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.     

Dietary selenium intake and risk of type 2 diabetes in a female population of western Algeria

Several studies have raised possible associations between high selenium exposure and type 2 diabetes. Here we investigate the association between dietary selenium intake and the risk of type 2 diabetes in a female population from western Algeria. The analytical study included a total sample of 290 women, 140 type 2 diabetics and 150 controls. The dietary selenium intake has been measured by a 72-hour dietary recall. The odds ratio (OR) and the corresponding 95% confidence interval (CI) were used to determine the relationship between dietary selenium intake and diabetes through logistic regression. The quartile in the range of recommended dietary selenium intake was considered as a reference. The average level of dietary selenium intake was 72.40 μg/day in diabetics and 70.30 μg/day in controls (P > 0.05). The odds ratio for diabetes, comparing the highest quartile of dietary selenium intake to the reference quartile was 2.21 (95% CI 1.06–4.38; P = 0.036). While the lowest quartile had an odds ratio of 2.52 (95% CI 1.25–5.09; P = 0.010). In conclusion, this study indicates that there is a significant association between the risk of type 2 diabetes and both high and low dietary selenium intake.     

CYP17 genotype modifies the association between lignan supply and premenopausal breast cancer risk in humans

Cytochrome P450c17alpha (CYP17) has been associated with alterations in steroid hormone levels and premenopausal breast cancer risk and could modify the association between phytoestrogen intake and breast cancer risk. We examined plasma concentrations of enterolactone and genistein, estimated dietary phytoestrogen intake, CYP17 5'-UTR MspA1 genetic polymorphism, and breast cancer risk in 267 premenopausal breast cancer patients and 573 age-matched population controls from Germany. Multivariate logistic regression was used to estimate breast cancer risk associated with quartiles of phytoestrogen intake by genotype and to investigate gene-nutrient interactions. Premenopausal breast cancer risk was not significantly associated with the CYP17 A2 genotype. We observed a significant modifying effect of CYP17 genotype on plasma enterolactone-associated breast cancer risk (P for interaction < 0.01). Plasma enterolactone was significantly inversely related to breast cancer risk only in A2A2 carriers, showing odds ratios and 95% CI of 0.02 (0.00-0.41) and 0.01 (0.00-0.21) for the third and fourth quartiles vs. the lowest quartile, respectively. This inverse association was also found for the calculated enterolignan production as well as matairesinol intake. Compared with A1A1 carriers with the lowest enterolactone supply, the risk reduction associated with a high enterolactone supply resulted in a comparably decreased breast cancer risk for all genotypes. For genistein, no clear indication for a differential effect by CYP17 genotype was obtained. Our results suggest that CYP17 genotype modifies the protective effect of lignans on premenopausal breast cancer risk. Women homozygous for A2 allele benefit most from high plasma enterolactone concentrations and a high consumption of dietary precursors.     

Dietary carotenoids and risk of breast cancer in Chinese women

There has been considerable interest in the role of carotenoids in the chemoprevention of cancer. However, the protective effect of carotenoids on breast cancer has been inconclusive. To investigate whether intake of lycopene, alpha-carotene, beta-carotene, beta-cryptoxanthin, and lutein/zeaxanthin is inversely associated with breast cancer risk, a case-control study was conducted in China during 2004-2005. The cases were 122 female patients aged 24-87 years with histopathologically confirmed breast cancer. 632 healthy women age-matched were randomly recruited from outpatient clinics. Habitual dietary intake and lifestyle were collected by face-to-face interview using a validated and reliable food frequency questionnaire. The USDA nutrient composition database was used to calculate intake of the specific carotenoids. Unconditional logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs), accounting for age, locality, education, body mass index, smoking, passive smoking, physical activity, number of children breastfed, menopausal status, oral contraceptive use, biopsy-confirmed benign breast diseases, family history of breast cancer, and total energy intake. Compared with the highest versus lowest quartile of intake, the adjusted ORs were 0.26 (95% CI 0.14-0.46) for lycopene, 0.38 (95% CI 0.21-0.71) for beta-carotene, 0.43 (95% CI 0.23-0.82) for beta-cryptoxanthin, and 0.37 (95% CI 0.20-0.68) for total carotenoids, with statistically significant tests for trend. There was no association with breast cancer for alpha-carotene and lutein/zeaxanthin. It is concluded that higher intake of lycopene, beta-carotene and beta-cryptoxanthin is associated to a lower risk of breast cancer among Chinese women. More research to examine the relationship between carotenoids and breast cancer risk is warranted.     

