Dietary B vitamin and methionine intakes and breast cancer risk among Chinese women

Methionine, folate, vitamin B(6), vitamin B(12), niacin, and riboflavin intakes may be related to breast carcinogenesis. These associations may vary by breast cancer type. Using the prospective cohort Shanghai Women's Health Study (1997-2008) including 718 Chinese breast cancer cases, the authors evaluated baseline dietary intake of these factors and breast cancer risk and whether the associations varied by menopausal status and estrogen receptor (ER) and progesterone receptor (PR) status. They estimated associations using hazard ratios and 95% confidence intervals from Cox proportional hazards regression models and stratified analyses by menopausal status and ER/PR status. Lowest quantile of intake was used as the comparison group. For postmenopausal women, dietary intakes of methionine and B vitamins were not associated with breast cancer risk. For premenopausal women, higher intake of folate was associated with decreased breast cancer risk (hazard ratio = 0.58, 95% confidence interval: 0.34, 0.99 for the highest vs. lowest quintile of intake). Only niacin intake was associated with ER+/PR+ breast cancer risk (hazard ratio = 1.62, 95% confidence interval: 1.07, 2.46; P for trend = 0.04 for the highest vs. lowest quartile of intake). Findings support the hypothesis that high folate intake may reduce breast cancer risk and that the association may vary by menopausal and ER/PR status.     

Dietary folate, vitamin B6, vitamin B12 and methionine intake and the risk of breast cancer by oestrogen and progesterone receptor status

Few studies have evaluated the relationship between the consumption of dietary folate and one-carbon metabolism-related nutrients and breast cancer risk defined by oestrogen receptor (ER) and progesterone receptor (PR) status. The objective of the present study was to examine the associations between dietary folate, vitamin B6, vitamin B12, and methionine intake and the risk of breast cancer by ER and PR status among Chinese women in Guangdong. A hospital-based case-control study was conducted from June 2007 to August 2008, with 438 cases and 438 age (5-year interval)- and residence (rural/urban)-matched controls. Dietary intake information was assessed using a validated FFQ administered through a face-to-face interview. Unconditional logistic regression models were used to calculate multivariate-adjusted OR and 95 % CI. A significant inverse association was found between dietary folate and vitamin B6 intake and breast cancer risk. The adjusted OR of the highest v. the lowest quartile were 0·32 (95 % CI 0·21, 0·49; P(trend) < 0·001) for dietary folate and 0·46 (95 % CI 0·30, 0·69; P(trend) < 0·001) for vitamin B6. No associations were observed for vitamin B12 and methionine intake. A significant inverse association between dietary folate intake and breast cancer risk was observed in all subtypes of ER and PR status. These findings suggest that dietary folate and vitamin B6 intakes were inversely associated with breast cancer risk. The inverse association did not differ by ER and/or PR status.     

Effect of Dietary Intake of Isoflavones on the Estrogen and Progesterone Receptor Status of Breast Cancer

To examine if higher intake of isoflavones prior to diagnosis was associated with a positive status of estrogen receptors (ER) and progesterone receptors (PR) in breast tumor tissue, a retrospective study was conducted in 2004 to 2005 in 756 Chinese women with histologically confirmed breast cancer. We administered a food frequency questionnaire by face-to-face interview to assess the intake of the isoflavones daidzein and genistein. Unconditional logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for potential confounders. Comparing the highest to lowest intake quartiles, the adjusted ORs for daidzein were 1.94 (95% CI = 1.20–3.32) and 2.18 (95% CI = 1.28–3.73) for ER positive and PR positive tumors, respectively, in premenopausal patients. The ORs for both ER and PR positive status combined were 2.48 (95% CI = 1.37–4.49) for daidzein and 1.94 (95% CI = 1.21–3.14) for genistein in premenopausal patients with statistically significant tests for trend. There was little or no evidence of associations in postmenopausal patients. We conclude that higher intake of daidzein and genistein before diagnosis was associated with ER and PR positive status in premenopausal Chinese women with breast cancer. The association might confer a more favorable prognosis.     

