Racial/ethnic disparities in breast cancer incidence may contain important evidence for understanding and control of the disease. Monitoring the incidence trends of breast cancer by race/ethnicity allows identification of high risk groups and development of targeted prevention programs.

Using population-based cancer registry data from the Los Angeles Cancer Surveillance Program, we examined the invasive female breast cancer incidence trends among the diverse racial/ethnic populations in Los Angeles County, California, from 1972 to 2007. Age-adjusted incidence rates (AAIR) and age-specific incidence rates (ASIR) were calculated and examined respectively for non-Hispanic (NH) white, black, Hispanic, Chinese, Filipina, Japanese, and Korean women by calendar year and time period.

Rising trends of AAIR were found in all racial/ethnic groups during the 1980s and 1990s. The breast cancer risk increased more substantially in Japanese and Filipinas than in Chinese and Koreans. During 2000–2007, the trends of AAIR declined significantly among NH white women and slightly in blacks, remained unchanged for Hispanics, and continued to rise significantly among all Asian subgroups. The patterns of ASIR by race/ethnicity changed dramatically over time. By 2000–2007, younger Hispanic women had the lowest breast cancer risk, replacing the Chinese and Koreans who formerly had the lowest risk.

Rapidly increasing breast cancer incidence trends among Asian-Americans underline the importance of behavioral and lifestyle changes as a result of acculturation on the development of the disease. The unique trends of breast cancer incidence by race/ethnicity suggest the need for targeted breast cancer control programs for different racial/ethnic populations.

Purpose

To evaluate the effect of obesity on survival among black women and white women with invasive breast cancer and to determine whether obesity explains the poorer survival of black women relative to white women.

Patients and Methods

We observed 4,538 (1,604 black, 2,934 white) women who were 35 to 64 years of age when diagnosed with incident invasive breast cancer between 1994 and 1998. Multivariate Cox regression models were used to examine the effect of body mass index (BMI, in kilograms per square meter) 5 years before diagnosis on risk of death from any cause and from breast cancer.

Results

During a median of 8.6 years of follow-up, 1,053 women died (519 black, 534 white), 828 as a result of breast cancer (412 black, 416 white). Black women were more likely to die than white women (multivariate-adjusted relative risk [RR], 1.33; 95% CI, 1.16 to 1.53). Compared with women with BMI of 20 to 24.9 kg/m2, those who were obese (BMI ≥ 30 kg/m2) had a greater risk of all-cause mortality (RR, 1.23; 95% CI, 1.04 to 1.47) and breast cancer–specific mortality (RR, 1.20; 95% CI, 0.99 to 1.46). These associations were observed among white women (all-cause RR, 1.54; 95% CI, 1.21 to 1.96; breast cancer RR, 1.46; 95% CI, 1.11 to 1.92), but not among black women (all-cause RR, 1.03; 95% CI, 0.81 to 1.29; breast cancer RR, 1.02; 95% CI, 0.79 to 1.33).

Conclusion

Obesity may play an important role in mortality among white but not black patients with breast cancer. It is unlikely that differences in obesity distributions between black women and white women account for the poorer survival of black women.

We examined oral contraceptive (OC) and menopausal hormonal therapy (MHT) use in relation to risk of B-cell non-Hodgkin lymphoma (NHL). Women under age 85 years participating in the California Teachers Study with no history of hematopoietic cancer were followed from 1995 through 2007. 516 of 114,131 women eligible for OC use analysis and 402 of 54,758 postmenopausal women eligible for MHT use analysis developed B-cell NHL. Multivariable adjusted and stratified Cox proportional hazards models were fit to estimate relative risks (RR) and 95% confidence intervals (95% CI). Ever versus never OC use was marginally associated with lower B-cell NHL risk, particularly among women first using OCs before age 25 years (RR=0.72, 95%CI=0.51-0.99); yet, no duration-response effect was observed. No association was observed for ever versus never MHT use among postmenopausal women (RR=1.05, 95%CI=0.83-1.33) overall, or by formulation (estrogen alone, ET, or estrogen plus progestin, EPT). Among women with no MHT use, having bilateral oophorectomy plus hysterectomy was associated with greater B-cell NHL risk than having natural menopause (RR=3.15, 95%CI=1.62-6.13). Bilateral oophorectomy plus hysterectomy was not associated with risk among women who used ET or EPT. These results indicate that exogenous hormone use does not strongly influence B-cell NHL risk.