Serum 25-hydroxyvitamin D, dietary calcium intake, and distal colorectal adenoma risk

Vitamin D has recently emerged as a potentially protective agent against colorectal neoplasia. We assessed the associations between dietary vitamin D, plasma 25-hydroxyvitamin D [25(OH)D], dietary calcium, and colorectal adenomas in a large screening sigmoidoscopy-based case-control study in Southern California. Because conversion of serum 25(OH)D to serum 1,25-vitamin D is highly regulated by serum calcium, we also assessed modification of the 25(OH)D-adenoma association by calcium intake. Cases were 473 subjects with a primary adenoma, and controls were 507 subjects who had no adenomas at sigmoidoscopy and no history of adenomas. Compared with those in the lowest quartile of intake, those in the highest quartile of dietary vitamin D had an adjusted odds ratio (OR) of 0.83 [95% confidence interval (CI) = 0.49-1.41] and those in the highest quartile of dietary calcium had an OR of 0.82 (95% CI = 0.49-1.25). There was a suggestion that plasma 25(OH)D may be protective in this population (OR for highest vs. lowest quartile = 0.74, 95% CI = 0.51-1.09). A significant protective effect of 25(OH)D was clearly evident only in those with calcium intakes below (OR = 0.40 for highest vs. lowest quartile, 95% CI = 0.22-0.71, p for trend = 0.005) and above (OR = 1.17, 95% CI = 0.69-1.99, p for trend = 0.94) the median calcium intake.     

A case-control study of risk factors for fibrocystic breast conditions: Shanghai Nutrition and Breast Disease Study, China, 1995-2000

This study was conducted to identify reproductive and dietary factors associated with benign proliferative mammary epithelial cell changes. Subjects were women enrolled in a randomized trial of breast self-examination in Shanghai, China. Women who developed fibrocystic breast conditions classified as nonproliferative (175 women), proliferative (181 women), or proliferative with atypia (33 women) between 1995 and 2000 and 1,070 unaffected trial participants were administered general risk factor and food frequency questionnaires. Conditional logistic regression was used to estimate adjusted odds ratios and 95% confidence intervals. High parity and consumption of fresh fruits and vegetables were more strongly associated with a reduced risk of proliferative and atypical lesions than with nonproliferative conditions. For the fourth quartile of consumption versus the first, odds ratios for lesions diagnosed as nonproliferative, proliferative, and proliferative with atypia were 0.4 (95% confidence interval (CI): 0.2, 0.7), 0.2 (95% CI: 0.1, 0.4), and 0.1 (95% CI: 0.03, 0.5), respectively, for fruit intake and 0.6 (95% CI: 0.3, 1.1), 0.4 (95% CI: 0.2, 0.7), and 0.1 (95% CI: 0.1, 0.9), respectively, for vegetable intake. Reduced but nonsignificant risks in relation to soy products were observed for proliferative and atypical lesions. No single nutrient or botanical family was appreciably more strongly associated with proliferative conditions than with nonproliferative conditions, after results were controlled for total fruit and vegetable consumption. A diet rich in fruits and vegetables may reduce cellular proliferation in the mammary epithelium; this is one mechanism by which such a diet could reduce risk of breast cancer.     

Population-based case-control study of amyotrophic lateral sclerosis in western Washington State. II. Diet

The association of nutrient intake with the risk of amyotrophic lateral sclerosis (ALS) was investigated in a population-based case-control study conducted in three counties of western Washington State from 1990 to 1994. Incident ALS cases (n = 161) were identified and individually matched on age and gender to population controls (n = 321). A self-administered food frequency questionnaire was used to assess nutrient intake. Conditional logistic regression analysis was used to compute odds ratios adjusted for education, smoking, and total energy intake. The authors found that dietary fat intake was associated with an increased risk of ALS (highest vs. lowest quartile, fiber-adjusted odds ratio (OR) = 2.7, 95% confidence interval (CI): 0.9, 8.0; p for trend = 0.06), while dietary fiber intake was associated with a decreased risk of ALS (highest vs. lowest quartile, fat-adjusted OR = 0.3, 95% CI: 0.1, 0.7; p for trend = 0.02). Glutamate intake was associated with an increased risk of ALS (adjusted OR for highest vs. lowest quartile = 3.2, 95% CI: 1.2, 8.0; p for trend < 0.02). Consumption of antioxidant vitamins from diet or supplement sources did not alter the risk. The positive association with glutamate intake is consistent with the etiologic theory that implicates glutamate excitotoxicity in the pathogenesis of ALS, whereas the associations with fat and fiber intake warrant further study and biologic explanation.     

