Dietary Patterns Derived by Reduced Rank Regression Are Inversely Associated with Type 2 Diabetes Risk across 5 Ethnic Groups in the Multiethnic Cohort

Background: Reduced rank regression (RRR) is an approach to identify dietary patterns associated with biochemical markers and risk of type 2 diabetes (T2D). Objective: We aimed to derive dietary patterns associated with adiponectin, leptin, C-reactive protein (CRP), and triglycerides (TGs) and to examine the prospective associations of these patterns with T2D risk in 5 ethnic/racial groups with differences in T2D rates. Methods: The Multiethnic Cohort (MEC) included 215,831 African-American, Japanese-American, Latino, Native Hawaiian, and white adults living in Hawaii and California who completed a validated quantitative food-frequency questionnaire in 1993-1996. T2D status was based on self-report with confirmation by administrative data. Serum CRP and TGs and plasma adiponectin and leptin were measured ∼10 y after baseline in a subset (n = 10,008) of participants. RRR was applied to dietary data and biomarker information of 10,008 MEC participants in the combined population and in each ethnic/racial group. RRR-derived dietary patterns, simplified by removal of foods that were not found to be important, were subsequently evaluated for association with T2D risk in 155,316 cohort members (8687 incident T2D cases diagnosed by 2010) by using Cox proportional hazards regression. Results: Combining ethnic/racial groups, we identified a dietary pattern low in processed and red meat, sugar-sweetened beverages, diet soft drinks, and white rice and high in whole grains, fruit, yellow-orange vegetables, green vegetables, and low-fat dairy that was inversely associated with CRP, TGs, and leptin and positively related to adiponectin. Comparing extreme tertiles, the dietary pattern predicted a 16-28% significantly lower T2D risk in the combined study population and also separately in African Americans, Japanese Americans, Latinos, Native Hawaiians, and whites. Ethnicity-specific derived patterns varied only modestly from the overall pattern and resulted in comparable associations with T2D. Conclusion: This identified dietary pattern may lower T2D risk through its impact on adipokines, by lowering chronic inflammation and dyslipidemia across 5 ethnic/racial groups.

Abstract P3-02-03: Accurate and reliable automated breast density measurements with no ionizing radiation using fat-water decomposition MRI

Objective Breast density(BD) is a measure of the distribution of variable tissue types within the breast and higher BD has been shown to positively correlate with breast cancer risk. As such, the accurate measurement of BD has become a priority for risk assessment and for evaluating the effects of prevention strategies aimed at reducing BD. Mammography(MG) is the most common method of BD determination but is limited by the exposure to ionizing radiation, particularly for studies requiring repeated measures. BD derived from fat-water decomposition magnetic resonance imaging(FWMRI-BD) has been proposed as an alternative, safe, and quantitative method for BD. To optimize its use, we developed a new FWMRI-BD that is automated, more accurate and reliable. In this study, we compare our automated method to digital MG and a previous reported algorithm for MRI derived BD.

Methods From a completed prevention trial, 42 pre- and post-menopausal patients receiving tamoxifen therapy for early stage breast cancer or as primary chemoprevention were identified. Patients had undergone prior digital MG within 6 months from the date of MRI scan and MG-BD was calculated using a well-established method(Cumulus). MRI scans were performed on a 1.5T GE Signa NV-CV/i scanner using an axial radial IDEAL-GRASE sequence to generate quantitative fat fraction maps of the entire breast. Total acquisition time was < 5 min and automated breast segmentation was applied to all scans. Only the contralateral, unaffected breast was analyzed. Pearson correlation analysis compared BD as measured by MG(range 0-100%) and FWMRI based methods. BD by FWMRI was initially calculated as the ratio of breast voxels with<80% apparent fat fraction(Fra80). Fra80 had been previously shown by our group to correlate with MG-BD(Spearman ρ=0.86, p<0.001). Here, BD was calculated using a new algorithm(FraG+W) that accounts for the total amount of fibroglandular tissue and water content in the breast after correction for fat-water signal intensity bias and fat-water signal shine-through. Reliability of FWMRI measurements was tested in 24 repeated scans from 9 patients and evaluated using intra-class correlation(ICC) analysis.

Results Table 1 shows the correlation and reliability analysis results between MG-BD and FWMRI-BD. Both FWMRI-BD measures(Fra80 and FraG+W) were strongly correlated with MG-BD. More importantly, they exhibit superior test-retest reliability(ICC>0.98) compared to MG-BD values from the literature(reported ICC range 0.91-0.95). FraG+W showed improvement over Fra80 in all measures tested including correlation to MG-BD, dynamic range, standard errors and ICC.

Table 1. Accuracy and Reliability of the FWMRI-BD measuresFWMRI-BDFra80FraG+WPearson correlation coefficient* with MG-BDR=0.86R=0.94Test-retest reliabilitystandard error0.02300.0134dynamic range0.0902 – 0.65370.0736 – 0.6588standard error/ dynamic range4.1%2.3%ICC [95% confidence interval]0.985 [0.966,0.993]0.990 [0.976,0.995]* All P-values < 1e-10

Conclusion The refined and automated FWMRI-BD that quantifies the entire fibroglandular and water content of the breast(FraG+W) strongly correlates with MG-BD and is more accurate and reliable than previous FWMRI-BD method.

Acknowledgement NIH grants CA149417, CA161534.

Citation Format: Ding J, Thompson PA, Gao Y, Marron MT, Wertheim BC, Altbach MI, Galons J-P, Roe DJ, Wang F, Maskarinec G, Thomson CA, Stopeck A, Huang C. Accurate and reliable automated breast density measurements with no ionizing radiation using fat-water decomposition MRI [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-02-03.

