Influencing factors of colostrum exposure to low-level lead and their relationship with early neural development of infants

BACKGROUND： Exposure to low-level lead has a toxic effect on the development of neonates, which has attracted wide attention. Colostrum lead level can be used as the indication of lead exposure. OBJECTIVE： To observe the relationship of colostrum lead level and the neurobehavioral development of infants. DESIGN： A prospective control observation. SETTING： Center for Maternal and Child Health, Shanxi Provincial Children＇s Hospital. PARTICIPANTS： Totally 128 neonates of full-term normal delivery, 76 male and 52 female, from Shanxi Provincial Maternal and Child Health Center and Jiexiu Maternal and Child Health Center were involved in this study. All the involved neonates had no peripartal ischemic/hypoxic history or fetus intrauterine developmental lag. Pregnant women had no various acute and chronic diseases in pregnancy, family history of neurological disease or occupational lead exposure. 128 portions of colostrum sample of full-term normal delivery were collected. Informed consents of detected items were obtained from the puerperants and their relatives. METHODS： ① Experimental grouping： Lead level in the colostrum was determined by atomic absorption spectrometry. According to lead level in the colostrum, the neonates were classified into two exposure groups of greater than or equal to 0.24 μmol/L in a high-level lead group and less than 0.24 μ mol/L in a low-level lead group. ② Experimental evaluation： Mental developmental index （MDI） and psychological developmental index （PDI） of 3-month-old infants were evaluated with Bayley Scales of Infant Development （BSID）. The relationships of MDI, PDI and colostrum lead level were performed correlation regression analysis; The relationship of colostrum lead level and development was performed multi-factor analysis with family environment and health questionnaires. MAIN OUTCOME MEASURES： ① Evaluation results of MDI and PDI. ② Multi-factor analysis results. RESULTS： Totally 128 neonates were involved in the study. Ten and eleven neonates were lost due to emigration in the high-level lead group and low-level lead group respectively, and the other 107 neonates participated in the final analysis. ① MDI and PDI in the high-level lead group were significantly lower than those in the low-level lead group, respectively （P 〈 0.01）; Regression analysis results showed that two developmental indexes were statistically negatively correlated with colostrum lead level （regression equation y = 1.9＋0.01x1,-0.04x2,＋0.04x3,＋0.03x4）. ② Four variables of the factors included by family environment and health questionnaires were taken into equation. Large maternal age, irrational dietary pattern in pregnancy and pollution degree of habitation environment in pregnancy were the risk factors of colostrum lead level （partial regression coefficien t =0.598 4,0.426 8,0.306 7,P 〈 0.05-0.01）, and calcium supplementation in pregnancy was a protective factor （partial regression coefficien t =-0.455 8, P 〈 0.01）. CONCLUSION： High colostrum lead level will have adverse effects on the early development of neonates; Large maternal age, irrational dietary pattern in pregnancy and pollution degree of habitation environment in pregnancy are the risk factors of colostrum lead level, and calcium supplementation in pregnancy was a protective factor.