Supplemental B-Vitamins and Risk of Upper Gastrointestinal Cancers in the Women's Health Initiative.

B-vitamins contribute to DNA synthesis, maintenance, and regulation. Few studies have examined associations of supplemental sources of B-vitamins with the incidence of upper gastrointestinal (GI) cancers [including gastric (GCA) and esophageal (ECA) cancers]; the only prior study to comprehensively examine such intakes reported potential elevated risks of ECA. We examined 159,401 postmenopausal women, ages 50-79 years at baseline, including 302 incident GCA and 183 incident ECA cases, over 19 years of follow-up within the Women's Health Initiative observational study and clinic trials. Adjusted Cox regression models estimated hazard ratios (HR) and 95% confidence intervals (CI) for associations of supplemental B-vitamins [riboflavin (B2), pyridoxine (B6), folic acid (B9), or cobalamin (B12)] with GCA and ECA risk, respectively. Although HRs were generally below 1.0, we observed no statistically significant associations between supplemental intakes of any of the evaluated B-vitamins with the risk of GCA or ECA. As the first prospective study to comprehensively assess these associations, our findings do not corroborate prior research indicating potential harm from supplemental B-vitamin intake for upper GI cancer risk. This study adds evidence that supplemental intakes of B-vitamins may be used by postmenopausal women without regard to their relationship with upper GI cancer risk.

Lifestyle and Cardiovascular Risk Factors Associated With Heart Failure Subtypes in Postmenopausal Breast Cancer Survivors.

Background: Breast cancer (BC) survivors experience an increased burden of long-term comorbidities, including heart failure (HF). However, there is limited understanding of the risk for the development of HF subtypes, such as HF with preserved ejection fraction (HFpEF), in BC survivors. Objectives: This study sought to estimate the incidence of HFpEF and HF with reduced ejection fraction (HFrEF) in postmenopausal BC survivors and to identify lifestyle and cardiovascular risk factors associated with HF subtypes. Methods: Within the Women's Health Initiative, participants with an adjudicated diagnosis of invasive BC were followed to determine the incidence of hospitalized HF, for which adjudication procedures determined left ventricular ejection fraction. We calculated cumulative incidences of HF, HFpEF, and HFrEF. We estimated HRs for risk factors in relation to HF, HFpEF, and HFrEF using Cox proportional hazards survival models. Results: In 2,272 BC survivors (28.6% Black and 64.9% White), the cumulative incidences of hospitalized HFpEF and HFrEF were 6.68% and 3.96%, respectively, over a median of 7.2 years (IQR: 3.6-12.3 years). For HFpEF, prior myocardial infarction (HR: 2.83; 95% CI: 1.28-6.28), greater waist circumference (HR: 1.99; 95% CI: 1.14-3.49), and smoking history (HR: 1.65; 95% CI: 1.01-2.67) were the strongest risk factors in multivariable models. With the exception of waist circumference, similar patterns were observed for HFrEF, although none were significant. In relation to those without HF, the risk of overall mortality in BC survivors with hospitalized HFpEF was 5.65 (95% CI: 4.11-7.76), and in those with hospitalized HFrEF, it was 3.77 (95% CI: 2.51-5.66). Conclusions: In this population of older, racially diverse BC survivors, the incidence of HFpEF, as defined by HF hospitalizations, was higher than HFrEF. HF was also associated with an increased mortality risk. Risk factors for HF were largely similar to the general population with the exception of prior myocardial infarction for HFpEF. Notably, both waist circumference and smoking represent potentially modifiable factors.

The association of delay in curative intent treatment with survival among breast cancer patients: findings from the Women's Health Initiative.