Intake of Energy-Dense Foods,Fast Foods,Sugary Drinks,and Breast Cancer Risk in African American and European American Women

Limiting energy-dense foods, fast foods, and sugary drinks that promote weight gain is a cancer prevention recommendation, but no studies have evaluated intake in relation to breast cancer risk in African American (AA) women. In a case-control study with 1692 AA women (803 cases and 889 controls) and 1456 European American (EA) women (755 cases and 701 controls), odds ratios (OR) and 95% confidence intervals (CI) for risk were computed, stratifying for menopausal and estrogen receptor (ER) status. Among postmenopausal EA women, breast cancer risk was associated with frequent consumption of energy-dense foods (OR = 2.95; 95% CI: 1.66–5.22), fast foods (OR = 2.35; 95% CI: 1.38–4.00), and sugary drinks (OR = 2.05; 95% CI: 1.13–3.70). Elevated risk of ER+ tumors in EA women was associated with energy-dense (OR = 1.75; 95% CI: 1.14–2.69) and fast foods (OR = 1.84; 95% CI: 1.22–2.77). Among AA women, frequent fast food consumption was related to premenopausal breast cancer risk (OR = 1.97; 95% CI: 1.13–3.43), and with ER+ tumors. Energy adjustment attenuated risk estimates in AA women, while strengthening them among EA women. Frequent consumption of energy-dense and fast foods that have poor nutritive value appeared to increase breast cancer risk in AA and EA women, with differences by menopausal status and ER status.     

Fruit, vegetable, and animal food intake and breast cancer risk by hormone receptor status

The effects of diet on breast cancer are controversial and whether the effects vary with hormone receptor status has not been well investigated. This study evaluated the associations of dietary factors with risk for breast cancer overall and by the hormone receptor status of tumors among Chinese women. The Shanghai Breast Cancer Study, a large, population-based, case-control study, enrolled 3,443 cases and 3,474 controls in 1996-1998 (phase I) and 2002-2005 (phase II); 2676 cases had estrogen receptor (ER) and progesterone receptor (PR) data. Dietary intake was assessed using a validated, quantitative, food frequency questionnaire. Odds ratios (OR) and 95% confidence intervals (95% CI) were derived from multivariate, polychotomous, unconditional logistic regression models. Total vegetable intake was inversely related to breast cancer risk, with an adjusted OR for the highest quintile of 0.80 (95% CI = 0.67-0.95; P trend = 0.02). Reduced risk was also related to high intake of allium vegetables (P trend = 0.01) and fresh legumes (P trend = 0.0008). High intake of citrus fruits and rosaceae fruits were inversely associated with breast cancer risk (P trend = 0.003 and 0.004, respectively), although no consistent association was seen for total fruit intake. Elevated risk was observed for all types of meat and fish intake (all P trend < 0.05), whereas intakes of eggs and milk were associated with a decreased risk of breast cancer (both P trend <0.05). There was little evidence that associations with dietary intakes varied across the 4 tumor subtypes or between ER+/PR+ and ER-/PR- tumors (P for heterogeneity >0.05). Our results suggest that high intake of total vegetables, certain fruits, milk, and eggs may reduce the risk of breast cancer, whereas high consumption of animal-source foods may increase risk. The dietary associations did not appear to vary by ER/PR status.     

Fruit,Vegetable, and Animal Food Intake and Breast Cancer Risk by Hormone Receptor Status

The effects of diet on breast cancer are controversial and whether the effects vary with hormone receptor status has not been well investigated. This study evaluated the associations of dietary factors with risk for breast cancer overall and by the hormone receptor status of tumors among Chinese women. The Shanghai Breast Cancer Study, a large, population-based, case-control study, enrolled 3,443 cases and 3,474 controls in 1996–1998 (phase I) and 2002–2005 (phase II); 2676 cases had estrogen receptor (ER) and progesterone receptor (PR) data. Dietary intake was assessed using a validated, quantitative, food frequency questionnaire. Odds ratios (OR) and 95% confidence intervals (95% CI) were derived from multivariate, polychotomous, unconditional logistic regression models. Total vegetable intake was inversely related to breast cancer risk, with an adjusted OR for the highest quintile of 0.80 (95% CI = 0.67–0.95; P trend = 0.02). Reduced risk was also related to high intake of allium vegetables (P trend = 0.01) and fresh legumes (P trend = 0.0008). High intake of citrus fruits and rosaceae fruits were inversely associated with breast cancer risk (P trend = 0.003 and 0.004, respectively), although no consistent association was seen for total fruit intake. Elevated risk was observed for all types of meat and fish intake (all P trend < 0.05), whereas intakes of eggs and milk were associated with a decreased risk of breast cancer (both P trend <0.05). There was little evidence that associations with dietary intakes varied across the 4 tumor subtypes or between ER+/PR+ and ER-/PR- tumors (P for heterogeneity >0.05). Our results suggest that high intake of total vegetables, certain fruits, milk, and eggs may reduce the risk of breast cancer, whereas high consumption of animal-source foods may increase risk. The dietary associations did not appear to vary by ER/PR status.     

