Samples

Children's Health

According to the auther the reason of this study is because of the emerging potential toxity in humans. The investigation done is on how urinary concentrations of phthalate metabolities is related to childrens intellectual functioning. He has taken a comprehensive study of elementary children in five cities in south Korea by taking a cross-section examination on  the urine phthalate concentrations on both the children and their mothers.  The findings show that they measured   “mono-2-ethylhexyl phthalate (MEHP) and mono (2-ethyl-5-oxohexyl) phthalate (MEOHP)” which are metabolies of “ di(2-ethylhexyl)phthalate (DEHP), and mono-nbutyl phthalate (MBP), a metabolite of dibutyl phthalate (DBP)” in the urine samples.  “The geometricmean (ln) concentrations of MEHP, MEOHP, and MBP were 21.3 μg/L [geometric SD (GSD) = 2.2 μg/L; range, 0.5-445.4], 18.0 μg/L (GSD = 2.4; range, 0.07-291.1), and 48.9 μg/L (GSD = 2.2; range, 2.1-1645.5), respectively”. The chronological results show that the full scale IQ and verbal IQ were nagatively associated with DEHP but not  WITH DBP metabolities. The results of this finding  are very comprehensive as thay also show that there is a negative relationship between trhe children vocabulary use and the concentration of the urine. After an extensive marternal IQ controll the findings shw that a large inverse relationship between DEHP metabolities and the use of vocabulary also remained. There is a difference between boys and girls as boys show a negative association between increasing MEHP phthalate concentrations and the total sum of DEHP metabolite concentrations while girls  shown  had little or no association between these variables. Howevr the auther does not show clear evidence on the same and critical study in the field is highly required.

In the methods of study the auther extensively talks of   a study conducted between april and october 2008 which was named “ Effects of Pollution on Neurobehavioral Development and future Policies to Protect our children”. The study assessed different elements such as Lead, Mercury and manganese in the dlood as welll as neurocognitive functioning of children including attention and concentration together with  their general intelligence. So as to asses the childrens marternal IQ, their child developmental state, their mothers were also interviewed. The study was well formulated and carried out as mothers were  given quistionares which were to be filled on the details regarding the surrounding environment. The study had followed all the rules and regulations as it had been passed by “The Institutional Review Board of Seoul National University Hospital”.  Applications had been sent to elementary children and their mothers for them to participate in the study and 667 children accompanied by their mothers turned in. While measuring childrens cognitive functioning, students were availed with a form,  “KEDI-WISC” which consisted  vocabularly, arithmetic, picture arrangement and block design tests. The form according to the auther is validated  with Korean children to use as a determiner of global estimates of intellectual functioning. Since the examiners in the study were not aware of the children IQ, they used  “Korean Wechsler Adult Intelligence Scale (K-WAIS) “ to their mothers while they were measuring  martenal cognitive function. The tests on this included  pure arrangement, vocalbulary use and block design tests.                               

On determining phthalate metabolites in urine  in the  study  “primary metabolite of dibutylphthalate, mono-n-butyl phthalate (MBP), andtwo secondary metabolites of DEHP, mono-2-ethylhexyl phthalate (MEHP) and mono(2-ethyl-5-oxohexyl)phthalate (MEOHP) were used”. Urine was collected using paper cups from  all the children who were subject to the study between nine and eleven in the morning. After collection, th urine was placed in containers  “(high-clarity polypropylene Falcon tubes)” and stored at –20°C  untill the analyzation of the samples. Field blanks consisted of purified water. Thesamples are then brought to room temperature and vortexed after thawing.   Acritical and extensive of the methods used has been well shown in the study following all steps and explanation of the procedures. At all  this study has a critical and technical approach as it takes the  reader through all the steps used in the study.

