Consumption of vegetables and fruits and risk of ovarian carcinoma

Diabetes risk reduction diet and ovarian cancer risk: an Italian case-control study

PURPOSE

To investigate the relation between a diabetes risk reduction diet (DRRD) and ovarian cancer.

METHODS

We used data from a multicentric case-control study conducted in Italy, including 1031 incident ovarian cancer cases and 2411 controls admitted to hospital centres for acute non-malignant disease. Subjects' diet prior to hospital admission was collected using a validated food frequency questionnaire. Adherence to the DRRD was measured using a score based on 8 dietary components, giving higher scores for greater intakes of cereal fiber, coffee, fruit, nuts, higher polyunsaturated to saturated fatty acids ratio, lower glycemic index of diet, and lower intakes of red/processed meat, and sweetened beverages/and fruit juices. Higher scores indicated greater adherence to the DRRD. Multiple logistic regression models were fitted to calculate the odds ratios (OR) of ovarian cancer and the corresponding 95% confidence intervals (CI) for approximate quartiles of the DRRD score.

RESULTS

The DRRD score was inversely related to ovarian cancer, with an OR of 0.76 (95%CI: 0.60-0.95) for the highest versus the lowest quartile of the score (p for trend = 0.022). The exclusion of women with diabetes did not change the results (OR = 0.75, 95%CI: 0.59-0.95). Inverse associations were observed in strata of age, education, parity, menopausal status, and family history of ovarian/breast cancer.

CONCLUSION

Higher adherence to a diet aimed at reducing the risk of diabetes was inversely associated with ovarian cancer. Further evidence from prospective investigations will be useful to support our findings.

Association between dietary intake and risk of ovarian cancer: a systematic review and meta-analysis

PURPOSE

It is unclear how dietary intake influences the ovarian cancer. The present paper sets out to systematically review and meta-analyze research on dietary intake to identify cases having high- or low-risk ovarian cancer.

METHODS

Scopus, PubMed, and Wiley Online Libraries were searched up to the date November 24, 2019. Two reviewers were requested to independently extract study characteristics and to assess the bias and applicability risks with reference to the study inclusion criteria. Meta-analyses were performed to specify the relationship between dietary intake and the risk of ovarian cancer identifying 97 cohort studies.

RESULTS

No significant association was found between dietary intake and risk of ovarian cancer. The results of subgroup analyses indicated that green leafy vegetables (RR = 0.91, 95%, 0.85-0.98), allium vegetables (RR = 0.79, 95% CI 0.64-0.96), fiber (RR = 0.89, 95% CI 0.81-0.98), flavonoids (RR = 0.83, 95% CI 0.78-0.89) and green tea (RR = 0.61, 95% CI 0.49-0.76) intake could significantly reduce ovarian cancer risk. Total fat (RR = 1.10, 95% CI 1.02-1.18), saturated fat (RR = 1.11, 95% CI 1.01-1.22), saturated fatty acid (RR = 1.19, 95% CI 1.04-1.36), cholesterol (RR = 1.13, 95% CI 1.04-1.22) and retinol (RR = 1.14, 95% CI 1.00-1.30) intake could significantly increase ovarian cancer risk. In addition, acrylamide, nitrate, water disinfectants and polychlorinated biphenyls were significantly associated with an increased risk of ovarian cancer.

CONCLUSION

These results could support recommendations to green leafy vegetables, allium vegetables, fiber, flavonoids and green tea intake for ovarian cancer prevention.

