Social inequalities and smoking-associated breast cancer - Results from a prospective cohort study

OBJECTIVE

The association between smoking and breast cancer has been found in most recent, large cohort studies. We wanted to investigate how smoking-associated breast cancer varies by level of education, a well-established measure of socioeconomic status.

METHODS

We included 302,865 women with 7490 breast cancer cases. Participants were assigned to low, moderate or high level of education and analyzed by smoking status (ever/never), and stratified by birth cohorts (≤1950>). We used Cox proportional hazard to estimate hazard ratios (HRs) and confidence intervals (CIs), adjusting for age, number of children, age at first childbirth, BMI, age at enrollment and physical activity.

RESULTS

Women born ≤1950 with low and moderate levels of education had a 40% increase in smoking-associated breast cancer risk (HR=1.40, 95% CI 1.25-1.57 and HR=1.14, 95% CI 1.05-1.24, respectively). Women in the same age group with high level of education did not have an increase in risk. No increased breast cancer risk was found among women born after 1950 for any level of education, when analyzed by smoking status. Longer duration of smoking before first childbirth was consistently associated with increasing risk of breast cancer in all three categories of education (all p for trends<0.01).

CONCLUSION

Smoking for several years before first childbirth increases the risk of breast cancer, regardless of educational level.

A priori-defined diet quality indexes and risk of type 2 diabetes: the Multiethnic Cohort

AIMS/HYPOTHESIS

Dietary patterns have been associated with the incidence of type 2 diabetes, but little is known about the impact of ethnicity on this relationship. This study evaluated the association between four a priori dietary quality indexes and risk of type 2 diabetes among white individuals, Japanese-Americans and Native Hawaiians in the Hawaii component of the Multiethnic Cohort.

METHODS

After excluding participants with prevalent diabetes and missing values, the analysis included 89,185 participants (11,217 cases of type 2 diabetes). Dietary intake was assessed at baseline with a quantitative food frequency questionnaire designed for use in the relevant ethnic populations. Sex- and ethnicity-specific HRs were calculated for the Healthy Eating Index-2010 (HEI-2010), the Alternative HEI-2010 (AHEI-2010), the Alternate Mediterranean Diet Score (aMED) and the Dietary Approaches to Stop Hypertension (DASH).

RESULTS

We observed significant inverse associations between higher DASH index scores and risk of type 2 diabetes in white men and women, as well as in Japanese-American women and Native Hawaiian men, with respective risk reductions of 37%, 31%, 19% and 21% (in the highest compared with the lowest index category). A higher adherence to the AHEI-2010 and aMED diet was related to a 13-28% lower risk of type 2 diabetes in white participants but not in other ethnic groups. No significant associations with risk of type 2 diabetes were observed for the HEI-2010 index.

CONCLUSIONS/INTERPRETATION

The small ethnic differences in risk of type 2 diabetes associated with scores of a priori-defined dietary patterns may be due to a different consumption pattern of food components and the fact that the original indexes were not based on diets typical for Asians and Pacific Islanders.

Ethnic differences in serum adipokine and C-reactive protein levels: the multiethnic cohort

BACKGROUND

Ethnic disparities in metabolic disease risk may be the result of differences in circulating adipokines and inflammatory markers related to ethnic variations in obesity and body fat distribution.

SUBJECTS/METHODS

In a cross-sectional design, we compared serum levels of leptin, adiponectin, C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in control subjects (321 men and 930 women) from two nested case-control studies conducted within the Multiethnic Cohort Study consisting of whites, Japanese Americans (JA), Latinos, African Americans (AA) and Native Hawaiians (NH). General linear models were applied to evaluate ethnic differences in log-transformed serum biomarker levels before and after adjusting for body mass index (BMI) at cohort entry.

RESULTS

In comparison to whites, significant ethnic differences were observed for all biomarkers except TNF-α. JA men and women had significantly lower leptin and CRP levels than whites, and JA women also had lower adiponectin levels. Leptin was significantly higher in AA women (P < 0.01), adiponectin was significantly lower in AA men and women (P = 0.02 and P < 0.001), and CRP and IL-6 were significantly higher in AA men and women. Lower adiponectin (P < 0.0001) and CRP (P = 0.03) levels were the only biomarkers in NH women that differed from whites; no statistically significant differences were seen for NH men and for Latino men and women. When adjusted for BMI at cohort entry, the differences between the lowest and the highest values across ethnic groups decreased for all biomarkers except adiponectin in men indicating that ethnic differences were partially due to weight status.