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.     

Adolescent lifestyle factors and adult breast density in U.S. Chinese immigrant women

We examined recalled measures of adolescent diet, physical activity, and body size in relation to adult breast density in 201 U.S. Chinese immigrant women recruited in January 2002 to May 2003 from Philadelphia region screening programs. Mammographic images were classified into 1 of 4 categories ranging from "entirely fatty" to "extremely dense." Questionnaires assessed diet and physical activity between ages 12-17, relative weight and height at age 10, and weight at age 18. To estimate odds ratios (ORs), we conducted logistic regression analyses using proportional odds models for polychotomous outcomes. Higher adult breast density was significantly associated with adolescent red meat intake (adjusted 3rd vs. 1st tertile OR = 3.0, 95% confidence interval (CI) 1.5-6.4, trend P = 0.003) but not with other adolescent factors. For the association of adult acculturation with breast density, adjustment for adolescent red meat intake attenuated the OR for the highest vs. lowest level of acculturation from 2.5 (95% CI 1.2-5.3) to 1.9 (95% CI 0.9-4.0). Greater adolescent red meat intake may have increased adult breast density and partly accounted for the strong association between acculturation and breast density in this sample of immigrant Chinese women. If confirmed by further study, dietary prevention efforts for breast cancer should be considered earlier in life.     

Dietary antioxidants and lung cancer risk: a case-control study in Uruguay.

To examine the protective role of dietary antioxidants (carotenoids, vitamin C, vitamin E, glutathione, and flavonoids) in lung cancer risk, a case-control study involving 541 cases of lung cancer and 540 hospitalized controls was carried out in Uruguay. The relevant variables were energy adjusted using the residuals method and then categorized in quartiles. Adjusted odds ratios (ORs) for antioxidants were calculated through unconditional logistic regression. With the exception of lycopene and vitamin C, the remaining antioxidants were associated with significant reductions in risk of lung cancer. Of particular interest was the inverse association between dietary glutathione and lung cancer [OR of quartile with highest intake compared with lowest quartile = 0.42, 95% confidence interval (CI) = 0.27-0.63]. Also, carotenoids and vitamin E were associated with significant reductions in risk of lung cancer (OR = 0.43, 95% CI = 0.29-0.64 for total carotenoids and OR = 0.50, 95% CI = 0.39-0.85 for vitamin E). A joint effect for high vs. low intakes of beta-carotene and glutathione was associated with a significant reduction in risk (OR = 0.32, 95% CI = 0.22-0.46). It could be concluded that dietary antioxidants are associated with a significant protective effect in lung carcinogenesis and that the inverse association for glutathione persisted after controlling for total vegetables and fruits.     

Diet and prostatic cancer: a case-control study in Hawaii

A total of 452 cases of prostatic cancer identified through the population-based Hawaii Tumor Registry during the period 1977-1983 and 899 age-matched population controls were interviewed on the island of Oahu from 1981 to 1983. All interviews of the subjects, who comprised five different ethnic groups, were conducted in the home by use of a quantitative dietary history method. Usual weekly intake of fat, zinc, and vitamins A and C, including supplements, was determined for each subject. Among men 70 years or older, but not among younger men, and mean weekly consumption of saturated fat, carotenes, and zinc, adjusted for age and ethnicity, was greater for cases than for controls. In a multiple logistic regression analysis, the odds ratio for the highest quartile of fat intake among the older men was 1.7 (95% confidence interval (CI) 1.0-2.8). The corresponding odds ratios were 1.6 (95% CI 1.0-2.5) for carotenes, 1.4 (95% CI 0.9-2.3) for total vitamin C, and 1.7 (95% CI 1.1-2.7) for total zinc. There were significant linear trends in the odds ratios for saturated fat and zinc, but no synergistic interactions among the nutrients. The findings suggest that several different components of the diet may contribute independently to the risk of prostatic cancer in elderly men.     

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.     

