Statistic Analysis of Efficacy of SOKI-MT in Lowering Lead*

LIU Xingdong,CAI Fengjing,QI Weiyun

(1.College of Mathematics and Information Science,Zhaoqing University,Zhaoqing 526061,Guangdong China;2.College of Mathematics and Information Science,Wenzhou University,Wenzhou 325035,Zhejiang China)

StatisticAnalysisofEfficacyofSOKI-MTinLoweringLead*

LIU Xingdong1,CAI Fengjing2,QI Weiyun1

(1.College of Mathematics and Information Science,Zhaoqing University,Zhaoqing 526061,Guangdong China;2.College of Mathematics and Information Science,Wenzhou University,Wenzhou 325035,Zhejiang China)

In this paper,by one-sample kolmogorov-smirnov test,paired samples T-test and spearman rank correlation coefficient test,the authors analyse the data of 200 cases of children lead poisoning before and after the treatment of SOKI-MT.The results show that the content of lead in the children is getting lower obviously after they took SOKI MT.

lead reduction;effect;statistic analysis;one-sample kolmogorov-smirnov test;T-test;rank correlation

1 Introduction

Lead is one of the heavy metals and a poisonous substance to animals.Inorganic lead is mainly taken in through ingestion and inhalation.Blood is one of the main body compartments that store lead.It delivers lead into organs and tissues,so that lead can bind to various sulfhydryl-containing amino acids on many enzymes and further interfere enzymatic reactions.Therefore,lead is toxic to metabolism and tissues,including heart,bones,intestines,kidneys,and reproductive,especially nervous systems and heme synthesis.Lead affects virtually every organ or system in the body,and the proposed mechanisms of lead toxicity involve fundamental biochemical processes.These proposed mechanisms include leads ability to inhibit or mimic the action of calcium and to interact with proteins.One of the best documented mechanisms is impairment of heme synthesis which results in adverse effects not limited to the hematopoietic system.Most of the lead in blood is bound to erythrocytes[1]but plasma is the biologically active compartment from which lead is available to cross cell membranes[2].

Moreover,lead poisoning possesses have more severe effects on children,especially on their mental and body development for lead can cause irreversible damage on brain,resulting in permanent nerve damage.Children are more prone to lead poisoning and toxicity compared with adults because of their hand-to-mouth behavior.Furthermore,the children’s digestive system absorbs lead more readily than an adult’s system,and their premature and developing central nervous system (CNS) is more vulnerable to lead toxicity than a mature CNS[3-5].It has been proved that severe nerve development defects occur at blood lead levels over 100 μg/dL.Even for low lead concentration,child may still suffer intellectual impairment.It has also been noticed that blood lead levels are correlated to children’s intelligence.According to WHO’s report (2004),IQ scores of children who had blood lead levels of 140 μg/dL decrease about 3 to 7 points.

At the same time,the study found that an increase in blood lead from 10 to 30 micrograms per deciliter is associated with only a small additional decline in IQ.For every 100 microg/dL increase in blood lead concentration,there was a 1 to 3-point decrement in IQ scores.Currently,children in China have suffered severe lead poisoning for the reported incidence is over 51.6%,which is domestic and global health concern[6-10].

Metallothionein (MT) is a low molecular weight protein (about 7 kDa),which belongs to a cysteine-rich protein family.Cysteine residues take up 30% amino residues of MTs,through which MTs form thiol group to bind heavy metals.Therefore,MTs hold the potential to remove Pb through its highly binding affinity to heavy metal.MTs have been shown to play a protective role in lead-induced toxicity,preventing plasma SH value decrease and enhancing lead excretion.In current study,200 cases of children lead poisoning were collected for further analysis (age ranging from 3 to 14).Their blood lead levels were measured before and after treatment (including using SOKI-MT,a MT in oral formulations).The effect of lead excretion was evaluated by SPSS analysis on blood lead level.

2 Statistic Model

2.1GaussianDistributionTestforSampleDataBeforeandAfterTakingSOKI-MTUsingOne-SampleKolmogorov-SmirnovTest

An attractive feature of this test is that the distribution of the K-S test statistic itself does not depend on the underlying cumulative distribution function being tested.Another advantage is that it is an exact test (the chi-square goodness-of-fit test depends on an adequate sample size for the approximations to be valid).The K-S test is used for the population from the continuous distribution (ie.,Gaussian,Uniform and Poisson distribution).

The Kolmogorov-Smirnov test is defined by H0:The data follow Gaussian distribution;H1:The data do not follow Gaussian distribution.The Kolmogorov-Smirnov test statistic is defined as

whereFis the theoretical cumulative distribution of the distribution being tested.For the large sample,the critical value is 1.36 and 1.63 forα=0.05 andα=0.01.In this paper,we use the 0.05 significance level.