Smoking and risk of ovarian cancer by histological subtypes: an analysis among 300 000 Norwegian women

BACKGROUND

We prospectively investigated the association between different measures of smoking exposure and the risk of serous, mucinous, and endometrioid ovarian cancers (OC) in a cohort of more than 300 000 Norwegian women.

METHODS

We followed 300 398 women aged 19-67 years at enrolment until 31 December 2013 for OC incidence through linkage to national registries. We used Cox proportional hazards models with attained age as the underlying time scale to estimate multivariable-adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) adjusted for relevant confounders.

RESULTS

During more than 5.9 million person-years and a median follow-up time of 19 years, 2336 primary invasive (1647, 71%) and borderline (689, 29%) OC were identified (53% serous, 19% mucinous). Compared with never smokers, current smokers who had smoked for ⩾10 years had a higher risk of mucinous OC (HR10-19 years vs never=1.73, 95% CI 1.24-2.42; HR⩾20 vs never=2.26, 95% CI 1.77-2.89, Ptrend <0.001). When stratified by invasiveness, current smokers had a higher risk of invasive mucinous OC (HR=1.78, 95% CI 1.20-2.64) and borderline mucinous OC (HR=2.26 95% CI, 1.71-2.97) (Pheterogeneity=0.34) than never smokers. Smoking was not associated with serous or endometrioid OC.

CONCLUSIONS

Using a very large cohort of women, the current analysis provides an important replication for a similar risk of invasive and borderline mucinous OC related to smoking.

Mammographic density assessed on paired raw and processed digital images and on paired screen-film and digital images across three mammography systems

BACKGROUND

Inter-women and intra-women comparisons of mammographic density (MD) are needed in research, clinical and screening applications; however, MD measurements are influenced by mammography modality (screen film/digital) and digital image format (raw/processed). We aimed to examine differences in MD assessed on these image types.

METHODS

We obtained 1294 pairs of images saved in both raw and processed formats from Hologic and General Electric (GE) direct digital systems and a Fuji computed radiography (CR) system, and 128 screen-film and processed CR-digital pairs from consecutive screening rounds. Four readers performed Cumulus-based MD measurements (n = 3441), with each image pair read by the same reader. Multi-level models of square-root percent MD were fitted, with a random intercept for woman, to estimate processed-raw MD differences.

RESULTS

Breast area did not differ in processed images compared with that in raw images, but the percent MD was higher, due to a larger dense area (median 28.5 and 25.4 cm2 respectively, mean √dense area difference 0.44 cm (95% CI: 0.36, 0.52)). This difference in √dense area was significant for direct digital systems (Hologic 0.50 cm (95% CI: 0.39, 0.61), GE 0.56 cm (95% CI: 0.42, 0.69)) but not for Fuji CR (0.06 cm (95% CI: -0.10, 0.23)). Additionally, within each system, reader-specific differences varied in magnitude and direction (p < 0.001). Conversion equations revealed differences converged to zero with increasing dense area. MD differences between screen-film and processed digital on the subsequent screening round were consistent with expected time-related MD declines.

CONCLUSIONS

MD was slightly higher when measured on processed than on raw direct digital mammograms. Comparisons of MD on these image formats should ideally control for this non-constant and reader-specific difference.

Involution of breast tissue and mammographic density

BACKGROUND

Mammographic density decreases and involution of breast tissue increases with age; both are thought to be risk factors for breast cancer. The current study investigated the relationship between involution or hormone treatment (HT) and breast density among multiethnic patients with breast cancer in Hawaii.

METHODS

Patients with breast cancer cases were recruited from a nested case-control study within the Multiethnic Cohort. HT use was self-reported at cohort entry and at the time of the density study. Mammographic density and involution in adjacent non-tumor breast tissue were assessed using established methods. Linear regression was applied to evaluate the correlation between involution and four density measures and to compute adjusted means by involution status while adjusting for confounders.

RESULTS

In the 173 patients with breast cancer, mean percent breast density was 41.2% in mammograms taken approximately 1 year before diagnosis. The respective proportions of women with no, partial, and complete involution were 18.5, 51.4, and 30.1%, respectively and the adjusted density values for these categories were 32.5, 39.2, and 40.2% (p = 0.15). In contrast, the size of the dense area was significantly associated with involution (p = 0.001); the values ranged from 29.7 cm² for no involution to 48.0 cm² for complete involution. The size of the total breast area but not of the non-dense areas was also larger with progressive involution. Percent density and dense area were significantly higher in women with combined HT use.

CONCLUSIONS

Contrary to previous reports, greater lobular involution was not related to lower mammographic density but to higher dense area. Possibly, percent density during the involution process depends on the timing of mammographic density assessment, as epithelial tissue is first replaced with radiographically dense stromal tissue and only later with fat.

Bioimpedence to Assess Breast Density as a Risk Factor for Breast Cancer in Adult Women and Adolescent Girls

