Endometriosis among women exposed to polybrominated biphenyls

PURPOSE: We examined the association between endometriosis and exposure to polybrominated biphenyls (PBBs) and polychlorinated biphenyls (PCBs) among women inadvertently exposed to PBBs in 1973. METHODS: Serum PBBs and PCBs were measured in the late 1970s. Women self-reported endometriosis at interview in 1997. We constructed Cox models to estimate the relative incidence of endometriosis in relation to PBB and PCB levels. RESULTS: Seventy-nine of 943 women (9%) reported endometriosis. Compared with women with low PBB exposure (or=4 ppb) (HR = 0.90; 95% CI, 0.51-1.59) exposure did not have increased incidence of endometriosis. Increased incidence of endometriosis was suggested among women exposed to moderate PCB (5-8 ppb) (HR = 1.67; 95% CI, 0.91-3.10) and high PCB (>or=8 ppb) (HR = 1.68; 95% CI, 0.95-2.98) levels compared with low PCB exposure (相似文献   

Polybrominated biphenyl exposure and benign breast disease in a cohort of US women

PURPOSE: We examined the relation between serum polybrominated biphenyl (PBB) levels and the risk of benign breast disease in a cohort of Michigan women unintentionally exposed to PBBs in 1973 and interviewed in 1997. METHODS: We used extended Cox models to generate adjusted hazard ratios; models included polychlorinated biphenyls (PCBs) and risk factors for benign breast disease reported in the literature. RESULTS: Two hundred fourteen (23%) of 951 women reported benign breast disease diagnosed by a physician. Compared with women with low PBB exposure, benign breast disease was not reported more frequently among those with moderate (>1-12 parts per billion [ppb]), (odds ratio [OR] 1.08, 95% confidence interval [CI] = 0.80-1.45), or high (>12 ppb), (OR 0.79, 95% CI = 0.46-1.38) PBB exposure. PCB exposure was also not associated with self-reported physician-diagnosed benign breast disease. Age, smoking, and annual number of health-care provider visits were significantly associated with benign breast disease. CONCLUSIONS: Our analysis did not demonstrate an association between serum PBB level and self- reported physician-diagnosed benign breast disease. We did observe an increased risk of benign breast disease for women who smoked, an association that has not been consistently found in previous studies.     

Changes in serum PBB and PCB levels over time among women of varying ages at exposure.

The identification of host factors that are predictors of changes in serum polyhalogenated biphenyl contaminants over time has been a difficult challenge in epidemiologic studies of exposed individuals. Of particular concern are age at exposure, reproductive and lactational histories, and changes in body mass index. Using both cross-sectional and longitudinal approaches, this study examined factors related to high initial serum PBB and PCB levels and changes in these levels over time among women of varying ages at exposure (n=1772; age range<1 to 45 years). In 1973, PBB exposure occurred through consumption of farm products contaminated with PBB added to cattle feed. Exposures to PCBs began in 1941 through PCB-contaminated silo sealant deteriorating into animal feed. The Michigan Department of Public Health began enrolling participants in 1977 and has continued to follow them through annual updates. At enrollment, questionnaires were administered to obtain demographic, lifestyle, and anthropometric measurements, medical/reproductive and occupational histories, and contaminated food consumption patterns. Blood samples were collected for PBB and PCB analysis at enrollment for all participants; additional serum tests were done on a subset of the population during follow-up. Median serum levels at enrollment were 2.0 ppb PBB and 5.0 ppb PCB. A decline in serum PBB level over an interval that ranged from 1 to 146 months (median=31) was observed for 44.6% of the women (median=1.0 ppb), while 12.2% showed an increase (median=1.0 ppb). PCB levels declined in 50.3% of the women (median=3.0 ppb) while 12.2% increased (median=2.0 ppb). Relative to women whose contaminant levels were stable, higher initial serum level was a predictor of decline for both PBB and PCB (OR=1.66, 95% CI 1.52-1.82; OR=3.26, 95% CI 2.58-4.12, respectively); a yearly increase in interval between tests was related to declining PCBs (OR=1.65, 95% CI 1.46-1.87). In addition, age< or =10 years at exposure (OR=1.72, 95% CI 1.03-2.86) and residence on a quarantined farm (OR=1.40, 95- CI 1.03-1.90) were predictors of a decrease in PBBs. Factors related to an increase in PBB levels were age< or =10 years at exposure (OR=0.30, 95% CI 0.10-0.96) and initial PBB level (OR=1.24, 95% CI 1.15-1.33); and for PCBs, high initial level (OR=1.34, 95% CI 1.17-1.53) and body mass index (OR=1.07, 95% CI 1.01-1.13). One or more live births during the interval between tests were not related to changing levels of either contaminant; breastfeeding data were not available for examination. Early age at exposure appears to be an important predictor of changes in serum PBB levels over time.     