Empirically derived dietary patterns and ovarian cancer risk: a meta-analysis

Dietary patterns, which reflect overall diet and possible nutrient and food interactions, have been reported to be related to ovarian cancer (OC) risk. However, studies on the relationship between dietary patterns and OC risk have been inconsistent. Thus, we carried out a systematic meta-analysis to assess the relationship between dietary patterns and the risk of OC. Relevant studies are identified by searching the Medline and Embase electronic databases up to December 2016. The Cochrane Q statistic and the I statistical were used to evaluate heterogeneity. A total of 22 studies fulfilled the inclusion criteria and were included in this meta-analysis. There was evidence of a decreased risk for OC in the highest versus the lowest categories of healthy dietary pattern [odds ratio (OR)=0.86; 95% confidence interval (CI): 0.74-0.99; P=0.04]. An increased risk of OC was shown for the highest versus the lowest category of a western-style dietary pattern (OR=1.19; 95% CI: 1.01-1.41; P=0.04). No significant association with OC risk was observed in the highest versus the lowest category of a heavy drinking pattern (OR=0.89; 95% CI: 0.67-1.19; P=0.42). The results of this meta-analysis suggest that a healthy dietary pattern is associated with reduced risk for OC and a western-style dietary pattern is associated with an increased risk of OC. Further studies are needed to confirm our results.

The effect of the type of dietary protein on the development of ovarian cancer

We evaluated whether different dietary protein qualities (isocaloric diets involving animal (casein) or plant protein (soy protein) could inhibit the ovarian cancer growth in mice and improve their prognosis and whether chemotherapy had different tumor reducing effects on these mice. In the mice of the 20% plant protein group, the ovarian cancer growth at 5 weeks after tumor implantation was clearly reduced in comparison to the mice in the 20% animal protein group (p< 0.001). The serum levels of insulin and IGF-1 levels were both lower in the mice of the 20% plant protein group than in the mice of the 20% animal protein group (p<0.001 and p<0.01, respectively). Immunohistochemistry revealed that the level of eukaryotic initiation factor 4E-binding protein 1 (p-4EBP1) activity―one of the major downstream effectors of the mTOR pathway ―of the plant protein group was significantly weaker than that of the animal protein group (p<0.001). The prognosis of the 20% plant protein group was better than that of the 20% animal protein group (log-rank test, p=0.0062). The ovarian cancer growth in the 20% plant protein plus cisplatin treatment group was not significantly reduced in comparison to the 20% animal protein plus cisplatin treatment group. Our findings suggest that a diet high in plant protein reduces the growth of human ovarian cancer cells in mice compared to a diet high in animal protein, ―possibly through the lack of activation of the IGF/Akt/mTOR pathway, and leads to a better prognosis with or without cisplatin treatment.

Fruit and vegetables and cancer risk: a review of southern European studies

High intakes of fruit and vegetables may reduce the risk of cancer at several sites. Evidence has been derived mainly from case-control studies. We reviewed the relationship between consumption of vegetables and fruit and the risk of several common cancers in a network of Italian and Swiss case-control studies including over 10,000 cases of fourteen different cancers and about 17,000 controls. Data were suggestive of a protective role of vegetable intake on the risk of several common epithelial cancers. OR for the highest compared with the lowest levels of consumption ranged from 0.2 (larynx, oral cavity and pharynx) to 0.9 (prostate). Inverse associations were found for both raw and cooked vegetables, although for upper digestive tract cancers the former were somewhat stronger. Similar inverse associations were found for cruciferous vegetables. Frequent consumption of allium vegetables was also associated with reduced risk of several cancers. Fruit was a favourable correlate of the risk of several cancers, particularly of the upper digestive tract, with associations generally weaker than those reported for vegetables. A reduced risk of cancers of the digestive tract and larynx was found for high consumption of citrus fruit. Suggestive protections against several forms of cancer, mainly digestive tract cancers, were found for high consumption of apples and tomatoes. High intakes of fibres, flavonoids and proanthocyanidins were inversely related to various forms of cancer. In conclusion, data from our series of case-control studies suggested a favourable role of high intakes of fruit and vegetables in the risk of many common cancers, particularly of the digestive tract. This adds evidence to the indication that aspects of the Mediterranean diet may have a favourable impact not only on CVD, but also on several common (epithelial) cancers, particularly of the digestive tract.

