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Biomedical subjects

I Hertz-Picciotto

Publications and source records attributed to I Hertz-Picciotto.

At least 19 recordsLinked to original sources
PubMed2005

Factors influencing the difference between maternal and cord blood lead.

AIMS: To determine the factors that affect why some infants receive higher exposures relative to the mother's body burden than do others. METHODS: A total of 159 mother-infant pairs from a cohort of women receiving prenatal care at Magee-Womens Hospital in Pittsburgh, PA from 1992 to 1995 provided blood samples at delivery for lead determination. The difference between cord and maternal blood lead concentration (PbB) and a dichotomous variable indicator of higher cord than maternal PbB, were examined as indicators of relative transfer. Women were interviewed twice during the pregnancy about lifestyle, medical history, calcium nutrition, and physical activity. RESULTS: Higher blood pressure was associated with relatively greater cord compared with maternal PbB, as was maternal alcohol use. Sickle cell trait and higher haemoglobin were associated with a lower cord relative to maternal blood lead PbB. No association was seen with smoking, physical exertion, or calcium consumption. CONCLUSION: While reduction in maternal exposure will reduce fetal exposure, it may also be possible to mitigate infant lead exposure by reducing transfer from the pregnant woman. Interventions aimed at reducing blood pressure and alcohol consumption during pregnancy may be useful in this regard.

Adult↗
PubMed2003

Maternal stress and preterm birth.

This study examined a comprehensive array of psychosocial factors, including life events, social support, depression, pregnancy-related anxiety, perceived discrimination, and neighborhood safety in relation to preterm birth (<37 weeks) in a prospective cohort study of 1,962 pregnant women in central North Carolina between 1996 and 2000, in which 12% delivered preterm. There was an increased risk of preterm birth among women with high counts of pregnancy-related anxiety (risk ratio (RR) = 2.1, 95% confidence interval (CI): 1.5, 3.0), with life events to which the respondent assigned a negative impact weight (RR = 1.8, 95% CI: 1.2, 2.7), and with a perception of racial discrimination (RR = 1.4, 95% CI: 1.0, 2.0). Different levels of social support or depression were not associated with preterm birth. Preterm birth initiated by labor or ruptured membranes was associated with pregnancy-related anxiety among women assigning a high level of negative impact weights (RR = 3.0, 95% CI: 1.7, 5.3). The association between high levels of pregnancy-related anxiety and preterm birth was reduced when restricted to women without medical comorbidities, but the association was not eliminated. The prospective collection of multiple psychosocial measures on a large population of women indicates that a subset of these factors is associated with preterm birth.

Adolescent↗
PubMed2001

Tetrachloroethylene in drinking water and birth outcomes at the US Marine Corps Base at Camp Lejeune, North Carolina.

A study of mean birth weight, small-for-gestational-age infants, and preterm birth was conducted at the US Marine Corps Base at Camp Lejeune, North Carolina, where drinking water was contaminated with volatile organic compounds. Tetrachloroethylene (PCE) was the predominant contaminant. The authors used multiple linear and logistic regression to analyze 1968-1985 data from 11,798 birth certificates. Overall, at most weak associations were observed between PCE exposure and study outcomes. However, associations were found between PCE exposure and birth-weight outcomes for infants of older mothers and mothers with histories of fetal loss. Adjusted mean birth-weight differences between PCE-exposed and unexposed infants were -130 g (90% confidence interval (CI): -236, -23) for mothers aged 35 years or older and -104 g (90% CI: -174, -34) for mothers with two or more previous fetal losses. Adjusted odds ratios for PCE exposure and small-for-gestational-age infants were 2.1 (90% CI: 0.9, 4.9) for older mothers and 2.5 (90% CI: 1.5, 4.3) for mothers with two or more prior fetal losses. These results suggest that some fetuses may be more vulnerable than others to chemical insult.

Birth Certificates↗
PubMed2001

Childhood morbidity and air pollution in the Teplice program.