Although high mammographic density is one of the strongest predictors of breast cancer risk, X-ray based mammography cannot be performed before the recommended screening age, especially not in adolescents and young women. Therefore, new techniques for breast density measurement are of interest. In this pilot study in Guam and Hawaii, we evaluated a radiation-free, bioimpedance device called Electrical Breast DensitometerTM (EBD; senoSENSE Medical Systems, Inc., Ontario, Canada) for measuring breast density in 95 women aged 31-82 years and 41 girls aged 8-18 years. Percent density (PD) was estimated in the women's most recent mammogram using a computer-assisted method. Correlation coefficients and linear regression were applied for statistical analysis. In adult women, mean EBD and PD values of the left and right breasts were 230±52 and 226±50 Ω and 23.7±15.1 and 24.2±15.2%, respectively. The EBD measurements were inversely correlated with PD (rSpearman=-0.52, p<0.0001); the correlation was stronger in Caucasians (rSpearman=-0.70, p<0.0001) than Asians (rSpearman=-0.54, p<0.01) and Native Hawaiian/Chamorro/Pacific Islanders (rSpearman=-0.34, p=0.06). Using 4 categories of PD (<10, 10-25, 26-50, 51-75%), the respective mean EBD values were 256±32, 249±41, 202±46, and 178±43 Ω (p<0.0001). In girls, the mean EBD values in the left and right breast were 148±40 and 155±54 Ω; EBD values decreased from Tanner stages 1 to 4 (204±14, 154±79, 136±43, and 119±16 Ω for stages 1-4, respectively) but were higher at Tanner stage 5 (165±30 Ω). With further development, this bioimpedance method may allow for investigations of breast development among adolescent, as well as assessment of breast cancer risk early in life and in populations without access to mammography.

Soy Food Intake and Biomarkers of Breast Cancer Risk: Possible Difference in Asian Women?

Soy foods may protect against breast cancer in Asian but not in Western populations. We examined if the levels of various markers of breast cancer risk and inflammation, as well as the effects of soy food consumption on these markers, differ between Asian and non-Asian premenopausal women in two soy intervention trials. One study randomized 220 women to a 2-yr intervention and the other one randomized 96 women in a crossover design to examine the effects of consumption of 2 daily soy servings on nipple aspirate fluid (NAF) volume; estrogens in serum, NAF, and urine; insulin-like growth factor-1 (IGF-1), IGF-binding protein 3, and inflammatory markers in serum; and mammographic densities. Mixed linear models were applied to assess ethnic differences in biomarkers and response to the soy diet. Serum C-reactive protein, serum leptin, NAF volume, and NAF estrone sulfate were lower, while urinary isoflavones were higher in Asian than in non-Asian women. A significant interaction (p_interaction = 0.05) between ethnicity and soy diet was observed for IGF-1 but not for other biomarkers. The current findings suggest possible ethnic differences in levels of biomarkers for breast cancer risk but little evidence that Asian women respond differently to soy foods than non-Asian women.

Ethnic admixture affects diabetes risk in native Hawaiians: the Multiethnic Cohort

BACKGROUND/OBJECTIVES

Obesity and diabetes rates are high in Native Hawaiians (NHs) who commonly have mixed ancestries. People of Asian ancestry experience a high risk of type 2 diabetes despite the relatively low body weight. We evaluated the impact of ethnic admixture on diabetes risk among NHs in the Multiethnic Cohort (MEC).

SUBJECTS/METHODS

On the basis of self-reports, 11 521 eligible men and women were categorized into NH/white, NH/other, NH alone, NH/Asian and the most common three ancestry admixture, NH/Chinese/white. Cox proportional hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated with the NH/white category as the reference group; covariates included known confounders-that is, body mass index (BMI), dietary and other lifestyle factors.

RESULTS

The NH alone category had the highest proportion of overweight and obese individuals and the NH/Asian category the lowest proportion. During 12 years of follow-up after cohort entry at 56 years, 2072 incident cases were ascertained through questionnaires and health plan linkages. All NH categories had higher HRs than the NH/white category before and after adjustment for BMI. In the fully adjusted models, the NH/Asian category showed the highest risk (HR=1.45; 95% CI: 1.27-1.65), followed by NH/other (HR=1.20; 95% CI: 1.03-1.39), NH/Chinese/white (HR=1.19; 95% CI: 1.04-1.37) and NH alone (HR=1.19; 95% CI: 1.03-1.37). The elevated risk by Asian admixture was more pronounced in normal weight than overweight/obese individuals.

CONCLUSIONS

These findings indicate that Asian admixture in NHs is associated with a higher risk for type 2 diabetes independent of known risk factors and suggest a role for ethnicity-related genetic factors in the development of this disease.

Among 4 Diet Quality Indexes, Only the Alternate Mediterranean Diet Score Is Associated with Better Colorectal Cancer Survival and Only in African American Women in the Multiethnic Cohort

BACKGROUND

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States, with a 5-y survival rate of ∼65%. Therefore, the identification of modifiable health factors to improve CRC survival is crucial.

OBJECTIVE

We investigated the association of 4 prediagnostic a priori diet quality indexes with CRC-specific and all-cause mortality in the Multiethnic Cohort (MEC).

METHODS

The MEC included >215,000 African-American, Native Hawaiian, Japanese-American, Latino, and white adults living in Hawaii and California who completed a validated quantitative food-frequency questionnaire in 1993-1996. CRC cases and deaths were identified through linkages to cancer registries and to state and national vital registries. Sex-specific HRs and 95% CIs were estimated for the Healthy Eating Index (HEI) 2010, the Alternative HEI (AHEI) 2010, the alternate Mediterranean Diet (aMED) score, and the Dietary Approaches to Stop Hypertension (DASH) index with CRC-specific and overall mortality as the primary outcomes. Ethnicity-specific analyses were the secondary outcomes.

RESULTS

Among 4204 MEC participants diagnosed with invasive CRC through 2010, 1976 all-cause and 1095 CRC-specific deaths were identified. A higher aMED score was associated with lower CRC-specific mortality in women [HR continuous pattern score divided by its respective SD (HR1SD): 0.86; 95% CI: 0.77, 0.96] but not in men (HR1SD: 1.01; 95% CI: 0.92, 1.11). A higher aMED score was also associated with lower all-cause mortality in women (HR1SD: 0.88; 95% CI: 0.81, 0.96) but not in men (HR1SD: 1.00; 95% CI: 0.93, 1.07). The HEI-2010, AHEI-2010, and DASH index were not significantly associated with CRC-specific or with all-cause mortality. The inverse relation for the aMED score was limited to African Americans and to colon (compared with rectal) cancer.

