Poisoning/blood , Lead Poisoning/diagnosis , Prospective Studies , Weight by Height/genetics , Weight by Height/physiology , MexicoABSTRACT
Este artículo se basa en una revisión de los principales estudios, tanto en animales como en humanos, que describen la relación entre la exposición al plomo y efectos adversos sobre el sistema reproductivo. Los datos presentados indican que la función reproductora puede ser especialmente sensible al plomo. El impacto en hombres de la exposición crónica a este metal incluye reducción de la libido, alteración en la espermatogénesis (reducción en cantidad y motilidad, e incremento de formas anormales), daño cromosómico, función prostática anormal y cambios en los niveles de testosterona; todos ellos relacionados con esterilidad. Estos efectos se observan en sujetos cuyas concentraciones se encuentran por arriba de los 40 mg/dL. Los datos informados en la mujer incluyen: alteraciones en el ciclo menstrual, esterilidad, aborto, ruptura prematura de membranas, preclampsia, hipertensión en el embarazo y parto prematuro. Aún cuando se han corroborado los efectos de altas concentraciones de plomo sobre la fertilidad, no es posible establecer conclusiones definitivas en cuanto a la exposición crónica a bajas concentraciones de este metal. Por lo tanto, es importante llevar a cabo investigaciones en este campo, que nos proporcionen los datos necesarios para establecer límites de exposición permisibles a nivel industrial y a nivel de la población general