2.2PairedT-TestforTraceElementsBeforeandAfterTakingSOKI-MT

Paired T-testis used to compare means on the same or related subject over time or in differing circumstances.The observed data are from the same subject or from a matched subject and are drawn from a population with a normal distribution.Subjects are often tested in a before-after situation (across time,with some intervention occurring such as a diet),or subjects are paired such as with twins,or with subject as alike as possible.The paired T-test is actually a test that the differences between the two observations is 0.So,ifDrepresents the difference between observations,the hypotheses are H0:D=0 (the difference between the two observations is 0);H1:D≠0 (the difference is not 0).The test statistic is t withn-1 degrees of freedom.If theP-value associated with t is low (<0.05),there is evidence to reject the null hypothesis.Thus,you would have evidence that there is a difference in means across the paired observations.

2.3SpearmanRankCorrelationforTraceElementsBeforeandAfterTakingSOKI-MT

The Spearman Rank Correlation Coefficient is used to discover the strength of a link between two sets of data.We test the correlation is really significant or not.The step is given as follows:

(1) Calculate the rank correlation coefficientrs.

① RankingRXiandRYiis achieved by the scores of the sampleXiandYifrom the highest to the lowest,e.g.giving the ranking “1” to the biggest number,“2” to the second biggest value and so on.The smallest value will get the lowest ranking.If the value is equal,the average rank is used；

③ Sumdi；

① We select the 0.05 significance level and test H0:ρs=0;H1:ρs≠0.

② Calculate p value fromu.

The above method is computed by SPSS.

3 Results

3.1Subjects

We studied a population of 200 children from three to fourteen years old.The content of trace elements(Cu,Zn,Ca,Mg,Fe,Pb) in the blood was observed.The data comes from the project named “The Investigation and Research of Children Lead Poisoning” which belongs to Zhanjiang SOKI Biotechnology Co.,Ltd.

3.2DataAnalysis

Demographic data for 200 children is given by table 1,which shows that the lowest blood lead density is 100.0 μg/L,the highest density is 370.0 μg/L,the mean is (131.37±39.444 7)μg/L and the median is 121.0 μg/L.

Table1 Demographic Data for Children in the Study

3.3Results

3.3.1 K-S Test Table 2 reports the one-sample Kolmogorov-Smirnov test.At the 0.05 significance level,the difference of Cu and Pb follows the normal distribution;however,other four index do not follow the normal distribution.As the sample number is larger,the large sample method is used for the paired T-test.

Table 2 One-Sample Kolmogorov-Smirnov Test

3.3.2 Paired T-Test The paired T-test result is shown in table 3.At the 0.05 significance level,we can not reject the null hypothesis and accept the hypothesis that there is no significant change for the content of Cu in blood before and after taking SOKI-MT asP=0.162>0.05.For other five elements,we accept the null hypothesis and regard that there is obvious change.According to mean of difference from table 3,we know that the content of Zn,Ca,Mg,Fe rise obviously and Pb fall significantly.Except the test for Cu,other test are statistically significant.

Table 3 Paired Samples Test

3.3.3 Spearman Rank Correlation Even data that have been taken in 10 logarithms do not follow Gaussian distribution at all.The spearman rank correlation is used to measure the degree of correlation.From table 4,there is no linkage between Pb and other elements.There is some linkage between Cu,Zn,Ca and Mg,although the correlation coefficients is no more than 0.35.The smaller coefficients between trace elements are caused by larger sample number possibly.

Table 4 Spearman Rank Correlation Coefficients

Note The shoulder mark a and b denote the rejection of null hypothesis at the 5% and 1% significance level respectively

4 Conclusion

The statistic analyses show that the blood lead density declines obviously after lead poisoning children take SOKI MT,and the content of blood Zn,Ca,Mg And Fe after intervene rise significantly.According to the spearman rank correlation,Pb is not associated with other elements,while the change of Cu,Zn,Ca,Mg and Fg are connected with each other.SOKI MT can help discharge lead in the body and increase the content of trace elements which is necessary to our body.The treatment of SOKI MT for lead poisoning is effective and can reduce the blood lead level obviously.

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(责任编辑 向阳洁)

索奇MT降铅疗效的统计分析

刘幸东1,蔡风景2,戚蔚韵1

(1.肇庆学院数学与信息科学学院，广东 肇庆 526061；2.温州大学数学与信息科学学院，浙江 温州325503)

应用数理统计中柯尔莫哥洛夫-斯米尔诺夫检验(简称K-S test)、配对样本的T检验、秩相关系数，对200例铅中毒儿童服用生物饮品索奇MT的前后数据进行分析.结果显示，铅中毒儿童在服用索奇MT后铅含量明显降低.

降铅；疗效；统计分析；柯尔莫哥洛夫-斯米尔诺夫检验；T检验；秩相关系数

O212

A

1007-2985(2014)01-0020-05

date：2013-10-25

National Natural Science Foundation of China (10971042)

Biography：LIU Xingdong (1960-),female,was born in Xingtai City,Hebei Province,professor of College of Mathematics and Information Science,Zhaoqing University;research area are mathematical statistics and data mining.

O212DocumentcodeA

10.3969/j.issn.1007-2985.2014.01.006