Selected antioxidants and risk of hormone receptor-defined invasive breast cancers among postmenopausal women in the Women's Health Initiative Observational Study

BACKGROUND: Few studies have evaluated carotenoids and vitamins C and E in association with the risk of breast cancers defined by estrogen receptor (ER) and progesterone receptor (PR) status. OBJECTIVE: We examined the associations between dietary and supplemental intakes of these nutrients and risk of breast cancers jointly defined by both ER and PR status among postmenopausal women. DESIGN: Our investigation was conducted in the Women's Health Initiative Observational Study. After following 84 805 women for an average of 7.6 y, 2879 incident invasive breast cancer cases had been ascertained, of whom 2509 had receptor data. We used Cox proportional hazards models to assess the associations of interest. RESULTS: Dietary alpha-carotene (highest versus lowest quintile: RR = 0.83; 95% CL = 0.70, 0.99; P for trend = 0.019), beta-carotene (highest versus lowest quintile: RR = 0.78; 95% CL = 0.66, 0.94; P for trend = 0.021), and lycopene (highest versus lowest quintile: RR = 0.85; 95% CL = 0.73, 1.00; P for trend = 0.064) were inversely associated with risk of ER+PR+breast cancer, but not with other breast cancer groups jointly defined by ER and PR status. Total or supplemental beta-carotene and dietary intakes of lutein+zeaxanthin and beta-cryptoxanthin were not associated with breast cancers defined by ER and PR status. Vitamin E (regardless of source) and dietary vitamin C were not associated with breast cancer. However, total and supplemental vitamin C intake had weak positive associations with breast cancer overall. CONCLUSION: Dietary intake of certain carotenoids might be differentially associated with risk of invasive breast cancers jointly defined by ER and PR status among postmenopausal women.     

Effect of dietary intake of phytoestrogens on estrogen receptor status in premenopausal women with breast cancer

Although many dietary studies have focused on breast cancer risk, few have examined dietary influence on tumor characteristics such as estrogen receptor (ER) status. Because phytoestrogens may modulate hormone levels and ER expression, we analyzed ER status and phytoestrogen intake in a case-case study of 124 premenopausal breast cancer patients. We assessed intake with a food-frequency questionnaire and obtained ER status from medical records. Rather than focusing on risk, we evaluated whether low intakes were more strongly associated with ER-negative tumors than with ER-positive disease. In logistic regression adjusting for potential confounders, threefold greater risks of ER-negative tumors relative to ER-positive tumors were associated with low intake of the isoflavones genistein (odds ratio, OR=3.50; 95% confidence interval, CI=1.43-8.58) and daidzein (OR=3.10; 95% CI=1.31-7.30). Low intake of the flavonoid kaempferol (OR=0.36; 95% CI=0.16-0.83), the trace element boron (OR=0.33; 95% CI=0.13-0.83), and the phytosterol beta-sitosterol (OR=0.42; 95% CI=0.18-0.98) were associated with decreased risk of ER-negative tumors relative to ER-positive disease. Other phytoestrogens were not significantly associated with ER status. Thus, in premenopausal patients, some phytoestrogens may affect breast carcinogenesis by influencing ER status. Such findings suggest new directions for mechanistic research on dietary factors in breast carcinogenesis that may have relevance for prevention and clinical treatment.     