Background

Oral contraceptives (OCs) are widely used in the U.S. Although the relation between OC use and breast cancer incidence has been widely studied, the few studies examining associations between OC use prior to breast cancer diagnosis and survival are inconsistent.

Methods

Women with invasive breast cancer participating in the Women's Contraceptive and Reproductive Experiences (CARE) Study, a population-based case-control study (4565 women ages 35–64 years), and the California Teachers Study (CTS) cohort (3929 women ages 28–91 years) were followed for vital status. 1064 women died in the CARE Study (median follow-up, 8.6 years) and 523 died in the CTS (median follow-up, 6.1 years). Cox proportional hazards regression provided hazard rate ratio estimates (RRs) with 95% confidence intervals (CIs) for risk of death from any cause and from breast cancer.

Results

No association was observed for any OC use prior to diagnosis and all-cause mortality (CARE Study: RR=1.01 (95% CI=0.86–1.19); CTS: RR=0.84 (95% CI=0.67–1.05)). A decreased risk of all-cause mortality was observed in the CTS among women with more than 10 years of OC use (RR=0.67, 95% CI=0.47–0.96); however, no trend of decreasing risk with increasing OC duration was observed (P-trend=0.22), and no association was observed in the CARE study. No associations were observed for breast cancer-specific mortality.

Conclusions

OC use is not associated with all-cause or breast cancer-specific mortality among women with invasive breast cancer.

Impact

These two independent studies demonstrated no overall association between OC use and survival among women with breast cancer.

Objective

Studies consistently demonstrate that physical activity is inversely associated with postmenopausal breast cancer. Whether this association is stronger among non-hormone users or former users of menopausal hormone therapy (HT) is of interest given the marked decline in HT use since 2002.

Methods

The Women’s Contraceptive and Reproductive Experiences Study, a population-based case-control study of invasive breast cancer, recruited white women and black women ages 35–64 years, and collected histories of lifetime recreational physical activity and HT use including estrogen-alone therapy (ET) and estrogen plus progestin therapy (EPT).

Results

Among postmenopausal women (1908 cases, 2013 control participants), breast cancer risk declined with increasing levels of lifetime physical activity among never HT users; among short-term HT users (fewer than 5 years); and current ET users; Ptrend values ranged from 0.004 to 0.016. In contrast, physical activity had no significant association with risk among long-term and past HT users and among current EPT users. No statistical evidence of heterogeneity was demonstrated for duration or currency of HT use.

Conclusion

Breast cancer risk decreases with increasing lifetime physical activity levels among postmenopausal women who have not used HT, have used HT for less than 5 years, or are current ET users yet this study was unable to demonstrate statistically that HT use modifies the relationship between physical activity and breast cancer. With profound changes in HT use occurring since 2002, it will be important in future studies to learn whether or not any association between physical activity and breast cancer among former HT users is a function of time since last HT use.