Plant foods, antioxidants, and prostate cancer risk: findings from case-control studies in Canada

Epidemiological data on most cancer sites suggest that consumption of plant foods, which contain high levels of antioxidants, might slow or prevent the appearance of cancer. We used data from three case-control studies to test this hypothesis. The total study population consisted of 617 incident cases of prostate cancer and 636 population controls from Ontario, Quebec, and British Columbia. Dietary information was collected by an in-person interview with a detailed quantitative dietary history. Unconditional logistic regression analyses were performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs). A decreasing, statistically significant association was found with increasing intakes of green vegetables (OR = 0.54, 95% CI = 0.40-0.71 for 4th quartile), tomatoes (OR = 0.64, 95% CI = 0.45-0.91), beans/lentils/nuts (OR = 0.69, 95% CI = 0.53-0.91), and cruciferous vegetables (OR = 0.69, 95% CI = 0.52-0.91 for 3rd quartile). Higher intakes of fruit were associated with higher ORs (OR = 1.51, 95% CI = 1.14-2.01 for 4th quartile), an effect that was seen for total fruit and citrus fruit, as well as for all other noncitrus fruits. Among the grains, refined-grain bread intake was associated with a decrease in risk (OR = 0.65 for 4th quartile), whereas whole-grain breakfast cereals were associated with a higher risk for prostate cancer. Of all the antioxidant nutrients studied, the ORs were higher with higher intakes of cryptoxanthin (OR = 1.44, 95% CI = 1.09-1.89 for 4th quartile). Exposure to certain dietary components of plant origin, which are potentially modifiable, indicates the theoretical scope for reducing the risk from prostate cancer. Future experimental studies or trials are warranted for further understanding.     

Dairy products, calcium intake, and breast cancer risk: a case-control study in China

The results of dairy food consumption and breast cancer risk are conflicting, and their relationship has not previously been studied in China. The objective of this study is to examine the association between dairy products, calcium intake, and breast cancer risk among Chinese women. A hospital-based case-control study was conducted among Chinese women in the Guangdong province from June 2007 to August 2008. Four hundred and thirty-eight consecutively recruited cases with primary breast cancer were frequency-matched to 438 controls on age and residence. Dietary intake information was collected by interviewers using a validated food frequency questionnaire. Odds ratios (ORs) and 95% confidence interval (CI) were estimated using unconditional multiple logistic regression adjusted for various potential confounders. We observed a statistically significant inverse association of dietary calcium intake with breast cancer risk, with the adjusted OR (95% CI) of 0.35 (0.22-0.56) comparing the highest with the lowest quartile. No significant association was found between dairy products measured either by dry weight of dairy product or dairy product protein intake and breast cancer risk. Our study supports a protective effect of high intake of dietary calcium on breast cancer risk, and no association with dairy product intake.     

Soy and isoflavone intake are associated with reduced risk of ovarian cancer in southeast china

To investigate whether intake of soy and isoflavones has an inverse association with ovarian cancer risk, a case-control study was conducted in Hangzhou, China. Cases were 254 patients with histologically confirmed epithelial ovarian cancer. The 652 controls comprised 340 hospital visitors, 261 non-neoplastic hospital outpatients, and 51 women recruited from the community. Habitual dietary intakes including 9 soy foods were measured by face-to-face interview using a validated and reliable food-frequency questionnaire. Unconditional logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) accounting for age, demographic characteristics, hormonal factors, and total energy intake. Intake of soy and isoflavones was inversely related to the risk of ovarian cancer. Compared with the highest versus the lowest quartile intake, the ORs were 0.50 (95% CI = 0.31-0.82) for total soy foods and 0.51 (95% CI = 0.31-0.85) for isoflavones. Among subgroups of soy foods and isoflavones, the ORs for soybeans, bean curd, daidzein, genistein, and glycitein were 0.35 (95% CI = 0.22-0.58), 0.49 (95% CI = 0.29-0.81), 0.52 (95% CI = 0.31-0.87), 0.50 (95% CI = 0.30-0.84), and 0.59 (95% CI = 0.35-0.97), respectively.     