PURPOSE: Delays in adjuvant breast cancer (BC) therapy have been shown to worsen outcomes. However, thus far studies have only evaluated delays to initial treatment, or a particular modality, such as chemotherapy, leaving uncertainty about the role of delay to subsequent therapy and the effects of cumulative delay, on outcomes. We investigated the associations of delays across treatment modalities with survival. METHODS: We included 3368 women with incident stage I-III BC in the Women's Health Initiative (WHI) enrolled in fee-for-service Medicare who underwent definitive surgery. This prospective analysis characterized treatment delays by linking WHI study records to Medicare claims. Delays were defined as > 8 weeks to surgery, chemotherapy, and radiation from diagnosis or prior treatment. We used Cox proportional hazards models to estimate BC-specific mortality (BCSM) and all-cause mortality (ACM) in relation to treatment delays. RESULTS: We found 21.8% of women experienced delay to at least one therapy modality. In adjusted analysis, delay to chemotherapy was associated with a higher risk of BCSM (HR = 1.71; 95% CI 1.07-2.75) and ACM (HR = 1.39; 95% CI 1.02-1.90); delay in radiation increased BCSM risk (HR = 1.49; 95% CI 1.00-2.21) but not ACM risk (HR = 1.19; 95% CI 0.99-1.42). Delays across multiple treatment modalities increased BCSM risk threefold (95% CI 1.51-6.12) and ACM risk 2.3-fold (95% CI 1.50-3.50). CONCLUSIONS: A delay to a single treatment modality and delay to a greater extent an accumulation of delays were associated with higher BCSM and ACM after BC. Timely care throughout the continuum of breast cancer treatment is important for optimal outcomes.

Trajectory of recurrent falls in post-menopausal breast cancer survivors and in matched cancer-free controls.

PURPOSE: Cross-sectional studies suggest that falls are prevalent among older breast cancer survivors. However, fall risk in this population has not been comprehensively examined. Therefore, we compared fall risk in older women post-breast cancer diagnosis to fall risk before cancer diagnosis and to risk in cancer-free matched controls. METHODS: Among 2019 women in the Women's Health Initiative with localized breast cancer diagnosed at age ≥ 60 years with fall assessment data for 3 years pre-diagnosis and 3 years post-diagnosis, recurrent fall risk post-diagnosis was compared to risk in 2019 cancer-free controls matched by age, year of WHI entry, and baseline fall frequency. Generalized estimating equations under a logistic regression model were used to compare fall recurrence in breast cancer survivors and controls. Multi-variable models were adjusted for the matching factors, race/ethnicity, body mass index, and multiple chronic conditions. RESULTS: In breast cancer survivors aged 70.8 years (mean) at diagnosis, over the 3-year pre-diagnosis interval, recurrent falls were reported by 18.5%. Over the 3-year post-diagnosis interval, recurrent falls were reported by 21.8% of breast cancer survivors and 20.0% of controls over the same time period (P = 0.27). Recurrent fall risk did not differ between breast cancer survivors and control women (OR 1.07, 95% CI 0.92-1.25), even after multi-variable adjustment. CONCLUSIONS: In contrast to prior reports, older breast cancer survivors were not more likely to experience recurrent falls than age-matched counterparts. These findings underscore the need for incorporation of cancer-free control populations in survivorship studies to distinguish cancer sequelae from processes related to aging.

Supplemental one-carbon metabolism related B vitamins and lung cancer risk in the Women's Health Initiative.

We and others have reported associations between B vitamins principally involved in one-carbon metabolism and increased lung cancer risk; however, results for women have been inconsistent. Here we report on the association of supplemental vitamins B6 , folic acid and B12 intake and lung cancer risk using data from the Women's Health Initiative (WHI) study of postmenopausal women. Between 1993 and 1998, 161,808 women were recruited to participate in the WHI at 40 clinical centers in the US. After exclusions, 159,232 women were available for analysis and followed prospectively for an average of 18.3 years. Among them, 3,836 incident lung cancer cases were diagnosed. At baseline, supplemental B vitamins from multivitamins, vitamin mixtures and individual supplements were assessed. Adjusted Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations between supplemental B vitamin intake and lung cancer risk. Relative to no intake, women who took ≥50 mg/day of vitamin B6 had 16% (HR 0.84, 95% CI: 0.71-0.99) reduced lung cancer risk. Associations did not differ significantly by smoking status or lung cancer histology. Intakes of folic acid and vitamin B12 were not associated with risk. There is a need for replication of our findings from other large, prospective studies with similar high-quality measurement of supplement intakes before any recommendations can be made at present on B6 supplementation for lung cancer prevention in women.

Pre-Diagnosis Exercise and Cardiovascular Events in Primary Breast Cancer: Women's Health Initiative.