Removal or impairment of ovaries before menopause may affect a woman's breast cancer risk by altering her cumulative exposure to ovarian hormones. The Women's Contraceptive and Reproductive Experiences Study, a population-based, multicenter case-control study of incident invasive breast cancer, recruited women aged 35–64 years (4,490 cases and 4,611 controls) who provided data on ovariectomy, hysterectomy, and tubal sterilization during in-person interviews. Controls were frequency-matched to cases by age, race, and study site. Unconditional logistic regression analysis was used. Women who had not undergone premenopausal reproductive surgery were the referent group. Bilateral ovariectomy was associated with reduced breast cancer risk overall (odds ratio (OR) = 0.59, 95% confidence interval (CI): 0.50, 0.69) and among women <45 years of age (ORs ranged from 0.31 to 0.52), but not among those who were older at surgery. It was also associated with a reduced risk for estrogen and progesterone receptor–positive tumors (OR = 0.63, 95% CI: 0.52, 0.75) but not receptor-negative tumors. Hysterectomy with ovarian conservation (OR = 0.83, 95% CI: 0.72, 0.96) and hysterectomy with partial ovary removal (OR = 0.73, 95% CI: 0.59, 0.91) were also associated with lower risk. No association with breast cancer risk was observed with tubal sterilization only or partial ovariectomy without hysterectomy. Reproductive organ surgeries may alter ovarian hormone levels, thereby affecting breast cancer risk.

Objective

To investigate whether obesity and hormone therapy (HT) are associated with ovarian cancer risk among women in the California Teachers Study cohort.

Methods

Of 56,091 women age ≥45 years, 277 developed epithelial ovarian cancer between 1995 and 2007. Multivariate Cox regression was performed.

Results

Among women who never used HT, greater adult weight gain, waist circumference and waist-to-height ratio, but not adult BMI, increased risk of ovarian cancer. Compared to women who never used HT and had a stable adult weight, risk of ovarian cancer was increased in women who gained ≥40 lb (relative risk (RR) 1.8, 95% confidence interval (CI): 1.0–3.0) or used HT for >5 years (RR 2.3 95% CI: 1.3–4.1). Having both exposures (RR 1.9, 95% CI: 0.99–3.5), however, did not increase risk more than having either alone. Results were similar for waist circumference and weight-to-height ratio; however, differences across HT groups were not statistically significant.

Conclusions

This study suggests that abdominal adiposity and weight gain, but not overall obesity, increase ovarian cancer risk and that there may be a threshold level beyond which additional hormones, whether exogenous or endogenous, do not result in additional elevation in risk. However, large pooled analyses are needed to confirm these findings.

Objective

To investigate whether hormone therapy (HT) and obesity are associated with endometrial cancer risk among postmenopausal women in the California Teachers Study cohort.

Methods

Of 28,418 postmenopausal women, 395 developed type 1 endometrial cancer between 1995 and 2006. Multivariate Cox regression was performed to estimate relative risks (RR), stratified by HT use (never used, ever estrogen-alone (ET), or exclusively estrogen-plus-progestin (EPT)).

Results

Among women who never used HT, overall and abdominal adiposity were associated with increased risk; when evaluated simultaneously, abdominal adiposity was more strongly associated (RR 2.2, 95% confidence interval (CI): 1.1–4.5 for waist ≥35 vs. <35 inches). Among women who ever used ET, risk was increased in women with BMI ≥25 kg/m2 (RR 1.6, 95% CI: 1.1–2.3 vs. <25 kg/m2). Neither overall nor abdominal obesity was associated with risk in women who exclusively used EPT (P-interaction<0.001 for BMI by HT use).

Conclusions

Among women who never used HT, risk was strongly positively related to obesity and may have been influenced more by abdominal than overall adiposity; however, due to small numbers, this latter finding requires replication. Among women who ever used ET, being overweight at baseline predicted higher risk, whereas use of EPT mitigated any effect of obesity.

Background

Although it is well established that combined estrogen-progestin therapy (EPT) increases breast cancer risk, questions remain regarding the impact of different formulations of hormones, whether certain women are at particularly high risk, and whether risk varies by tumor subtype.

Methods

We investigated hormone therapy (HT) use in relation to breast cancer risk in the California Teachers Study cohort; after a mean follow-up of 9.8 years 2,857 invasive breast cancers were diagnosed.

