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Background: Although research suggests that type II diabetes mellitus (DM-2) is associated with overall and breast cancer-specific decreased survival, most prior studies of breast cancer survival investigated the effect of preexisting DM-2 without assessing the effect of DM-2 diagnosed at or after breast cancer diagnosis. This study examined the relationship between DM-2 diagnosed before and after breast cancer diagnosis and overall survival. Methods: This study uses linked Department of Defense cancer registry and medical claims data from 9,398 women diagnosed with breast cancer between 1998 and 2007. Cox proportional hazards models were used to assess the association between DM-2 and overall survival. Results: Our analyses showed that women with DM-2 diagnosed before breast cancer diagnosis tended to have a higher risk of mortality compared with women without diabetes [HR = 1.17; 95% confidence interval (CI), 0.95-1.44] after adjustment for potential confounders. Similarly, patients diagnosed with DM-2 at or after breast cancer diagnosis had increased mortality compared with women without DM-2 (HR = 1.39; 95% CI, 1.16-1.66). The similar tendency was also observed among most subgroups when results were stratified by race, menopausal status, obesity, tumor hormone receptor status, and stage. Conclusions: Using data from a health system that provides universal health care to its beneficiaries, this study showed an increased risk of death associated with DM-2, regardless of whether it was diagnosed before or at/after breast cancer diagnosis. Impact: These results suggest the potential effects of factors independent of the timing of DM-2 clinical diagnosis on the association of DM-2 with overall survival. Cancer Epidemiol Biomarkers Prev; 27(1); 50-57. ©2017 AACR ., (©2017 American Association for Cancer Research.)

Background: Postmastectomy breast reconstruction increased approximately 20% between 1998 and 2008 in the United States and has been found to improve body image, self-esteem, and quality of life. These procedures, however, tend to be less common among minority women, which may be due to variations in health care access. The Department of Defense provides equal health care access, thereby affording an exceptional environment in which to assess whether racial variations persist when access to care is equal., Methods: Linked Department of Defense cancer registry and medical claims data were used. The receipt of reconstruction was compared between white women (n = 2974) and black women (n = 708) who underwent mastectomies to treat incident histologically confirmed breast cancer diagnosed from 1998 through 2007., Results: During the study period, postmastectomy reconstruction increased among both black (27.3% to 40.0%) and white (21.8% to 40.6%) female patients with breast cancer. Receipt of reconstruction did not vary significantly by race (odds ratio, 0.93; 95% confidence interval, 0.76-1.15). Reconstruction decreased significantly with increasing age, tumor stage, and receipt of radiotherapy and was significantly more common in more recent years and among active service women, TRICARE Prime (health maintenance organization) beneficiaries, and women whose sponsor was an officer., Conclusions: The receipt of breast reconstruction did not vary by race within this equal-access health system, indicating that the racial disparities reported in previous studies may have been due in part to variations in access to health care. Additional research to determine why a large percentage of patients with breast cancer do not undergo reconstruction might be beneficial, particularly because these procedures have been associated with noncosmetic benefits., (Published 2014. This article is a U.S. Government work and is in the public domain in the USA.)

Background: Compared to non-inflammatory breast cancer (non-IBC), inflammatory breast cancer (IBC) has less favorable survival and is more likely to be estrogen receptor (ER) and progesterone receptor (PR) negative. ER-/PR- tumors, regardless of histology, have less favorable survival. While black women are more likely to have IBC and ER-/PR- tumors than white women, it is unclear whether the racial disparity in survival is explained by these factors. The objective of this study was to assess racial/ethnic differences in breast cancer survival by inflammatory status and hormone receptor status., Methods: This study examined breast cancer mortality among non-Hispanic white (NHW), Hispanic white, black, and Asian/Pacific Islander (API) women diagnosed between 1990 and 2004 using the National Cancer Institute's Surveillance, Epidemiology, and End Results data. Kaplan-Meier survival curves and Cox proportional hazard ratios (HRs) assessed the relationship between race/ethnicity and survival., Results: Black women had significantly poorer survival than NHW women regardless of inflammatory status and hormone receptor status. Compared to NHWs, the HRs for black women were 1.32 (95 % confidence interval (CI) 1.21-1.44), 1.43 (95 % CI 1.20-1.69), and 1.30 (95 % CI 1.16-1.47) for IBC, IBC with ER+/PR+, and with ER-/PR-, respectively. Similar HRs were found for non-IBC, non-IBC with ER+/PR-, and non-IBC with ER-/PR-. API women had significantly better survival than NHW women regardless of inflammatory status and hormone receptor status., Conclusion: Compared to NHW women, black women had poorer survival regardless of inflammatory status and hormone receptor status and API women had better survival. These results suggest that factors other than inflammatory status and hormone receptor status may play a role in racial/ethnic disparities in breast cancer survival.

