Dietary intake of selected micronutrients and breast-cancer risk

The relation between 17 micronutrients and breast-cancer risk was analyzed in a case-control study conducted between 1993 and 1999 in the Swiss Canton of Vaud. Cases were 289 women with incident, histologically confirmed breast cancer, and controls were 442 women admitted to the same hospital for a wide spectrum of acute non-neoplastic conditions unrelated to long-term modifications of diet. Dietary habits were investigated using a validated food-frequency questionnaire. Odds ratios (ORs) were obtained after allowance for age, education, parity, menopausal status, body mass index, total energy intake and alcohol drinking. For several micronutrients, the ORs tended to decline with increasing tertile of intake, with significant inverse trends in risk for potassium (OR for the highest tertile = 0.21), total carotenoids (OR = 0.42), lycopene (OR = 0.43), folic acid (OR = 0.45), vitamin C (OR = 0.19), vitamin E (OR = 0.37) and vitamin B(6) (OR = 0.54). In a model including a continuous term for the 7 micronutrients significantly related to breast cancer, the only persisting significant inverse relations were for vitamin C (OR = 0.23) and lycopene (OR = 0.64).     

Nutrient intake and ovarian cancer: an Italian case-control study

Objective: The role of selected macronutrients, cholesterol, and fatty acids in the etiology of epithelial ovarian cancer was analyzed using data from a case–control study carried out in five Italian areas between January 1992 and December 1999. Methods: Cases comprised 1031 women with incident, histologically confirmed epithelial ovarian cancer, admitted to the major teaching and general hospitals of the study areas. Controls comprised 2411 women admitted for acute, non-neoplastic conditions to the same network of hospitals. Information on dietary habits was elicited using a validated food-frequency questionnaire including 78 food groups and recipes. Odds ratios (OR) and their corresponding 95% confidence intervals (CI) were computed by subsequent quintiles of nutrient intake. Results: Direct associations with ovarian cancer emerged for starch intake (OR = 1.4 in the highest vs the lowest quintile of intake; 95% CI 1.1–1.8), while inverse associations emerged for monounsaturated (OR = 0.7; 95% CI 0.5–0.9), and polyunsaturated (OR = 0.7; 95% CI 0.5–0.9) fatty acids. Among fatty acids, oleic (OR = 0.7; 95% CI 0.5–0.9), linoleic (OR = 0.7; 95% CI 0.5–0.9), and linolenic (OR = 0.8; 95% CI 0.6–1.0) acids were inversely related to ovarian cancer. When, however, six macronutrients were included in the same model, only the adverse effect of high starch intake remained significant. Results were consistent in separate strata of menopausal status, parity, and energy intake. Conclusions: Starch was directly associated, and unsaturated fatty acids were inversely associated, with ovarian cancer risk.     

Dietary patterns and risk of gastric cancer: a case-control study in Uruguay

Background Gastric cancer is a frequent malignancy in the Uruguayan population. In northern counties, incidence rates reach high figures (age-standardized rates [ASR], 37.3 per 100000 men and 18.3 per 100000 women). Diet is a major determinant in gastric carcinogenesis. Because foods or food groups have the advantage over nutrients in being most directly related to dietary recommendations, we decided to conduct a case-control study on the relationships between food groups and risk of gastric cancer. For this purpose, we included 240 cases and 960 controls.Methods In the present study we employed three analytical approaches: (1) individual food group analysis, (2) factor analysis, and (3) analysis of empirical scores of risk. Individual analysis of food groups was performed by multiple unconditional logistic regression, with food groups being the explanatory variables. Nineteen food groups were created and categorized in tertiles according to the control distribution. Factor analysis aggregated intercorrelated foods in broader eating patterns. In this study we were able to identify three factors or patterns, arbitrarily labeled starchy, healthy, and mixed. Finally, empirical scores of risk were created after examining the risk of each individual food and summing each significant item. This resulted in a risk enhancing score and a protective score. Both scores were categorized in tertiles according to the control distribution.Results The individual analysis of food groups showed increased risks of gastric cancer for rice, salted meat, stewed meat, white bread, potatoes, and tubers. On the other hand, raw vegetables, total fruits, legumes, and black tea were inversely associated with risk of gastric cancer. All three dietary patterns, generated by factor analysis, were significantly associated with gastric carcinoma risk. Whereas the starchy factor was directly associated with gastric cancer, the healthy and mixed patterns were strongly protective. Finally, the risk enhancing empirical score displayed an increased risk of gastric cancer (odds ratio [OR], 4.1, 95% confidence interval [CI], 2.6–6.6), whereas the protective score showed an important reduction in risk, of 0.38.Conclusion This study displayed consistent results from three different approaches. Concerning different food groups, stewed and processed meat are rich in salt; rice, tubers, and winter squash are sources of starch; and vegetables and fruits are rich in ascorbic acid and carotenoids. All these substances have been strongly related to gastric carcinogenesis. Furthermore, this study suggests that diets rich in vegetables and fruits and with low amounts of salty and starchy foods are recommendable for the prevention of gastric cancer.     