CONCLUSIONS

These findings demonstrate the ethnic variations in circulating adipokine and CRP levels before and after adjustment for BMI. Given the limitation of BMI as a general measure of obesity, further investigation with visceral and subcutaneous adiposity measures are warranted to elucidate ethnicity-related differences in adiposity in relation to disparities in obesity-related disease risk.

The influence of whole grain products and red meat on intestinal microbiota composition in normal weight adults: a randomized crossover intervention trial

Intestinal microbiota is related to obesity and serum lipid levels, both risk factors for chronic diseases constituting a challenge for public health. We investigated how a diet rich in whole grain (WG) products and red meat (RM) influences microbiota. During a 10-week crossover intervention study, 20 healthy adults consumed two isocaloric diets, one rich in WG products and one high in RM. Repeatedly data on microbiota were assessed by 16S rRNA based denaturing gradient gel electrophoresis (DGGE). A blood sample and anthropometric data were collected. Mixed models and logistic regression were used to investigate effects. Microbiota showed interindividual variability. However, dietary interventions modified microbiota appearance: 8 bands changed in at least 4 participants during the interventions. One of the bands appearing after WG and one increasing after RM remained significant in regression models and were identified as Collinsella aerofaciens and Clostridium sp. The WG intervention lowered obesity parameters, while the RM diet increased serum levels of uric acid and creatinine. The study showed that diet is a component of major relevance regarding its influence on intestinal microbiota and that WG has an important role for health. The results could guide investigations of diet and microbiota in observational prospective cohort studies. Trial registration: ClinicalTrials.gov NCT01449383.

Abstract 2170: Body mass index and non-Hodgkin lymphoma survival in an ethnically diverse population: The Multiethnic Cohort study

Introduction: Obesity increases the risk of death for several malignancies including breast and colon cancer. However, for non-Hodgkin's lymphoma (NHL), the association between pre-diagnostic body mass index (BMI) and survival is unclear. We examined the association between BMI before diagnosis and overall and NHL-specific survival in the Multiethnic Cohort (MEC) study of African Americans, Native Hawaiians, Japanese Americans, Latinos, and Caucasians.

Methods: MEC participants free of NHL at cohort entry and diagnosed with NHL as identified through linkages to SEER cancer registries and the National Death Index during follow-up were included in the current analyses (N=1348). Body mass index (BMI) was based on self-reported weight and height at cohort entry. Cox proportional hazards regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for pre-diagnostic BMI categories in relation to all-cause and NHL-specific mortality while adjusting for known confounders.

Results: The mean time from cohort entry to NHL diagnosis was 7.2±3.9 years (range: 0.0-15.0 years). The mean age at NHL diagnosis was 70.6 (range 45-89) years and the mean BMI at cohort entry was 26.5±4.7 kg/m2. After a mean follow-up of 4.3±3.5 years, 679 deaths including 457 NHL-specific deaths occurred. In multivariable models, obese patients (BMI ≥30.0) had higher all-cause (HR = 1.55, 95%CI = 1.21-2.00) and NHL-specific (HR = 1.84, 95%CI = 1.35-2.52) mortality compared to patients with high-normal BMI (22.5-24.9 kg/m2). For overweight patients (BMI 25.0-29.9), the respective HRs were 1.29 (95%CI = 1.05-1.58) and 1.47 (95%CI = 1.14-1.89). A 35% higher risk of all-cause mortality was also observed in patients with low-normal BMI. When BMI was included in the model as a continuous variable, the risk of NHL-specific mortality increased by 3.3% for every increase in one unit of BMI (HR = 1.03, 95% CI = 1.01-1.06, ptrend = 0.004). Stratification by NHL type suggested a higher NHL-specific mortality risk for chronic lymphocytic leukemia/small lymphocytic lymphoma than for diffuse large B-cell lymphoma and follicular lymphoma. The interaction of BMI with ethnicity (p=0.83) was not significant.

Conclusions: Pre-diagnostic obesity may be related to poorer overall and NHL-specific survival in NHL patients. Therefore, prediagnostic BMI may be a suitable prognostic marker for NHL patients.