Results

Compared to women who had never used HT, women who reported 15 or more years of estrogen therapy (ET) use had 19% greater risk of breast cancer (95% Confidence Interval (CI), 1.03-1.37), while women using EPT for 15 or more years had 83% greater risk (95% CI, 1.48-2.26). Breast cancer risk was highest among women using continuous combined EPT regimens. Risks associated with EPT and ET use were increased with duration of HT use for women with body mass index (BMI)<29.9 kg/m2 but not for women with BMI≥30 kg/m2. Elevated risks associated with EPT and ET use were confined to tumors that were positive for both estrogen and progesterone receptors and those that were HER2+ but were slightly diminished for HER2- tumors.

Conclusions

Breast cancer risks increased with longer duration of ET and EPT use, and risks were highest for continuous-combined EPT use. Further, risks varied by BMI and tumor subtype.

Impact

These findings underscore the need for personalized risk-benefit discussions with women contemplating HT use.

A low meat diet and regular non-steroidal anti-inflammatory drugs (NSAIDs) have been associated with decreased mortality among colorectal cancer (CRC) patients. Here we investigated the association between pre-diagnosis usual meat consumption and CRC-specific mortality, and whether meat consumption modifies the previously noted association between NSAID use and CRC-specific mortality among women in the California Teachers Study (CTS) cohort. Women joining CTS in 1995–1996 without prior CRC diagnosis, diagnosed with incident CRC during follow-up through December 2007, were eligible for inclusion. Meat intake (frequency and serving size) and NSAID use (aspirin or ibuprofen use) were ascertained via self-administered questionnaires before diagnosis. Vital status and cause of death were determined by linkage with mortality files. Multivariable Cox proportional hazards regression models were used to estimate hazard ratios (HR) for death and 95% confidence intervals (CI). Pre-diagnosis meat consumption was not associated with CRC-specific mortality among 704 CRC patients (and 201 CRC-specific deaths), comparing patients in the lowest consumption tertile (0–5.4 medium-size servings/week) to those with higher consumption. Regular NSAID use (1–3 times/week, 4–6 times/week, daily) vs. none was associated with decreased CRC-specific mortality among patients in the lowest meat consumption tertile (HR=0.22, 95% CI 0.06–0.82), but not among patients in the higher meat intake tertiles. The previously observed mortality risk reduction among female CRC patients associated with regular NSAID use was restricted to patients who reported low meat intake before diagnosis. These findings have implications for CRC survivorship and tertiary CRC prevention.

Objective

Large body size has been associated with decreased risk of breast cancer in premenopausal, but with increased risk in postmenopausal women. Limited information is available about African American women and differences by estrogen- and progesterone-receptor (ERPR) status.

Methods

We analyzed data from the Women's Contraceptive and Reproductive Experiences (CARE) Study among 3,997 white and African American breast cancer case patients diagnosed in 1994-98 and 4,041 control participants aged 35 to 64. We calculated multivariate odds ratios (ORs) as measures of relative risk of breast cancer associated with self-reported body mass index (BMI) at age 18 and 5 years before diagnosis (recent BMI).

Results

Risk tended to decrease with increasing BMI at age 18 in all women (ORBMI≥25 kg/m2 vs <20kg/m2=0.76, 95% CI:0.63–0.90, Ptrend=0.005) and with recent BMI in premenopausal women (ORBMI ≥35 kg/m2 vs <25kg/m2=0.81, 95% CI:0.61–1.06, Ptrend=0.05), unmodified by race. Among postmenopausal white but not African American women, there was an inverse relation between recent BMI and risk. High recent BMI was associated with increased risk of ERPR positive tumors among postmenopausal African American women (ORBMI ≥35 kg/m2 vs <25kg/m2=1.83, 95% CI:1.08–3.09, Ptrend=0.03).

Conclusion

Among women at age 35-64, BMI at age 18 is inversely associated with risk of breast cancer, but association with recent BMI varies by menopause status, race and hormone receptor status.

Impact

Our findings indicate that studies of BMI and breast cancer should consider breast cancer subtypes.