Intake of vitamins A, C, and E and folate and the risk of ovarian cancer in a pooled analysis of 10 cohort studies

PURPOSE

Vitamins A, C, and E and folate have anticarcinogenic properties and thus might protect against cancer. Few known modifiable risk factors for ovarian cancer exist. We examined the associations between dietary and total (food and supplemental) vitamin intake and the risk of invasive epithelial ovarian cancer.

METHODS

The primary data from 10 prospective cohort studies in North America and Europe were analyzed. Vitamin intakes were estimated from validated food frequency questionnaires in each study. Study-specific relative risks (RRs) were estimated using the Cox proportional hazards model and then combined using a random-effects model.

RESULTS

Among 501,857 women, 1,973 cases of ovarian cancer occurred over a median follow-up period of 7-16 years across studies. Dietary and total intakes of each vitamin were not significantly associated with ovarian cancer risk. The pooled multivariate RRs [95% confidence intervals (CIs)] for incremental increases in total intake of each vitamin were 1.02 (0.97-1.07) for vitamin A (increment: 1,300 mcg/day), 1.01 (0.99-1.04) for vitamin C (400 mg/day), 1.02 (0.97-1.06) for vitamin E (130 mg/day), and 1.01 (0.96-1.07) for folate (250 mcg/day). Multivitamin use (vs. nonuse) was not associated with ovarian cancer risk (pooled multivariate RR = 1.00, 95% CI 0.89-1.12). Associations did not vary substantially by study, or by subgroups of the population. Greater vitamin intakes were associated with modestly higher risks of endometrioid tumors (n = 156 cases), but not with other histological types.

CONCLUSION

These results suggest that consumption of vitamins A, C, and E and folate during adulthood does not play a major role in ovarian cancer risk.

Cruciferous vegetables consumption and the risk of ovarian cancer: a meta-analysis of observational studies

Background

To quantify the effect of cruciferous vegetable consumption on the incidence of ovarian cancer by meta-analyzing the existing observational studies and provides quantitative and high-level evidence.

Methods

A detailed literature search of Medline and EMBASE for all relevant papers published. A meta-analysis was conducted for the association between cruciferous vegetable consumption and risk of ovarian cancer.

Results

A total of 4,306 cases in 375,562 controls in 11 independent studies were identified in this current meta-analysis. The result of this current meta-analysis, including 6 case-control and 5 cohort studies, indicated that cruciferous vegetable intake was associated with a reduced risk of ovarian cancer. Cruciferous vegetable consumption was associated with a reduced risk of ovarian cancer in case-control studies (RR=0.84; 95% CI, 0.75-0.94) but not in cohort studies (RR=1.00; 95% CI, 0.85-1.11).

Conclusions

The results from this meta-analysis of observational studies demonstrate that cruciferous vegetable consumption is a prospective factor of the ovarian cancer. However, more in-depth studies are warranted to report more detailed results, including other specific vegetables within the cruciferous vegetable family.

Virtual slides

The virtual slide (s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1116708293115581.

Reality check: there is no such thing as a miracle food

A recent episode of the Dr. Oz Show suggested endive, red onion, and sea bass as foods that can decrease the risk of ovarian cancer by up to 75%. However, the scientific evidence supporting these recommendations is limited. This commentary discusses some of the concerns related to the promotion of "miracle foods" by the media. Nutritional scientists and epidemiologists should be cognizant of the public health messages that are taken from their individual studies and not sensationalize the findings of a single study.

Dietary intake and ovarian cancer risk: a systematic review

Ovarian cancer is a leading cause of gynecological cancer death. There is a need to identify modifiable dietary risk factors for this disease. To evaluate the role of diet in ovarian cancer risk, we performed a PRISMA-directed systematic review that included prospective cohort studies with >200 cases (n = 24). Higher risk for ovarian cancer was shown for total, animal, and dairy fat (five of nine studies), as well as total nitrate and possibly total vitamin C. No associations were demonstrated for red meat, fiber, vitamin A, vitamin E, β-carotene, or folate. Vegetables were associated with lower risk in one of three studies; fruit showed no association, although risk estimates were all greater than 1.0. Isoflavones and flavonoids were associated with modestly lower risk in two studies and tea intake was associated with lower risk in one of two studies. This review suggests that no specific dietary factors are consistently associated with ovarian cancer risk. Data by tumor subtypes are limited, but suggest that differential associations by tumor subtype may exist and should be evaluated. Studies of ample sample size, varied exposure, which can better control for dietary measurement error, are needed to fully define dietary recommendations for ovarian cancer prevention.