Physical activity and risk of ovarian cancer: an Italian case-control study

The relationship between physical activity and the risk of ovarian cancer was analyzed using data from a case-control study conducted between 1992 and 1999 in Italy. Cases were 1,031 women with incident, histologically confirmed, invasive epithelial ovarian cancer and controls were 2,411 women admitted to hospital for acute non-neoplastic, non-hormonal conditions. Compared to women with the lowest level of occupational physical activity, the ORs of ovarian cancer obtained adjusting for center, year of interview and age for women with the highest level of physical activity were 0.70, 0.52 and 0.64 (all statistically significant) respectively, at ages 15-19, 30-39 and 50-59 years, with significant trends in risk for the 2 youngest age groups. The corresponding ORs became 0.89, 0.67 and 0.76 after further allowance for several co-variates of ovarian cancer, including education, which was positively associated with cancer risk. No significant association was found with leisure-time physical activity though the risk was below unity in women with the highest level of activity. The multivariate OR was 0.44 for women with the highest level of combined occupational plus leisure-time physical activity. The inverse relationship between occupational physical activity and ovarian cancer risk was not heterogeneous across strata of selected co-variates.     

Nutrient intake patterns and gastric cancer risk: A case-control study in Belgium

A case-control study on gastric cancer risk in relation to nutrient composition of diet was conducted in the 2 Belgian provinces of Oost-Vlaanderen and Liège as part of a large epidemiological study on cancers of the digestive tract, also including colorectal cancer. The statistical analysis was carried out on a total of 301 men and women aged 35–74 years with histologically confirmed stomach tumors and 2,851 population controls. Dietary intake assessments were obtained by interview, using a dietary history questionnaire. Gastric cancer risk was increased for diets rich in mono- and disaccharides, according to statistical models based on energy-adjusted residuals [odds ratio (OR) = 1.88 for upper vs. lower quartiles of energy-adjusted intakes] or energy decomposition models, but showed no increase for high intake of polysaccharides. Intake of polyunsaturated fats, particularly linoleic acid, was inversely associated with gastric cancer risk. High intake of vitamin C, beta carotene and vitamins B1 (thiamine), B3 (nicotinic acid) or B6 (pyridoxine) was also associated with decreased risk, whereas increased risk was observed for high intake of vitamin A (retinol) or vitamin B2 (riboflavin). Many of these associations between gastric cancer risk and nutrient composition were similar to those found in the analysis of a parallel study on cancers of the colon and rectum. Int. J. Cancer 78:415–420, 1998. © 1998 Wiley-Liss, Inc.     

Dietary carotenoids and risk of gastric cancer: a case-control study in Uruguay.