Citation Format: Qi Jie Nicholas Leo, Nicholas J. Ollberding, Lynne R. Wilkens, Laurence N. Kolonel, Brian E. Henderson, Loic Le Marchand, Gertraud Maskarinec. Body mass index and non-Hodgkin lymphoma survival in an ethnically diverse population: The Multiethnic Cohort study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2170. doi:10.1158/1538-7445.AM2014-2170

The association between lifetime smoking exposure and breast cancer mortality--results from a Norwegian cohort

Several recent cohort studies have found an association between smoking and breast cancer, but the association between lifetime smoking exposure and breast cancer mortality is less well described. We examined whether smoking before breast cancer diagnosis is a predictor of breast cancer mortality in a large cohort with more than 4.1 million years of follow-up, with a special focus on women who initiated smoking before first childbirth. Information on smoking status was collected before breast cancer diagnosis and used to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) of breast cancer mortality in a cohort of 302,865 Norwegian women with 1106 breast cancer deaths. Women were enrolled between 1974 and 2003 and followed up through linkages to national registries until 31 December 2007. We found that breast cancer mortality was slightly but significantly increased for current (HR = 1.15, 95% CI 1.01-1.32) and ever (HR = 1.15, 95% CI 1.02-1.30) smokers as compared to never smokers. No statistically significantly increased mortality was found for women who initiated smoking before first childbirth, and no dose-response association was revealed for any of the different measures of smoking exposure. A large proportion of heavy smokers may have died from other causes than breast cancer during follow-up, possibly diluting our results. This study found that lifetime smoking exposure had a significantly increased risk of breast cancer mortality compared with never smokers.

Abstract 2917: The association of smoking before first childbirth with breast cancer risk is independent from alcohol use and does not seem to differ across ethnic groups: the multiethnic cohort study

Background; The association of smoking with breast cancer is still the subject of scientific inquiry. In early studies, women often reported starting to smoke after their first live childbirth, while in the most recent cohort studies the women started before giving birth. In the former studies smokers had no increased risk of breast cancer, while the latter studies report that smokers have an increased risk of breast cancer. The purpose of the present study was to prospectively examine whether active smoking increases the risk of breast cancer overall and among non-drinkers of alcohol, as well as according to onset of smoking in relation to first childbirth, and according to race/ ethnicity in the MEC, a mature cohort study that enrolled older women of five ethnic groups who are predominately non-drinkers of alcohol.

Methods: We followed 88,374 women, enrolled at age 45-75 years as part of the Multiethnic Cohort Study. Breast cancer was ascertained by linkage to the Surveillance, Epidemiology, and End Results (SEER) Program cancer registries covering the states of Hawaii and California through December 2007. We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) while adjusting for relevant confounders.

Results: During a mean follow-up of 12 years, 3,821 women developed invasive breast cancer. Compared with never smokers, smoking characteristics showed consistent dose-response associations with breast cancer risk [age at smoking initiation (ptrend =0.002), smoking duration (ptrend =0.03), number of cigarettes smoked daily (ptrend=0.01) and pack-years (ptrend=0.003)]. The patterns for non-drinkers were quite similar to those for women overall, although with the smaller sample sizes, only the test for trend for total lifetime use (pack-years) was statistically significant (ptrend =0.02). Among parous women, those who had smoked three or more years before their first live childbirth had an increased risk of breast cancer of 20% overall (95% CI 1.07-1.36) and among non-drinkers only ( 95% CI 1.01-1.43), compared with never smokers. For parous women, both Native Hawaiians (ptrend =0.02) and whites (ptrend =0.03) showed a positive dose-response relationship between duration of smoking before the first childbirth and breast cancer risk. The test for heterogeneity for the association between ever /never smoking and breast cancer risk by ethnic groups was not significant (p=0.49).

Conclusions: We found that the smoking-related increase in breast cancer risk is similar for drinkers and non-drinkers of alcohol. Our data do not support any difference for the smoking and breast cancer association for the five examined racial/ethnic groups although this may be due to lack of power.

Citation Format: Inger T. Gram, Song-Yi Park, Melissa A. Little, Laurence N. Kolonel, Gertraud Maskarinec, Lynne R. Wilkens, Brian E. Hendereson, Loic Le Marchand. The association of smoking before first childbirth with breast cancer risk is independent from alcohol use and does not seem to differ across ethnic groups: the multiethnic cohort study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2917. doi:10.1158/1538-7445.AM2014-2917

Oestrogen levels in serum and urine of premenopausal women eating low and high amounts of meat

OBJECTIVE

Based on the hypothesis that high-meat diets may increase breast cancer risk through hormonal pathways, the present analysis compared oestrogens in serum and urine by meat-eating status.

DESIGN

Intervention with repeated measures.

SETTING

Two randomized soya trials (BEAN1 and BEAN2) among premenopausal healthy women.

SUBJECTS

BEAN1 participants completed seven unannounced 24 h dietary recalls and donated five blood and urine samples over 2 years. BEAN2 women provided seven recalls and three samples over 13 months. Serum samples were analysed for oestrone (E₁) and oestradiol (E₂) using RIA. Nine oestrogen metabolites were measured in urine by LC-MS. Semi-vegetarians included women who reported consuming <30 g of red meat, poultry and fish daily, and pescatarians those who reported consuming <20 g of meat/poultry but >10 g of fish daily. All other women were classified as non-vegetarians. We applied mixed models to compute least-square means by vegetarian status adjusted for potential confounders.