BACKGROUND: A study of morbidity of children aged 0 to 3 years was conducted in two districts in the Czech Republic. Comparisons were made between children living in Teplice district, known for its high air pollution, and children living in Practice, a district with consistently lower particulate and SO2 exposures. METHODS AND RESULTS: The children were selected for the follow up based on deliveries from May 1994 to December 1966. Childhood morbidity during the first three years of life of 452 children was extracted from their pediatric records. Diagnoses were coded using the International Classification of Diseases--10th edition, and categorized into broad groupings. Children born in Teplice experienced a significantly higher rate of otitis media and otalgia, gastrointestinal infections, upper respiratory infections, and pneumonia, but did not differ in their risk for bronchitis or for viral infections such as varicella. These findings remained after multiple linear regression models adjusted for education, maternal age, maternal smoking, and other smokers in the household, breastfeeding, and attendance at day care. CONCLUSIONS: Air pollution may alter early childhood susceptibility to infection, but other differences between the districts must be considered: systematic diagnostic differences for several health outcomes comparing pediatricians in Teplice vs. Practice, differences in health-care seeking behavior by the parents, and inadequate control for confounding.

Air Pollution↗
PubMed2001

Case-cohort analysis of agricultural pesticide applications near maternal residence and selected causes of fetal death.

The potential association between fetal death and residential proximity to agricultural pesticide applications was examined in 10 California counties for 1984. A case-cohort analysis utilized 319 cases of selected causes of fetal death other than congenital anomalies and 611 non-cases. A statewide database of all applications of restricted pesticides was linked to maternal address; residential proximity within 1 mile (1.6 km) provided a surrogate for daily exposure. Pesticides were grouped by chemical class and mechanism of acetylcholinesterase inhibition. Multivariate proportional hazards models using time-dependent exposure variables were fit for each pesticide grouping. Overall, pesticides showed no strong association with fetal death. Slightly elevated risks were observed for women who resided near applications of halogenated hydrocarbons, carbamates, estrogenic pesticides, and carbamate acetylcholinesterase inhibitors during the second trimester, with hazard ratios of 1.3 (95% confidence interval (CI): 1.0, 1.8), 1.3 (95% CI: 1.0, 1.8), 1.4 (95% CI: 0.8, 2.5), and 1.3 (95% CI: 1.0, 1.8), respectively. In a month-by-month analysis, elevated risks were observed when exposure occurred during gestational months 3 and 4 for carbamates and carbamate inhibitors and during months 4 and 5 for halogenated hydrocarbons. Since previous studies have relied on personal recall of exposure, major strengths of this study were the objective source for environmental pesticide exposure assessment and the use of data on the timing of exposure.

California↗
PubMed2001

[Environmental pollution and childhood morbidity].

BACKGROUND: A study of morbidity of children aged 0 to 3 years was organized in two districts in the Czech Republic. Comparisons were drawn between children living in district Teplice, known for its high air pollution, and those living in Practice, the district with consistently lower particulate and SO2 exposures. METHODS AND RESULTS: 452 children of the follow up study were born between May 1994 and December 1996. Childhood morbidity during the first three years of life was obtained from their pediatric records. Diagnoses were coded using the International Classification of Diseases--the 10th edition, and categorized into broad groups. Children born in Teplice experienced a significantly higher rate of otitis media (and otalgia), gastrointestinal infections, upper respiratory infections, and pneumonia, but they did not differ in the risk of bronchitis or that of viral infections such as varicella. These findings remained valid after the multiple linear regression models were calculated and adjusted for education, maternal age, maternal smoking, and other smokers in the household, breastfeeding, and attendance at the day care. CONCLUSIONS: Air pollution may alter early childhood susceptibility to infection, but other differences between the districts have to be considered: systematic diagnostic differences for several health outcomes between pediatricians in Teplice and Practice, differences in health-care seeking approach of parents, and some hitherto unidentified factors.

Air Pollution↗
PubMed2001

Comparison of assessment methods for pesticide exposure in a case-control interview study.

In epidemiologic studies, much of the variation in disease risk estimates associated with occupational pesticide exposure may be due to variation in exposure classification. The authors compared five different methods of using interview information to assess occupational pesticide exposure in a US-Canada case-control study of neuroblastoma (1992-1994). For each method, exposure assignment was compared with that of a reference method, and neuroblastoma effect estimates were calculated. Compared with the reference method, which included a complete review of occupation, industry, job tasks, and exposure-specific activities, the use of occupation-industry groups alone or in combination with general job task information diluted the exposed group by including individuals who were unlikely to have been truly exposed. The effect estimates representing associations between each exposure method and neuroblastoma were different enough to influence the study's conclusions, especially when the exposure was rare (for maternal occupational pesticide exposure, the odds ratio was 0.7 using the reference exposure assessment method and 3.2 using the occupation-industry group exposure assessment method). Exposure-specific questions about work activities can help investigators distinguish truly exposed individuals from those who report exposure but are unlikely to have been exposed above background levels and from those who have not been exposed but are misclassified as exposed because of their employment in an occupation-industry group determined a priori to be exposed.