In the period 1997-1999, 120 incident and histologically verified cases of stomach cancer were frequency matched on age, sex, residence and urban/rural status with 360 controls in order to study the role of diet in gastric cancer in Uruguay. Our attention was focused on the role of carotenoids in gastric carcinogenesis, after controlling for major confounders. According to the results, vitamin A, alpha-carotene and lycopene were associated with strong inverse relationships with stomach cancer (OR of stomach cancer for high alpha-carotene intake 0.34, 95% CI 0.17-0.65). Joint exposure to high intakes of alpha-carotene and vitamin C intakes were associated with a strong reduction in risk (OR 0.11, 95% CI 0.03-0.36). It was also suggested that high lycopene intake explained most of the reduction in risk of gastric cancer associated with vegetable intake, whereas no such effect was observed for fruit intake.     

Dietary phytoestrogen intake and premenopausal breast cancer risk in a German case-control study

A diet high in isoflavonoids (soy) is associated with lower breast cancer risk in Asian populations. Due to the low soy intake, dietary lignans may be the more important phytoestrogen class in Western populations. We used a population-based case-control study of breast cancer by age 50 in southern Germany to evaluate the association between dietary intake of different phytoestrogens and premenopausal breast cancer risk. Dietary information was collected from 278 premenopausal cases and 666 age-matched controls, using a validated FFQ. Using multivariate logistic regression, the highest vs. lowest intake quartiles of daidzein and genistein yielded significantly reduced ORs (95% CI) for breast cancer risk of 0.62 (0.40-0.95) and 0.47 (0.29-0.74), respectively. The protective effects of daidzein and genistein were found only for hormone receptor-positive tumors. High intake of other isoflavonoids, e.g., formononetin and biochanin A, as well as the sum of isoflavonoids were not associated with a decrease in risk. Breast cancer risk significantly decreased with a high intake of the plant lignan matairesinol (OR = 0.58, 95% CI 0.37-0.94) but not secoisolariciresinol or the sum of plant lignans. However, both estimated mammalian lignans, enterodiol and enterolactone, were inversely associated with breast cancer risk, with ORs (95% CI) of 0.61 (0.39-0.98) and 0.57 (0.35-0.92), respectively. No effect was found for total phytoestrogen intake. Our results suggest an important role of dietary intake of daidzein and genistein, despite low levels, as well as of matairesinol and mammalian lignans to reduce premenopausal breast cancer risk in this study population.     

Dietary carotenoids and risk of colon cancer: case-control study

Some epidemiological studies suggest that consumption of fruits and vegetables with a high carotenoid content may protect against colon cancer (CC). The evidence, however, is not completely consistent. Given the inconsistencies in findings in previous studies and continued interest in identifying modifiable risk factors for CC, a case-control study of French-Canadian in Montreal, Canada, was undertaken to examine the possible association between dietary carotenoids and CC risk and to investigate whether this association varies in relation to lifestyle factors such as smoking or diet, and particularly the high consumption of long-chain polyunsaturated fatty acids (LCPUFA). A total of 402 colorectal cases (200 males and 202 females) and 688 population-based controls matched for age, gender and place of residence were interviewed. Dietary intake was assessed through a validated food frequency questionnaire that collected information on over 200 food items and recipes. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated in unconditional logistic regression models. After adjustment for important variables such as total energy intake, no association was found between dietary intake of carotenoids and CC risk. For women with high intakes of LCPUFA, an inverse association was found between lutein + zeaxanthin and CC risk. ORs were 0.41; 95%CI (0.19-0.91), p=0.03 for eicosapentaenoic acid, and OR=0.36, 95%CI (0.19-0.78), p=0.01 for docosahexaenoic acid, when the upper quartiles of intake were compared to the lower. Among never-smokers, a significantly reduced risk of CC was associated with intake of beta-carotene [OR=0.44, 95%CI (0.21-0.92) and p=0.02], whereas an inverse association was found between lycopene intake and CC risk [OR=0.63, 95%CI (0.40-0.98) and p=0.05] among smokers. The results of our study suggest that a diet rich in both lutein + zeaxanthin and LCPUFAs may help prevent CC in French-Canadian females.     