CONCLUSIONS

The aMED score was related to lower mortality only in African-American women (1 of 5 ethnic groups studied). The results should be interpreted with caution due to the small numbers of cases within ethnic groups and the issue of multiple testing.

Understanding the Motivation for Conventional and Complementary/Alternative Medicine Use Among Men With Prostate Cancer

Hypothesis: The incidence of prostate cancer and the prevalence of complementary and alternative medicine (CAM) use among prostate cancer patients have been increasing. An understanding of the underlying motivations for men to turn to CAM is essential to achieve optimal outcomes. The authors hypothesized that CAM users and nonusers differ in their assessment of conventional and CAM treatments and explored perceptions, feelings, ideas, and experiences among prostate cancer patients who made a decision to use or not to use CAM. Study Design: This qualitative study is based on in-person interviews with prostate cancer patients selected from a population-based survey. Methods: The authors conducted semistructured interviews with 27 prostate cancer patients of Asian and Caucasian ethnicity, 18 of whom used CAM and 9 of whom did not. Using qualitative research methods, they examined perceptions of conventional medicine and CAM and contrasted viewpoints of CAM users and nonusers. Based on the patients’ statements, the authors developed a model representing the viewpoints and thought patterns of CAM users as contrasted with those patients who did not use CAM. Results: The interviews revealed notable differences in viewpoints between CAM users and nonusers in 4 areas. The following themes that were important to CAM users emerged from the analysis: a view of CAM as safe and holistic coupled with a view of conventional medicine as an aggressive and isolated treatment; concern about side effects, in particular, impotence and incontinence from conventional cancer therapy; a belief in the potential efficacy of CAM despite the lack of evidence; and a need to gain a sense of control. Although nonusers expressed similar concerns about side effects of conventional treatment and considered CAM harmless, they assigned different priorities to these issues in their decision making. Conclusions: In this study, no single theme was solely responsible for CAM use among prostate cancer patients. Instead, multiple ideas woven together led patients toward CAM use. An understanding of patients’ thought processes may aid health care professionals in initiating a dialogue about decision making and potential side effects.

Abstract 1742: Smoking and risk of mucinous epithelial ovarian cancer among 300,000 women

Background

In 2012, The International Agency for Research on Cancer classified mucinous epithelial ovarian cancer as tobacco related. In a recent pooled analysis of 51 epidemiological studies, smoking was associated with an increased risk of mucinous epithelial ovarian cancer, but not with other ovarian cancer histological subtypes. The main purpose of this study was to examine impact of smoking related increase in epithelial ovarian cancer according to histological subtypes and invasiveness in a large prospective cohort study.

Methods

We followed 300,398 Norwegian women born between 1899 and 1975, recruited from 1974 to 2003, by linkage to national virtually complete registries through December 2013. The three prospective cohort studies conducted by the Norwegian Institute of Public Health and included in the analysis were the Norwegian Counties Study (1974-1988), the 40 Years Study (1985-1999), and the Cohort of Norway (CONOR) Study (1994-2003). Their data were merged and analyzed altogether. We used Cox proportional hazard models to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between smoking status, smoking-intensity and duration and epithelial ovarian cancer (EOC) histological subtypes. We used multivariable analyses stratified by birth cohort (≤1950&gt;) and cohort study, and tested for heterogeneity by BMI, attained education and physical activity.

Results

During &gt;5.9 million person-years, with a median follow-up of 19 years, 2,336 primary epithelial ovarian cancers (EOC) were identified, of which 1,647 (71%) invasive and 689 (29%) borderline. In our study, 38.0% of women were current, 21.1% former and 40.8% never smokers. Current versus never smokers risk of all histological subtypes of invasive EOC (multivariable HR = 0.97 95% CI, 0.86-1.08) was significantly different from the corresponding risk of all histological subtypes of borderline epithelial ovarian tumours (multivariate HR = 1.55 95% CI, 1.29-1.85) (pheterogeneity &lt; 0.0001). Compared with never smokers, current smokers had more than doubled risk of mucinous epithelial ovarian cancer (HR = 2.09 95% CI, 1.67-2.62). When stratified according invasiveness the corresponding figure was an increased risk of 78% [HR = 1.78 95% CI, 1.20-2.64 (ncases = 138)] for invasive mucinous epithelial ovarian cancer and more than doubled risk [HR = 2.26 95% CI, 1.71-2.97 (ncases = 302)] for borderline mucinous epithelial ovarian cancer (pheterogeneity = 0.34). Women who had smoked for more than 10 years had a 42% (HR = 1.42 95% CI, 1.07-1.88) increased risk of mucinous epithelial ovarian tumous compared to never smokers. The corresponding risk for those who smoked for longer than 20 years was increased with (HR = 2.13 95% CI, 1.68-2.70) (ptrend &lt; 0.001).

Conclusions

In this study smoking increases the risk of mucinous epithelial ovarian cancer in similar extent for invasive and borderline tumours.

Citation Format: Idlir Licaj, Bjarne Koster Jacobsen, Randi Marie Selmer, Gertraud Maskarinec, Elisabete Weiderpass, Inger Torhild Gram. Smoking and risk of mucinous epithelial ovarian cancer among 300,000 women. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1742.