Adult↗
PubMed2001

Sexual activity during late pregnancy and risk of preterm delivery.

OBJECTIVE: To examine the association between sexual activity during late pregnancy and preterm delivery. METHODS: Women at least 16 years old and carrying singleton fetuses were recruited between 24 and 29 weeks' gestation from prenatal clinics in central North Carolina. They were interviewed by telephone about sexual activity before and during pregnancy. One hundred eighty-seven women delivered between 29 and 36 weeks and had a follow-up interview after delivery. Four hundred nine women who were selected randomly from the cohort served as controls and had a follow-up interview between 29 and 36 weeks (mean gestational age 39.2 weeks). RESULTS: Intercourse during late pregnancy was associated with a reduced risk of preterm delivery. The conditional odds ratio (OR) was 0.34 and 95% confidence interval (CI) 0.23, 0.51 for preterm delivery within 2 weeks after intercourse. Similar decreased risk for preterm delivery was found with recent female orgasm. Adjusting for race, age, education, and living with a partner had little effect on results. Cases were more likely than controls to report poorer health, medical reasons for reducing sexual activity, less interest in sex, and receipt of advice to restrict sexual activity during pregnancy. Results did not differ substantially according to presence or absence of bacterial vaginosis at 28 weeks. CONCLUSION: These data provide evidence against the hypothesis that sexual activity generally increases risk of preterm delivery between 29 and 36 weeks. However, we cannot exclude the possibility that a small subgroup of susceptible women might have adverse consequences of sexual activity.

Adult↗
PubMed2001

A reproducible approach to the reporting of organochlorine compounds in epidemiologic studies.

A growing body of research indicates that the most biologically active PCB congeners and organochlorines are not the most abundant components in human and wildlife samples. As researchers attempt measurement on a wider pool of less abundant compounds, they inevitably face quantification problems. To address this problem and enhance comparability across studies, we propose a standardized approach to report organochlorines that is based on a reproducible method to determine the limit of quantification (LQ). Two statistical methods are incorporated into our approach, one by Gibbons termed the Alternative Minimum Level (AML), and one based on determining a region of stable relativestandard deviation in instrument response (RSD). We illustrate our approach using historical samples collected during the 1960s from a cohort of pregnant women enrolled in the Child Health and Development Study. The results are applicable to determining the LQ of any method, and are of utmost importance to environmental scientists conducting trace organic analyses of complex mixtures. Our results demonstrate that: (1) precision as measured by RSD is the most important criterion in determining LQ; (2) the AML routinely isolates a region of constant RSD; and (3) the precision of the instrument detector response as measured with pure standards locates the LQ applicable for real samples - that is, the true limits of quantification reside in the detector, not the matrix effects or analyte recoveries associated with real samples. A corollary of these findings is that bias due to matrix effects and analyte recoveries can be assessed separately from precision and LQdetermination. Previous approaches involved spiking matrix blanks to determine LQ, a problematic strategy for real world, complex matrices. We have now validated the use of pure standards in LQ determination, an approach that is practical and accessible to most analysts.

Animals↗
PubMed2001

Retrospective vs. prospective coital frequency and menstrual cycle length in a contraceptive effectiveness trial.

PURPOSE: To determine how well information at enrollment would predict coital frequency and menstrual segment length during a prospective contraceptive effectiveness trial. METHODS: We compared retrospective reports of monthly coital frequency and menstrual segment (cycle) length with prospective information for women participating in a contraceptive trial of the Reality((R)) female condom. RESULTS: Participants reported slightly higher mean monthly coital frequency and slightly longer menstrual segments prior to the study than during the study (12.6 acts vs. 12.0 acts per month and 30.8 days vs. 28.4 days). We examined the actual distribution of differences between the retrospective and prospective measures and found considerable variability. Among the 195 participants studied, parous women were less likely to predict accurately menstrual segment length (OR 0.4; 95% CI 0.3--0.9), while older women were more likely to predict accurately coital frequency (OR 1.9; 95% CI 0.9--3.3). CONCLUSIONS: Coital frequency and menstrual segment length vary considerably over time. Hence, prospective data collection is essential to accurately characterize these variations and to properly interpret results from contraceptive trials and other studies concerned with fecundability and hazards of reproduction.

