Monday, May 23, 2011

Mama mia! What an absurd piece of reporting about those evil pesticides!

We find below an account of a reasonable piece of research but the authors obviously did not like what they found. I gather that they are from a group of people opposed to pesticide use and they clearly wanted to say that pesticides fry the brains of kids.

But their data does not show that. The Abstract below concentrated on IQ at 12 months. Why? That is an absurdity. There is no way you can get a useful estimate of IQ at 12 months. About 4 years would be the minimum.

And since they had data from children at later ages, the whole thing begins to smell. I therefore read the full research report and discovered that the findings at the oldest age were described as "imprecise". "Imprecise"? That is not a term usually found in statistical reporting. I can only assume that they mean "not statistically significant" In other words, the whole thing is a crock.

And here's the amusing bit: For the white kids in the sample, having lots of pesticides in you made you SMARTER at 12 months!

Why did they bother reporting such sh*t? They have made a mockery of themselves and their cause. Stephanie the Angel is an angel of darkness, it would seem ("Engel" is German/Yiddish for Angel).
Prenatal Exposure to Organophosphates, Paraoxonase 1, and Cognitive Development in Childhood

By Stephanie M. Engel et al.


Background: Prenatal exposure to organophosphate pesticides has been shown to negatively impact child neurobehavioral development. Paraoxonase 1 (PON1) is a key enzyme in the metabolism of organophosphates.

Objective: To examine the relationship between biomarkers of organophosphate exposure, PON1, and cognitive development at ages 12 and 24 months, and 6 to 9 years.

Methods: The Mount Sinai Children’s Environmental Health Study enrolled a multiethnic prenatal population in New York City between 1998 and 2002 (n= 404). Third trimester maternal urines were collected and analyzed for organophosphate metabolites (n = 360). Prenatal maternal blood was analyzed for PON1 activity and genotype. Children returned for neurodevelopment assessments at ages 12 months (n = 200), 24 months (n = 276), 6 to 9 (n = 169) years.

Results: Prenatal total dialkylphosphate metabolite level was associated with a decrement in mental development at 12 months among blacks and Hispanics. These associations appeared to be enhanced among children of mothers who carried the PON1 Q192R QQ genotype, which imparts slow catalytic activity for chlorpyrifos oxon. In later childhood, increasing prenatal total dialkyl- and dimethylphosphate metabolites were associated with decrements in perceptual reasoning in the maternal PON1 Q192R QQ genotype, with a monotonic trend consistent with greater decrements with increasing prenatal exposure.

Conclusion: Our findings suggest that prenatal exposure to organophosphates negatively impacts cognitive development, particularly perceptual reasoning, with evidence of effects beginning at 12 months and continuing through early childhood. PON1 may be an important susceptibility factor for these deleterious effects.


Rough, Virginia, very rough (Your pesticide conclusions, that is)

The study described below is of unusually high quality, so its negligible findings are all the more impressive for that. The researchers had a good measure of child IQ and even measured maternal IQ: Most unusual. And their measure of maternal pesticide exposure was direct rather than inferential. And they even used standard deviations in subsectioning their data -- a big advance on the rubbishy use of extreme quintiles that one so often encounters in the medical literature.

A simple Pearson product moment coefficient would have been more informative but such statistics tend to expose how little of the variance is explained by the variable of interest so one understands why all but the bold avoid supplying such information (Disclosure: I ALWAYS used Pearsonian correlations in reporting my own research findings).

At the end of the day, however, an IQ difference of 1.4 points is well within the margin of error at age 7 years. I would describe the findings in exactly the opposite way to how the authors describe them. I would say that the study is a strong indication that pesticides have negligible to nil effects on child IQ.

And a maybe amusing bit: The amount of pesticide in her had no effect on the mother's IQ. I quote: "There were no significant interactions between CPF and any covariates". Do you grow out of having pesticide in you?

("Rauh" is German/Yiddish for rough)
7-Year Neurodevelopmental Scores and Prenatal Exposure to Chlorpyrifos, a Common Agricultural Pesticide

By Virginia Rauh et al.


BACKGROUND: In a longitudinal birth cohort study of inner-city mothers and children (Columbia Center for Children’s Environmental Health), we have previously reported that prenatal exposure to chlorpyrifos (CPF) was associated with neurodevelopmental problems at child age 3 years.

OBJECTIVE: The goal of the study was to estimate the relationship between prenatal CPF exposure and neurodevelopment among cohort children at age 7 years.

METHODS: In a sample of 265 children, participants in a prospective study of air pollution, we measured prenatal CPF exposure using umbilical cord blood plasma (picograms/gram plasma), and 7-year neurodevelopment using the Wechsler Intelligence Scales for Children (WISC-IV). Linear regression models were used to estimate associations, with covariate selection based on two alternate approaches.

RESULTS: On average, for each standard deviation increase in exposure (4.61 pg/g), Full-Scale IQ declined by 1.4%, and Working Memory declined by 2.8%. Final covariates included maternal educational level, maternal IQ, and quality of the home environment. There were no significant interactions between CPF and any covariates, including the other chemical exposures measured during the prenatal period (environmental tobacco smoke and polycyclic aromatic hydrocarbons).

CONCLUSIONS: We report evidence of deficits in Working Memory Index and Full-Scale IQ as a function of prenatal CPF exposure at 7 years of age. These findings are important in light of continued widespread use of CPF in agricultural settings and possible longer-term educational implications of early cognitive deficits.


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