OBJECTIVES: The purpose of this study was to investigate whether pre-diagnosis exercise reduces the risk of subsequent cardiovascular events (CVEs) in women with primary breast cancer. BACKGROUND: Cardiovascular disease (CVD) is the leading nonmalignant cause of death in patients with cancer, and it is the leading cause of death in women with primary breast cancer who are older than 65 years of age. METHODS: Using a prospective design, 4,015 patients with confirmed diagnosis of primary breast cancer enrolled in the Women's Health Initiative (WHI) completed a self-report questionnaire assessing leisure-time physical activity (i.e., exercise) in metabolic equivalent task (MET) hours per week. Age- and multivariable-adjusted Cox proportional hazards models were used to estimate associations between pre-diagnosis exercise and new-onset CVEs (i.e., heart failure [HF], myocardial infarction [MI], angina, coronary revascularization, peripheral arterial disease [PAD], carotid artery disease, transient ischemic attack [TIA], stroke, and cardiovascular death). RESULTS: Median follow-up was 12.7 years and 8.2 years for cardiovascular disease (CVD) mortality and CVEs, respectively, with 324 CVEs, including 89 MIs, 49 new diagnoses of HF, and 215 CVD deaths. In multivariable analysis, the incidence of composite CVEs decreased across increasing total MET h/week categories (p = 0.016). Compared with <2.5 MET-hours per week, the adjusted hazard ratio (HR) was 0.80 (95% confidence interval [CI]: 0.59 to 1.09) for 2.5 to <8.6 MET h/week; 0.9 (95% CI: 0.64 to 1.17) for 8.6 to <18 MET h/week; and 0.63 (95% CI: 0.45 to 0.88) for ≥18 MET h/week. CONCLUSION: Pre-diagnosis exercise exposure is associated with a significant graded reduction in subsequent CVEs in long-term survivors of primary breast cancer.

An analysis of the association between statin use and risk of endometrial and ovarian cancers in the Women's Health Initiative.

BACKGROUND: Statins have anti proliferative activity in vitro against endometrial and ovarian cancer and can affect levels of reproductive hormones. We analyzed data from the Women's Health Initiative (WHI) to assess whether statins are associated with risk of endometrial and ovarian cancer. METHODS: The WHI study included 161,808 postmenopausal women in which incident cases of endometrial (n = 1377) and ovarian cancer (n = 763) were identified over an average of 10.8 (SD + 3.3) years. Information on statin use and risk factors was collected at baseline and follow-up. Cox proportional hazards regression was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for the association of statin use and risk of endometrial and ovarian cancer. All statistical tests were two-sided. RESULTS: Statins were used at baseline by 7.5% women and by up to 25% at year nine. The multivariable adjusted HR for risk of endometrial cancer for baseline statin use was 0.74, 95% C.I. 0.59-0.94 and for ovarian cancer was 1.15, 95% C.I. 0.89-1.50. In time-dependent models, statins were not associated with endometrial cancer (HR 0.91, 95% C.I. 0.76-1.08) however there was an increased risk of ovarian cancer (HR 1.30, 95% CI 1.04-1.62), largely attributed to the effect of the hydrophilic statin, pravastatin (1.89, 95% CI 1.24-2.88). CONCLUSIONS: There was a reduction in risk of endometrial cancer among statin users at baseline but not in time-dependent models. Pravastatin use was associated with an increased risk of ovarian cancer. Analyses of larger numbers of cases are needed to evaluate these findings.

The Women's Health Initiative (WHI) Life and Longevity After Cancer (LILAC) Study: Description and Baseline Characteristics of Participants.

Background: The Women's Health Initiative (WHI) Life and Longevity After Cancer (LILAC) study offers an important opportunity to advance cancer research by extending the original WHI studies to examine survivorship in women diagnosed with cancer during their participation in WHI.Methods: The goals of LILAC are to (i) obtain cancer treatment information and long-term cancer outcomes for women diagnosed with one of eight selected cancers (breast, endometrial, ovarian, lung, and colorectal cancers, and melanoma, lymphoma, and leukemia); (ii) augment the existing WHI biorepository with fixed tumor tissue from the solid tumor sites for cancers diagnosed since 2002; and (iii) develop, refine, and validate methods to use administrative data to capture treatment and recurrence data. Methods for accomplishing these goals are described, as are results from the initial LILAC participant survey.Results: A total of 9,934 WHI participants living with cancer were eligible for LILAC participation, of which 78% (N = 7,760) agreed to participate. Among the three most prevalent cancer types, 54% are breast cancer survivors, 11% are melanoma survivors, and 10% are survivors of colorectal cancer.Conclusions: In addition to describing this resource, we present pertinent lessons that may assist other investigators interested in embedding survivorship research into existing large epidemiologic cohorts.Impact: The LILAC resource offers a valuable opportunity for researchers to study cancer survivorship and issues pertinent to cancer survivors in future studies. Cancer Epidemiol Biomarkers Prev; 27(2); 125-37. ©2017 AACR.