Diabetes and endometrial cancer: an Italian case-control study

We considered the association between diabetes and risk of endometrial cancer using data from a large case-control study conducted in Italy. Cases were 752 women with incident, histologically confirmed endometrial cancer < 75 years of age (median age 60 years, range 28-74) admitted to a network of hospitals in Milan. Controls were 2,606 patients (median age 54 years, range 25-74) aged < 75 years, admitted for acute non-neoplastic, non-gynecological, non-hormone-related conditions to the same network of hospitals where cases had been identified. A total of 132 (17.6%) cases and 116 controls (4.5%) reported a history of diabetes. The corresponding multivariate odds ratio (OR) was 2.9 [95% confidence interval (CI) 2.2-3.9]. No association emerged with diabetes diagnosed under age 40 (likely to be insulin-dependent diabetes), whereas the OR of endometrial cancer was 3.1 (95% CI 2.3-4.2) for diabetes diagnosed at age > or = 40 years. The OR of endometrial cancer in women with history of diabetes was 3.0 for women with a body mass index (BMI) (QI) kg/m2 < 25, 3.6 for those with a BMI of 25-29, and 3.3 for those with a BMI > or = 30. No consistent interaction or modifying effect was observed for any other covariate. Our results confirm that non-insulin-dependent diabetes is associated with the risk of endometrial cancer. The association may be mediated through elevated oestrogen levels in diabetic women, hyperinsulinemia or insulin-like growth factor-I (IGF-I).     

Dietary quercetin intake and risk of gastric cancer: results from a population-based study in Sweden

BackgroundTo study the impact of the dietary antioxidant quercetin on risk of gastric adenocarcinoma.Patients and methodsUsing data from a large Swedish population-based case–control study of gastric cancer (505 cases and 1116 controls), we studied the association between quercetin and risk of anatomic (cardia/noncardia) and histological (intestinal and diffuse) subtypes of gastric cancer.ResultsWe found strong inverse associations between quercetin and the risk of noncardia gastric adenocarcinoma, with an adjusted odds ratio (OR) of 0.57 (95% confidence interval 0.40–0.83) for the highest quintile (≥11.9 mg) of daily quercetin intake relative to the lowest quintile of intake (<4 mg quercetin/day), supported by a significant decreasing linear trend (P value < 0.001). Similar findings were observed for the intestinal and diffuse subtype. For cardia cancer, we found a less evident and nonsignificant inverse relationship. The protection of quercetin appeared to be stronger among female smokers, with the OR leveled of at values <0.2 in quintiles 3–5 (>6 mg quercetin/day).ConclusionsHigh dietary quercetin intake is inversely related to the risk of noncardia gastric adenocarcinoma, and the protection appears to be particularly strong for women exposed to oxidative stress, such as tobacco smoking.     

Intake of selected micronutrients and risk of colorectal cancer

The relationship between various micronutrients and colorectal cancer risk was investigated using data from a case-control study conducted between January 1992 and June 1996 in Italy. Cases were 1,953 incident, histologically confirmed colorectal cancers (1,225 of the colon and 728 of the rectum), admitted to the major teaching and general hospitals in the study areas, and 4,154 controls with no history of cancer, admitted to hospitals in the same catchment areas for acute, non-neoplastic diseases unrelated to the digestive tract and requiring no long-term modifications of the diet. Dietary habits were investigated using a validated food-frequency questionnaire. Odds ratio (ORs) were computed after allowance for age, sex and other potential confounding factors, including physical activity, total energy and fibre intake. For most micronutrients, ORs were below unity with increasing quintile of intake. The most consistent protective effects were for carotene, riboflavin and vitamin C (Multivariate ORs from the continuous model, with unit set as the difference between the upper cut-point of the 4th quintile and that of the 1st one, were 0.65, 0.73 and 0.80, respectively). Inverse relationships were observed also for calcium and vitamin D (ORs of 0.85 and 0.93, respectively). When the combined effect of calcium and vitamin D and selected anti-oxidants was considered, the OR reached 0.46 in subjects reporting high calcium/vitamin D and high anti-oxidant intake compared to those reporting low intake of both groups of micronutrients. Most results were apparently stronger for colon cancer and among females. Our results provide further support for a protective effect of several micronutrients on colorectal cancer risk and some indications for a specific and stronger effect of selected anti-oxidants. Int. J. Cancer 73:525–530, 1997. © 1997 Wiley-Liss, Inc.     