RESULTS

The mean age of the 272 participants was 41·9 (SD 4·5) years. Serum E₁ (85 v. 100 pg/ml, P = 0·04) and E₂ (140 v. 154 pg/ml, P = 0·04) levels were lower in the thirty-seven semi-vegetarians than in the 235 non-vegetarians. The sum of the nine urinary oestrogen metabolites (183 v. 200 pmol/mg creatinine, P = 0·27) and the proportions of individual oestrogens and pathways did not differ by meat-eating status. Restricting the models to the samples collected during the luteal phase strengthened the associations.

CONCLUSIONS

Given the limitations of the study, the lower levels of serum oestrogens in semi-vegetarians than non-vegetarians need confirmation in larger populations.

Disparity in diabetes risk across Native Hawaiians and different Asian groups: the multiethnic cohort

We evaluated the impact of body mass index (BMI) and lifestyle risk factors on ethnic disparity in diabetes incidence among 89 198 Asian, Native Hawaiian, and white participants of the Multiethnic Cohort who completed multiple questionnaires. After 12 years of follow-up, 11 218 new cases were identified through self-report and health plan linkages. BMI was lowest in Chinese/Koreans, Japanese, and Filipinos (22.4, 23.5, and 23.9 kg/m(2)). Using Cox regression, the unadjusted hazard ratios were 1.9 (Chinese/Korean), 2.1 (Japanese, Mixed-Asian), 2.2 (Filipino), 2.5 (Native Hawaiian), and 2.6 (part-Asian) as compared with whites. With BMI added, the risk for Japanese, Filipinos, Chinese/Koreans, and mixed-Asians increased (8%-42%) but declined in part-Asians and Native Hawaiians (17%-31%). When lifestyle and dietary factors were also included, the risk was attenuated in all groups (6%-14%). Despite their lower BMI, Asian Americans have a higher diabetes risk than whites, but dietary and lifestyle factors do not account for the excess risk.

Urinary isoflavonoid excretion as a biomarker of dietary soy intake during two randomized soy trials

We evaluated urinary isoflavonoid excretion as a biomarker of dietary isoflavone intake during two randomized soy trials (13-24 months) among 256 premenopausal women with a total of 1,385 repeated urine samples. Participants consumed a high-soy diet (2 servings/day) and a low-soy diet (<3 servings/week), completed 7 unannounced 24-hour dietary recalls, and donated repeated urine samples, which were analyzed for isoflavonoid excretion by liquid chromatography methods. We computed Spearman correlation coefficients and applied logistic regression to estimate the area under the curve. Median overall daily dietary isoflavone intakes at baseline, during low- and high-soy diet were 2.3, 0.2, and 60.4 mg aglycone equivalents, respectively. The corresponding urinary isoflavonoid excretion values were 0.4, 1.0, and 32.4 nmol/mg creatinine. Across diets, urinary isoflavonoid excretion was significantly associated with dietary isoflavone intake (rs=0.51, AUC=0.85; p<0.0001) but not within diet periods (rs=0.05-0.06, AUC=0.565-0.573). Urinary isoflavonoid excretion is an excellent biomarker to discriminate between low- and high-soy diets across populations, but the association with dietary isoflavone intake is weak when the range of soy intake is small.

Obesity and non-Hodgkin lymphoma survival in an ethnically diverse population: the Multiethnic Cohort study

PURPOSE

Obesity increases mortality for several malignancies, but for non-Hodgkin lymphoma (NHL), the association between body mass index (BMI) and survival is unclear. We examined the association of pre-diagnostic BMI with overall and NHL-specific survival in the multiethnic cohort (MEC) study of African Americans, Native Hawaiians, Japanese Americans, Latinos, and Caucasians.

METHODS

MEC participants free of NHL at cohort entry and diagnosed with NHL during follow-up were included in the analyses (n = 1,331). BMI was based on self-reported weight and height at cohort entry and after 6.1 years of cohort entry. Cox proportional hazards regression was used to calculate hazard ratios (HR) and 95 % confidence intervals (CI) with BMI as time-varying exposure in relation to all-cause and NHL-specific mortality while adjusting for known confounders.

