低铅暴露对学龄前儿童神经行为的影响(英文)

Effect of low-level lead exposure on neurobehavioral function in preschool children

背景:环境铅污染日趋严重,铅致中枢神经系统发育的毒性较为突出。目的:观察低血铅水平对学龄前儿童神经行为的影响,为预防儿童行为问题提供依据。设计:抽样调查。单位:中山大学公共卫生学院儿少卫生教研室。对象:于2004-09/10随机整群抽取珠海市某居民区幼儿园211名4～6岁儿童为研究对象,其中男109名,女102名。方法:采指端末梢血20μL,原子吸收石墨炉法测定血铅,以血铅水平100μg/L为界,分为高血铅组(>100μg/L),低血铅组(<100μg/L),又以不同血铅水平再分为<50μg/L组、50μg/L～组、100μg/L～组、150～μg/L组、250μg/L～组。采用Achenbach儿童行为量表和自拟调查表(包括可能影响儿童神经行为的因素,如年龄、性别、抚养方式和家庭文化背景等)进行问卷调查,在专业人员指导下,由家长填写。结果与血铅值进行简单相关和多元逐步回归分析。主要观察指标:①血铅水平和Achenbach儿童行为量表各因子分。②血铅值与行为因子分相关分析。结果:发放问卷211份,回收211份,有效211份,有效率100%。①高血铅组外向行为得分及行为异常率(13.28±6.26,18.26%)显著高于低血铅组(9.98±5.46,7.29%)(t=4.0677,χ2=5.470,P<0.05),Achenbach儿童行为量表内向得分及总分两组差异无显著性意义。②不同组别血铅水平行为异常率差异有显著性(χ2=13.695,P<0.01),进一步两两比较,血铅≥150μg/L行为异常率显著高于前3组(χ2分别为4.727,6.261,5.168;4.503,5.911,4.928,P均<0.05),表明血铅≥150μg/L时,儿童行为异常率显著增多。③血铅对数值与多动、攻击、违纪因子分显著正相关(r=0.3164,0.2828,0.1886,P<0.05)。与肥胖、分裂、残忍、性问卷无相关性(r=0.1024,0.0942,0.1183,0.0926,P>0.05)。④经逐步回归分析,多动、攻击及违纪因子分列入回归方程,这表明在控制家庭,社会等混杂因素后,铅对儿童外向行为的影响依然存在,有统计学意义。结论:低水平铅暴露对幼儿外向行为具有负性影响。

BACKGROUND： Environment pollution due to lead is severe day by day, and the lead-induced developmental toxiecity of central nervous system is prominent. OBJECTIVE： To observe the effect of lead at low exposure level on neurobehavioral function of preschool children and provide basis for preventing childhood behavior disorders. DESIGN： Sampling survey. SETTING： Department of Children and Adolescent Health, Public Health College, Sun Yat-sen University. PARTICIPANTS： Totally 211 children of 4-6 years （109 boys and 102 girls） were enrolled from a kindergarten of a populated area of Zhuhai City by randomized cluster sampling from September to October 2004. METHODS： 20 mL peripheral blood of finger tip was collected. Blood lead was determined with graphite stove atomic absorption spectrometry. According to the amount of blood lead, the children were divided into high hlood lead exposure group （〉 100 μg/L） and low blood lead exposure group （〈 100 μg/l.）. Furthermore, they were also assigned into 〈 50 μg/L group, 50 μg/L- group, 100 μg/L- group, 150 μg/L- group, 250μg/L group. Achenbach＇s Child Behavior Checklist （CBCL） and self-designed questionnaire （composed of possibly effective factor on children＇s neurobehavioral function, such as age, sex, cultivation, family background and so on） were applied, filled by their parents under the instruction of professional staffs. Results and blood lead value were analyzed with first order eorrelation and multiple factors stepwise regressive analysis. MAIN OUTCOME MEASURES： ①Blood lead level and each factor scores of CBCL, ②correlation analysis between blood lead value and behavioral factor score. RESULTS： A total of 211 questionnaires were sent out, and 211 were retrieved with 211 effective questionnaires. The effective rate was 100%. ① Score on externalizing and behavioral disorder rate in the high blood lead exposure group （13.28±6.26,18.26%） was significantly higher than those in the low blood lead exposure group （9,98±5,46,7.29%）（ t=4,067 7,X^2 =5.470, P 〈 0,05 ）. There was insignificant difference in score on internalizing and total score of CBCL between the low and high blood lead exposure groups,②）The behavioral disorder rate of different blood lead level had significance （X^2=13,695,P 〈 0,01 ）, The behavioral disorder rate in blood lead ≥ 150 μg/L was obviously higher than that of the former 3 groups after further pairwise comparison （X^2 were 4.727, 6.261, 5.168; 4,503, 5,911, 4.928, P 〈 0,05）, which revealed that the child behavioral disorder rate markedly increased when the blood lead was ≥150 μg/L. ③Blood lead logarithm value had positive correlation with the scores on hyperactivity, aggression and defiance （r=0.316 4,0.282 8,0,188 6,P〈 0.05）, and had no correlation with obesity, desintegration, truculence and sexual questionnaire （r=0.102 4,0.094 2,0,118 3,0,092 6, P 〉 0.05 ）,④After the stepwise regression analysis, the scores on hyperactivity, aggression and defiance factors were included in the regression equation, The results suggested that the effeet of lead on child externalizing behavior still remained, and kept statistical meaning after confounding factors, such as controlling family and society, etc. CONCLUSION： Low-level lead exposure has adverse effects on external- izing behavior in preschool children.