Background: Annual surveillance mammography is recommended after a diagnosis of breast cancer. Previous studies have suggested that surveillance mammography varies by demographics and initial tumor characteristics, which are related to an individual's access to health care. The Military Health System of the Department of Defense provides beneficiaries with equal access health care and thus offers an excellent opportunity to assess whether racial differences in surveillance mammography persist when access to care is equal., Methods: Among female beneficiaries with a history of breast cancer, logistic regression was used to assess racial/ethnic variations in the use of surveillance mammography during 3 periods of 12 months each, beginning 1 year after diagnosis adjusting for demographic, tumor, and health characteristics., Results: The rate of overall surveillance mammography decreased from 70% during the first year to 59% during the third year (P < .01). Although there was an overall tendency for surveillance mammography to be higher among minority women compared with non-Hispanic white women, after adjusting for covariates, the difference was found to be significant only during the first year among black women (odds ratio [OR], 1.46; 95% confidence interval [95% CI], 1.10-1.95) and the second year among Asian/Pacific Islander (OR, 2.29; 95%CI, 1.52-3.44) and Hispanic (OR, 1.92; 95%CI, 1.17-3.18) women. When stratified by age at diagnosis and type of breast cancer surgery performed, significant racial differences tended to be observed among younger women (aged < 50 years) and only among women who had undergone mastectomies., Conclusions: Minority women were equally or more likely than non-Hispanic white women to receive surveillance mammography within the Military Health System. The racial disparities in surveillance mammography reported in other studies were not observed in a system with equal access to health care., (Copyright © 2013 American Cancer Society.)

Background: Studies on the effect of comorbidities on breast cancer operation have been limited and inconsistent. This study investigated whether pre-existing comorbidities influenced breast cancer surgical operation in an equal access health care system., Methods: This study was based on linked Department of Defense cancer registry and medical claims data. The study subjects were patients diagnosed with stage I to III breast cancer during 2001 to 2007. Logistic regression was used to determine if comorbidity was associated with operation type and time between diagnosis and operation., Results: Breast cancer patients with comorbidities were more likely to receive mastectomy (odds ratio [OR] = 1.27; 95% confidence interval [CI], 1.14 to 1.42) than breast conserving surgery plus radiation. Patients with comorbidities were also more likely to delay having operation than those without comorbidities (OR = 1.27; 95% CI, 1.14 to 1.41)., Conclusions: In an equal access health care system, comorbidity was associated with having a mastectomy and with a delay in undergoing operation., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: Although the overall age-adjusted incidence rates for female breast cancer are higher among whites than blacks, mortality rates are higher among blacks. Many attribute this discrepancy to disparities in health care access and to blacks presenting with later stage disease. Within the Department of Defense (DoD) Military Health System, all beneficiaries have equal access to health care. The aim of this study was to determine whether female breast cancer treatment varied between white and black patients in the DoD system., Methods: The study data were drawn from the DoD cancer registry and medical claims databases. Study subjects included 2308 white and 391 black women diagnosed with breast cancer between 1998 and 2000. Multivariate logistic regression analyses that controlled for demographic factors, tumor characteristics, and comorbidities were used to assess racial differences in the receipt of surgery, chemotherapy, and hormonal therapy., Results: There was no significant difference in surgery type, particularly when mastectomy was compared with breast-conserving surgery plus radiation (blacks vs whites: odds ratio [OR], 1.1; 95% confidence interval [CI], 0.8-1.5). Among those with local stage tumors, blacks were as likely as whites to receive chemotherapy (OR, 1.2; 95% CI, 0.9-1.7) and hormonal therapy (OR, 1.0; 95% CI, 0.6-1.4). Among those with regional stage tumors, blacks were significantly less likely than whites to receive chemotherapy (OR, 0.4; 95% CI, 0.2-0.7) and hormonal therapy (OR, 0.5; 95% CI, 0.3-0.8)., Conclusions: Even within an equal access health care system, stage-related racial variations in breast cancer treatment are evident. Studies that identify driving factors behind these within-stage racial disparities are warranted., (Copyright © 2011 American Cancer Society.)