Reproductive outcomes among women exposed to a brominated flame retardant in utero

The authors studied 194 women exposed to polybrominated biphenyls (PBB) in utero when their mothers consumed products accidentally contaminated in Michigan in 1973. Generalized estimating equations were used to examine the effect of in utero PBB exposure on adult pregnancy-related outcomes. Compared to those with the lowest exposure (≤1 ppb), those with mid-range (>1-3.16 ppb) and high (≥3.17 ppb) PBB exposure had increased odds of spontaneous abortion with wide confidence intervals (odds ratio [OR] = 2.75, 95% confidence interval [CI] = 0.64-11.79, OR = 4.08, 95% CI = 0.94-17.70; respectively; p for trend = .05). Exposure during infancy to PBB-contaminated breast milk further increased this risk. Time to pregnancy and infertility were not associated with in utero exposure to PBB. Future studies should examine the suggested relationship between spontaneous abortion and other brominated flame retardants.     

Growth in girls exposed in utero and postnatally to polybrominated biphenyls and polychlorinated biphenyls

BACKGROUND: Accidental contamination with polybrominated biphenyls (PBBs) of the Michigan food supply in 1973 led to the exposure of more than 4000 individuals and to formation of the PBB cohort registry (1976-1979). At enrollment, measurements were taken of serum PBB and polychlorinated biphenyl (PCB), possible endocrine disrupting chemicals. METHODS: We examined the association of estimated PBB and PCB exposure during pregnancy with current height and weight in 308 daughters, 5-24 years of age (mean age 15.2 years), born to women in the cohort. We estimated prenatal PBB exposure using maternal enrollment serum PBB and a model of PBB elimination. Prenatal PCB exposure was estimated using maternal enrollment serum PCB because background-level exposure through diet was ongoing. Self-reported height and weight were obtained from a 1997-1998 health survey. RESULTS: We found no association between prenatal PBB exposure and either daughter's current height or daughter's weight adjusted for height; however, prenatal PCB exposure above 5 parts per billion was associated with reduced weight adjusted for height. Exposure through breastfeeding did not modify the association. CONCLUSIONS: Mothers with PCB levels above the median had daughters whose current weights were 11 pounds lower than that of the daughters whose mothers had levels below the median. This study provides evidence that prenatal exposure to PCBs may affect growth.     

Consumption of PCB-contaminated sport fish and risk of spontaneous fetal death.

Spontaneous fetal death has been observed among various mammalian species after exposure to polychlorinated biphenyls (PCBs). Our exposure-based cohort study assessed the relationship between consumption of PCB-contaminated Lake Ontario sport fish and spontaneous fetal death using 1820 multigravid fertile women from the 1990-1991 New York State Angler Cohort Study. Fish consumption data were obtained from food frequency questionnaires and history of spontaneous fetal death from live birth certificates. Analyses were stratified by number of prior pregnancies and controlled for smoking and maternal age. No significant increases in risk for fetal death were observed across four measures of exposure: a lifetime estimate of PCB exposure based on species-specific PCB levels; the number of years of fish consumption; kilograms of sport fish consumed in 1990-1991; and a lifetime estimate of kilograms eaten. A slight risk reduction was seen for women with two prior pregnancies at the highest level of PCB exposure (odds ratio = 0.36; 95% CI, 0.14-0.92) and for women with three or more prior pregnancies with increasing years of fish consumption (odds ratio = 0.97; 95% CI, 0.94-0.99). These findings suggest that consumption of PCB-contaminated sport fish does not increase the risk of spontaneous fetal death.     

