Objectives: Polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE) are ubiquitous toxic environmental contaminants. Prenatal and early life exposures affect pubertal events in ...experimental animals. We studied whether prenatal or lactational exposures to background levels of PCBs or DDE were associated with altered pubertal growth and development in humans.
Study design: Follow-up of 594 children from an existing North Carolina cohort whose prenatal and lactational exposures had previously been measured. Height, weight, and stage of pubertal development were assessed through annual mail questionnaires.
Results: Height of boys at puberty increased with transplacental exposure to DDE, as did weight adjusted for height; adjusted means for those with the highest exposures (maternal concentration 4+ ppm fat) were 6.3 cm taller and 6.9 kg larger than those with the lowest (0 to 1 ppm). There was no effect on the ages at which pubertal stages were attained. Lactational exposures to DDE had no apparent effects; neither did transplacental or lactational exposure to PCBs. Girls with the highest transplacental PCB exposures were heavier for their heights than other girls by 5.4 kg, but differences were significant only if the analysis was restricted to white girls.
Conclusions: Prenatal exposures at background levels may affect body size at puberty.
Exposure to high levels of many pesticides has both acute and long-term neurologic consequences, but little is known about the neurotoxicity of chronic exposure to moderate levels of pesticides. We ...analyzed cross-sectional data from 18,782 white male licensed private pesticide applicators enrolled in the Agricultural Health Study in 1993-1997. Applicators provided information on lifetime pesticide use and 23 neurologic symptoms typically associated with pesticide intoxication. An indicator of more symptoms (≥ 10 vs. < 10) during the year before enrollment was associated with cumulative lifetime days of insecticide use: odds ratios (95% confidence intervals) were 1.64 (1.36-1.97) for 1-50 days, 1.89 (1.58-2.25) for 51-500 days, and 2.50 (2.00-3.13) for > 500 days, compared with never users. A modest association for fumigants > 50 days, 1.50 (1.24-1.81) and weaker relationships for herbicides > 500 days, 1.32 (0.99-1.75) and fungicides > 50 days, 1.23 (1.00-1.50) were observed. Pesticide use within the year before enrollment was not associated with symptom count. Only associations with insecticides and fumigants persisted when all four pesticide groups were examined simultaneously. Among chemical classes of insecticides, associations were strongest for organophosphates and organochlorines. Associations with cumulative exposure persisted after excluding individuals who had a history of pesticide poisoning or had experienced an event involving high personal pesticide exposure. These results suggest that self-reported neurologic symptoms are associated with cumulative exposure to moderate levels of fumigants and organophosphate and organochlorine insecticides, regardless of recent exposure or history of poisoning.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Polychlorinated biphenyls (PCBs) are persistent pollutants that are ubiquitous in the food chain, and detectable amounts are in the blood of almost every person in most populations that have been ...examined. Extensive evidence from animal studies shows that PCBs are neurotoxins, even at low doses. Interpretation of human data regarding low-level, early-life PCB exposure and subsequent neurodevelopment is problematic because levels of exposure were not similarly quantified across studies. We expressed the exposure levels from 10 studies of PCB and neurodevelopment in a uniform manner using a combination of data from original investigators, laboratory reanalyses, calculations based on published data, and expert opinion. The mainstay of our comparison was the median level of PCB 153 in maternal pregnancy serum. The median concentration of PCB 153 in the 10 studies ranged from 30 to 450 ng/g serum lipid, and the median of the 10 medians was 110 ng/g. We found that a) the distribution of PCB 153 exposure in most studies overlapped substantially, b) exposure levels in the Faroe Islands study were about 3-4-fold higher than in most other studies, and c) the exposure levels in the two recent U.S. studies were about one-third of those in the four earlier U.S. studies or recent Dutch, German, and northern Québec studies. Our results will facilitate a direct comparison of the findings on PCBs and neurodevelopment when they are published for all 10 studies.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The insecticide 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) is still used for disease control in some areas, resulting in high levels of human exposure. The main degradation product of DDT is ...1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), an antiandrogen. In animal experiments, in utero exposure to DDE decreases anogenital distance in male offspring. In these models, anogenital distance serves as a measure of fetal androgen action. The authors designed the present study to examine the hypothesis that in utero exposure to DDE decreases anogenital distance in newborn human males. A cross-sectional study of 781 newly delivered male infants was conducted in 2002–2003 in Chiapas, México, where DDT had recently been used for malaria control. Measurements of anogenital distance and penile dimensions were taken, and a sample of the mother's blood was drawn. In this population, the range of serum DDE levels was large (0.8–398 μg/liter). The authors, using two-sided tests, found no evidence that exposure in utero to DDE was related to reduced androgen action as reflected by anogenital distance or penile dimensions at birth. If DDE has important antiandrogenic action in humans, it may be manifest only at higher levels of exposure or via effects on other outcomes.