Background: We investigated risk factor patterns for subtypes of breast cancer characterized by joint estrogen receptor (ER) and progesterone receptor (PR) status in a hospital-based case-control study., Methods: ER and PR tumor status were determined immunohisotchemically. Risk factors of interest were entered into a multiple polychotomous logistic regression model simultaneously; odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Using this model, cases in the four tumor subtypes (ER+PR+, ER-PR-, ER+PR-, ER-PR+) were compared simultaneously to controls. A Wald test for heterogeneity across the four subtypes was conducted, as well as a case-case comparison between the two most biologically disparate subtypes, ER+PR+ and ER-PR-., Results: The receptor status distribution was as follows: 33% ER+PR+, 34% ER-PR-, 20% ER+PR-, and 13% ER-PR+. Among 317 cases and 401 controls, we found significant heterogeneity across the four tumor subtypes for older age at first full-term pregnancy (p=0.04) and post-menopausal status (p=0.04). For older age at first full-term pregnancy, an elevated risk was found for the ER+PR- subtype (OR=2.5; 95% CI: 1.2-5.1). For post-menopausal status, elevated risks were found for both the ER+PR+ (OR=2.4; 95% CI: 1.1-4.9) and ER+PR- (OR=7.2; 95% CI: 2.4-21.7) subtypes. From the case-case comparisons, we found that cases, who had consumed alcohol for more than 1 year were 3.4 times more likely to have ER+PR+ tumors than ER-PR- tumors (95% CI: 1.4-8.4)., Conclusions: Certain breast cancer risk factors may vary by ER and PR status, and joint ER/PR status should be taken into account in future studies of risk factor estimates.

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.

Studies have suggested that breast cancer risk factor profiles may vary according to joint estrogen receptor (ER) and progesterone receptor (PR) tumor status. Most of the published literature to date which has investigated the association between exposure to organochlorine compounds and breast cancer has reported null or weak associations. If, indeed, the classification by hormonal receptor status identifies different forms of breast cancer, then assessing the risk of exposure to polychlorinated biphenyls (PCBs) on breast cancer as one disease or stratifying based on ER or PR status alone may obscure the association between PCBs and breast cancer. A hospital-based case-control study of 266 cases and 347 benign breast disease controls was conducted to examine the association of blood serum and adipose tissue concentrations of PCBs with breast cancer by joint ER/PR status. Total PCBs were measured in blood serum, and the following PCB congeners were measured in breast adipose tissue: 74, 118, 138, 153, 156, 170, 180, 183, 187. We did not detect any clear relationship or change in breast cancer risk based on joint ER/PR tumor status for body burden of PCBs, whether measured in blood serum or breast adipose tissue, by total PCBs or for specific congeners. These results confirm previous findings in the literature of no positive association between environmental exposure to PCBs and risk of breast cancer.

Alcohol consumption has been inconsistently associated with breast cancer risk. Recent studies suggest that genetic polymorphisms of glutathione S-transferases (GSTs) may modify this relation. To determine if breast cancer risk is associated with GSTM1 and GSTT1 genetic polymorphisms, and to evaluate the effect modification between GST genotypes and alcohol consumption in the risk of breast cancer, we conducted a case-control study in the state of Connecticut in the period 1998 and 2001. Cases were histologically confirmed, incident breast cancer patients in New Haven County, CT. Controls were randomly selected from women histologically confirmed to be without breast cancer. The study results show that, while GSTM1 genotypes were not associated with breast cancer risk, GSTT1-null genotype was associated with a significant 90% increased risk for postmenopausal women (OR=1.9, 95% CI 1.2-3.0). Analysis by GST genotypes and alcohol consumption shows that GSTM1A ever-drinking women had a 2.5-fold (OR=2.5, 95% CI 1.1-5.5) increased risk of breast cancer compared to the GSTM1A never-drinkers, and the risk increases with duration and daily amount of alcohol consumption. Postmenopausal women with GSTT1-null genotype, who consumed a lifetime of >250 kg of spirit-equivalents, had an almost seven-fold increased risk (OR=6.8, 95% CI 1.4-33.9), and drinking commencing at younger ages appears to carry a higher risk. An OR of 8.2 (95% CI 1.2-57.4) was observed for those with GSTM1A, and GSTT1-null genotypes who had consumed a lifetime of >250 kg of spirit-equivalents. In conclusion, alcohol consumption may increase breast cancer risk among those who carry susceptible GST genotypes.