Age at menarche and tanner stage in girls exposed in utero and postnatally to polybrominated biphenyl

Accidental contamination of the Michigan food chain with polybrominated biphenyls (PBBs) led to the exposure of more than 4,000 individuals in 1973. Because PBB exposure is suspected to disrupt endocrine function, we assessed pubertal development in females 5-24 years of age (N = 327) who were exposed to PBB in utero and, in many cases, through breastfeeding. We estimated in utero PBB exposure using maternal serum PBB measurements taken after exposure (1976-1979) and extrapolated to time of pregnancy using a model of PBB decay. We found that breastfed girls exposed to high levels of PBB in utero (> or =7 parts per billion) had an earlier age at menarche (mean age = 11.6 years) than breastfed girls exposed to lower levels of PBB in utero (mean age = 12.2-12.6 years) or girls who were not breastfed (mean age = 12.7 years). This association persisted after adjustment for potential confounders (menarche ratio = 3.4, 95% confidence interval = 1.3-9.0). Perinatal PBB exposure was associated with earlier pubic hair stage in breastfed girls, but little association was found with breast development. The associations observed here lend support to the hypothesis that pubertal events may be affected by pre- and postnatal exposure to organohalogens.     

The influence of age at exposure to PBBs on birth outcomes

The determination of critical windows of susceptibility to environmental chemical exposures and health has become a major public health focus. This study examined the association between early age at exposure to polybrominated biphenyls (PBBs) and subsequent birth weight and gestational length in offspring among females. The study population consisted of 1111 births that occurred among 560 women enrolled in the Michigan PBB Cohort from 1975 to 1994. Maternal age at exposure was categorized into three groups:<10 years (n = 64), 11-16 years (n = 149), and 17-42 years (n = 347). Overall serum PBB levels ranged from 0 to 1490 ppb, with a median of 2, 3, and 2 ppb in the three age groups, respectively. Separate mixed-effects linear regression models were used to evaluate the effect of age at exposure (years) and initial PBB level (ppb) on birth weight (grams) and gestational age (weeks), controlling for gestational age (weeks) (in the model examining effects on birth weight), BMI (kg/m(2)) and serum PCB level at enrollment (ppb), maternal age and paternal education at delivery, parity, infant gender, interval between the initial serum test and date of delivery (years), and the trimester in which prenatal care was initiated. Relative to the oldest age group, age<10 years at exposure was the most important predictor of increased birth weight (estimated regression coefficient = 225 g, P = 0.012). Infant birth weight increased approximately 16 g for every 10 ppb increase in serum PBBs (P=0.004). There was no association between initial PBB levels and gestational age, nor were initial serum PCB levels associated with either infant birth weight or gestational length. These results provide support for the hypothesis that early age at exposure may be an important determinant in subsequent health effects due to environmental chemical exposures.     

Polychlorinated biphenyl (PCB) exposure and diabetes: results from the Anniston Community Health Survey

Background: Polychlorinated biphenyls (PCBs) manufactured in Anniston, Alabama, from 1929 to 1971 caused significant environmental contamination. The Anniston population remains one of the most highly exposed in the world.Objectives: Reports of increased diabetes in PCB-exposed populations led us to examine possible associations in Anniston residents.Methods: Volunteers (n = 774) from a cross-sectional study of randomly selected households and adults who completed the Anniston Community Health Survey also underwent measurements of height, weight, fasting glucose, lipid, and PCB congener levels and verification of medications. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the relationships between PCBs and diabetes, adjusting for diabetes risk factors. Participants with prediabetes were excluded from the logistic regression analyses.Results: Participants were 47% African American, 70% female, with a mean age of 54.8 years. The prevalence of diabetes was 27% in the study population, corresponding to an estimated prevalence of 16% for Anniston overall; the PCB body burden of 35 major congeners ranged from 0.11 to 170.42 ppb, wet weight. The adjusted OR comparing the prevalence of diabetes in the fifth versus first quintile of serum PCB was 2.78 (95% CI: 1.00, 7.73), with similar associations estimated for second through fourth quintiles. In participants < 55 years of age, the adjusted OR for diabetes for the highest versus lowest quintile was 4.78 (95% CI: 1.11, 20.6), whereas in those ≥ 55 years of age, we observed no significant associations with PCBs. Elevated diabetes prevalence was observed with a 1 SD increase in log PCB levels in women (OR = 1.52; 95% CI: 1.01, 2.28); a decreased prevalence was observed in men (OR = 0.68; 95% CI: 0.33, 1.41).Conclusions: We observed significant associations between elevated PCB levels and diabetes mostly due to associations in women and in individuals < 55 years of age.     