Dietary factors and gastric cancer in Korea: a case-control study.

To assess gastric cancer (GC) risk in relation to dietary intake in Korea, a case-control study was performed. Trained dietitians interviewed 136 patients diagnosed with GC, and the same number of controls were selected by matching sex, age and hospital. A significant decrease in GC risk was observed with increased intake of Baiechu kimchi (prepared with salted Chinese cabbage and red pepper, etc.), Baiechu kimchi-stew, garlic, mushroom and soybean milk. On the contrary, a significant increase in the risk of GC was observed with increased intake of cooked rice with bean, charcoal grilled beef, pollack soup, Kkakduki (a kind of kimchi prepared with salted radish and red pepper, etc.), Dongchimi (a kind of kimchi prepared with radish and a large quantity of salt water) and cooked spinach. In food groups, increased intake of soybean products was associated with decreased risk of GC. Intake of citrus fruits rather than total fruits was shown to have a protective effect on the risk of GC, but was not significant. In this study, intake of total vegetables was shown to have a protective effect, whereas high nitrate-containing vegetables increased the risk of GC. In conclusion, our study suggests that the risk of GC decreased with high consumption of fresh vegetables and fruits, whereas high consumption of foods rich in nitrate and carcinogenic substances produced during the cooking process increased the risk of GC.     

Dietary folate intake and lung cancer risk in former smokers: a case-control analysis.

No studies have focused on the role of dietary folate intake in risk of lung cancer in former smokers, in whom dietary folate intake is less likely confounded with current smoking. Therefore, we evaluated the association between dietary folate intake and risk of lung cancer in a population of 470 histopathologically confirmed incident lung cancer cases from M. D. Anderson Cancer Center and 472 cancer-free controls from enrollees at a community-based multispecialty physician practice, frequency-matched on age (5 years), sex, and ethnicity. Dietary folate intake levels were estimated from a National Cancer Institute standard food frequency questionnaire. Unconditional logistic regression analyses were used to calculate the crude and adjusted ORs and their 95% CIs. Dietary folate intake from natural food was significantly higher among the controls than among the cases (P < 0.001), and folate intake above the control median value was associated with a 40% decreased risk of lung cancer (adjusted OR, 0.60; 95% CI, 0.45-0.79). A significant inverse dose-response relationship between increasing dietary folate and decreasing risk of lung cancer was also evident (adjusted OR, 1.02; 95% CI, 0.71-1.47; OR, 0.67; 95% CI, 0.46-0.99; and OR, 0.53; 95% CI, 0.35-0.80 for the second, third, and fourth quartiles of average folate intake, respectively; P for trend <0.001). A more pronounced inverse association between dietary folate intake and lung cancer risk was observed among subjects who drank alcohol, had smoked relatively more, those who did not take supplemental folate, and those who reported a family history of lung cancer. Our data suggest that there is a possible protective role of dietary folate in lung carcinogenesis, a finding which may have implications in public health and cancer prevention.     

Intake of selected micronutrients and the risk of breast cancer

To investigate the relation between selected micronutrients and breast cancer risk, we conducted a case-control study of breast cancer between June 1991 and April 1994 in 6 Italian areas. The study included 2569 women admitted to the major teaching and general hospitals of the study areas with histologically confirmed incident breast cancer and 2588 control women with no history of cancer, who were admitted to hospitals in the same catchment areas for acute, non-neoplastic, nongynecological conditions unrelated to hormonal or digestive tract diseases or to long-term modifications of the diet. Dietary habits, including alcoholic beverage consumption, were investigated using a validated food frequency questionnaire, including 78 foods or food groups, several types of alcoholic beverages, some “fat intake pattern” questions and some open sections for foods consumed frequently by the subject and not reported in the questionnaire. To control for potential confounding factors, several multiple logistic regression models were used. When major correlates, energy intake and the mutual confounding effect of the various micronutrients were taken into account, beta-carotene, vitamin E and calcium showed a significant inverse association with breast cancer risk. The estimated odds ratios of the 5th quintile compared to the lowest one were 0.84 for beta-carotene, 0.75 for vitamin E and 0.81 for calcium. No significant association emerged for retinol, vitamin C, thiamin, riboflavin, iron and potassium. Our results suggest that a diet rich in several micronutrients, particularly beta-carotene, vitamin E and calcium, may be protective against breast cancer. © 1996 Wiley-Liss, Inc.     