Dietary intakes of total and specific lignans are associated with clinical breast tumor characteristics

Dietary lignans may affect breast cancer by modifying tumor characteristics likely to affect prognosis. We investigated usual dietary intakes of total and specific lignans with tumor characteristics in 683 women with breast cancer and 611 healthy women without breast cancer enrolled in the Data Bank and BioRepository at Roswell Park Cancer Institute (RPCI). Clinicopathologic data were abstracted from the RPCI breast cancer database. Dietary lignan intakes were calculated from FFQ. OR and 95% CI were estimated with logistic regression adjusting for potential confounders and stratified by menopausal status. Women in the highest compared to the lowest tertile of total lignan intakes had a 40-50% lower odds of breast cancer regardless of menopausal status and substantially reduced odds of an invasive tumor, especially among premenopausal women [OR 0.48 (95% CI 0.26-0.86)]. Lignan intakes were inversely associated with odds of grade 3 tumors among premenopausal women. Lignan intakes were inversely associated with risk of estrogen receptor (ER) negative (ER(-)) breast cancer among premenopausal women [OR 0.16 (95% CI 0.03-0.44)] and particularly triple negative tumors [ER(-), progesterone receptor negative, HER2 negative; OR 0.16 (95% CI 0.04-0.62)]. There were significant differences in the contribution to these effects by specific lignans, especially matairesinol and lariciresinol. In summary, in this case-control study of dietary lignan intakes and breast cancer, we found that higher lignan intakes were associated with lower risks of breast cancer with more favorable prognostic characteristics. Future investigations are warranted to explore the strong associations observed with ER(-) cancer in premenopausal women.     

Associations of weight,weight change,and body mass with breast cancer risk in Hispanic and non-Hispanic white women

PURPOSE: A wealth of studies have examined the effects of weight, weight gain, and obesity on breast cancer risk; however, few have examined this relationship in Hispanic white women, a population with the highest rate of obesity in the U.S. METHODS: A population-based case-control study was conducted in New Mexico of Hispanic (n = 694) and non-Hispanic (n = 813) white women with incident breast cancer during the period of January 1, 1992 through December 31, 1994. Conditional logistic regression models were fitted to estimate the relative risk of breast cancer for levels of weight, weight change, and body mass index (BMI) and to assess differences in the effects by ethnicity, menopausal status, early life BMI, and estrogen receptor/progesterone receptor (ER/PR) expression in tumors. RESULTS: Weight change from age 18 to usual adult weight was associated with increased risk of breast cancer among Hispanics [4th quartile vs. baseline, odds ratio (OR): 2.41; 95% confidence interval (CI): 1.45-4.03] with no substantial variation by menopausal status. In non-Hispanic white women, weight change was a risk factor for those in the post-menopausal group (4th quartile vs. baseline, OR: 2.27; 95% CI: 1.09-4.73). The effect of usual BMI (test for interaction p = 0.04) and weight change (test for interaction p = 0.03) differed by ethnicity. Increased risk from weight gain was largely restricted to women who were lean at age 18 and those with ER(+)/PR(+) tumors. Height, weight at age 18, and BMI at age 18 were not associated with risk in either ethnic group. CONCLUSIONS: Weight change and obesity are risk factors for breast cancer in both Hispanic and non-Hispanic white women. However, the risk for Hispanic women is evident independent of menopausal status, while the risk for non-Hispanics is apparent in post-menopausal women. Due to the increasing prevalence of adult obesity, particularly among Hispanic women, adult weight gain may be an important modifiable risk factor for the primary prevention of breast cancer among Hispanic populations.     

Diet and Expression of Estrogen Alpha and Progesterone Receptors in Malignant Mammary Tissue

Estrogen receptor (ER) and/or progesterone receptor (PR) expression has been associated with more favorable breast cancer prognosis. Results on the differential association of diet with ER and/or PR positive and negative tumors have been inconclusive. In a large case-control study conducted in Athens, Greece, we investigated whether diet is associated with the expression of ER-alpha or PR in mammary tumors of 421 women with histologically confirmed breast cancer. Diet was assessed through an extensive food frequency questionnaire and results were analyzed using multiple logistic regression. After controlling for non-nutritional variables and mutually adjusting for energy-generating nutrients and ethanol, carbohydrate intake was inversely associated with ER-alpha (P = 0.04) and PR (P = 0.10) expression. The odds ratios (OR) per one standard deviation increment were 0.69 with 95% confidence interval (95% CI) 0.48-0.98 for ER-alpha and 0.72 (95% CI 0.49–1.07) for PR expression. No consistent or statistically significant associations were noted for any of the other energy-generating nutrients or food groups examined. Although in these data no strong relations of qualitative aspects of diet with hormone receptor expression in breast cancer tumors were evident, the inverse association of carbohydrate intake with ER-alpha, and perhaps PR, expression merits further study in future investigations.     