Polybrominated biphenyls, polychlorinated biphenyls, body weight, and incidence of adult-onset diabetes mellitus

BACKGROUND: Prior studies have reported an increased risk of diabetes related to polychlorinated biphenyl (PCB) exposure. No study has yet investigated whether polybrominated biphenyls (PBBs), which are similar in chemical structure, increase the incidence of diabetes. METHODS: The Michigan PBB cohort was established in 1976 and surveyed again in 1991-1993 and in 2001. PBB and PCB serum levels were measured from blood collected at enrollment. To determine the incidence of adult-onset diabetes, we analyzed cohort members without diabetes at enrollment, ages 20 years and older, with known PBB and PCB levels, who participated in at least 1 follow-up survey (n = 1384). Using Poisson regression, we determined the incidence density ratio (IDR) of diabetes for different serum levels of PBB and PCB, controlling for age, body mass index, smoking, and alcohol consumption at enrollment. RESULTS: Analyzing 25 years of follow-up data, we did not find that higher PBB serum levels were a risk factor for the incidence of diabetes mellitus. However, in women, but not in men, higher PCB serum levels were associated with increased incidence of diabetes (IDR = 2.33; 95% confidence interval = 1.25-4.34 in the highest PCB group compared with the lowest). In both men and women, overweight and obesity increased the diabetes incidence. CONCLUSIONS: We found no association between PBB serum levels and diabetes incidence. In women, there was a positive linear association of diabetes incidence with PCB serum levels at enrollment. This finding is in agreement with 2 prior studies indicating a higher relative risk of diabetes in PCB-exposed women.     

Maternal exposure to airborne polychlorinated biphenyls (PCBs) and risk of adverse birth outcomes

Human health effects of airborne lower-chlorinated polychlorinated biphenyls (LC-PCBs) are largely unexplored. Since PCBs may cross the placenta, maternal exposure could potentially have negative consequences for fetal development. We aimed to determine if exposure to airborne PCB during pregnancy was associated with adverse birth outcomes. In this cohort study, exposed women had lived in PCB contaminated apartments at least one year during the 3.6 years before conception or the entire first trimester of pregnancy. The women and their children were followed for birth outcomes in Danish health registers. Logistic regression was performed to estimate odds ratios (OR) for changes in secondary sex ratio, preterm birth, major congenital malformations, cryptorchidism, and being born small for gestational age. We performed linear regression to estimate difference in birth weight among children of exposed and unexposed mothers. All models were adjusted for maternal age, educational level, ethnicity, and calendar time. We identified 885 exposed pregnancies and 3327 unexposed pregnancies. Relative to unexposed women, exposed women had OR 0.97 (95% CI 0.82, 1.15) for secondary sex ratio, OR 1.13 (95% CI 0.76, 1.67) for preterm birth, OR 1.28 (95% CI 0.81, 2.01) for having a child with major malformations, OR 1.73 (95% CI 1.01, 2.95) for cryptorchidism and OR 1.23 (95% CI 0.88, 1.72) for giving birth to a child born small for gestational age. The difference in birth weight for children of exposed compared to unexposed women was ? 32 g (95% CI—79, 14). We observed an increased risk of cryptorchidism among boys after maternal airborne LC-PCB exposure, but due to the proxy measure of exposure, inability to perform dose–response analyses, and the lack of comparable literature, larger cohort studies with direct measures of exposure are needed to investigate the safety of airborne LC-PCB exposure during pregnancy

     

Case-control study of PCBs,other organochlorines and breast cancer in Eastern Slovakia