Farmworkers experience many work-related hazards, including exposure to neurotoxicants. We compared neurobehavioral performance of 288 farmworkers in central Florida who had done farm work for at ...least 1 month with 51 controls who had not. Most of the farmworkers had worked in one or more of three types of agriculture: ornamental ferns, nurseries, or citrus fruit. We collected information on farm work history in a structured interview and evaluated neurobehavioral performance using a battery of eight tests. Analyses were adjusted for established confounders including age, sex, education, and acculturation. Ever having done farm work was associated with poor performance on four tests-digit span odds ratio (OR) = 1.90; 95% confidence interval (CI), 1.02-3.53, tapping (coefficient = 4.13; 95% CI, 0.00-8.27), Santa Ana test (coefficient = 1.34; 95% CI, 0.29-2.39), and postural sway (coefficient = 4.74; 95% CI, -2.20 to 11.7)-but had little effect on four others: symbol digit latency, vibrotactile threshold, visual contrast sensitivity, and grip strength. Associations with farm work were similar in magnitude to associations with personal characteristics such as age and sex. Longer duration of farm work was associated with worse performance. Associations with fern work were more consistent than associations with nursery or citrus work. Deficits related to the duration of work experience were seen in former as well as current farmworkers, and decreased performance was related to chronic exposure even in the absence of a history of pesticide poisoning. We conclude that long-term experience of farm work is associated with measurable deficits in cognitive and psychomotor function.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background: Higher levels of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), the major degradation product of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT), have been related to shorter ...duration of breast-feeding in previous studies. If DDE truly shortens lactation, this has public health importance regarding infant mortality and the use of DDT for malaria control. Objective: Our aim was to assess the relationship of maternal DDE concentrations with length of subsequent lactation. Methods: We conducted a relatively large study in a highly exposed area of Mexico. We followed 784 mother-son pairs to determine length of lactation. DDE and DDT were measured in maternal serum obtained within a day of delivery. We fit proportional hazard models with and without stratifying by previous breast-feeding, because an association of DDE with duration of lactation among those who breast-fed previously could be attributed to a noncausal mechanism. Results: Compared with those with DDE concentrations ≤ 3.00 micro/g, the adjusted hazard ratios of weaning according to DDE category were, for concentrations 3.01-6.00 microg/g, 1.27 95% confidence interval (CI), 1.04-1.55; for concentrations 6.01-9.00 microg/g, 1.23 (95% CI, 0.92-1.63); and for concentrations > 9.00 microg/g, 1.17 (95% CI, 0.92-1.49). The corresponding ratios for women who previously breast-fed were 1.40 (95% CI, 1.06-1.87); 1.91 (95% CI, 1.24-2.93); and 1.76 (95% CI, 1.22-2.53). Those for women who had not breast-fed previously were 1.14 (95% CI, 0.86-1.52); 0.90 (95% CI, 0.61-1.31); and 0.91 (95% CI, 0.66-1.26), Conclusions: Data from our relatively large study in a highly exposed area of Mexico did not support the hypothesis that exposure to DDE shortens length of lactation. The association seen in women who previously breast-fed was likely attributed to a noncausal mechanism. Nonetheless, whether DDT has other important adverse effects on humans is still an open question.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Studies of long-term effects of breastfeeding on the health of both infants and mothers often rely on maternal recall of breastfeeding duration after several decades. The authors evaluated this ...recall by 140 college-educated, US women 69–79 years of age who breastfed a child in 1940–1956 and recorded the duration both prospectively in a diary for the Menstruation and Reproductive History Study and retrospectively in a questionnaire in 1990–1991. Mean prospective breastfeeding duration was 5.6 months (range, 1–12 months). Mean reporting difference, questionnaire minus diary duration, was 0.0 months, with a standard deviation of 2.7 months; women who recorded short durations tended to overreport, while women who noted long durations underreported. The weighted kappa statistic for reporting agreement was 0.55 (95% confidence interval: 0.42, 0.67), with better recall observed for women in the youngest quintile at recall, firstborns, and infants with more siblings. Ever having breastfed was recalled by 94% of women. For categories of 1–3, 4–6, 7–9, and 10–12 months, recalled breastfeeding duration was correctly classified by 54% of women and was classified within ±1 category by 89%. The observed misclassification, if nondifferential with respect to outcome, would appreciably attenuate estimates of dose-response associations between breastfeeding duration and later health.