Diet and expression of estrogen alpha and progesterone receptors in malignant mammary tissue

Estrogen receptor (ER) and/or progesterone receptor (PR) expression has been associated with more favorable breast cancer prognosis. Results on the differential association of diet with ER and/or PR positive and negative tumors have been inconclusive. In a large case-control study conducted in Athens, Greece, we investigated whether diet is associated with the expression of ER-alpha or PR in mammary tumors of 421 women with histologically confirmed breast cancer. Diet was assessed through an extensive food frequency questionnaire and results were analyzed using multiple logistic regression. After controlling for non-nutritional variables and mutually adjusting for energy-generating nutrients and ethanol, carbohydrate intake was inversely associated with ER-alpha (P = 0.04) and PR (P = 0.10) expression. The odds ratios (OR) per one standard deviation increment were 0.69 with 95% confidence interval (95% CI) 0.48-0.98 for ER-alpha and 0.72 (95% CI 0.49-1.07) for PR expression. No consistent or statistically significant associations were noted for any of the other energy-generating nutrients or food groups examined. Although in these data no strong relations of qualitative aspects of diet with hormone receptor expression in breast cancer tumors were evident, the inverse association of carbohydrate intake with ER-alpha, and perhaps PR, expression merits further study in future investigations.     

Dietary phytoestrogens are not associated with risk of overall breast cancer but diets rich in coumestrol are inversely associated with risk of estrogen receptor and progesterone receptor negative breast tumors in Swedish women

Results from epidemiological and experimental studies indicate that phytoestrogens may protect against breast cancer. Because one of the biological effects of phytoestrogens is probably estrogenic, it's possible that the preventive effect on breast cancer differs by estrogen receptor (ER) or progesterone receptor (PR) status of the tumor. We evaluated the associations between dietary phytoestrogen (isoflavonoids, lignans, and coumestrol) intake and risk of breast cancer and whether the ER/PR statuses of the tumor influence this relationship. In 1991-2 a prospective population-based cohort study among Swedish pre- and postmenopausal women was performed, making questionnaire data available for 45,448 women. A total of 1014 invasive breast cancers were diagnosed until December 2004. Cox proportional hazards models were performed to estimate multivariate risk ratios, 95% CI for associations with risk of breast cancer. Intakes of lignan, isoflavonoid, or coumestrol were not associated with breast cancer risk overall or before or after 50 y of age. The effects of lignans or isoflavonoids were independent of receptor status. However, intake of coumestrol was associated with decreased risk of receptor negative tumors (ER-PR-) but not positive tumors. The risk of ER-PR- tumors was significantly lower (50%) in women with intermediate coumestrol intake compared with those who did not consume any. In conclusion, we found no association between intake of isoflavonoids or lignans and breast cancer risk. Our results of a decreased risk of ER-PR- tumors in women with intermediate intake of coumestrol could be due to chance because of the low intake. The results should be confirmed in other studies.     

Association between family history of cancer and breast cancer defined by estrogen and progesterone receptor status

There are recent data to suggest that risk factors for breast cancer may differ according to whether the tumor expresses detectable levels of the estrogen receptor (ER) and progesterone receptor (PR). While a family history of breast cancer is one of the most consistent predictors of the disease, we recently reported a modest inverse association with ER+PR− tumors. However, the definition of a family history of cancer did not consider second-degree relatives or cancer sites that may be etiologically related. The current report presents additional data analysis from the Iowa Women's Health Study, a prospective population-based cohort study conducted among 41,837 postmenopausal women. At baseline in 1986, respondents provided information on family history of cancers of the breast, ovaries, or uterus/endometrium in their mothers, sisters, daughters, maternal and paternal grandmothers, and maternal and paternal aunts. Data on family history of prostate cancer in fathers and brothers and age at onset of breast cancer in mothers and sisters were collected in 1992. Cohort members were followed for cancer incidence through the statewide tumor registry. After 7 years and more than 235,000 person-years of follow-up, 939 incident cases of breast cancer were identified. Information was obtained from the tumor registry on ER (+/−) and PR (+/−) status for 610 cases (65.0%). A family history of breast cancer in first-degree relatives was associated with increased risk (relative risk [RR] = 1.4; 95% confidence interval [CI]: 1.1–1.6) for all receptor-defined subtypes of breast cancer except ER+PR− tumors (RR = 0.7; 95% CI: 0.3–1.4). These results were unchanged when data on second-degree relatives were included. When the onset of breast cancer in relatives occurred at or before the age of 45 years, increased risks were evident only for ER−PR+ and ER−PR− tumors (RR = 2.3 and 3.3, respectively). Conversely, when relatives were affected with breast cancer after the age of 45 years, increased risks were most apparent for ER+PR+ and ER−PR+ tumors (RR = 1.3 and 3.2, respectively). A family history of prostate cancer in first-degree relatives was associated with a 1.2-fold increased risk of breast cancer (95% CI: 0.98–1.50), largely a reflection of the association with ER−PR− tumors (RR = 1.5; 95% CI: 0.8–3.0). The small numbers of cases in some categories and the corresponding wide CIs preclude definitive conclusions, but these data are at least suggestive that joint stratification of breast tumors on ER and PR status may be useful in partitioning breast cancer families into more homogeneous subsets. © 1996 Wiley-Liss, Inc.     