Low-to-moderate alcohol consumption and breast cancer risk by age 50 years among women in Germany

Studies of the association between alcohol drinking and breast cancer show a tendency towards an increase in risk for high consumption levels but yield less consistent results for low-to-moderate levels, particularly among premenopausal women. In a population-based case-control study in Germany, the authors determined the effect of alcohol consumption at low-to-moderate levels on breast cancer risk among women up to age 50 years. The study included 706 case women whose breast cancer had been newly diagnosed in 1992-1995 and 1,381 residence- and age-matched controls. In multivariate conditional logistic regression analysis, the adjusted odds ratios for breast cancer were 0.71 (95% confidence interval (CI): 0.54, 0.91) for average ethanol intake of 1-5 g/day, 0.67 (95% CI: 0.50, 0.91) for intake of 6-11 g/day, 0.73 (95% CI: 0.51, 1.05) for 12-18 g/day, 1.10 (95% CI: 0.73, 1.65) for 19-30 g/day, and 1.94 (95% CI: 1.18, 3.20) for > or = 31 g/day. The association with high daily ethanol intake of > or = 19 g was modified by educational level, such that odds ratios were 3.7, 1.6, and 0.7 for women with low, moderate, and high levels of education, respectively. These data suggest that low-level consumption of alcohol does not increase breast cancer risk 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.     

Raw and cooked vegetables, fruits, selected micronutrients, and breast cancer risk: a case-control study in Germany

In 1998-2000, a case-control study of breast cancer was conducted in Heidelberg, Germany. Three hundred ten consecutively recruited cases with primary breast cancer were matched according to 10-yr age groups to 353 controls with conditions unrelated to diet or endocrine disorders. Intake of raw vegetables, total vegetables, and whole-grain products was inversely associated with breast cancer risk (highest vs. lowest quartile adjusted odds ratio [OR] 0.51, 95% confidence interval [CI] 0.31-0.84; OR = 0.62, 95% CI = 0.38-1.02; and OR = 0.57; 95% CI = 0.34-0.95, respectively). Also, high intake of some selected vitamins and minerals possessing putative DNA-stabilizing properties displayed significant inverse risk associations. Adjusted ORs were as follows: vitamin C (OR = 0.49, 95% CI = 0.2-0.88), folate equivalents (OR = 0.47, 95% CI = 0.25-0.88), b-carotene (OR = 0.46, 95% CI = 0.27-0.80), zinc (OR = 0.35, 95% CI = 0.15-0.78), and copper (OR = 0.51, 95% CI = 0.31-1.03). In contrast, no significant association with risk was seen for an increased intake of fruits, cooked vegetables, fiber, calcium, manganese, or iron. In this population of German women, components of raw vegetables and some micronutrients appear to decrease breast cancer risk.     

Dairy Products,Calcium Intake,and Breast Cancer Risk: A Case-Control Study in China

The results of dairy food consumption and breast cancer risk are conflicting, and their relationship has not previously been studied in China. The objective of this study is to examine the association between dairy products, calcium intake, and breast cancer risk among Chinese women. A hospital-based case-control study was conducted among Chinese women in the Guangdong province from June 2007 to August 2008. Four hundred and thirty-eight consecutively recruited cases with primary breast cancer were frequency-matched to 438 controls on age and residence. Dietary intake information was collected by interviewers using a validated food frequency questionnaire. Odds ratios (ORs) and 95% confidence interval (CI) were estimated using unconditional multiple logistic regression adjusted for various potential confounders. We observed a statistically significant inverse association of dietary calcium intake with breast cancer risk, with the adjusted OR (95% CI) of 0.35 (0.22–0.56) comparing the highest with the lowest quartile. No significant association was found between dairy products measured either by dry weight of dairy product or dairy product protein intake and breast cancer risk. Our study supports a protective effect of high intake of dietary calcium on breast cancer risk, and no association with dairy product intake.     

Vegetables, fruits, and related nutrients and risk of breast cancer: a case-control study in Uruguay

To evaluate whether the protective effect associated with vegetables and fruits in breast cancer could be explained by nutrients and bioactive substances present in these plant foods, we carried out a case-control study in Uruguay including 400 cases and 405 controls. The intake of vegetables, fruits, and related nutrients was estimated with a food frequency questionnaire on 64 food items. This questionnaire allowed the calculation of total energy intake, and nutrients were calorie adjusted by the residuals method. Odds ratios for study variables were estimated by unconditional multiple logistic regression. Total vegetable, total fruit, dietary fiber, vitamin C, vitamin E, lycopene, folate, and total phytosterol intakes were inversely associated with breast cancer risk [4th quartile odds ratio for total vegetable intake = 0.41, 95% confidence interval = 0.26-0.65, p (for trend) = 0.004]. The association with total vegetable intake was not independent of lycopene intake. The results related to vegetable and nutrient intakes are consistent with antioxidant and antiestrogenic effects. This could be mediated, among other nutrients, by dietary fiber and lycopene intake. The role of other unmeasured phytochemicals, correlated with dietary fiber and lycopene intakes, cannot be ruled out.