This case-control study was designed to investigate association between polychlorinated biphenyls (PCBs) and risk of breast cancer in an area of high environmental exposure in the Michalovce district of eastern Slovakia. Incident breast cancer cases from the Michalovce district diagnosed between May 1997 and May 1999 were recruited through the Oncology Department of the District Hospital. A total of 15 individual PCB congeners, 2,2'-bis(4-chlorophenyl)-1,1-dichloroethylene (DDE), 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT), and hexachlorobenzene (HCB) were measured in the serum of 24 breast cancer patients and 88 population controls in 1998-1999. The median levels of total PCBs were similar in cases (2586 ng/g of lipid) and controls (2682 ng/g of lipid). Higher serum levels (highest vs. lowest tertile) of total PCBs (odds ratio (OR)=0.42, 95% CI 0.10-1.82, p-for trend=0.31), group 1 congeners (OR=0.37, 95% CI 0.10-1.43, P-for trend=0.02), group 2 congeners (OR=0.32, 95% CI 0.07-1.56, P-for trend=0.60), and group 3 congeners (OR=0.49, 95% CI 0.12-2.04, P-for trend=0.51) were inversely associated with risk of breast cancer. Higher serum levels of DDE (OR=3.04, 95% CI 0.65-14.3, P-for trend=0.10) were positively associated with risk of breast cancer, while there was no association for DDT (OR=1.19, 95% CI 0.27-5.23, P-for trend=0.68), and an inverse association for HCB (OR=0.45, 95% CI 0.06-3.19, P-for trend=0.67). While generally not statistically significant, PCB and HCB levels were inversely associated with risk of breast cancer in this highly exposed population. DDE, but not DDT, was positively associated with risk.     

Serum polychlorinated biphenyls, cytochrome P-450 1A1 polymorphisms, and risk of breast cancer in Connecticut women

Recent epidemiologic studies have suggested that genetic polymorphisms in the cytochrome P-450 1A1 gene (CYP1A1) may affect the relation between environmental exposure to polychlorinated biphenyls (PCBs) and breast cancer risk. The authors report results from a case-control study evaluating the potential effect of gene-environment interaction between CYP1A1 and serum PCB levels on breast cancer risk among Caucasian women in Connecticut. The study included 374 case women with histologically confirmed breast cancer and 406 noncancerous controls with information on both serum PCB level and CYP1A1 genotype (1999-2002). Compared with women who had the homozygous wild-type CYP1A1 m2 genotype, significantly increased risks of breast cancer were found for women with the CYP1A1 m2 variant genotype (odds ratio (OR) = 2.1, 95% confidence interval (CI): 1.1, 3.9), especially postmenopausal women (OR = 2.4, 95% CI: 1.1, 5.0). Risks associated with the CYP1A1 m2 variant genotype were highest for all women (OR = 3.6, 95% CI: 1.5, 8.2) and postmenopausal women (OR = 4.3, 95% CI: 1.6, 12.0) with higher serum PCB levels (611-2,600 ng/g). The CYP1A1 m1 and m4 genotypes were not associated with breast cancer risk independently or in combination with PCB exposure. In summary, the CYP1A1 m2 genetic polymorphism was associated with increased risk of female breast cancer and may modify the relation between PCB exposure and breast cancer risk.     

Occupational paternal exposure to benzene and risk of spontaneous abortion.

OBJECTIVE--The purpose of this study was to evaluate the risk of spontaneous abortion among the wives of male workers occupationally exposed to benzene. METHODS--The wives of 823 men working in two chemical plants at the time of the study were asked to complete a questionnaire describing their pregnancies. The analysis of the 1739 pregnancies that ended in a spontaneous abortion or a birth is presented. The firms' payroll records provided all workers' employment history, including dates. Benzene exposure, graded at two levels (< 5, > or = 5 ppm), was determined for every job, so that benzene exposure for each worker's entire professional life (at these companies) could be assessed. This information was linked to the dates of the pregnancies reported in the questionnaires to enable the exposure status of each pregnancy to be defined (1270 non-exposed and 274 exposed). The frequency of spontaneous abortion, defined as the number of spontaneous abortions divided by the total of spontaneous abortions and births was evaluated. RESULTS--When adjusted for tobacco consumption, mother's age and pregnancy order, the odds ratio of the association between paternal exposure to approximately 5 ppm of benzene and the risk of spontaneous abortion was close to and statistically not different from unity (OR = 1.1; 95% CI (0.7-1.8). CONCLUSION--In this study paternal exposure to benzene did not increase the risk of spontaneous abortion.     