Purpose

Among unanswered questions is whether menopausal use of estrogen therapy (ET) or estrogen-plus-progestin therapy (CHT) increases risk of developing fatal breast cancer, i.e developing and dying of breast cancer. Using a population-based case-control design, we estimated incidence rate ratios of fatal breast cancer in postmenopausal hormone therapy (HT) users compared to non-users by type, duration, and recency of HT use.

Methods

HT use prior to breast cancer diagnosis in 278 women who died of breast cancer within 6 years of diagnosis (cases) was compared with use in 2,224 controls never diagnosed with breast cancer using conditional logistic regression. Measures taken to address potential bias and confounding inherent in case-control studies included collecting and adjusting for detailed data on demographic and other factors potentially associated both with hormone therapy use and breast cancer.

Results

Fifty-six percent of cases and 68% of controls reported HT use. Among current 3+ year HT users, odds ratios and 95% confidence intervals for death were 0.83 (0.50, 1.38) and 0.69 (0.44, 1.09), respectively, for exclusive use of CHT or of ET, and were 0.94 (0.59, 1.48) and 0.70 (0.45, 1.07) for any use of CHT or of ET regardless of other hormone use.

Conclusion

Point estimates suggest no increased risk of fatal breast cancer with HT use, although 50% increases in risk in longer-term current CHT users cannot be ruled out.

Introduction

Cancer is rare in adolescents and young adults (AYA), but these patients have seen little improvement in survival in contrast to most other age groups. Furthermore, participation in research by AYAs is typically low. We conducted a study to examine the feasibility of recruiting a population-based sample of AYA survivors to examine issues of treatment and health outcomes.

Methods

Individuals diagnosed in 2007–08 and age 15–39 at the time of diagnosis with acute lymphocytic leukemia, Hodgkin lymphoma, non-Hodgkin lymphoma, germ cell cancer or sarcoma were identified by 7 Surveillance, Epidemiology, and End-Results (SEER) cancer registries, mailed surveys within 14 months after diagnosis and again a year later, and had medical records reviewed.

Results

525 (43%) of the eligible patients responded, 39% refused and 17% were lost to follow-up. Extensive efforts were required for most potential respondents (87%). 76% of respondents completed the paper rather than online survey version. In a multivariate model, age, cancer site, education and months from diagnosis to the first mailing of the survey were not associated with participation, although males (p < 0.01), Hispanics and non-Hispanic blacks (p < 0.001) were less likely to participate. 91% of survivors completing the initial survey completed the subsequent survey.

Discussion

Despite the response rate, those who participated adequately reflected the population of AYA cancer survivors. The study demonstrates that cancer registries are valuable foundations for conducting observational, longitudinal population-based research on AYA cancer survivors.

Implications for Cancer Survivors

Achieving a reasonable response rate in this population is possible, but requires extensive resources.

The clinical importance of human epidermal growth factor receptor-2 (HER2) in breast cancer is now clearly established given that expression of this tumor marker is used to guide therapy and as a prognostic indicator. Despite its now routine evaluation in breast cancer patients, population-based data are lacking because information on HER2 status is not routinely collected in the majority of population-based cancer registries. We assessed feasibility of collecting HER2 data and its completeness in three registries in the Surveillance, Epidemiology and End Result (SEER) Program. Among a sample of invasive first primary breast cancer patients diagnosed between June and December 2007, HER2 tests had been performed on 96.5% (N=522), and test results were available for 95.2% (N=515) of patients. The majority of HER2 tests were performed by immunohistochemistry (IHC) alone (50.9%), 35.3% by both IHC and fluorescence in situ hybridization (FISH) and 11.8% of tests by FISH alone. As a result of these findings SEER registries will collect HER2 data on all invasive breast cancer patients as an optional data element for those diagnosed in 2009 and HER2 will likely be a required data element for these patients in 2010.