Objective: It has been suggested that functional polymorphisms in genes encoding tobacco carcinogen-metabolizing enzymes may modify the relationship between tobacco smoking and breast cancer risk. We sought to determine if there is a gene-environment interaction between GSTM I (GSTM1A and GSTM1B), and GSTT1 genotypes and cigarette smoking in the risk of breast cancer., Methods: Cases and controls were recruited in a case-control study conducted in Connecticut from 1994 to 1998. Cases were histologically confirmed, incident breast cancer patients, and controls were randomly selected from women histologically confirmed to be without breast cancer. A total of 338 cases and 345 controls were genotyped for GSTM1 and GSTT1 ., Results: None of the GSTM 1 genotypes, either alone or in combination with cigarette smoking, was associated with breast cancer risk. There was, however, a significantly increased risk of breast cancer among postmenopausal women with a GSTTI null genotype (OR= 1.9, 95% CI 1.2-2.9). There were also indications of increased risk of breast cancer associated with cigarette smoking for postmenopausal women with GSTT1-null genotype, especially for those who commenced smoking before age 18 (OR = 2.9, 95% CI 1.0-8.8)., Conclusion: Women with a GSTT1-null genotype may have an increased breast cancer risk, especially postmenopausal women who started smoking at younger ages.

This case-control study was designed to test the hypothesis that the risk of breast cancer varies by type and colour of the hair colouring products used. A total of 608 cases and 609 controls were included in the study. We found no increased risk associated with the overall use of hair dye products or exclusive use of permanent or temporary types of hair dye products. Among those who reported to have exclusively used semi-permanent types of hair colouring products, some of the ORs were elevated. However, none of the ORs related to age at first use, duration of use, total number of applications, and years since first use, was statistically significant. There was also no increased risk of breast cancer associated with exclusive use of dark or light hair colouring products, or use of mixed types or colours of hair dye products. We also found no increased risk of breast cancer associated with hair dye use based on an individual's reason for using a hair colouring product, such as to cover grey or to change natural hair colour. These data suggest that the use of hair colouring products does not have a major impact on the risk of breast cancer.

In this report, we examined the relationship between lactation and breast cancer risk, in a case-control study of breast cancer, conducted in Connecticut between 1994 and 1998. Included were 608 incident breast cancer cases and 609 age frequency matched controls, aged 30-80 years old. Cases and controls were interviewed by trained study interviewers, using a standardized, structured questionnaire, to obtain information on lactation and other major risk factors. Parous women who reported ever lactation had a borderline significantly reduced risk of breast cancer (OR = 0.83, 95% CI, 0.63-1.09). An OR of 0.53 (95% CI, 0.27-1.04) was observed in those having breastfed more than 3 children compared to those who never lactated. Women having breastfed their first child for more than 13 months had an OR of 0.47 (95% CI, 0.23-0.94) compared to those who never breastfed. Lifetime duration of lactation also showed a risk reduction while none of the ORs were statistically significant. Further stratification by menopausal status showed a risk reduction related to lactation for both pre- and postmenopausal women, while the relationship is less consistent for the latter. These results support an inverse association between breastfeeding and breast cancer risk., (Copyright 2001 Cancer Research Campaign.)

Background: Polychlorinated biphenyls (PCB) have been a major environmental health concern because of their wide distribution and persistence in the environment. Estimating joint effects of all congeners in a single analysis is complicated by correlation among exposure levels, and the resulting collinearity makes the results difficult to interpret., Methods: Patients with breast-related surgery at Yale-New Haven Hospital were interviewed using a standardized questionnaire, and breast adipose tissue samples were analysed for nine PCB congeners (74, 118, 138, 153, 156, 170, 180, 183, 187). The study recruited 490 women (304 cases and 186 controls) between 1994 and 1997. Logistic ridge regression was used to analyse the instability caused by collinearity., Results: Although total PCB did not appear to be associated with breast cancer risk, significant differences in effect were observed among the nine congeners. Logistic ridge regression demonstrated a protective effect on breast cancer risk for a potentially anti-oestrogenic and dioxin-like congener, 156, while two phenobarbital, CYP1A and CYP2B inducers had an adverse effect, 180 and 183. This analysis also suggested that a protective effect for another phenobarbital congener, 153, was largely explained by instability caused by collinearity., Conclusions: These results indicate that studies of PCB congeners and health require an in-depth statistical analysis in order to better understand the complex issues related to their collinearity.