RESULTS

The mean age at NHL diagnosis was 70.5 (range 45-89) years. After a mean follow-up of 4.3 ± 3.5 years, 667 deaths including 450 NHL-specific deaths occurred. In multivariable models, obese patients (BMI ≥30.0 kg/m(2)) had higher all-cause (HR 1.46, 95 % CI 1.13-1.87) and NHL-specific (HR 1.77, 95 % CI 1.30-2.41) mortality compared with patients with high-normal BMI (22.5-24.9 kg/m(2)). For overweight patients (BMI = 25.0-29.9 kg/m(2)), the respective HRs were 1.21 (95 % CI 0.99-1.49) and 1.36 (95 % CI 1.06-1.75). Cases with low-normal BMI (<22.5 kg/m(2)) experienced a significant 45 % higher all-cause and a 40 % higher NHL-specific mortality. After stratification by NHL type, the adverse effect of BMI was stronger for chronic lymphocytic leukemia/small lymphocytic lymphoma than for diffuse large B cell lymphoma and follicular lymphoma.

CONCLUSIONS

Pre-diagnostic BMI may be a suitable prognostic marker for NHL patients.

Mammographic density phenotypes and risk of breast cancer: a meta-analysis

BACKGROUND

Fibroglandular breast tissue appears dense on mammogram, whereas fat appears nondense. It is unclear whether absolute or percentage dense area more strongly predicts breast cancer risk and whether absolute nondense area is independently associated with risk.

METHODS

We conducted a meta-analysis of 13 case-control studies providing results from logistic regressions for associations between one standard deviation (SD) increments in mammographic density phenotypes and breast cancer risk. We used random-effects models to calculate pooled odds ratios and 95% confidence intervals (CIs). All tests were two-sided with P less than .05 considered to be statistically significant.

RESULTS

Among premenopausal women (n = 1776 case patients; n = 2834 control subjects), summary odds ratios were 1.37 (95% CI = 1.29 to 1.47) for absolute dense area, 0.78 (95% CI = 0.71 to 0.86) for absolute nondense area, and 1.52 (95% CI = 1.39 to 1.66) for percentage dense area when pooling estimates adjusted for age, body mass index, and parity. Corresponding odds ratios among postmenopausal women (n = 6643 case patients; n = 11187 control subjects) were 1.38 (95% CI = 1.31 to 1.44), 0.79 (95% CI = 0.73 to 0.85), and 1.53 (95% CI = 1.44 to 1.64). After additional adjustment for absolute dense area, associations between absolute nondense area and breast cancer became attenuated or null in several studies and summary odds ratios became 0.82 (95% CI = 0.71 to 0.94; P heterogeneity = .02) for premenopausal and 0.85 (95% CI = 0.75 to 0.96; P heterogeneity < .01) for postmenopausal women.

CONCLUSIONS

The results suggest that percentage dense area is a stronger breast cancer risk factor than absolute dense area. Absolute nondense area was inversely associated with breast cancer risk, but it is unclear whether the association is independent of absolute dense area.

Serum coenzyme Q₁₀, α-tocopherol, γ-tocopherol, and C-reactive protein levels and body mass index in adolescent and premenopausal females

OBJECTIVE

Lipid-soluble antioxidants are associated with a lower incidence for many chronic diseases of aging, possibly by preventing damage from chronic inflammation. In the current study, we compared serum levels of coenzyme Q₁₀ (CoQ₁₀), α-tocopherol, γ-tocopherol, and C-reactive protein (CRP) between adolescent girls and premenopausal women to assess changes from childhood to midlife.

METHODS

Baseline serum CoQ₁₀, α-tocopherol, γ-tocopherol, and CRP levels were measured in 207 girls (13-19 years) and 183 premenopausal women (34-47 years) using standard methods and the 2 age groups were compared by t test. The influence of age, body mass index (BMI), and race/ethnicity and interaction effects on serum values were assessed using analysis of covariance. Pearson correlation coefficients were used to assess associations between pairs of lipid micronutrients.

RESULTS

Overall, adolescent girls had significantly lower mean serum CoQ₁₀, α-tocopherol, γ-tocopherol, and CRP levels relative to premenopausal women (CoQ10: 376 vs 544 ng/mL, p < 0.0001; α-tocopherol: 6.9 vs 13.5 μg/mL, p < 0.0001; γ-tocopherol: 1.3 vs 1.7 μg/mL, p < 0.0001; CRP: 1.29 vs 2.13 mg/L, p < 0.0001). The differences in CoQ₁₀ and tocopherols remained significant after adjustment for BMI and race/ethnicity. CoQ₁₀ was significantly and positively correlated to α- and γ-tocopherol, and BMI was positively associated with CRP and γ-tocopherol in both groups.