Background

Non-steroidal anti-inflammatory drug (NSAID) use has been associated with decreased colorectal cancer (CRC) risk. However, NSAID effects on clinical outcomes after CRC diagnosis are not well-defined. We investigated the association of pre-diagnosis NSAID use and mortality after CRC diagnosis among women in the California Teachers Study (CTS) cohort.

Methods

Women under 85 years participating in the CTS, without prior CRC diagnosis at baseline (1995-1996), and diagnosed with CRC during follow-up through December 2005, were eligible for analysis of the association of pre-diagnosis NSAID use and mortality. NSAID use (including aspirin, and ibuprofen) was collected through a self-administered questionnaire. Cancer occurrence was identified through California Cancer Registry linkage. Multivariable Cox proportional hazards regression models were used to estimate hazard ratios (HR) for death and 95% confidence intervals (CI).

Results

Among 621 CRC cases identified, 64% reported no pre-diagnosis regular NSAID use, 17% reported use 1-6 days/week, and 20% reported daily use; duration of NSAID use < 5 years was reported by 17% and ≥5 years reported by 18%. Regular pre-diagnosis NSAID use (1-3 days/week, 4-6 days/week, daily) vs. none was associated with improved overall survival (OS) (HR=0.71, 95% CI 0.53-0.95) and CRC-specific survival (CRC-SS) (HR=0.58, 95% CI 0.40-0.84) after adjustment for clinically relevant factors. Pre-diagnosis NSAID use ≥5 years (versus none) was associated with improved OS (HR=0.55, 95% CI 0.37-0.84) and CRC-SS (HR=0.40, 95% CI 0.23-0.71) in adjusted analyses.

Conclusions

When used regularly or over a prolonged duration prior to CRC diagnosis, NSAIDs are associated with decreased mortality among female CRC cases.

Introduction

Long-term physical activity is associated with lower breast cancer risk. Little information exists on its association with subsequent survival.

Methods

California Teachers Study cohort members provided information in 1995–1996 on long-term (high school through age 54 years) and recent (past 3 years) participation in moderate and strenuous recreational physical activities. The 3,539 women diagnosed with invasive breast cancer after cohort entry and through December 31, 2004, were followed through December 31, 2005. Of these, 460 women died, 221 from breast cancer. Moderate and strenuous physical activities were combined into low (≤0.50 hr/wk/yr of any activity), intermediate (0.51–3.0 hr/wk/yr of moderate or strenuous activity but no activity >3.0 hr/wk/yr) or high activity (>3.0 hr/wk/yr of either activity type). Multivariable relative risks (RR) and 95% confidence intervals (CI) for mortality were estimated using Cox proportional hazards methods, adjusting for race/ethnicity, estrogen receptor status, disease stage, and baseline information on comorbidities, body mass index, and caloric intake.

Results

Women with high or intermediate levels of long-term physical activity had lower risk of breast cancer death (RR=0.53, 95% CI=0.35–0.80; and RR=0.65, 95% CI=0.45–0.93, respectively) than women with low activity levels. These associations were consistent across estrogen receptor status and disease stage, but confined to overweight women. Deaths due to causes other than breast cancer were related only to recent activity.

Conclusions

Consistent long-term participation in physical activity before breast cancer diagnosis may lower risk of breast cancer death, providing further justification for public health strategies to increase physical activity throughout the lifespan.

Both migraine and breast cancer are hormonally mediated diseases, and it is biologically plausible that women with a history of migraine may have a reduced breast cancer risk. However, this relationship has only been assessed in a single relatively small study that was unable to assess the impact of migraine triggers, that are also well established breast cancer risk factors (e.g., use of alcohol and exogenous hormones), on the inverse association observed. Utilizing data on 4,568 breast cancer cases and 4,678 controls who participated in a multi-center population-based case-control study in the United States, we evaluated the association between migraine history and breast cancer risk using unconditional logistic regression. Migraine history data were obtained from structured in-person interviews. Women with a history of migraine had a reduced risk of breast cancer [odds ratio (OR): 0.74, 95% confidence interval (CI): 0.66–0.82]. This risk did not differ by menopausal status, age at migraine diagnosis, use of prescription migraine medications, or when analyses were restricted to women who avoided various migraine triggers (including alcohol, exogenous hormones, and smoking). These data support a previous finding that a history of migraine may be associated with a reduced risk of breast cancer. It extends the prior report in observing that this relationship holds for both premenopausal and postmenopausal women and is independent of exposure to common migraine triggers.