南方女性复发性流产环境因素分析

目的:探讨南方女性不明原因复发性流产(undentifiedrecurrentspontaneousabortion,URSA)流行病学因素。方法:对326例URSA及400例正常对照育龄妇女进行健康问卷调查,用Logistic回归模型,纳入体重指数(BMI)、自然流产家族史、吸烟史、被动吸烟史、饮酒史、饮咖啡史,找出有独立意义的环境危险因素,并对自然流产次数3次及≥4次者进行分层分析。结果:吸烟史、饮酒史和饮咖啡史不是URSA的危险因素,短时间被动吸烟(1h/天)及长时间被动吸烟(≥1h/天)是URSA的危险因素,OR及95%CI分别是2.30,1.50～3.52及4.76,3.24～6.99。家族史及BMI≥24.0kg/m2是URSA危险因素,OR及95%CI分别是2.12,1.28～3.49及1.55,1.12～2.14。结论:被动吸烟史、BMI≥24.0kg/m2、自然流产家族史是中国南方女性URSA独立危险因素。     

Plasma levels of polychlorinated biphenyls (PCB) and the risk of soft tissue sarcoma

Background::Soft tissue sarcoma (STS) is a heterogeneous group of rare neoplasms whose aetiology is largely unknown. Dioxin and dioxin-like compounds, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and polychlorinated biphenyls (PCBs), are potential risk factors for STS.Objectives:To investigate the relation of 17 PCBs congeners, assessed in human plasma, with STS risk.Methods:We conducted a case-control study in Italy, including 52 STS cases and 99 hospital-based controls. Selected PCB were extracted by high-performance liquid chromatography (HPLC) and measured with gas chromatography-mass spectrometry (GC-MS). Odds ratios (OR), and the corresponding 95% confidence intervals (CI), were estimated through multivariate logistic regression models.Results:The most frequently detected PCB congeners were 138, 170, 180 and 149 (detected in 40-77% of controls). The OR for the sum of all 17 PCB congeners was 1.20 (95% CI 0.50-2.92). In categorical analysis no consistent association was found for individual congeners and for groups based on Wolff’s classification or the degree of chlorination. For continuous estimates, borderline positive associations emerged for Wolff’s groups 2A (OR 1.23, 95% CI 0.97-1.55), 2B (OR 1.34, 95% CI 1.00-1.77, and 3 (OR 1.19, 95% CI 0.96-1.49), for moderately (OR 1.20, 95% CI 0.96-1.51) and highly (OR 1.18, 95% CI 0.99-1.41) chlorinated PCBs, and for congeners 170 (OR 1.26, 95% CI 0.98-1.63), 180 (OR 1.26, 95% CI 0.97-1.64) and 138 (OR 1.45, 95% CI 1.02-2.04).Discussion:Most associations between PCBs and STS risk were not significant, but, given the limited sample size, we cannot exclude moderate associations.Key words: Soft tissue sarcoma, polychlorinated biphenyls, epidemiology, environmental risk factors, chemical contaminants, case-control study     

Relations of gestational length and timing and type of incomplete pregnancy to ovarian cancer risk

While the protective nature of parity with respect to ovarian cancer has been well documented, whether a history of incomplete pregnancy affects ovarian cancer risk is uncertain. Data collected from 739 epithelial ovarian cancer cases and 1,313 community controls in the Delaware Valley from 1994 to 1998 were used to evaluate the relation between gestational length and timing of first induced or spontaneous abortion and ovarian cancer risk. Incomplete pregnancy was not associated with ovarian cancer among nulliparous women or among ever-pregnant women either before or after adjustment for relevant confounders (for nulliparous women, odds ratio (OR) = 1.12, 95% confidence interval (CI): 0.66, 1.89; for ever-pregnant women, OR = 0.95, 95% CI: 0.76, 1.18). Among unigravid women, one full-term pregnancy was more protective than an incomplete pregnancy (adjusted OR = 0.29, 95% CI: 0.15, 0.57). These results were independent of the type of pregnancy loss. Among ever-pregnant women, a spontaneous abortion before a first birth provided significant protection (adjusted OR = 0.47, 95% CI: 0.30, 0.75), while no significant effect was found for an induced abortion prior to a first birth (adjusted OR = 0.80, 95% CI: 0.44, 1.47). These data do not support an independent association between incomplete pregnancies, either spontaneous or induced, and ovarian cancer risk.     

Non–Dioxin-Like Polychlorinated Biphenyls and Risk of Endometriosis

Background

Endometriosis, a gynecologic disorder affecting 8–10% of reproductive-age women in the United States, is defined as the presence of endometrial tissue outside the uterus and is linked to pelvic pain and infertility. Environmental contaminants, including polychlorinated biphenyls (PCBs), are hypothesized to contribute to endometriosis risk through effects on steroid hormones.