Abstract 4345: Association of smoking with breast cancer risk by estrogen and progesterone receptor status: the multiethnic cohort

Background: The 2014 report of the Surgeon General put forward seven major summary points for the smoking and breast cancer relationship that needed to be addressed. One of these was that there was insufficient evidence to conclude that the risk of breast cancer from smoking differs between women diagnosed with ER+ tumors and those diagnosed with ER-tumors. The purpose of the present study was to examine whether the previously-reported association between risk of breast cancer and smoking in the Multiethnic Cohort (MEC) differed by ER+, ER-, PR+ or PR-tumor status.

Methods: From 1993 to 2010, we followed 83,300 women who were enrolled in the MEC at 45-75 years of age. We identified cancer cases via linkages to the statewide Hawaii and California cancer registries through December 2010. We used Cox proportional hazards regression with age as the underlying time scale to estimate multivariate-adjusted hazard ratios (HR) and 95% confidence intervals (CI) for the associations between different measures of smoking exposure and the four types of tumors according to hormone receptor status. The included covariates were selected a priori. For parous women, we also estimated breast cancer risk by category

of age at smoking initiation in relation to first childbirth (after or within 1 year before first childbirth, 1-5 years before, or &gt;5 years before) compared with parous never smokers for each tumor type.

Results: At cohort entry, the mean age of the participants was 62 years. Of these women, 45% reported at baseline that they had ever smoked. During a mean follow-up of 15 years, 4,484 women developed invasive breast cancer of which 2,417 (53.9%) had known status for at least one hormone tumor receptor. Altogether, 1,939 women were diagnosed with ER+, 469 with ER-, 1,548 with PR + and 688 with PR- hormone receptor status. The HRs associated with ever versus never smoking were similar for the tumor subtypes: ER+(1.05, 95% CI: 0.95, 1.15), ER-(0.99, 95% CI: 0.82, 1.20), PR+ (1.06, 95% CI: 0.96, 1.18), PR- (1.00, 95% CI: 0.85, 1.17). Compared with never smokers, ever smokers who had smoked more than 20 pack-years had a 17% a higher risk of ER+ (1.17, 95% CI 1.01-1.35) and an 11% higher risk of ER- (1.11, 95% CI 0.83-1.49) breast cancer.

Among parous women, those who had smoked more than 5 years before their first live childbirth had an increased risk of ER+ breast cancer of 45% (95% CI 1.18-1.77) and a non-statistically significant increase for ER- breast cancer of 13% (95% CI 0.72-1.76) than never smokers. The respective values for women with PR+ and PR- tumors were 37% (95% CI 1.09-1.73) and 43% (95% CI 1.03-2.01).

Conclusions: Parous women who had smoked more than five years before their first childbirth seem to have the most noticeable risk regardless of tumor type. The current data do not support any difference for the smoking and breast cancer association by hormone receptor status although this may be due to lack of power.

Citation Format: Inger T. Gram, Song-Yi Park, Laurence N. Kolonel, Gertraud Maskarinec, Lynne R. Wilkens, Christopher Haiman, Loic Le Marchand. Association of smoking with breast cancer risk by estrogen and progesterone receptor status: the multiethnic cohort. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4345.

Association of estrogen measurements in serum and urine of premenopausal women

AIMS

We evaluated conjugated and unconjugated urinary estrogen metabolites as surrogate biomarkers for serum levels of unconjugated E1 and E2 in premenopausal women.

MATERIALS & METHODS

Repeated blood and urine samples were analyzed for estrogens and their metabolites using radioimmunoassays and liquid chromatography/mass spectrometry.

RESULTS

The strongest correlation (r = 0.39) was observed between serum E1 and urinary E1 and E2. The correlations of urinary E2 (r = 0.35), E1 (r = 0.29), all E2 metabolites (r = 0.30), all E1 metabolites (r = 0.23) and total estrogens (r = 0.26) with serum E2 were only moderate although statistically significant. All correlations were substantially stronger for Whites than Asians.

CONCLUSION

Urinary E2 emerged as the best predictor for serum E1 and E2, but the large intra-subject variability in urinary estrogen levels limits its use as a biomarker.

Breast cancer risk variants at 6q25 display different phenotype associations and regulate ESR1, RMND1 and CCDC170

We analyzed 3,872 common genetic variants across the ESR1 locus (encoding estrogen receptor α) in 118,816 subjects from three international consortia. We found evidence for at least five independent causal variants, each associated with different phenotype sets, including estrogen receptor (ER(+) or ER(-)) and human ERBB2 (HER2(+) or HER2(-)) tumor subtypes, mammographic density and tumor grade. The best candidate causal variants for ER(-) tumors lie in four separate enhancer elements, and their risk alleles reduce expression of ESR1, RMND1 and CCDC170, whereas the risk alleles of the strongest candidates for the remaining independent causal variant disrupt a silencer element and putatively increase ESR1 and RMND1 expression.

International Consortium on Mammographic Density: Methodology and population diversity captured across 22 countries

Mammographic density (MD) is a quantitative trait, measurable in all women, and is among the strongest markers of breast cancer risk. The population-based epidemiology of MD has revealed genetic, lifestyle and societal/environmental determinants, but studies have largely been conducted in women with similar westernized lifestyles living in countries with high breast cancer incidence rates. To benefit from the heterogeneity in risk factors and their combinations worldwide, we created an International Consortium on Mammographic Density (ICMD) to pool individual-level epidemiological and MD data from general population studies worldwide. ICMD aims to characterize determinants of MD more precisely, and to evaluate whether they are consistent across populations worldwide. We included 11755 women, from 27 studies in 22 countries, on whom individual-level risk factor data were pooled and original mammographic images were re-read for ICMD to obtain standardized comparable MD data. In the present article, we present (i) the rationale for this consortium; (ii) characteristics of the studies and women included; and (iii) study methodology to obtain comparable MD data from original re-read films. We also highlight the risk factor heterogeneity captured by such an effort and, thus, the unique insight the pooled study promises to offer through wider exposure ranges, different confounding structures and enhanced power for sub-group analyses.