Introduction

Although pregnancy-related factors such as nulliparity and late age at first full-term pregnancy are well-established risk factors for invasive breast cancer, the roles of these factors in the natural history of breast cancer development remain unclear.

Methods

Among 52,464 postmenopausal women participating in the California Teachers Study (CTS), 624 were diagnosed with breast carcinoma in situ (CIS) and 2,828 with invasive breast cancer between 1995 and 2007. Multivariable Cox proportional hazards regression methods were used to estimate relative risks associated with parity, age at first full-term pregnancy, breastfeeding, nausea or vomiting during pregnancy, and preeclampsia.

Results

Compared with never-pregnant women, an increasing number of full-term pregnancies was associated with greater risk reduction for both breast CIS and invasive breast cancer (both P trend < 0.01). Women having four or more full-term pregnancies had a 31% lower breast CIS risk (RR = 0.69, 95% CI = 0.51 to 0.93) and 18% lower invasive breast cancer risk (RR = 0.82, 95% CI = 0.72 to 0.94). Parous women whose first full-term pregnancy occurred at age 35 years or later had a 118% greater risk for breast CIS (RR = 2.18, 95% CI = 1.36 to 3.49) and 27% greater risk for invasive breast cancer (RR = 1.27, 95% CI = 0.99 to 1.65) than those whose first full-term pregnancy occurred before age 21 years. Furthermore, parity was negatively associated with the risk of estrogen receptor-positive (ER+) or ER+/progesterone receptor-positive (PR+) while age at first full-term pregnancy was positively associated with the risk of ER+ or ER+/PR+ invasive breast cancer. Neither of these factors was statistically significantly associated with the risk of ER-negative (ER-) or ER-/PR- invasive breast cancer, tests for heterogeneity between subtypes did not reach statistical significance. No clear associations were detected for other pregnancy-related factors.

Conclusions

These results provide some epidemiologic evidence that parity and age at first full-term pregnancy are involved in the development of breast cancer among postmenopausal women. The role of these factors in risk of in situ versus invasive, and hormone receptor-positive versus -negative breast cancer merits further exploration.

Objective

To evaluate the reproductive and lifestyle correlates of a surgically confirmed diagnosis of endometriosis or adenomyosis in a large prospective cohort.

Setting

The California Teachers Study (CTS), an ongoing prospective study of female teachers and school administrators established from the rolls of the California State Teachers Retirement System.

Patients

Diagnoses of endometriosis and adenomyosis were identified from California statewide hospital patient discharge records for CTS cohort members with no prior history of endometriosis. Women with an incident surgical diagnosis of endometriosis (n=229) or adenomyosis (n=961) were compared to disease-free women in the same age range (for endometriosis, n=43,493; for adenomyosis, n=79,495).

Main Outcome Measure(s)

Logistic regression methods were used to calculate age-adjusted and multivariable-adjusted prevalence odds ratios (POR) and associated 95 percent confidence intervals (CI) for self-reported menstrual and reproductive characteristics.

Results

Women diagnosed with endometriosis were younger than those diagnosed with adenomyosis. Factors significantly associated with endometriosis were having a mother or sister with endometriosis and nulligravidity. Factors significantly associated with adenomyosis were increasing parity, early menarche (≤10 years of age), and having short menstrual cycles (≤24 days in length). Women who were obese were also more likely to have a diagnosis of adenomyosis.