Experimental studies show that hormonal and nonhormonal activities of polychlorinated biphenyls (PCBs) are structure dependent, suggesting that the breast cancer risk associated with PCBs may vary according to specific PCB congeners. In 1994-1997, the authors conducted a case-control study of Connecticut women to investigate whether breast cancer risk is associated with body burden of PCBs and varies by PCB congeners. A total of 304 breast cancer cases and 186 controls aged 40-79 years were recruited into the study. Fresh breast adipose tissue was analyzed for PCBs. The age- and lipid-adjusted geometric mean tissue levels of total PCBs were not significantly different (p = 0.46) for the cases (478.6 parts per billion) and controls (494.1 parts per billion). The covariate-adjusted odds ratio was 0.7 (95% confidence interval: 0.4, 1.1) for all study participants when the third tertile was compared with the lowest tertile. No individual congeners or groups of congeners were associated with a significantly increased risk of breast cancer. Further stratification by type of breast disease; menopausal, parity, and lactation status; and body size also showed no significant association with body levels of PCBs. These results suggest that environmental exposure to PCBs may not substantially affect breast cancer risk.

Exposure to electromagnetic fields (EMFs) from use of electric blankets and other in-home electrical appliances has been hypothesized to increase breast cancer risk. To test the hypothesis, the authors analyzed data from a case-control study of female breast cancer conducted in Connecticut in 1994-1997. A total of 608 incident breast cancer patients and 609 age frequency-matched controls, 31-85 years old, were interviewed by trained study interviewers using a standardized, structured questionnaire to obtain information on lifetime use of various in-home electrical appliances. A total of 40% of the cases and 43% of the controls reported regular use of electric blankets in their lifetime, which gave an adjusted odds ratio of 0.9 (95% confidence interval (CI): 0.7, 1.1). For those who reported using electric blankets continuously throughout the night, the adjusted odds ratio was 0.9 (95% CI: 0.7, 1.2) when compared with never users. The risk did not vary according to age at first use, duration of use, or menopausal and estrogen receptor status. The authors also did not find an association between use of other major in-home electrical appliances and breast cancer risk. In conclusion, exposure to EMFs from in-home electrical appliance use was not found to increase breast cancer risk in this study.

This case-control study was designed to investigate the relationship between polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2'-bis(p-chlorophenyl)ethylene (DDE) and breast cancer risk in Connecticut. Cases were incident breast cancer patients who were either residents of Tolland County or who had a breast-related surgery at the Yale-New Haven Hospital in New Haven County. Controls were randomly selected from Tolland County residents or from patients who had newly diagnosed benign breast diseases or normal tissue at Yale-New Haven Hospital. A total of 475 cases and 502 controls had their serum samples analyzed for PCBs and DDE in 1995-1997. The age- and lipid-adjusted geometric mean serum level of DDE was comparable between the cases (460.1 ppb) and controls (456.2 ppb). The geometric mean serum level of PCBs was also comparable between cases (733.1 ppb) and controls (747.6 ppb). After adjustment for confounding factors, odds ratios of 0.96 (95% confidence interval, 0.67-1.36) for DDE and 0.95 (95% confidence interval, 0.68-1.32) for PCBs were observed when the third tertile was compared with the lowest. Further stratification by parity, lactation, and menopausal and estrogen receptor status also showed no significant association with serum levels of DDE or PCBs. The results by PCB congener groups also showed no major increased risk associated with any of the congener groups. Our study does not support the hypothesis that DDE and PCBs, as encountered through environmental exposure, increase the risk of female breast cancer.