Smoking and Risk of Breast Cancer in a Racially/Ethnically Diverse Population of Mainly Women Who Do Not Drink Alcohol: The MEC Study

We prospectively examined the association between smoking and the risk of breast cancer in a racially/ethnically diverse population comprising mainly women who did not drink alcohol. From 1993 to 2010, we followed 83,300 women who were enrolled in the Multiethnic Cohort Study at 45-75 years of age. We identified cancer cases via linkage to the Surveillance, Epidemiology, and End Results Program cancer registries that covered the states of Hawaii and California through December 2010. We used Cox proportional hazards models to estimate hazard ratios and 95% confidence intervals while adjusting for confounders that were decided a priori. During a mean follow-up of 15 years, 4,484 women developed invasive breast cancer. Compared with parous never smokers, women who had smoked for more than 20 pack-years and initiated smoking more than 5 years before their first childbirth had an overall risk of breast cancer that was 35% higher (hazard ratio = 1.35, 95% confidence interval: 1.13, 1.63). Among women who did not drink alcohol, the risk was 40% higher (hazard ratio = 1.40, 95% confidence interval: 1.08, 1.81). This higher risk did not significantly differ among racial/ethnic groups (P(interaction) = 0.82). We found that various measures of smoking exposure were associated with a higher risk of breast cancer, especially smoking initiated many years before first childbirth, and that risk did not differ by alcohol consumption (yes vs. no) or racial/ethnic group.

Racial and ethnic disparities in the impact of obesity on breast cancer risk and survival: a global perspective

Obesity is a global concern, affecting both developed and developing countries. Although there are large variations in obesity and breast cancer rates worldwide and across racial/ethnic groups, most studies evaluating the impact of obesity on breast cancer risk and survival have been conducted in non-Hispanic white women in the United States or Europe. Given the known racial/ethnic differences in tumor hormone receptor subtype distribution, obesity prevalence, and risk factor profiles, we reviewed published data for women of African, Hispanic, and Asian ancestry in the United States and their countries of origin. Although the data are limited, current evidence suggests a stronger adverse effect of obesity on breast cancer risk and survival in women of Asian ancestry. For African Americans and Hispanics, the strength of the associations appears to be more comparable to that of non-Hispanic whites, particularly when accounting for subtype and menopausal status. Central obesity seems to have a stronger impact in African-American women than general adiposity as measured by body mass index. International data from countries undergoing economic transition offer a unique opportunity to evaluate the impact of rapid weight gain on breast cancer. Such studies should take into account genetic ancestry, which may help elucidate differences in associations between ethnically admixed populations. Overall, additional large studies that use a variety of adiposity measures are needed, because the current evidence is based on few studies, most with limited statistical power. Future investigations of obesity biomarkers will be useful to understand possible racial/ethnic biological differences underlying the complex association between obesity and breast cancer development and progression.

Excess body weight and colorectal cancer survival: the multiethnic cohort

PURPOSE

Excess body weight is a risk factor for colorectal cancer (CRC) and may also adversely affect survival in CRC patients.

METHODS

This study examined the relation of body mass index (BMI), which was self-reported at cohort entry and after 5.7 ± 0.8 years, with CRC-specific and all-cause survival among 4,204 incident cases of invasive CRC in the multiethnic cohort. Cox regression analysis with age as time metric and BMI as time-varying exposure was applied to estimate hazard ratios (HR) and 95% confidence intervals (CIs) while adjusting for relevant covariates.

RESULTS

Over 6.0 ± 4.7 years of follow-up, 1,976 all-cause and 1,095 CRC-specific deaths were recorded. The mean time interval between cohort entry and diagnosis was 7.6 ± 4.7 years. No association with CRC-specific survival was detected in men (HR5units = 0.94; 95%CI 0.84-1.04) or women (HR5units = 0.98; 95%CI 0.89-1.08). In men, all-cause survival also showed no relation with BMI (HR5unit = 0.97; 95%CI 0.90-1.06), whereas it was reduced in women (HR5units = 1.10; 95%CI 1.03-1.18). Interactions of BMI with ethnicity were only significant for obesity. Obese Latino and overweight Native Hawaiian men as well as overweight African-American women experienced significantly better CRC-specific survival than whites. Overweight Japanese men and African-American women had better all-cause survival and obese Latino women had the lowest all-cause survival (HRobese = 1.74; 95%CI 1.08-2.80).

CONCLUSIONS

This analysis detected little evidence for an adverse effect of excess body weight on CRC-specific survival, but all-cause survival was reduced in women. These findings suggest that adiposity may be less important for CRC survival than as an etiologic factor.

Nutritional factors and non-Hodgkin lymphoma survival in an ethnically diverse population: the Multiethnic Cohort

Background/Objectives

To understand the possible effect of modifiable health behaviors on the prognosis of the increasing number of non-Hodgkin lymphoma (NHL) survivors, we examined the pre-diagnostic intake of major food groups with all-cause and NHL-specific survival in the Multiethnic Cohort (MEC).

Subjects/Methods

This analysis included 2,339 participants free of NHL at cohort entry and diagnosed with NHL as identified b cancer registries during follow-up. Deaths were ascertained through routine linkages to state and national death registries. Cox proportional hazards regression was applied to estimate hazard ratios (HR) and 95% confidence intervals (CI) for overall and NHL-specific mortality according to prediagnostic intake of vegetables, fruits, red meat, processed meat, fish, legumes, dietary fiber, dairy products, and soy foods assessed by food frequency questionnaire.