American Cancer Society Guidelines on nutrition and physical activity for cancer prevention: reducing the risk of cancer with healthy food choices and physical activity

The American Cancer Society (ACS) publishes Nutrition and Physical Activity Guidelines to serve as a foundation for its communication, policy, and community strategies and, ultimately, to affect dietary and physical activity patterns among Americans. These Guidelines, published approximately every 5 years, are developed by a national panel of experts in cancer research, prevention, epidemiology, public health, and policy, and they reflect the most current scientific evidence related to dietary and activity patterns and cancer risk. The ACS Guidelines focus on recommendations for individual choices regarding diet and physical activity patterns, but those choices occur within a community context that either facilitates or creates barriers to healthy behaviors. Therefore, this committee presents recommendations for community action to accompany the 4 recommendations for individual choices to reduce cancer risk. These recommendations for community action recognize that a supportive social and physical environment is indispensable if individuals at all levels of society are to have genuine opportunities to choose healthy behaviors. The ACS Guidelines are consistent with guidelines from the American Heart Association and the American Diabetes Association for the prevention of coronary heart disease and diabetes, as well as for general health promotion, as defined by the 2010 Dietary Guidelines for Americans and the 2008 Physical Activity Guidelines for Americans.

Healthy eating index and ovarian cancer risk

The evidence for a role of diet on ovarian cancer prevention remains inconclusive. While many studies have evaluated individual foods and food groups, the evaluation of a comprehensive dietary quality index for predicting cancer risk has received little attention. This study investigates the association between the Healthy Eating Index (HEI), which reflects adherence to the current USDA Dietary Guidelines for Americans and ovarian cancer risk in a population-based case-control study in New Jersey. A total of 205 cases and 390 controls completed the Block 98.2 food frequency questionnaire (FFQ) in addition to reporting on potential risk factors for ovarian cancer. FFQ data were then utilized to calculate the HEI score, and cup, ounce, gram, or caloric equivalents for the 12 different food groups comprising the index. In multivariate models, the OR for the highest tertile of the HEI score compared with the lowest (reflecting a better diet compared with a worse diet) was 0.90 (95% CI: 0.55-1.47). There was limited evidence for a statistically significant association between any of the 12 individual food components and ovarian cancer risk. Based on this study's results, neither individual food groups nor dietary quality showed potential for preventing ovarian cancer.

Current understanding of risk factors for ovarian cancer

OPINION STATEMENT

Ovarian cancer is the deadliest gynecologic cancer. Unlike many cancers such as breast, cervical and colon cancers, there is no easily clinically identifiable pre-malignant phase of this malignancy making early identification difficult. Similarly, unlike lung, head and neck, and skin cancers, there is not easily identifiable risk factor making prevention short of oophorectomy difficult. Even so, theories as to the causative factors of ovarian cancer continue to evolve making our understanding of the genesis of ovarian cancer more clear. Genetics, parity, environment, hormonal factors, and inflammation all play an important and pivotal role in the development of ovarian cancer. The most current understanding of these elements and their respective contribution to the development of this cancer are presented in this chapter.