Background: Organochlorine compounds, including organochlorine pesticides, have been suggested by some, but not all, studies to be associated with female breast-cancer risk. So far, studies relating organochlorine compounds and breast-cancer risk have mainly focused on polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) as risk factors for female breast cancer. This paper examines the hypothesis that environmental exposure to trans-nonachlor (TNC) and oxychlordane (OCD), a major metabolite of the insecticide chlordane, increases the, Methods: A total of 304 histologically confirmed, incident primary breast-cancer patients and 186 histologically confirmed incident benign breast-disease controls were included in the study between 1994 and 1997. Breast adipose tissue not needed for diagnostic purposes was collected and analysed for TNC, OCD and other organochlorine compounds. A standardised, structured questionnaire was used to obtain information on major known, or suspected, risk factors for breast cancer., Results: The age and lipid-adjusted geometric mean adipose-tissue levels of OCD were similar between the cases [36.4 p.p.b., 95% confidence interval (CI) 34.7-38.2 p.p.b.] and controls (38.0 p.p.b., 95% Cl 35.7-40.6 p.p.b.). The age and lipid-adjusted geometric mean adipose-tissue levels of TNC between the cases (55.5 p.p.b., 95% CI 52.6-58.5 p.p.b.) and controls (58.1 p.p.b., 95% CI 54.2-62.3 p.p.b.) were also similar. There was no association between breast-cancer risk and mean adipose-tissue levels of OCD and TNC. The covariate-adjusted odds ratio (OR) was 0.7 (95% CI 0.4-1.3) for OCD and 1.1 (95% CI 0.6-1.9) for TNC, when the highest quartile was compared with the lowest. The risk also did not vary based on oestrogen or progesterone receptor status or menopausal status., Discussion: We found no significantly increased risk of breast cancer associated with breast adipose-tissue levels of OCD or TNC; this is consistent with recent epidemiological studies, indicating that environmental exposure to organochlorine compounds does not have an overall significant impact on breast-cancer risk.

A case-control study was conducted in Connecticut from 1994 to 1997 to investigate the relation between dichlorodiphenyldichloroethane (DDE) and dichlorodiphenyltrichloroethane (DDT) exposure and breast cancer risk. Cases and controls were women aged 40-79 years, who had breast-related surgery at the Yale-New Haven Hospital and from whose surgical specimen the authors could obtain at least 0.4 g of breast adipose tissue for chemical analyses. A total of 304 incident breast cancer cases (including 62 in situ carcinomas) and 186 benign breast disease controls were recruited into the study. Tissue levels of DDE and DDT were measured using gas chromatography. Statistical significance for comparisons of mean levels of DDE and DDT was calculated using analysis of variance and rank sum tests. A logistic regression model was used to estimate the association and to control confounding. The age-adjusted geometric mean tissue level of DDE for cases (736.5 ppb) was similar to that for the controls (784.1 ppb). DDT levels were also similar for cases (51.8 ppb) and controls (55.6 ppb). The adjusted odds ratio is 0.9 (95% confidence interval: 0.5, 1.5) for DDE and 0.8 (95% confidence interval: 0.5, 1.5) for DDT when the highest quartile was compared with the lowest. These results do not support an association between adipose tissue levels of DDE and DDT and breast cancer risk.

Background: Epidemiologic studies have recently related benzene hexachloride (BHC) to breast carcinoma risk. Experimental studies have also shown that beta-BHC is weakly estrogenic, hence supporting the alleged association. By directly comparing beta-BHC levels in breast adipose tissue from incident breast carcinoma cases and controls, this study examined the hypothesis that exposure to beta-BHC increases the risk of breast carcinoma in females., Methods: A total of 490 Connecticut women (304 cases and 186 controls) were enrolled in the study during the period 1994-1997. Cases were patients ages 40-79 years with histologically confirmed incident primary breast carcinoma. Controls were patients with histologically confirmed incident benign breast disease. Breast adipose tissue was collected and analyzed for BHC isomers. A linear logistic regression model was used to adjust for potential confounders in estimating the association of exposure with disease., Results: No significant differences in breast adipose tissue levels of beta-BHC were observed between the cases and their controls overall, nor by menopausal status or estrogen and progesterone receptor status of the breast carcinoma cases. A nonsignificant reduced risk was observed among all subjects and among pre- and postmenopausal women when the highest quartile was compared with the lowest. Parous women with higher beta-BHC levels, regardless of lactation status, had a nonsignificantly reduced breast carcinoma risk, whereas a nonsignificantly increased risk was observed among nulliparous women with higher beta-BHC levels, based on very few study subjects., Conclusions: The results of this study do not support the hypothesis that increasing adipose tissue levels of beta-BHC are associated with an increased risk of breast carcinoma in females.