CONCLUSIONS

Lower serum CoQ₁₀, α-tocopherol, γ-tocopherol, and CRP levels in adolescent girls compared to women suggests that adolescents may have a reduced need for antioxidants possibly due to their lower BMI and inflammatory status as indicated by CRP.

Ethnic differences and predictors of colonoscopy, prostate-specific antigen, and mammography screening participation in the multiethnic cohort

PURPOSE

Given the relation between screening and improved cancer outcomes and the persistence of ethnic disparities in cancer mortality, we explored ethnic differences in colonoscopy, prostate-specific antigen (PSA), and mammography screening in the Multiethnic Cohort Study.

METHODS

Logistic regression was applied to examine the influence of ethnicity as well as demographics, lifestyle factors, comorbidities, family history of cancer, and previous screening history on self-reported screening participation collected in 1999-2002.

RESULTS

The analysis included 140,398 participants who identified as white, African American, Native Hawaiian, Japanese American, US born-Latino, or Mexican born-Latino. The screening prevalences overall were mammography: 88% of women, PSA: 45% of men, and colonoscopy: 35% of men and women. All minority groups reported 10-40% lower screening utilization than whites, but Mexican-born Latinos and Native Hawaiian were lowest. Men were nearly twice as likely to have a colonoscopy (OR=1.94, 95% CI=1.89-1.99) as women. A personal screening history, presence of comorbidities, and family history of cancer predicted higher screening utilization across modalities, but to different degrees across ethnic groups.

CONCLUSIONS

This study confirms previously reported sex differences in colorectal cancer screening and ethnic disparities in screening participation. The findings suggest it may be useful to include personal screening history and family history of cancer into counseling patients about screening participation.

Isoflavones in Japanese and Caucasian men with prostate cancer in Hawaii

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Background: Recently, several studies have reported that soy isoflavones and the ability to produce Equol, an active derivative of soy isoflavone, may play a role in the suppression of prostate cancer. An Equol-producing bacterium, Slackia sp. strain NATTS has been identified in stool cultures. To further investigate this relationship, we evaluated Japanese-Americans (JA) and whites (W) in Hawaii, with and without prostate cancer, with regards to dietary soy intake, serum isoflavone levels, and the presence of stool NATTS. Methods: The serum levels of Daidzein, Genistein, Glysitein, Dihydrodaidzein (DHD), Equol, o-desmethylangolensin (o-DMA) and total isoflavone was determined in 65 JA (34 patients with prostate cancer , 31 controls) and 68 W (34 patients with prostate cancer , 34 controls) subjects. The control group consisted of age matched cancer-free male subjects. To evaluate Equol producing ability, we assessed the presence of NATTS in stool samples. All subjects completed a lifetime dietary soy consumption survey. Results: The serum level of Genistein and o-DMA were significantly higher in JA (Genistein: W 21.5±54.0, JA 61.8±150.9, p=0.04; o-DMA: W 0, JA 2.0±7.9, p=0.04). Daizein level trended higher in JA (W 13.9±34.7, JA 33.3±84.0, p=0.09). Glysitein level was significantly higher in W (W 35.7±10.4, JA 30.7±15.5, p=0.03). No differences were noted in DHD and Equol levels between W and JA. Total isoflavone level trended higher in JA (W 76.3±104.9, JA 135.1±245.6, p=0.07). There were no differences in serum isoflavone level between prostate cancer patients and controls for both JA and W. Only 10 of 120 stool samples were positive for NATTS (8.6%), a rate much lower than seen in Japan. JA showed higher intake of soy than W. Conclusions: The high soy consumption and isoflavone levels in JA may be related to the observed lower incidence of prostate cancer relative to W in Hawaii. The near absence of equal producers in Hawaii JA may contribute to their higher incidence of prostate cancer compared to Japan based Japanese. These results suggest that both soy isoflavone levels and Equol production may be inversely associated with prostate cancer incidence.

Plasma 25-hydroxyvitamin D3 is associated with decreased risk of postmenopausal breast cancer in whites: a nested case-control study in the multiethnic cohort study

BACKGROUND

Higher sunlight exposure is correlated with lower incidence of breast cancer in ecological studies, but findings from prospective studies regarding the association of circulating levels of vitamin D with the risk of breast cancer have been null. The objective of this study was to examine the relation between plasma levels of vitamin D and the risk of postmenopausal breast cancer.

METHODS

We conducted a nested case-control study within the Multiethnic Cohort Study of five race/ethnic groups (white, African-American, Native Hawaiian, Japanese, and Latino) from Hawaii and Los Angeles between 2001 and 2006. Pre-diagnostic plasma levels of 25-hydroxyvitamin D2 [25(OH)D2], 25-hydroxyvitamin D3 [25(OH)D3] and 25(OH)D (sum of 25(OH)D2 and 25(OH)D3) were examined among 707 postmenopausal breast cancer cases and matched controls.

