| Objective:Lead, cadmium and its compounds are a class of industrial poisons and environmental pollutants that can damaging human health . Long-term low level exposure effects of heavy metals on the newborn is a multi-system, the most serious is the development of nervous system damage, most of the research focused on lead and cadmium on children's health hazards, mainly for the psychological and behavioral changes movement disorders, hyperactivity, impulsivity, decreased attention, increased aggression, integration dysfunction, diminished ability to mimic other.For the selected object and the use of means, the current related literature on lead and cadmium on growth and development of neonatal research findings are not uniform. There are two points: First, on the adverse effects of neonatal neurological development, one argue that a higher concentration (cord blood lead 70-100ug/L or more, umbilical cord blood cadmium 5 ug/L and above) has cause fetal growth and development obvious damage, another point out that affect the lower concentrations, not even the critical value. The second is the impact on neonatal physical development, one believe that the high concentration lead and cadmium could damage the physical growth of newborn, another argue that no effect on physical development. As has been inconclusive, so lead and cadmium on growth and development of newborns has been in the ascendant.To further clear lead, cadmium concentrations association on neonatal growth and development, to explore the lower levels of lead and cadmium exposure on neonatal neurological development and physical development with or without impact. This study selected the general population of cord blood in Guangzhou City, Lead, cadmium and zinc, copper, iron, calcium, magnesium, sodium, potassium and other metals, metal content of umbilical cord blood and neonatal behavioral neurological, hearing and development, physical development of the relationship between umbilical cord blood the relationship between heavy metals and other metals and to explore the family, the environment and other factors during pregnancy on the pregnancy case of lead, cadmium and other metal exposure levels, so as to toxic effects of lead and cadmium exposure prevention and intervention measures for providing further evidence.Methods:Application prevalence survey and case-control study, Select the maternal and fetal, neonatal in the second half of 2009 in Guangdong Province women and children's hospital,through collected umbilical cord blood samples, using atomic absorption spectrometry of lead, cadmium and zinc, copper, iron, calcium, magnesium, sodium, potassium and other metal Elements for testing. 1 hour after birth, using "Zhu Futang Practical Pediatrics," recorded in the seventh edition of the methodology and measurement standards, measurement of birth weight, length and head circumference. 24-72 hours of birth, using teoae method for newborns left ear, right ear for bilateral hearing screening. Birth within a week, such as the revised application Bao Xiulan neonatal behavioral neurological assessment method 20 (NBNA) on neonatal neurobehavioral testing and evaluation conducted. Week after birth, through a questionnaire survey to maternal occupational exposure to the working environment, living environment, maternal smoking and passive smoking, dietary habits and health conditions during pregnancy. Using survey data entry Epidata3.0 software, carefully verify the data, excluding incomplete data objects, import SPSS13.0 software for statistical analysis. Using t test, chi-square test, univariate and multivariate linear regression, univariate and multivariate Logistic regression analysis, analysis of umbilical cord blood lead, cadmium and zinc, copper, iron, calcium, magnesium, sodium, potassium and other content and neonatal neurological behavior, hearing and development, the relationship between physical development and study of lead and cadmium exposure factor.Results:1. 231 cases of neonatal cord blood heavy metal, the average level of lead was 28.22±1.76ug/L, belong a low concentration of blood lead within the state's standards; cadmium less than 0.5ug/L of 195 cases accounting for 84.4%, higher than equal to 0.5ug/L in the case of 36, 15.6%, belong a low concentration of blood cadmium within the national standard; the average levels of zinc, copper, iron, calcium, magnesium, sodium, potassium were 26.20±1.22×10-3,15.59±1.31×10-3,9.26±1.12,1.42±1.14,1.43±1.08,73.38±1.13,52.29±1.13 (mmol/L).2. 231 cases of average birth weight was 3.25±4.10kg, the average birth length was 55.26±3.45cm, the average head circumference at birth was 33.65±1.24cm. NBNA scoring average 37.75±1.39, 221 cases more than 36 points, passing rate was 95.7%. Hearing screening in which 215 cases, 191 cases through the left ear hearing screening, by rate of 93.2%; through the right ear hearing screening 185 patients, 90.2% pass rate.3. Physical development of the simple linear analysis and multiple linear regression analysis showed that the low concentration of cord blood lead, cadmium and neonatal physical development of the association was not significant. Physical development of the multiple linear regression results show that cord blood iron concentration positively correlated with birth weight (P<0.05), with the cord blood iron concentration increased, birth weight; cord blood magnesium concentration and birth length negative correlation (P<0.05), with the cord blood magnesium concentration increased, decreased birth weight; low concentrations of lead and cadmium on the neonatal physical development was not significant.4. Physical development of the simple linear analysis and multiple linear regression analysis showed that the low concentration of cord blood lead, cadmium and neurobehavioral development of the newborns was no significant association on. Neurodevelopmental Multiple linear regression analysis showed that cord blood copper concentration and infant NBNA score negatively correlated with cord blood concentrations of copper up, baby NBNA score decreased. Sodium concentration and infant cord blood NBNA score positively correlated with copper levels in cord blood increased, rising infant NBNA score.5. Physical development of the simple linear analysis and multiple linear regression analysis showed that the low concentration of cord blood lead, cadmium and newborn hearing on the development of the association was not significant. Single factor in the right ear and hearing tests Logistic multivariate analysis, the umbilical cord blood lead is a risk factor for development of the right ear hearing, P<0.1, OR estimate was 2.145 (95% CI: 1.184, 3.887).. Multivariate Logistic left ear hearing test analysis, cord blood iron concentration and development of left ear hearing protection factor, P<0.1 6. In the relationship between heavy metals and other metals found in studies: lead and umbilical cord blood calcium, sodium cord blood were negatively correlated (correlation coefficients were -0.154, -0.176, P<0.05.), With the umbilical cord blood increase in calcium concentration, umbilical cord blood lead level decreased, with increased cord blood sodium concentration, umbilical cord blood lead level decreased,the other found no statistical correlation.Conclusions:1. Studies show that low concentrations of umbilical cord blood lead (28.22 ug/L) and neonatal left ear, right ear hearing was negatively related to development of neonatal hearing risk factors, including damage to the right ear is more sensitive, pregnant women should try to to avoid lead exposure. Guangzhou neonatal iron above the national average, while the calcium lower than the national average. The study did not find cord blood lead, cadmium and birth length, weight, head circumference, and the relationship between neurobehavioral development.2. The impact of the initial calcium concentration in cord blood was observed more than 1.33mmol/L compared to lower the concentration of lead significantly. The impact of the initial sodium concentration in cord blood was observed more than 68mmol/L compared to lower the concentration of lead significantly.In addition, cord blood zinc was protective factors birth weight, suggesting that zinc supplementation during pregnancy can contribute to fetal development. |
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