Conclusions

These observations provide the first epidemiologic profile of women with a surgical diagnosis of adenomyosis and indicate that this profile differs from that of women with a surgical diagnosis of endometriosis. Our results also suggest that adenomyosis but not endometriosis is associated with increased endogenous exposure to estrogen.

Introduction

Recent, international declines in breast cancer incidence are unprecedented, and the causes remain controversial. Few data sources can address breast cancer incidence trends according to pertinent characteristics like hormone therapy use history.

Methods

We used the prospective California Teachers Study to evaluate changes in self-reported use of menopausal hormone therapy (HT) between 1995 to 1996 and 2005 to 2006 and age-adjusted breast cancer incidence among 74,647 participants aged 50 years or older. Breast cancer occurrence was determined by linkage with the California Cancer Registry.

Results

During 517,286 woman years of follow up, 565 in situ and 2,668 invasive breast cancers were diagnosed. In situ breast cancer incidence rates in this population did not change significantly from 2000 to 2002 to 2003 to 2005, whereas rates of invasive breast cancer declined significantly by 26.0% from 528.0 (95% confidence intervals (CI) = 491.1, 564.9) per 100,000 women in 2000 to 2002 to 390.6 (95% CI = 355.6, 425.7) in 2003 to 2005. The decline in invasive breast cancer incidence rates was restricted to estrogen receptor-positive tumors. In 1996 to 1999 and 2000 to 2002 invasive breast cancer incidence was higher for women who reported current HT use especially estrogen-progestin (EP) use at baseline than for never or past users; but by 2003 to 2005 rates were comparable between these groups. For women who were taking EP in 2001 to 2002,75% of whom had stopped use by 2005 to 2006, incidence had declined 30.6% by 2003 to 2005 (P = 0.001); whereas incidence did not change significantly for those who never took HT (P = 0.33).

Conclusions

Few data resources can examine prospectively individual HT use and breast cancer diagnosis. Stable in situ breast cancer rates imply consistent levels of screening and suggest recent declines in invasive breast cancer to be explained predominantly by changes in HT use.

Background

Non-Hodgkin lymphoma (NHL) is a malignancy etiologically linked to immunomodulatory exposures and disorders. Endogenous female sex hormones may modify immune function and influence NHL risk. Few studies have examined associations between reproductive factors, which can serve as surrogates for such hormonal exposures, and NHL risk by subtype.

Methodology/Principal Findings

Women in the California Teachers Study cohort provided detailed data in 1995–1996 on reproductive history. Follow-up through 2007 identified 574 women with incident B-cell NHL. Hazard rate ratios (RR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models to assess associations between reproductive factors and all B-cell NHL combined, diffuse large B-cell lymphomas, follicular lymphomas, and B-cell chronic lymphocytic leukemias/small lymphocytic lymphomas. Pregnancy was marginally associated with lower risk of B-cell NHL (RR = 0.84, 95% CI = 0.68–1.04). Much of the reduction in risk was observed after one full-term pregnancy relative to nulligravid women (RR = 0.75, 95% CI = 0.54–1.06; P for trend <0.01), particularly for diffuse large B-cell lymphomas (P for trend = 0.13), but not among women who had only incomplete pregnancies. Age at first full-term pregnancy was marginally inversely associated with B-cell NHL risk overall (P for trend = 0.08) and for diffuse large B-cell lymphomas (P for trend = 0.056). Breast feeding was not associated with B-cell NHL risk overall or by subtype.

Conclusions

Full-term pregnancy and early age at first full-term pregnancy account for most of the observed reduction in B-cell NHL risk associated with gravidity. Pregnancy-related hormonal exposures, including prolonged and high-level exposure to progesterone during a full-term pregnancy may inhibit development of B-cell NHL.

Background

Early age at first birth and multiparity reduce the risk of estrogen receptor and progesterone receptor (ERPR) positive breast cancer, whereas breastfeeding reduces the risk of both ERPR-positive and ERPR-negative cancers.

Methods

We used multivariable logistic regression analysis to investigate whether age at first birth (