Results

The mean age at diagnosis was 71.8±8.5 years. During 4.5±4.1 years of follow-up, 1,348 deaths, including 903 NHL-specific deaths, occurred. In multivariable models, dairy intake was associated with higher all-cause mortality (highest vs. lowest tertile: HR=1.14, 95% CI 1.00–1.31, p_trend=0.03) and NHL-specific (HR=1.16, 95% CI 0.98–1.37) mortality. Legume intake above the lowest tertile was related to significant 13–16% lower all-cause and NHL-specific mortality, while red meat and fish intake in the intermediate tertiles was associated with lower NHL-specific mortality. No association with survival was detected for the other food groups.

Conclusion

These data suggest that pre-diagnostic dietary intake may not appreciably contribute to NHL survival although the higher mortality for dairy products and the better prognosis associated with legumes agree with known biologic effects of these foods.

A comprehensive evaluation of interaction between genetic variants and use of menopausal hormone therapy on mammographic density

INTRODUCTION

Mammographic density is an established breast cancer risk factor with a strong genetic component and can be increased in women using menopausal hormone therapy (MHT). Here, we aimed to identify genetic variants that may modify the association between MHT use and mammographic density.

METHODS

The study comprised 6,298 postmenopausal women from the Mayo Mammography Health Study and nine studies included in the Breast Cancer Association Consortium. We selected for evaluation 1327 single nucleotide polymorphisms (SNPs) showing the lowest P-values for interaction (P int) in a meta-analysis of genome-wide gene-environment interaction studies with MHT use on risk of breast cancer, 2541 SNPs in candidate genes (AKR1C4, CYP1A1-CYP1A2, CYP1B1, ESR2, PPARG, PRL, SULT1A1-SULT1A2 and TNF) and ten SNPs (AREG-rs10034692, PRDM6-rs186749, ESR1-rs12665607, ZNF365-rs10995190, 8p11.23-rs7816345, LSP1-rs3817198, IGF1-rs703556, 12q24-rs1265507, TMEM184B-rs7289126, and SGSM3-rs17001868) associated with mammographic density in genome-wide studies. We used multiple linear regression models adjusted for potential confounders to evaluate interactions between SNPs and current use of MHT on mammographic density.

RESULTS

No significant interactions were identified after adjustment for multiple testing. The strongest SNP-MHT interaction (unadjusted P int <0.0004) was observed with rs9358531 6.5kb 5' of PRL. Furthermore, three SNPs in PLCG2 that had previously been shown to modify the association of MHT use with breast cancer risk were found to modify also the association of MHT use with mammographic density (unadjusted P int <0.002), but solely among cases (unadjusted P int SNP×MHT×case-status <0.02).

CONCLUSIONS

The study identified potential interactions on mammographic density between current use of MHT and SNPs near PRL and in PLCG2, which require confirmation. Given the moderate size of the interactions observed, larger studies are needed to identify genetic modifiers of the association of MHT use with mammographic density.

Abstract 882: Obesity, comorbidity and endometrial cancer survival: the multiethnic cohort

Background: Endometrial cancer (EC) is the most common gynecologic cancer diagnosed in the United States. With &gt;750,000 survivors in 2014, EC comprises the second largest group of female cancer survivors. Higher body mass index (BMI) and other medical comorbidities have been suggested to negatively impact EC survival; however, data in minority populations with rising EC incidence and mortality (i.e. Asian Americans, African Americans, Latinas, etc.) are scarce. We examined the association of pre-diagnostic BMI and obesity-related comorbidities with overall survival in African-American, Japanese, Native Hawaiian, Latino and white women in the Multiethnic Cohort.

Methods: Women with complete risk factor data who developed endometrial cancer during follow up were included in the analysis (N = 998). BMI and obesity-related comorbidities (diabetes, hypertension, heart attack and stroke) were self-reported at cohort entry and at subsequent follow-ups. Cox's models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) with time-varying exposures in relation to all-cause mortality while adjusting for age at diagnosis, tumor characteristics, treatment, and education.

Results: The mean age at EC diagnosis was 67.7 ± 8.5 years. The mean follow-up period was 7.3 ± 5.3 years from diagnosis to death or end of follow up during which time a total of 323 deaths were observed, 84 (26%) of which were due to EC. The mean BMI was 29.9 kg/m2 and 53% of women had at least one comorbid condition. The prevalence of obesity and comorbid conditions varied across ethnic groups (P&lt;0.0001). The prevalence of obesity (BMI ≥30 kg/m2) ranged from 18% in Japanese Americans to 69% in Hawaiians. The prevalence of women with at least one comorbid condition ranged from 38% in whites to 76% in African Americans. Women with a BMI ≥35 kg/m2 had an increased risk of all-cause mortality [HR = 1.55 (95% CI: 1.06, 2.28)] compared with women with BMI &lt;25 kg/m2. Women with two or more comorbid conditions also had a higher risk of all-cause mortality (HR = 1.61; 95% CI: 1.12, 2.31) compared to those with no medical comorbidities. There was evidence of ethnic differences in the comorbidity and all-cause mortality association (P interaction = 0.02); the presence of two or more comorbidities was significantly associated with all-cause mortality in whites (HR = 2.98; 95% CI: 1.34, 6.63) and Japanese Americans (HR = 3.47; 95% CI: 1.19, 10.14), but not in African Americans (HR = 0.88; 95% CI: 0.42, 1.82), Latinas (HR = 1.16; 95% CI: 0.45, 2.96), and Native Hawaiians (HR = 0.95; 95% CI: 0.22, 4.02).