Plasma equol concentration is not associated with breast cancer and fibrocystic breast conditions among women in Shanghai, China.

Equol (a bacterial metabolite of the soy isoflavone daidzein) is produced by 30% to 50% of humans and may be associated with health outcomes. We hypothesized that plasma equol would be inversely associated with risks of fibrocystic breast conditions (FBC) and breast cancer (BC). Plasma from women in a breast self-examination trial in Shanghai with BC (n=269) or FBC (n=443), and age-matched controls (n=1027) was analyzed for isoflavones. Equol was grouped into categories (<20, 20-<45, and ≥45nmol/L) and, among women with daidzein ≥20nmol/L, the log10 equol:daidzein ratio was grouped into tertiles. Where available, non-cancerous tissue (NCT) adjacent to the carcinomas from women with BC were classified as non-proliferative or proliferative (n=130 and 172, respectively). The lesions from women with FBC were similarly classified (n=99 and 92, respectively). Odds ratios (OR) and 95% confidence intervals (CI) were calculated across equol categories and tertiles of log10 equol:daidzein ratio. Equol categories were not associated with FBC or BC (P>.05). For log10 equol:daidzein, compared to controls there were positive associations in the mid tertile for proliferative FBC (OR 2.06, 95% CI 1.08-3.93), BC with proliferative NCT (OR 2.95, 95% CI 1.37-6.35), and all BC regardless of histology (OR 2.37, 95% CI 1.43-3.95). However, trends in ORs with increasing plasma equol values or equol:daidzein ratios were not observed (P>.05). The results of this study do not provide evidence that equol plays a role in the etiology of these breast conditions. However, further work is needed to confirm or refute this conclusion.

Medication use trajectories of postmenopausal breast cancer survivors and matched cancer-free controls.

While adverse medical sequelae are associated with breast cancer therapies, information on breast cancer impact on medication use is limited. Therefore, we compared medication use before and after diagnosis of early stage breast cancer to medication use in matched, cancer-free controls. Of 68,132 Women's Health Initiative participants, 3726 were diagnosed with breast cancer and, after exclusions, in 1731 breast cancer cases, medication use before and >3 years after diagnosis (mean 5.3 ± 2.1 SD) was compared to use in 1731 cancer-free matched controls on similar inventory dates. The medication category number at follow-up inventory was the primary study outcome. Medication category use (n, mean, SD) was comparable at baseline and significantly increased at follow-up in both cases (2.48 ± 1.66 vs. 4.15 ± 2.13, baseline vs follow-up, respectively, P < .0001) and controls (2.44 ± 1.67 vs. 3.95 ± 2.13, respectively, P < .0001), with clinically marginal but statistically significant additional medication category use by cases (0.20 ± 2.40, P < .0001). Tamoxifen users used somewhat more selected medication categories at follow-up assessment (mean 3.40 ± 1.89 vs. 3.21 ± 1.99, respectively, P = 0.05), while aromatase inhibitor users used more medication categories (mean 4.85 ± 2.10 vs. 4.44 ± 1.94, respectively, P = 0.02). No increase in medication category was seen in cases who were not current endocrine therapy users. Breast cancer survivors having only a clinically marginal increase in medication use compared to cancer-free controls. These findings highlight the importance of incorporation of control populations in studies of cancer survivorship.

Risk of Pancreatic Cancer in Female Textile Workers in Shanghai, China, Exposed to Metals, Solvents, Chemicals, and Endotoxin: Follow-Up to a Nested Case-Cohort Study.

OBJECTIVE: We studied associations between pancreatic cancer and occupational exposures to metals, solvents, chemicals, and endotoxin in a cohort of female textile workers in Shanghai, China. To assess the longer-term influences of these agents on pancreatic cancer we extended follow-up of this previously studied cohort. METHODS: We utilized a job exposure matrix to assess occupational exposures for 481 pancreatic cancer cases and a randomly selected sub-cohort of 3191 non-cases. We calculated hazard ratios and 95% confidence intervals using Cox proportional hazards modeling adapted for the case-cohort design. RESULTS: We observed a statistically significant trend of increasing hazard ratios associated with solvent exposure, but no associations with any of the remaining occupational exposures, including endotoxin and metals. CONCLUSIONS: Our findings of increasing risk of pancreatic cancer with solvent exposures are consistent with published literature.

