A commentary on some epidemiology data for chlorpyrifos

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Extensive animal and human studies on chlorpyrifos (CPF) point to changes in a blood enzyme as its first biological effect, and governments and health groups around the world have used this effect in the determination of its safe dose. Preventing this first biological effect, referred to in risk assessment parlance as the critical effect, is part and parcel of chemical regulation in general and of CFP specifically. Rauh et al. (2011), one of the published studies from the Columbia Center for Children's Environmental Health (CCCEH), reported evidence of deficits in Working Memory Index and Full-Scale IQ in children at 7 years old as a function of prenatal CPF exposures that are much lower than levels causing cholinesterase inhibition. Since the raw data on which Rauh et. al. (2011) publicly-funded (in part) findings were based have not been made available despite repeated requests, we show extracted data in Fig. 1A and 1E of Rauh et al. (2011), and plotted these extracted data as response versus log dose, a common risk assessment approach. Surprisingly, a significant portion of the data stated to be available in Rauh et al. (2011) were not found in these published figures, perhaps due to data point overlay. However, the reported associations of chlorpyrifos levels with Working Memory and Full Scale IQ were also not replicated in our analysis due perhaps to this missing data. Multiple requests were made to Rauh et al. (2011) for access to data from this, in part, publicly funded study, so that confirmation could be attempted. This general lack of data and inconsistency with cholinergic responses in other researches raises concerns about the lack of data transparency.