RESULTS

Using conditional logistic regression models, 20 ng/mL increases of plasma 25(OH)D3 (odds ratio (OR) 0.28; 95% confidence interval (CI) 0.14-0.56) and 25(OH)D (OR 0.43; 95% CI 0.23-0.80) were inversely associated with breast cancer risk among white women, but not among women in other race/ethnic groups. Using two-segmented, piecewise-linear logistic regression models, the change-points of the ORs, either for 25(OH)D3 or for 25(OH)D, were detected as 20 ng/mL among whites.

CONCLUSIONS

Circulating 25(OH)D3 and 25(OH)D were associated with a reduced risk of postmenopausal breast cancer among whites, but not in other ethnic groups, who reside in low latitude regions.

Methods for assessing and representing mammographic density: an analysis of 4 case-control studies

To maximize statistical power in studies of mammographic density and breast cancer, it is advantageous to combine data from several studies, but standardization of the density assessment is desirable. Using data from 4 case-control studies, we describe the process of reassessment and the resulting correlation between values, identify predictors of differences in density readings, and evaluate the strength of the association between mammographic density and breast cancer risk using different representations of density values. The pooled analysis included 1,699 cases and 2,422 controls from California (1990-1998), Hawaii (1996-2003), Minnesota (1992-2001), and Japan (1999-2003). In 2010, a single reader reassessed all images for mammographic density using Cumulus software (Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada). The mean difference between original and reassessed percent density values was -0.7% (95% confidence interval: -1.1, -0.3), with a correlation of 0.82 that varied by location (r = 0.80-0.89). Case status, weight status, age, parity, density assessment method, mammogram view, and race/ethnicity were significant determinants of the difference between original and reassessed values; in combination, these factors explained 9.2% of the variation. The associations of mammographic density with breast cancer and the model fits were similar using the original values and the reassessed values but were slightly strengthened when a calibrated value based on 100 reassessed radiographs was used.

The effects of soy consumption before diagnosis on breast cancer survival: the Multiethnic Cohort Study

This study tested the hypothesis that prediagnostic soy intake was inversely associated with all-cause and breast cancer-specific mortality. The analyses included 3842 women in the Multiethnic Cohort (MEC) study of African Americans, Native Hawaiians, Japanese Americans, Latinos, and Caucasians, who completed a quantitative food frequency questionnaire, aged ≥50 yr at cohort entry, and diagnosed with primary invasive breast cancer following cohort entry (1993-2007). Hazard ratios (HR) and 95% confidence intervals (CI) were estimated from Cox proportional hazards regression with adjustment for known clinical and lifestyle factors. During a mean follow-up after diagnosis of invasive breast cancer of 6.2 ± 3.8 yr, there were 804 deaths including 376 breast cancer-specific deaths. The HR (95%CI) for all-cause and breast cancer-specific morality comparing the highest versus lowest tertiles were 1.03 (0.81-1.33) and 1.03 (0.71-1.50) for soy products and 0.99 (0.82-1.20) and 0.95 (0.71-1.28) for total isoflavones, respectively (Ptrend > 0.60 for all). There was limited evidence of differences by hormone receptor status, tumor stage, or ethnic group. Prediagnostic soy intake was unrelated to mortality in postmenopausal women. Our findings are consistent with the literature that soy consumption does not adversely affect breast cancer survival in women.

Prediagnostic serum tocopherol levels and the risk of non-hodgkin lymphoma: the multiethnic cohort

BACKGROUND

Compromised immunity and chronic inflammation are thought to contribute to the development of non-Hodgkin lymphoma (NHL). Because tocopherols protect cells through antioxidant mechanisms, they may play a role in NHL etiology.

METHODS

This nested case-control study within the Multiethnic Cohort examined the association of prediagnostic serum tocopherols levels measured in 271 NHL cases and 538 matched controls by high-pressure liquid chromatography/photodiode array detection with NHL risk. Conditional logistic regression was used to calculate ORs and 95% confidence intervals (CI).