Menopausal estrogen therapy and non-Hodgkin's lymphoma: A post-hoc analysis of women's health initiative randomized clinical trial.

Estrogens are important immunomodulators, exerting significant effects on cell proliferation, apoptosis, cytokine production and differentiation of hematopoietic cells. Estrogen receptors are expressed on normal B and T lymphocytes, bone marrow and in leukemia and lymphoma cell lines. Epidemiologic evidence for the association of menopausal hormone use with risk of non-Hodgkin's lymphoma (NHL) has been mixed; however, all of the investigations have been observational. We analyzed the data from Women's Health Initiative hormone therapy trials where conjugated equine estrogens (CEE; 0.625 mg/d) plus medroxyprogesterone acetate (MPA; 2.5 mg/d) (n = 16,654) or CEE alone (women with prior hysterectomy) (n = 10,685) were tested against placebos and the intervention lasted a median of 5.6 years in the CEE + MPA trial and 7.2 years in the CEE alone trial. During 13 years of follow-up through September 20, 2013 383 incident NHL cases were identified. We used the intent-to-treat approach to calculate incidence rates of NHL, hazards ratios (HR) and 95% confidence intervals (CI) by treatment group. Incidence of NHL was virtually the same in the treatment and placebo groups. The HR was 1.02 (95%CI 0.74-1.39) for CEE alone, 0.98 (95% CI 0.76-1.28) for CEE+MPA, and 1.00 (95% CI 0.82-1.22) for both combined. There were no specific NHL subtypes associated with either type of the treatment, except a marginally decreased risk of plasma cell neoplasms (HR= 0.53 95% CI 0.27-1.03) in the CEE-alone group. These results do not support a role of estrogen alone or combined with progestin in the development of NHL among postmenopausal women.

Insecticide exposure and farm history in relation to risk of lymphomas and leukemias in the Women's Health Initiative observational study cohort.

PURPOSE: Relationships of farm history and insecticide exposure at home or work with lymphohematopoietic (LH) neoplasm risk were investigated in a large prospective cohort of US women. METHODS: In questionnaires, women self-reported history living or working on a farm, personally mixing or applying insecticides, insecticide application in the home or workplace by a commercial service, and treating pets with insecticides. Relationships with non-Hodgkin lymphoma (NHL), chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, plasma cell neoplasms, and myeloid leukemia were investigated using Cox proportional hazard models. Age and farming history were explored as effect modifiers. RESULTS: The analysis included 76,493 women and 822 NHL cases. Women who ever lived or worked on a farm had 1.12 times the risk of NHL (95% confidence interval [CI] = 0.95-1.32) compared to those who did not. Women who reported that a commercial service ever applied insecticides in their immediate surroundings had 65% higher risk of CLL/SLL (95% CI = 1.15-2.38). Women aged less than 65 years who ever applied insecticides had 87% higher risk of DLBCL (95% CI = 1.13-3.09). CONCLUSIONS: Insecticide exposures may contribute to risk of CLL/SLL and DLBCL. Future studies should examine relationships of LH subtypes with specific types of household insecticides.

Hormone Use, Reproductive History, and Risk of Lung Cancer: The Women's Health Initiative Studies.

INTRODUCTION: Results from the Women's Health Initiative clinical trials demonstrated no increase in the risk of lung cancer in postmenopausal women treated with hormone therapy (HT). We conducted a joint analysis of the Women's Health Initiative observational study data and clinical trials data to further explore the association between estrogen and estrogen-related reproductive factors and lung cancer risk. METHODS: Reproductive history, oral contraceptive use, and postmenopausal HT were evaluated in 160,855 women with known HT exposures. Follow-up for lung cancer was through September 17, 2012; 2467 incident lung cancer cases were ascertained, with median follow-up of 14 years. RESULTS: For all lung cancers, women with previous use of estrogen plus progestin of less than 5 years (hazard ratio = 0.84; 95% confidence interval = 0.71-0.99) were at reduced risk. A limited number of reproductive factors demonstrated associations with risk. There was a trend toward decreased risk with increasing age at menopause (ptrend = 0.04) and a trend toward increased risk with increasing number of live births (ptrend = 0.03). Reduced risk of non-small-cell lung cancer was associated with age 20-29 years at first live birth. Risk estimates varied with smoking history, years of HT use and previous bilateral oophorectomy. CONCLUSIONS: Indirect measures of estrogen exposure to lung tissue, as used in this study, provide only weak evidence for an association between reproductive history or HT use and risk of lung cancer. More detailed mechanistic studies and evaluation of risk factors in conjunction with estrogen receptor expression in the lung should continue as a role for estrogen cannot be ruled out and may hold potential for prevention and treatment strategies.