Objective

We evaluated serum concentrations of certain noncoplanar PCBs, which have no or only weak dioxin-like properties, as risk factors for endometriosis.

Methods

In a case–control study of Group Health enrollees in western Washington State, 20 PCB congeners were measured in serum from surgically confirmed endometriosis cases that were newly diagnosed between 1996 and 2001 (n = 251) and from female controls matched for age and reference year (n = 538).

Results

Summed and estrogenic PCB concentrations were not associated with endometriosis risk [summed: odds ratio (OR) = 1.3; 95% confidence interval (CI), 0.8–2.2; estrogenic: OR = 1.1; 95% CI, 0.8–1.4]. Although several congener-specific ORs were statistically above or below the null (PCB 170: third quartile vs. lowest: OR = 0.5; 95% CI, 0.3–0.9; PCB 196: third quartile vs. lowest: OR = 0.4; 95% CI, 0.2–0.7; PCB 201: second vs. lowest: OR = 0.5; 95% CI, 0.3–0.8; third quartile vs. lowest: OR = 0.4; 95% CI, 0.2–0.7), there were no overall consistent patterns of endometriosis risk.

Conclusions

Taken in context with other North American studies, our findings suggest that noncoplanar PCB concentrations consistent within the range of exposure currently observed in western Washington State do not contribute meaningfully to endometriosis risk.     

Hormonal Factors and Pancreatic Cancer in Women

PURPOSE: The aim of the study was to evaluate hormonal risk factors for carcinoma of the exocrine pancreas among postmenopausal women.

METHODS: Mailed questionnaire data from 52 cases and 233 population-based controls in Ontario were used to assess parity, age at first birth, and other hormonal factors on pancreatic cancer risk.

RESULTS: Reduced risk was seen with three or more pregnancies [adjusted odds ratio (OR) = 0.22, 95% confidence interval (CI) = 0.07–0.65] and use of oral contraceptives (adjusted OR = 0.36, 95% CI = 0.13–0.96), whereas no significant associations were found for age at menarche or menopause, or estrogen replacement therapy. Among parous women, later age at first full-term pregnancy significantly increased the risk of this cancer (adjusted OR = 4.05, 95% CI = 1.50–10.92 for ages 25–29 years, adjusted OR = 3.78, 95% CI = 1.02–14.06 for ages 30+ years).

CONCLUSIONS: Our data support the hypothesis that pancreatic cancer is, at least in part, an estrogen-dependent disease; there is growing epidemiological evidence that aspects of reproductive history and hormonal exposure are associated with risk of this disease.     

Maternal Exposure to a Brominated Flame Retardant and Genitourinary Conditions in Male Offspring

Background

The upward trend in industrial nations in the incidence of male genitourinary (GU) conditions may be attributed to increased exposure to endocrine disruptors. Polybrominated biphenyl (PBB), a brominated flame retardant, is one such suspected endocrine disruptor.

Objective

We investigated the relationship between maternal serum levels of PBBs and GU conditions among male offspring exposed in utero.

Methods

In this cohort study of sons born to women accidentally exposed to PBBs during 1973–1974, we examined self-reported data on GU conditions among male offspring in relation to maternal serum PBB levels. We used generalized estimating equations to calculate odds ratios (ORs), controlling for gestational age at birth.

Results

Of 464 sons, 33 reported any GU condition (13 hernias, 10 hydroceles, 9 cryptorchidism, 5 hypospadias, and 1 varicocele). Four reported both hernia and hydrocele, and one both hernia and cryptorchidism. After adjustment for gestational age at birth, sons of highly exposed women (> 5 ppb) were twice as likely to report any GU condition compared with sons of the least exposed women [≤1 ppb; OR = 2.0; 95% confidence interval (CI), 0.8–5.1]. This risk was increased when we excluded sons born after the exposure but before the mother’s serum PBB measurement (OR = 3.1; 95% CI, 1.0–9.1). We found evidence of a 3-fold increase in reported hernia or hydrocele among sons with higher PBB exposure (test of trend p-value = 0.04). Neither hypospadias nor cryptorchidism was individually associated with PBB exposure.

Conclusions

Although cryptorchidism and hypospadias were not associated with in utero PBB exposure, this study suggests that other GU conditions may be associated with exposure to endocrine-disrupting chemicals during development.