Dietary Intake of Soy Protein and Tofu in Association With Breast Cancer Risk Based on a Case-Control Study

Soy food and its constituents may protect against breast cancer, but the association between soy intake and decreased breast cancer risk is inconsistent. We evaluated the relationship between breast cancer risk and the dietary intake of soy protein as measured by total soy food and tofu intake. Histologically confirmed cases ( n = 362) were matched to controls by age (within 2 yr) and menopausal status. High soy protein intake was associated with reduced breast cancer risk in analyses adjusted for potential confounders including dietary factors among premenopausal women (odds ratio [OR] = 0.39 in the highest quintile, 95% confidence interval [CI] = 0.22–0.93, P for trend = 0.03) and postmenopausal women (OR = 0.22, 95% CI = 0.06–0.88, P for trend = 0.16). We also found an inverse association between total tofu intake and breast cancer risk among premenopausal women (for total tofu intake, OR = 0.23 in the highest quintile, 95% CI = 0.11–0.48, P for trend < 0.01; for at least 1 serving of tofu as the main ingredient per day, OR = 0.26, 95% CI = 0.13–0.55, P for trend < 0.01). We concluded that increased regular soy food intake at a level equivalent to traditional Korean consumption levels may be associated with a reduced risk of breast cancer, and this effect is more pronounced in premenopausal women.     

Dietary intake of soy protein and tofu in association with breast cancer risk based on a case-control study

Soy food and its constituents may protect against breast cancer, but the association between soy intake and decreased breast cancer risk is inconsistent. We evaluated the relationship between breast cancer risk and the dietary intake of soy protein as measured by total soy food and tofu intake. Histologically confirmed cases (n = 362) were matched to controls by age (within 2 yr) and menopausal status. High soy protein intake was associated with reduced breast cancer risk in analyses adjusted for potential confounders including dietary factors among premenopausal women (odds ratio [OR] = 0.39 in the highest quintile, 95% confidence interval [CI] = 0.22-0.93, P for trend = 0.03) and postmenopausal women (OR = 0.22, 95% CI = 0.06-0.88, P for trend = 0.16). We also found an inverse association between total tofu intake and breast cancer risk among premenopausal women (for total tofu intake, OR = 0.23 in the highest quintile, 95% CI = 0.11-0.48, P for trend < 0.01; for at least 1 serving of tofu as the main ingredient per day, OR = 0.26, 95% CI = 0.13-0.55, P for trend < 0.01). We concluded that increased regular soy food intake at a level equivalent to traditional Korean consumption levels may be associated with a reduced risk of breast cancer, and this effect is more pronounced in premenopausal women.     

Long-term Dietary Acrylamide Intake and Breast Cancer Risk in a Prospective Cohort of Swedish Women

