After two mailings and a reminder postcard, non-respondents were telephoned to complete the questionnaire. Multiple studies have demonstrated that PCBs can disrupt normal endocrine function in a variety of ways. The questionnaire collected data on relevant non-occupational risk factors such as medical and reproductive history including number, dates, and outcomes of pregnancies , race and ethnicity, education, height, weight, smoking, and family medical history. Data on workers from all three plants were recently updated using new job-exposure matrices JEMs to estimate exposures [ 34 , 44 - 46 ]; these data were used in mortality and incidence studies of PCB-exposed workers [ 39 - 43 ]. As del Rio Gomez et al.
Multiple studies have demonstrated that PCBs can disrupt normal endocrine function in a variety of ways. Due to their lipophilic properties, PCBs and DDE are found in fatty fish, which is a major source of exposure to humans [ 13 ]. Results Maternal body mass index at age 20, smoking status, and race did not vary between those occupationally exposed and those unexposed before the child's conception. Exposure variables and covariates Cumulative PCB exposure to the time of the index conception was calculated from the plant-specific JEMs. Research has shown that named reviews, although not of better quality than anonymous reviews, are not of worse quality either. We have decided to introduce initially a system of open reviewing if the reviewers agree explicitly. This discovery led to an increased focus on the potential of organochlorines to alter the sex ratio and maternal exposure to other organochlorines, i. Therefore in the interests of transparency, it seems fair to let authors know who has reviewed their paper. Job categories were rated qualitatively for intensity baseline, low, medium, high and frequency continuous, intermittent of PCB exposures. Many journals, including the BMJ, have moved to a system of open reviewing, whereby authors know the names of reviewers of their papers. What does it mean? They hypothesize that "dioxin-like compounds might have a negative effect on the viability of the Y-chromosome carrying sperm or on the development of XY-fertilised eggs. Acknowledgments This work was partly supported by a grant in aid for scientific research from the Ministry of Health and Welfare, Japan. How and why is still an open question, and it will be interesting to see the hypothesis proposed by AMAP's researchers when the study is released. Furthermore, changes in sex ratios observed over time are apparently unrelated to increased environmental contamination in the Arctic [ 10 ]. Bivariate analyses were conducted to identify potential confounding variables using either the Chi-square test for categorical variables or linear regression for continuous variables. Methylmercury is formed from inorganic mercury by aquatic microbes and is neurotoxic [ 15 ]. On the other hand, some reviewers might hide behind the cloak of anonymity to make unfair criticisms so as to reduce the chances of publication by rivals. Along with the cohort and JEM updates, an interview study of cancer and reproductive history was conducted among the 5, women who worked for at least one year at any of the three capacitor plants; these methods have been described in detail previously [ 43 ]. PCBs also continue to be produced as an inadvertent byproduct of commercial paint and pigment production and weathering on outdoor surfaces [ 3 , 4 ]. Chan School of Public Health. Births occurring prior to the earliest date at which PCBs were used in a given plant were excluded to prevent confounding by time period, since all these early births would be non-occupationally exposed by definition. The CHEF studies were performed in accordance with the Helsinki declaration and were approved by the Faroese ethical review committee and the institutional review board at Harvard T. Confounder adjusted logistic regression models were used to assess the associations between maternal exposures and the secondary sex ratio. The Massachusetts plant also opened 10 years prior to the New York plant and 19 years prior to the Indiana plant note that the Massachusetts plant was operating during World War II, when production demands were high to support war efforts.
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