Occupational exposures and risk of stomach and esophageal cancers: update of a cohort of female textile workers in Shanghai, China.

BACKGROUND: Associations between stomach and esophageal cancer and exposures to dusts, metals, chemicals, and endotoxin in the workplace are not very well understood, particularly in women. METHODS: We followed 267,400 female textile workers in Shanghai, China for cancer incidence from 1989 to 2006. Stomach (n = 1374) and esophageal (n = 190) cancer cases were identified and a comparison subcohort (n = 3187) was randomly selected. Cox proportional hazard modeling was used, adjusting for age and smoking. RESULTS: Increasing stomach cancer risk was observed with increasing duration of synthetic fiber dust exposure (p = 0.03), although the magnitude of effect was small (20 + years: HR = 1.2, 95% CI 1.1-1.4). Trends with endotoxin exposure were modestly inversed for esophageal cancer and increased for stomach cancer, but with little deviation from a null association. CONCLUSIONS: Our findings demonstrate that long durations of synthetic fiber dust exposure can increase stomach cancer risk in women, but provide limited support for associations with other textile industry exposures.

Shift work and breast cancer among women textile workers in Shanghai, China.

PURPOSE: Although night-shift work has been associated with elevated risk of breast cancer in numerous epidemiologic studies, evidence is not consistent. We conducted a nested case-cohort study to investigate a possible association between shift work including a night shift and risk of breast cancer within a large cohort of women textile workers in Shanghai, China. METHODS: The study included 1,709 incident breast cancer cases and 4,780 non-cases. Data on historical shift work schedules were collected by categorized jobs from the factories, where the study subjects had worked, and then were linked to the complete work histories of each subject. No jobs in the factories involved exclusively night-shift work. Therefore, night shift was evaluated as part of a rotating shift work pattern. Hazard ratios and 95 % confidence intervals were calculated using Cox proportional hazards modeling adapted for the case-cohort design for years of night-shift work and the total number of nights worked. Additionally, analyses were repeated with exposures lagged by 10 and 20 years. RESULTS: We observed no associations with either years of night-shift work or number of nights worked during the entire employment period, irrespective of lag intervals. Findings from the age-stratified analyses were very similar to those observed for the entire study population. CONCLUSIONS: The findings from this study provide no evidence to support the hypothesis that shift work increases breast cancer risk. The positive association between shift work and breast cancer observed in Western populations, but not observed in this and other studies of the Chinese population, suggests that the effect of shift work on breast cancer risk may be different in Asian and Caucasian women.

Mammography interval and breast cancer mortality in women over the age of 75.

The purpose of this study is to evaluate the relationship between mammography interval and breast cancer mortality among older women with breast cancer. The study population included 1,914 women diagnosed with invasive breast cancer at age 75 or later during their participation in the Women's health initiative, with an average follow-up of 4.4 years (3.1 SD). Cause of death was based on medical record review. Mammography interval was defined as the time between the last self-reported mammogram 7 or more months prior to diagnosis, and the date of diagnosis. Multivariable adjusted hazard ratios (HR) and 95 % confidence intervals (CIs) for breast cancer mortality and all-cause mortality were computed from Cox proportional hazards analyses. Prior mammograms were reported by 73.0 % of women from 7 months to ≤2 year of diagnosis (referent group), 19.4 % (>2 to <5 years), and 7.5 % (≥5 years or no prior mammogram). Women with the longest versus shortest intervals had more poorly differentiated (28.5 % vs. 22.7 %), advanced stage (25.7 % vs. 22.9 %), and estrogen receptor negative tumors (20.9 % vs. 13.1 %). Compared to the referent group, women with intervals of >2 to <5 years or ≥5 years had an increased risk of breast cancer mortality (HR 1.62, 95 % CI 1.03-2.54) and (HR 2.80, 95 % CI 1.57-5.00), respectively, p trend = 0.0002. There was no significant relationship between mammography interval and other causes of death. These results suggest a continued role for screening mammography among women 75 years of age and older.