The association between dietary acrylamide intake and the incidenceof invasive breast cancer was examined among 61,433 Swedishwomen who were cancer free and completed a food frequency questionnairein 1987–1990 and again in 1997. During a mean follow-upof 17.4 years, a total of 2,952 incident cases of breast cancerwere diagnosed in the cohort. In multivariate analyses controllingfor breast cancer risk factors, no statistically significantassociation was observed between long-term acrylamide intake(assessed at baseline and in 1997) and the risk of breast cancer,overall or by estrogen receptor (ER) and progesterone receptor(PR) status. The multivariate rate ratios comparing extremequartiles of acrylamide intake were 0.91 (95% confidence interval(CI): 0.80, 1.02) for overall breast cancer, 0.89 (95% CI: 0.74,1.08) for ER+PR+ tumors, 1.17 (95% CI: 0.84, 1.64) for ER+PR–tumors, and 0.91 (95% CI: 0.61, 1.38) for ER–PR–tumors. The association between acrylamide intake and breastcancer risk did not differ by smoking status. These findingsfor Swedish women do not support the hypothesis that dietaryacrylamide is positively associated with risk of breast cancer,at least not within the ranges of acrylamide consumed by thispopulation. acrylamide; breast neoplasms; cohort studies; diet; prospective studies     

Case-control study of lifetime physical activity and breast cancer risk

A population-based case-control study of 1,233 incident breast cancer cases and 1,237 controls was conducted in Alberta, Canada, in 1995-1997 to examine the effect of lifetime physical activity patterns on breast cancer risk. No associations between physical activity and breast cancer were found for premenopausal women. For postmenopausal women in the highest quartile (> or =161 metabolic equivalent (MET)-hours/week per year) versus the lowest quartile (<104.8 MET-hours/week per year) of lifetime total physical activity, the adjusted odds ratio was 0.70 (95% confidence interval (CI): 0.52, 0.94). When the risks associated with each type of activity were examined for postmenopausal women, household and occupational activity conferred the largest risk reductions (odds ratio (OR) = 0.57, 95% CI: 0.41, 0.79 and OR = 0.59, 95% CI: 0.44, 0.81, respectively, for highest vs. lowest quartiles of activity), while recreational activity was not associated with any risk reductions. For postmenopausal women, the authors found stronger risk reductions for those who were also nonsmokers (OR = 0.64, 95% CI: 0.46, 0.88), non-alcohol-drinkers (OR = 0.39, 95% CI: 0.11, 0.77), or nulliparous (OR = 0.22, 95% CI: 0.07, 0.70) when they compared the highest with the lowest quartile of lifetime total physical activity. This study provides evidence that lifetime total activity reduces risk of postmenopausal breast cancer.     

Dietary Patterns and Breast Cancer Risk in Korean Women

We evaluated the association between dietary patterns and breast cancer risk according to menopausal and hormone receptor status among Korean women. In a study with 357 cases and 357 age-matched controls, dietary patterns (vegetable-seafood and meat-starch) were derived via principle component analysis based on 39 food groups from a food frequency questionnaire. The relation between dietary patterns and breast cancer risk was assessed by using multivariate logistic regression. The vegetable-seafood pattern was inversely associated with breast cancer risk [odds ratio (OR) and 95% confidence interval (CI) for high vs. low intake = 0.14 (0.08–0.25); P for trend < 0.001]. No association between the meat-starch pattern and breast cancer risk was found. The association between dietary patterns and breast cancer risk was not modified by menopausal and combined hormone receptor status. These findings indicate that a diet rich in vegetables and seafood is associated with a decreased breast cancer risk in Korean women.     

Dietary Fat,Cooking Fat,and Breast Cancer Risk in a Multiethnic Population

Our objective was to examine the association between dietary fat intake, cooking fat usage, and breast cancer risk in a population-based, multiethnic, case-control study conducted in the San Francisco Bay area. Intake of total fat and types of fat were assessed with a food frequency questionnaire among 1,703 breast cancer cases diagnosed between 1995 and 1999 and 2,045 controls. In addition, preferred use of fat for cooking was assessed. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). High fat intake was associated with increased risk of breast cancer (highest vs. lowest quartile, adjusted OR = 1.35, 95% CI = 1.10–1.65, P _trend < 0.01). A positive association was found for oleic acid (OR = 1.55, 95% CI = 1.14–2.10, P _trend < 0.01) but not for linoleic acid or saturated fat. Risk was increased for women cooking with hydrogenated fats (OR = 1.58, 95% CI = 1.20–2.10) or vegetable/corn oil (rich in linoleic acid; OR = 1.30, 95% CI = 1.06–1.58) compared to women using olive/canola oil (rich in oleic acid). Our results suggest that a low-fat diet may play a role in breast cancer prevention. We speculate that monounsaturated trans fats may have driven the discrepant associations between types of fat and breast cancer.