RESULTS

We observed U-shaped associations with NHL for total and α-tocopherols [Ptrend < 0.01 for polynomial terms (3 df)]. The ORs (95% CI) for total tocopherols, which consisted primarily of α-tocopherol, were 0.41 (0.25-0.68), 0.52 (0.32-0.85), 0.39 (0.23-0.65), and 0.78 (0.47-1.29) for the second to fifth quintiles as compared with the first. The risk estimates were similar for α-tocopherol but nonsignificant for β- and γ-tocopherol combined and for γ-tocopherol. Adjustment for serum lipids strengthened the nonlinear associations for total and α-tocopherols. Serum total tocopherol levels were higher for vitamin E supplement users at cohort entry than nonusers (21.32 ± 9.04 vs. 17.72 ± 7.43 μg/mL; P < 0.0001), but supplement use was not associated with NHL risk. No heterogeneity in risk estimates was detected by sex, ethnicity, vitamin E supplement use, or NHL subtype.

CONCLUSIONS

Circulating tocopherols, at levels likely reflecting adequate dietary intakes, may be protective against NHL, whereas higher intakes from supplementation may not be beneficial.

IMPACT

The association between serum tocopherol levels and NHL risk provides possible new insights into the etiology of NHL.

Cytology in nipple aspirate fluid during a randomized soy food intervention among premenopausal women

Because soy food consumption may influence breast tissue activity, we examined its effect on the presence of epithelial cells in nipple aspirate fluid (NAF). In a randomized, crossover design, 82 premenopausal women completed a high-soy and a low-soy diet for 6 mo each, separated by a 1-mo washout period. They provided NAF samples at baseline, 6 mo, and 13 mo during the midluteal phase of the menstrual cycle. Papanicolaou-stained cytology slides (for 33 women at baseline, 24 at low-soy, and 36 at high-soy) were evaluated in women with sufficient NAF. Mixed models evaluated the effect of the high-soy diet on epithelial cytology as compared to baseline and the low-soy diet. At the end of the high-soy diet, cytological subclass had decreased in 8 (24%) and increased in 3 (9%) women as compared to baseline, whereas the respective values were 3 (14%) and 6 (29%) for the low-soy diet samples (P = 0.32). Only the change in subclass indicated a trend in lower cytological class (P = 0.06). Contrary to an earlier report, the number of NAF samples with hyperplastic epithelial cells did not increase after a soy intervention in amounts consumed by Asians.

Prediagnostic leptin, adiponectin, C-reactive protein, and the risk of postmenopausal breast cancer

Obesity has been associated with an increased risk of postmenopausal breast cancer. Adipokines and systemic inflammation have been hypothesized to underlie this association. In a case-control study nested within the Multiethnic Cohort, conditional logistic regression was used to calculate the ORs and 95% confidence intervals (CI) for postmenopausal breast cancer associated with prediagnostic levels of serum leptin, adiponectin, the leptin:adiponectin ratio, and C-reactive protein (CRP). The 706 cases and 706 controls were matched on ethnicity, location (Hawaii or Los Angeles), birth year, date and time of blood draw, hours fasting before blood draw, and hormone replacement therapy use at blood draw. Higher circulating levels of leptin [ORQ4 vs. Q1, 1.94 (1.37-2.75); Ptrend ≤ 0.001), the leptin:adiponectin ratio [OR, 1.91 (1.36-2.68); Ptrend = 0.005], and CRP [OR, 1.41 (1.01-1.96); Ptrend = 0.014] were associated with an increased risk of postmenopausal breast cancer. The positive associations for these markers remained after adjustment for body mass index (BMI). No associations were detected for adiponectin. These data suggest that adipokines and systemic inflammation may be associated with the risk of postmenopausal breast cancer independently of BMI. Further prospective studies examining the role of adipokines and inflammatory processes in the etiology of postmenopausal breast cancer are warranted. Cancer Prev Res; 6(3); 188-95. ©2013 AACR.

It's time for clinicians to reconsider their proscription against the use of soyfoods by breast cancer patients

The impact of soyfood intake on breast cancer risk has been intensely investigated. This focus can be attributed to soyfoods being uniquely rich dietary sources of isoflavones. Isoflavones are classified as both phytoestrogens and selective estrogen receptor (ER) modulators. The finding that dietary genistein, the primary soybean isoflavone, stimulates the growth of existing mammary tumors in ovariectomized athymic mice implanted with ER-positive breast cancer cells has led many oncologists to advise their patients against the use of soyfoods. However, the clinical evidence indicates that isoflavone exposure has little effect on markers of breast cancer risk. Furthermore, a pooled analysis that involved 9,514 breast cancer survivors found higher isoflavone intake was associated with a statistically significant 25% reduction in recurrence over the average 7.4-year follow-up period. Given the clinical and epidemiologic data, our position is that clinicians should allow soyfood use by patients for whom soyfoods already represent a normal part of their diet, and should not discourage other breast cancer survivors from moderate consumption.