RESUMO
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
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: Lead (Pb) exposure during pregnancy may increase the risk of adverse maternal, infant, or childhood health outcomes by interfering with hypothalamic-pituitary-adrenal-axis function. We examined relationships between maternal blood or bone Pb concentrations and features of diurnal cortisol profiles in 936 pregnant women from Mexico City. METHODS: From 2007-11 we recruited women from hospitals/clinics affiliated with the Mexican Social Security System. Pb was measured in blood (BPb) during the second trimester and in mothers' tibia and patella 1-month postpartum. We characterized maternal HPA-axis function using 10 timed salivary cortisol measurements collected over 2-days (mean: 19.7, range: 14-35 weeks gestation). We used linear mixed models to examine the relationship between Pb biomarkers and cortisol area under the curve (AUC), awakening response (CAR), and diurnal slope. RESULTS: After adjustment for confounders, women in the highest quintile of BPb concentrations had a reduced CAR (Ratio: -13%; Confidence Interval [CI]: -24, 1, p-value for trend < 0.05) compared to women in the lowest quintile. Tibia/patella Pb concentrations were not associated with CAR, but diurnal cortisol slopes were suggestively flatter among women in the highest patella Pb quantile compared to women in the lowest quantile (Ratio: 14%; CI: -2, 33). BPb and bone Pb concentrations were not associated with cortisol AUC. CONCLUSIONS: Concurrent blood Pb levels were associated with cortisol awakening response in these pregnant women and this might explain adverse health outcomes associated with Pb. Further research is needed to confirm these results and determine if other environmental chemicals disrupt hypothalamic-pituitary-adrenal-axis function during pregnancy.
Assuntos
Poluentes Ambientais/análise , Hidrocortisona/análise , Chumbo/análise , Patela/química , Saliva/química , Tíbia/química , Adolescente , Adulto , Biomarcadores/análise , Ritmo Circadiano , Cidades , Estudos Transversais , Feminino , Humanos , México , Gravidez/fisiologia , Adulto JovemRESUMO
The authors evaluated the effects that maternal bone lead stores have in anthropometry at birth in 223 mother-infant pairs. The participants were recruited between April and November 1994. Anthropometric data were collected within the first 12 hr following delivery. Maternal information was obtained 1 mo after delivery occurred. Bone lead burden was determined with in-vivo K-x-ray fluorescence of the tibia (cortical bone) and the patella (trabecular bone). The authors transformed anthropometric measurements to an ordinal 5-category scale, and the association of measurements with other factors was evaluated with ordinal logistic-regression models. Mean bone lead levels were 9.8 microgram/gm bone mineral and 14.4 microgram/gm bone mineral for the tibia and patella, respectively. Birth length of newborns decreased as tibia lead levels increased. Compared with women in the lower quintiles of the distribution of tibia lead, those in the upper quintile had a 79% increase in risk of having a lower birth length newborn (odds ratio = 1.79; 95% confidence interval = 1.10, 3.22). The authors adjusted by birth weight, and the effect was attenuated--but nonetheless significant. Patella lead was positively and significantly related to the risk of a low head circumference score; this score remained unaffected by inclusion of birth weight. The authors estimated the increased risk to be 1.02 per microgram lead/gm bone mineral (95% confidence interval = 1.01, 1.04 per microgram lead/gm bone mineral). Odds ratios did not vary substantially after the authors adjusted for birth weight and other important determinants of head circumference.
Assuntos
Estatura/efeitos dos fármacos , Cabeça/crescimento & desenvolvimento , Recém-Nascido/crescimento & desenvolvimento , Intoxicação por Chumbo/complicações , Intoxicação por Chumbo/patologia , Chumbo/análise , Patela/química , Complicações na Gravidez/patologia , Efeitos Tardios da Exposição Pré-Natal , Tíbia/química , Adulto , Antropometria , Peso ao Nascer/efeitos dos fármacos , Carga Corporal (Radioterapia) , Cefalometria , Feminino , Humanos , Chumbo/sangue , Intoxicação por Chumbo/sangue , Modelos Logísticos , Masculino , México , Razão de Chances , Valor Preditivo dos Testes , Gravidez , Complicações na Gravidez/sangue , Fatores de Risco , Espectrometria por Raios X , Saúde da População Urbana/estatística & dados numéricosRESUMO
Lesions of the anterior cruciate ligament are extremely common and frequently demand surgical treatment in order to avoid disabling sequels. The use of a central one-third of the patellar tendon as an autograft for surgical reconstruction of a damaged cruciate ligament is common. Although several investigations in human and animal models have demonstrated long-term graft viability, there have been cases of loosening and rupture of the graft. In these occasions, a new substitute for the torn structure must be found. Owing to its inherent accessibility, the patellar tendon has been elected one of the choices of donor tissue. In order to evaluate the characteristics of the remaining scar, we performed a histochemical and ultrastructural study using biopsy material obtained from the central one-third of the donor tendon of 8 patients. This material was analyzed by comparing the ultrastructural picture with the results obtained using the specific method for collagen-containing fibers (Picrosirius-polarization) by light microscopy; four normal patellar tendons were used as controls. Despite the resemblance with the normal tissue, our results show that the healed tissue does not restore the tendon ad integrum, neither at the light microscopic nor at the electron microscopic levels. Structural differences can be responsible for biomechanical alterations. Impaired biomechanical properties can, at least partly, explain some of the clinical complications observed in patients submitted to this surgical technique. However, without performing biomechanical studies in this kind of tendons, we are neither allowed to encourage nor to reject the use of scars as donor tissue for a second surgery.