Conclusions: Our results show that higher pre-diagnosis BMI and the presence of two or more comorbidities increase the risk of overall death among multiethnic women diagnosed with EC. Clear identification and targeted managements of these conditions may improve overall survival after EC diagnosis.

Citation Format: Veronica Wendy Setiawan, Gertraud Maskarinec, Yvonne G. Lin, Dongyun Yang, Lynne R. Wilkens, Brian E. Henderson, Loic Le Marchand. Obesity, comorbidity and endometrial cancer survival: the multiethnic cohort. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 882. doi:10.1158/1538-7445.AM2015-882

Adherence to cancer prevention recommendations and antioxidant and inflammatory status in premenopausal women

For cancer prevention, the World Cancer Research Fund and American Institute for Cancer Research (WCRF/AICR) emphasise recommendations to improve individual behaviour, including avoidance of tobacco products, maintaining a lean body mass, participating in physical activity, consuming a plant-based diet, and minimising the consumption of energy-dense foods, such as sodas, red and processed meats and alcohol. In the present study of 275 healthy premenopausal women, we explored the association of adherence scores with levels of three biomarkers of antioxidant and inflammation status: serum C-reactive protein (CRP), serum γ-tocopherol and urinary F2-isoprostane. The statistical analysis applied linear regression across categories of adherence to WCRF/AICR recommendations. Overall, seventy-two women were classified as low ( ≤ 4), 150 as moderate (5-6), and fifty-three as high adherers ( ≥ 7). The unadjusted means for CRP were 2.7, 2.0 and 1.7 mg/l for low, moderate and high adherers (P trend= 0.03); this association was strengthened after adjustment for confounders (P trend= 0.006). The respective values for serum γ-tocopherol were 1.97, 1.63 and 1.45 μg/ml (P trend= 0.02 before and P trend= 0.03 after adjustment). Only for urinary F2-isoprostane, the lower values in high adherers (16.0, 14.5, and 13.3 ng/ml) did not reach statistical significance (P trend= 0.18). In an analysis by BMI, overweight and obese women had higher biomarker levels than normal weight women; the trend was significant for CRP (P trend< 0.001) and γ-tocopherol (P trend= 0.003) but not for F2-isoprostane (P trend= 0.14). These findings suggest that both adherence to the WCRF/AICR guidelines and normal BMI status are associated with lower levels of biomarkers that indicate oxidative stress and inflammation.

Polymorphisms in a Putative Enhancer at the 10q21.2 Breast Cancer Risk Locus Regulate NRBF2 Expression

Genome-wide association studies have identified SNPs near ZNF365 at 10q21.2 that are associated with both breast cancer risk and mammographic density. To identify the most likely causal SNPs, we fine mapped the association signal by genotyping 428 SNPs across the region in 89,050 European and 12,893 Asian case and control subjects from the Breast Cancer Association Consortium. We identified four independent sets of correlated, highly trait-associated variants (iCHAVs), three of which were located within ZNF365. The most strongly risk-associated SNP, rs10995201 in iCHAV1, showed clear evidence of association with both estrogen receptor (ER)-positive (OR = 0.85 [0.82-0.88]) and ER-negative (OR = 0.87 [0.82-0.91]) disease, and was also the SNP most strongly associated with percent mammographic density. iCHAV2 (lead SNP, chr10: 64,258,684:D) and iCHAV3 (lead SNP, rs7922449) were also associated with ER-positive (OR = 0.93 [0.91-0.95] and OR = 1.06 [1.03-1.09]) and ER-negative (OR = 0.95 [0.91-0.98] and OR = 1.08 [1.04-1.13]) disease. There was weaker evidence for iCHAV4, located 5' of ADO, associated only with ER-positive breast cancer (OR = 0.93 [0.90-0.96]). We found 12, 17, 18, and 2 candidate causal SNPs for breast cancer in iCHAVs 1-4, respectively. Chromosome conformation capture analysis showed that iCHAV2 interacts with the ZNF365 and NRBF2 (more than 600 kb away) promoters in normal and cancerous breast epithelial cells. Luciferase assays did not identify SNPs that affect transactivation of ZNF365, but identified a protective haplotype in iCHAV2, associated with silencing of the NRBF2 promoter, implicating this gene in the etiology of breast cancer.

Novel Associations between Common Breast Cancer Susceptibility Variants and Risk-Predicting Mammographic Density Measures

Mammographic density measures adjusted for age and body mass index (BMI) are heritable predictors of breast cancer risk, but few mammographic density-associated genetic variants have been identified. Using data for 10,727 women from two international consortia, we estimated associations between 77 common breast cancer susceptibility variants and absolute dense area, percent dense area and absolute nondense area adjusted for study, age, and BMI using mixed linear modeling. We found strong support for established associations between rs10995190 (in the region of ZNF365), rs2046210 (ESR1), and rs3817198 (LSP1) and adjusted absolute and percent dense areas (all P < 10(-5)). Of 41 recently discovered breast cancer susceptibility variants, associations were found between rs1432679 (EBF1), rs17817449 (MIR1972-2: FTO), rs12710696 (2p24.1), and rs3757318 (ESR1) and adjusted absolute and percent dense areas, respectively. There were associations between rs6001930 (MKL1) and both adjusted absolute dense and nondense areas, and between rs17356907 (NTN4) and adjusted absolute nondense area. Trends in all but two associations were consistent with those for breast cancer risk. Results suggested that 18% of breast cancer susceptibility variants were associated with at least one mammographic density measure. Genetic variants at multiple loci were associated with both breast cancer risk and the mammographic density measures. Further understanding of the underlying mechanisms at these loci could help identify etiologic pathways implicated in how mammographic density predicts breast cancer risk.