Earlier studies have provided inconclusive results relating hexachlorobenzene (HCB), an organochlorine fungicide, to female breast cancer risk. The current study, with a total of 304 breast cancer cases and 186 controls recruited in Connecticut between 1994 and 1997, examined the association by directly comparing breast adipose tissue levels of HCB between incident breast cancer cases and noncancer controls. The cases and controls were patients who had breast biopsies or surgery at the Yale-New Haven Hospital (New Haven, CT) and histologically diagnosed either as breast cancer or benign breast disease. Information on major known or suspected risk factors for breast cancer was obtained through in-person interview by trained interviewers. No significant difference in mean breast adipose tissue levels of HCB was observed between breast cancer patients (21.0 ppb) and controls (19.1 ppb) in this large case-control study. The risk also did not vary significantly by menopausal status, estrogen or progesterone receptor status of the breast cancer cases, breast cancer histology, stage of diagnosis, or type of benign breast disease. Among parous women who reported ever breast feeding, an odds ratio (OR) of 0.5 [95% confidence interval (CI), 0.2-1.4] was observed when the highest quartile was compared with the lowest quartile. However, no association was observed among parous women who reported never breast feeding (OR = 0.7; 95% CI, 0.3-1.7 for the fourth quartile). For nulliparous women, the adjusted OR was 2.1 (95% CI, 0.5-8.8) for the third tertile when compared with the lowest based on few subjects. Therefore, our study does not support a positive association between environmental exposure to HCB and risk of breast cancer.

Studies of the association between physical activity and breast cancer have yielded inconsistent findings. These findings may be related to a true null association or an inability to measure physical activity with enough precision to measure a protective relation. The authors reviewed and critiqued physical activity measurement methods used in published studies of the association between physical activity and breast cancer. The authors examined the quality of physical activity measures in 20 published studies. A summary score was created to rank the quality of the activity score. Studies with higher scores had a more precise measure of physical activity. Physical activity measurement methods were different in each study. Activity was measured by job classification, occupational tasks, participation in competitive athletics, and recreational and leisure-time pursuits. The recall period for physical activity ranged from a lifetime to the past year. Comparison of quality scores showed no associations between the precision of activity measures and the study results. Future studies of physical activity and breast cancer should utilize standardized methods to measure physical activity. Researchers should be encouraged to choose a measure based on hypotheses regarding physical activity and breast cancer mechanisms. Studies also should extend to subgroups of women with differences in other breast cancer risk factors, such as body mass, menopausal status, and hormone replacement status.

We conducted a nested case-control study with 1,925 women enrolled in a polybrominated biphenyl (PBB) registry to examine the association between breast cancer and serum PBBs. Twenty women who developed breast cancer were matched to 290 control subjects on sex, race, and age. Women with serum PBB levels of 2.0-3.0 parts per billion (ppb) [odds ratio (OR) = 3.5; 95% confidence interval (CI) = 0.9-13] or 4.0 ppb or greater (OR = 3.1; 95% CI = 0.8-12) had a higher estimated risk for breast cancer than women with less than 2.0 ppb. The odds ratios were unchanged when available breast cancer risk factors were included in the analysis.

Occupational cancer mortality was evaluated among approximately three million female pensioners from urban areas of the former USSR. In 1970, these women experienced 14,918 cancer deaths. Occupational data were obtained from death certificates and the 1970 USSR National Population Census. Thirty-five occupational groups, including nine predominantly professional or office-work groups and 26 groups involving physical labor, were evaluated. The expected mortality rates were based on the urban female population of the USSR in 1970. Data for all cancer sites combined, and cancers of the esophagus, stomach, colon, rectum, lung, breast, cervix, and hematopoietic system are presented. Among all female pensioners, there were significant increases of all cancers combined (rate ratio [RR] = 1.05), and cancers of the breast (RR = 1.3), cervix (RR = 1.3), and the hematopoietic system (RR = 1.2), and a significant deficit of cancer of the esophagus (RR = 0.8). Many well-established associations between cancer and occupation among men were observed among the study group of female pensioners, such as stomach and lung cancer among miners, and hematopoietic malignancies among scientists and physicians. Other associations, to be investigated further, also were observed, such as excess lung cancer among waitresses. The peak employment period for this cohort of women was during World War II and the postwar period, when Soviet women outnumbered men almost two-to-one. Consequently, many of the women held jobs that are typically held by men. Thus, this study provides valuable information on occupational risks to women that may be relevant in other countries where women increasingly are being employed in jobs traditionally held by men.