Use of Medicare data to identify coronary heart disease outcomes in the Women's Health Initiative.

BACKGROUND: Data collected as part of routine clinical practice could be used to detect cardiovascular outcomes in pragmatic clinical trials or clinical registry studies. The reliability of claims data for documenting outcomes is unknown. METHODS AND RESULTS: We linked records of Women's Health Initiative (WHI) participants aged ≥65 years to Medicare claims data and compared hospitalizations that had diagnosis codes for acute myocardial infarction or coronary revascularization with WHI outcomes adjudicated by study physicians. We then compared the hazard ratios for active versus placebo hormone therapy based solely on WHI-adjudicated events with corresponding hazard ratios based solely on claims data for the same hormone trial participants. Agreement between WHI-adjudicated outcomes and Medicare claims was good for the diagnosis of myocardial infarction (κ, 0.71-0.74) and excellent for coronary revascularization (κ, 0.88-0.91). The hormone:placebo hazard ratio for clinical myocardial infarction was 1.31 (95% confidence interval, 1.03-1.67) based on WHI outcomes and 1.29 (95% confidence interval, 1.00-1.68) based on Medicare data. The hazard ratio for coronary revascularization was 1.09 (95% confidence interval, 0.88-1.35) based on WHI outcomes and 1.10 (95% confidence interval, 0.89-1.35) based on Medicare data. The differences between hazard ratios derived from WHI and Medicare data were not significant in 1000 bootstrap replications. CONCLUSIONS: Medicare claims may provide useful data on coronary heart disease outcomes among patients aged ≥65 years in clinical research studies. CLINICAL TRIALS REGISTRATION INFORMATION: URL: www.clinicaltrials.gov. Unique identifier: NCT00000611.

Investigating the association of lactation history and postmenopausal breast cancer risk in the Women's Health Initiative.

Prolonged lactation (≥24 mo) has been associated with reduced breast cancer risk. This research examined this association in postmenopausal women in the Women's Health Initiative (WHI) Hormone Trial (HT) and Observational Study (OS). This retrospective cohort analysis included 69,358 predominantly overweight (65.4%), white (83.2%) postmenopausal women without breast cancer. Women in the HT were randomized to 0.625 mg conjugated equine estrogen (CEE), 0.625 CEE + 2.5 mg medroxyprogesterone acetate (CEE/MPA), or placebo. OS participants had no restrictions on hormone use. Lactation history was assessed via WHI Reproductive History Questionnaire. Most women breastfed at least 1 mo (58.0%); 35.4% breastfed 1-2 children; and 6.5% stated having breastfed ≥24mo. Women in the HT-CEE who breastfed their first child between 20-24 yr of age demonstrated a nonsignificant decreased risk of breast cancer (HR: 0.62; 95% CI: 0.38, 1.01). OS participants who reported CEE/MPA hormone use and age of first breastfeeding ≥30 yr showed a significant increased risk of breast cancer (HR: 1.66; 95% CI: 1.14, 2.41). Risk was increased if age of last breastfeeding was ≥35yr (HR: 1.50; 95% CI: 1.05, 2.14). This research did not demonstrate a significantly decreased risk of postmenopausal breast cancer in women who breastfed for ≥24 mo during their lifetime.

Occupational exposure to magnetic fields and breast cancer among women textile workers in Shanghai, China.

Exposure to magnetic fields (MFs) is hypothesized to increase the risk of breast cancer by reducing production of melatonin by the pineal gland. A nested case-cohort study was conducted to investigate the association between occupational exposure to MFs and the risk of breast cancer within a cohort of 267,400 female textile workers in Shanghai, China. The study included 1,687 incident breast cancer cases diagnosed from 1989 to 2000 and 4,702 noncases selected from the cohort. Subjects' complete work histories were linked to a job-exposure matrix developed specifically for the present study to estimate cumulative MF exposure. Hazard ratios and 95% confidence intervals were calculated using Cox proportional hazards modeling that was adapted for the case-cohort design. Hazard ratios were estimated in relation to cumulative exposure during a woman's entire working years. No association was observed between cumulative exposure to MFs and overall risk of breast cancer. The hazard ratio for the highest compared with the lowest quartile of cumulative exposure was 1.03 (95% confidence interval: 0.87, 1.21). Similar null findings were observed when exposures were lagged and stratified by age at breast cancer diagnosis. The findings do not support the hypothesis that MF exposure increases the risk of breast cancer.