Humans are always exposed to mixtures of polychlorinated biphenyls (PCBs), so assessment of their health effects is complicated. Because the original sources are relatively standard mixtures that ...change in predictable ways while traversing the environment, there is substantial uniformity in the congener mixtures people carry. To the extent that concentrations are highly correlated, measuring multiple congeners within correlated groups would be unnecessary and estimation of separate biologic effects would be impossible. We examined correlation patterns in previously collected data on 38 congeners (and 14 other organochlorines) from 497 human milk samples from Canada from 1992. Congeners 138, 153, 156, 157, 170, 183, 187, 194, 199, and 203 were highly intercorrelated; 180 had slightly lower correlations with this group. Congeners 74, 105, and 118 were highly intercorrelated and moderately to highly correlated with the first group. Congener 99 had moderate correlations with both these groups, and congener 66 had lesser correlations with the primary group. In contrast, congeners 28, 44, 49, 60, 90/101, 128, 137, and 193 showed little correlation with any other congeners. The remaining 14 congeners were uninformative; they were quantified in fewer than 30% of samples, and varying lipid concentrations meant that those quantified were not necessarily at higher concentrations than those not quantified. In study of human health effects of PCBs, the congener pattern present in the population under study should be examined when deciding which congeners to measure; instead of solely redundant or uninformative congeners, attention should be given to other congeners that may be more useful in addressing the question of interest.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Dichlorodiphenyldichloroethane (DDE) and polychlorinated biphenyls (PCB) are widespread environmental contaminants that have
been postulated to increase the risk of diseases such as non–Hodgkin's ...lymphoma, breast cancer, as well as lead to early menopause.
Studies assessing the effect of organochlorine exposure often can only measure organochlorine levels once, such as at study
enrollment, which may not be an etiologically relevant time period. We assessed the temporal changes in DDE and PCBs and the
predictors of those changes using interview data and DDE and PCB measures collected from 123 women who were enrolled in a
baseline study from 1978 to 1982 and followed up in 2003 to 2004. Baseline and follow-up organochlorine levels were compared
using Spearman correlations (r s ), and predictors of the rate of change in log concentration were evaluated using linear regression models. Although serum
concentrations dramatically declined (median follow-up to baseline concentration ratio was 16% for DDE and 45% for PCB), baseline
and follow-up measures were strongly correlated for DDE (r s = 0.72) and moderately correlated for PCBs (r s = 0.43). Prediction of follow-up PCB levels was substantially improved (r s = 0.75) with data on initial concentration, length of lactation, baseline body mass index, and percent change in body fat,
whereas DDE prediction improved slightly (r s = 0.83) with data on lactation and baseline body mass index. These findings suggest that a single organochlorine measure
provides considerable information on relative ranking at distant times and that the predictive power can be improved, particularly
for PCBs, with information on a few predictors. (Cancer Epidemiol Biomarkers Prev 2008;17(10):2729–36)
PURPOSE: To determine whether weight at birth is related to prenatal exposure to persistent organochlorine compounds.
METHODS: Birth weight was obtained for 197 singleton infants drawn from the ...general population born in two cities in Ukraine in 1993 to 1994. Concentrations of seven organochlorine pesticides (p,p′-DDT, p,p′-DDE, β-hexachlorocyclohexane, hexachlorobenzene, trans-nonachlor, oxychlordane, heptachlor epoxide) and 11 polychlorinated biphenyl congeners measured in maternal milk taken at four or five days after birth were used as an index of prenatal exposure.
RESULTS: The greatest differences were seen for β-hexachlorocyclohexane, with a pattern not suggestive of dose–response; infants in the lowest tertile were small, those in the central tertile were large, and those in the upper tertile were average. Adjustment for gestational age and other potential confounders had little effect on these patterns. Infants in the two upper tertiles for p,p′-DDE were larger than those in the lower tertile, with the effect being more striking after adjustment for gestational age. Adjustment for potential confounders made the pattern disappear. Other chemicals showed no convincing evidence of effects.
CONCLUSIONS: Prenatal exposure to the chemicals studied, at concentrations currently seen in this population, does not impact weight at birth.
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