Adult↗
PubMed2001

Residential pesticide exposure and neuroblastoma.

Neuroblastoma is the most common neoplasm in children under 1 year of age. We examined the relation between residential exposure to pesticides and neuroblastoma, using data from a case-control study of risk factors for neuroblastoma. Incident cases of neuroblastoma (N = 538) were identified through the Pediatric Oncology Group and the Children's Cancer Group. One age-matched control was identified for each case by random digit dialing. Telephone interviews with each parent collected information on residential exposure to pesticides. Pesticide use in both the home and garden were modestly associated with neuroblastoma [odds ratio (OR) = 1.6 (95% confidence interval [95% CI] = 1.0-2.3, and OR = 1.7 (95% CI = 0.9-2.1), respectively]. Compared with infants [OR = 1.0 (95% CI = 0.6-2.0)], stronger associations were found for garden pesticides in children diagnosed after 1 year of age [OR = 2.2 (95% CI = 1.3-3.6)], which suggests that pesticides may act through a mechanism more common for neuroblastomas in older children. There was no evidence of differential pesticide effects in subgroups of neuroblastoma defined by MYCN oncogene amplification or tumor stage.

Canada↗
PubMed2001

A case-control study of pesticides and fetal death due to congenital anomalies.

We examined the association between late fetal death due to congenital anomalies (73 cases, 611 controls) and maternal residential proximity to pesticide applications in ten California counties. A statewide database of all applications of restricted pesticides was linked to maternal address to determine daily exposure status. We examined five pesticide chemical classes. The odds ratios from logistic regression models, adjusted for maternal age and county, showed a consistent pattern with respect to timing of exposure; the largest risks for fetal death due to congenital anomalies were from pesticide exposure during the 3rd-8th weeks of pregnancy. For exposure either in the square mile of the maternal residence or in one of the adjacent 8 square miles, odds ratios ranged from 1.4 (95% confidence interval = 0.8-2.4) for phosphates, carbamates, and endocrine disruptors to 2.2 (95% confidence interval = 1.3-3.9) for halogenated hydrocarbons. Similar odds ratios were observed when a more restrictive definition of nonexposure (not exposed to any of the five pesticide classes during the 3rd-8th weeks of pregnancy) was used. The odds ratios for all pesticide classes increased when exposure occurred within the same square mile of maternal residence.

Abnormalities, Drug-Induced↗
PubMed2001

Reconciling animal and human data in a cancer risk assessment of acrylonitrile.

OBJECTIVES: Bioassays of rats exposed to acrylonitrile have consistently detected an elevated incidence of central nervous system (CNS) cancer. In contrast, epidemiologic studies have not found a statistically stable increase in CNS cancer mortality. The purpose of this paper is to examine whether or not CNS cancers predicted from the most appropriate inhalation bioassay in rats are consistent with CNS cancers observed in 3 recent, large epidemiologic studies. METHODS: A linearized multistage model was fit to dose-response data from a rat inhalation bioassay to estimate carcinogenic potency. This potency was applied to epidemiologic studies of acrylonitrile-exposed workers. After adjustment for less than complete lifetime follow-up in the epidemiologic studies, consistency was examined between CNS cancers predicted by the model fit to the animal data for the exposure levels and sample sizes of the epidemiologicy studies and the CNS cancers observed in the epidemiologic studies. RESULTS: The model predicted totals of 17.7, 3.6, and 7.6 CNS cancer deaths for the studies. These predictions were not far from the observed CNS cancer deaths (12, 6, and 6) and were well within their 95% confidence intervals of 6.9-22.3, 2.2-13.1, and 2.2-13.1, respectively. CONCLUSIONS: The CNS cancer potency estimated from the best available inhalation bioassay was consistent with the observed deaths in the epidemiologic studies as long as continuous lifetime exposure was chosen as the exposure metric. The lack of observed excess in CNS cancer among the studied workers may have been due to low exposures, insufficient follow-up times, or both.

Acrylonitrile↗