While doing the statistcal analysis the study, used t-tests of the students or “(ANOVAs)” for testing continues variables and the chisquare test for categorical mvariables. A comprehensive use of  linear regression analysis was used in the study to analyse the association between “urine phthalate (MEOHP,MEHP, and MBP) concentration and WISC IQ scores”. Since the distribution of the metabolite was skewed in the sample, log-transformed values were highly used.

From the variables on the analysis carried out regression models have been built. Taking th IQ score as the primary dependent variable and the urine phthalate

concentrations as the primary independent variables.  A set of covariates based on the predicators childrens cognitive functioning helped to perform the regression analysis.  After this study models have been improved on the developmental socioeconomic and IQ variables. The study however does not give us clear evidence on the martenal IQ as it present models with and without  the Martenal IQ. In the study all analysis were considered important.

The study in their results analyzing the relationship between environmental exposure to phthalates and children’s IQ scores show that there is a negative association between IQ and urine phthalates in humans. The study is of great significance comparing it with other studies that have been done since its the first to show the above results. It is there true to say that a child’s IQ may be affected by genetic, educational, familial and social factors.however these results may contrast with any  observed association between the line of study and the income. To help readers nunderstand this , this study tried to determine whether “phthalates were inversely associated with children’scognition independent of potential confounders”. Before the study could adjust for martenal IQ, it found inverse relationships between “MEHP, MEOHP, and the sum of secondarymetabolites for DEHP and the children’sFSIQ, VIQ, and vocabulary and block design Scores” also vocabulary score was negatively associated with MBP. This study found that maternal IQ is one of the cofounders of children’s IQ. The study also found that adjusting for a confounder that has a stronger effect than the valuable of interest can most of the time lead to underratings in the true effect of this variable. Control for maternal IQ according to the study had a great impact on the effect size of the alliance between phthalates and IQ. It may act as a confounder especially if the maternal IQ and the level of phthalates in children  have a link to each other. It is noted that MIQ might have had an influence on the childrens environmental exposure to the substances which were to be seen on th level of phthalate metabolites.   All in all MIQ have effects on the children IQ, therefore affecting affecting the association between child IQ and phthalate level however the study revealed that after MIQ, MEHP, MEOHP, and the sum of secondary metabolites of DEHP had been adjusted there were inverse relationships with children’s vocabulary scores. We cannot at whtsoever means say that this study provided enough evidence of a definative association between phthalates with children’s IQ indipendent of MIQ because there could be a residual confounding of matarnal IQ. The study shows that children are of special concern regarding phthalate exposure due to their neurodevelopmental state. Also if they are subjected to neurotoxic agents, there is likelyhood that they will suffer due to critical periods of vulnerability for their developing nerves. Even after birth, Neurotoxic agents could disrupt the temporal and regional emergence of critical

Developmental processes.

Even if this study has most of advantages, it has some disadvantages. Atleast 16 phthalene metabolites in urine can be measured but in this study only three were measured which were limited to the specifications of the study. They measured three based on availability of standard samples, childrens likely exposure, and technical experience of the analysis. They only used one measurement, which may not have same results as when they would have in examining the level and severity of chronic exposure. Judging from a single spot-urine measurement could have given wrong answers, as it may not reflect long term-exposure since Phthalates

are rapidly metabolized and excreted. However, on phthalate measurements over time according to other different studies, there is moderate consistency. The study assumes that when multiple experiments are consistent, then a single measurement reflects a typical measurement. Another limitation is that the study did not show results of maternal levels of exposure. Also the maternal IQ had a large effect size on the associations making it not possible to tell whether the quality of the home environment and stimulation provided in the home could be  potential confounders.

This article is a succes as it gives the readers a clear picture of what was carried out , the mode of study, the evidence used, materials and methods. Many of the readers would get  the objectives of the writer and accesit according to his or her expectations. However, the study has been based on many assumptions making the reader to doubt its results. I would recommend that as you read this article it is critical that you have your objective of the findings and the discussion made by the writer keeping in mind that  it has its own advantages and disadvantages.

 

 

 

 

 

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