Dietary intake of fruit and vegetable and lung cancer risk: a case-control study in Harbin, northeast China.

BACKGROUND: We studied the relationship between dietary intake of vegetables and fruit and lung cancer risk in Harbin, Heilongjiang province, northeast China, an area with a very high baseline risk of lung cancer in both sexes. PATIENTS AND METHODS: We used data from a case-control study, conducted from 1987 to 1990, among 218 cases with incident, histologically confirmed lung cancer and 436 controls admitted to the same hospitals as cases with non-neoplastic, non-lung diseases unrelated to smoking and other potential risk factors for lung cancer. RESULTS: Compared with the lowest tertile of intake of vegetables, fruit or both, the multivariate odds ratios (ORs) for the highest tertile of intake were 0.39 [95% confidence interval (CI) 0.25-0.62], 0.73 (95% CI 0.48-1.11) and 0.40 (95% CI 0.25-0.63), respectively. In particular, high intake of Chinese cabbage (OR = 0.53), chives (OR = 0 .54), carrots (OR = 0.51) and celery (OR = 0.40) was inversely associated with lung cancer. The OR was more than six-fold elevated for smokers reporting low intake of vegetables, and more than four-fold elevated for smokers reporting low intake of fruit, as compared with never smokers reporting high intake of these items. CONCLUSION: In agreement with previous studies, we found an inverse relation between vegetable and fruit intake and lung cancer risk in both strata of current and never smokers.     

Breast cancer risk factors in Italian women: a multicentric case-control study

To evaluate the importance of several risk factors for breast cancer in the Italian female population, a large multicentric case-control study was conducted in 10 breast clinics in Italy. The study included 1,556 women affected by breast cancer, histologically and/or cytologically confirmed. Controls were 1,505 women admitted to a hospital in the same town, matched with cases for residence and with the same age distribution of the Italian female population. The risk factors considered in this study were family history of breast cancer, reproductive history, height and weight, use of oral contraceptives, other hormonal therapies and smoking history. The results of this study confirm the significant role of a positive family history of breast cancer (RR = 2.37); the relative risk was even higher when a first-degree relative was affected or the breast cancer was bilateral. The analysis of the reproductive history showed a significant trend of increasing risk with increasing age at first birth and, although less evident, with increasing number of children. Quetelet's index (kg/m-2) was positively correlated with breast cancer risk, mostly in postmenopausal women. Among other studied factors, only late age at menopause confirmed an increased risk for breast cancer, whereas age at menarche, use of oral contraceptives and smoking histories did not show any significant correlation with breast cancer risk. These results are in substantial agreement with other international studies, but represent an interesting contribution to studies about the Italian female population.     

Dietary fiber intake and ovarian cancer risk: a prospective cohort study

There is some evidence from case–control studies that dietary fiber intake might be inversely associated with ovarian cancer risk, but there are limited prospective data. Therefore, we examined ovarian cancer risk in association with intake of dietary fiber in a prospective cohort of 49,613 Canadian women enrolled in the National Breast Screening Study (NBSS), who completed a self-administered food frequency questionnaire between 1980 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. Data from the food frequency questionnaire were used to estimate intake of total dietary fiber, of fiber fractions, and of fiber from various sources. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between energy-adjusted quartile levels of fiber intake and ovarian cancer risk. During a mean 16.4 years of follow-up, we observed 264 incident ovarian cancer cases. Total dietary fiber and fiber fractions were not associated with ovarian cancer risk in this study population.