Flavonoid intake and ovarian cancer risk in a population-based case-control study

Several recent studies have evaluated the association between dietary flavonoid intake and ovarian cancer risk, and all reported significant or suggestive inverse associations with certain flavonoids or flavonoid subclasses; however, most of these studies were small to moderate in size. We, therefore, examined this association in a large, population-based case-control study. We calculated intake of 5 common dietary flavonoids (myricetin, kaempferol, quercetin, luteolin, and apigenin), as well as total intake of these flavonoids, for 1,141 cases and 1,183 frequency-matched controls. We used unconditional logistic regression to estimate the relative risk (RR) of ovarian cancer for each quintile of flavonoid intake when compared with the lowest quintile. We did not observe an association between total flavonoid intake and ovarian cancer risk. The multivariable-adjusted RR for the highest versus lowest quintile of total flavonoid intake was 1.06 (95% confidence interval [CI] = 0.78-1.45). In analyses of each individual flavonoid, only intake of apigenin was associated with a borderline significant decrease in risk (RR, highest vs. lowest quintile = 0.79, 95% CI = 0.59-1.06; p-trend = 0.26), and this association was significant after adjustment for intake of the other 4 individual flavonoids (comparable RR = 0.72, 95% CI = 0.53-0.98; p-trend = 0.09). These results provide limited support for an association between flavonoid intake and ovarian cancer risk. However, given the findings of previous studies and the biologic plausibility of this association, additional studies are warranted.

The role of antioxidants and vitamin A in ovarian cancer: results from the Women's Health Initiative

Antioxidant nutrients and carotenoids have been inconsistently associated with ovarian cancer risk. We examined the relationship between intake of dietary and supplemental antioxidant nutrients including vitamins C, E, and selenium as well as carotenoids and vitamin A and ovarian cancer in 133,614 postmenopausal women enrolled in the Women's Health Initiative (WHI) study. Dietary intake was assessed using a food frequency questionnaire, and ovarian cancer endpoints were centrally adjudicated. Cox regression models were used to estimate the risk for invasive ovarian cancer in relation to each of the antioxidant nutrients and carotenoids under consideration using models stratified for a WHI study component. A total of 451 cases of invasive ovarian cancer were diagnosed over 8.3 yr of follow-up. Dietary intake at baseline was not significantly different for cases vs. controls. Cases reported greater intake of supplemental vitamin C (358.0 mg/day vs. 291.6 mg/day, respectively; P = 0.024). Multivariate modeling (P for trend) of the risk for developing ovarian cancer did not suggest any significant relationships among dietary factors and ovarian cancer risk. The results from this prospective study of well-nourished, postmenopausal women suggest that intake of dietary antioxidants, carotenoids, and vitamin A are not associated with a reduction in ovarian cancer risk.

Ovarian cancer hormonal and environmental risk effect

To understand the influence of hormonal and environmental factors on the risk of ovarian cancer, it is important to remember the established risk factors and postulated mechanisms that lead to the development of ovarian cancer. Several risk factors have been identified as increasing the risk of epithelial ovarian cancer, including low pariety, infertility, early age of menarche, and late age of menopause. This article discusses the different hypotheses and focuses on hormonal and environmental risk factors, as well the chemoprevention of epithelial ovarian cancer.

A prospective study of dietary flavonoid intake and incidence of epithelial ovarian cancer

Flavonoids are antioxidant compounds found in plants, including fruits, vegetables and tea. No prior prospective studies have examined the association between intake of flavonoids in the flavonol and flavone subclasses and ovarian cancer risk. We analyzed the association between intake of 5 common dietary flavonoids and incidence of epithelial ovarian cancer among 66,940 women in the Nurses' Health Study. We calculated each participant's intake of myricetin, kaempferol, quercetin, luteolin and apigenin from dietary data collected at multiple time points, and used Cox proportional hazards regression to model the incidence rate ratio (RR) of ovarian cancer for each quintile of intake. Our analysis included 347 cases diagnosed between 1984 and 2002, and 950,347 person-years of follow-up. There was no clear association between total intake of the 5 flavonoids examined and incidence of ovarian cancer (RR = 0.75 for the highest versus lowest quintile, 95% confidence interval [CI] = 0.51-1.09). However, there was a significant 40% decrease in ovarian cancer incidence for the highest versus lowest quintile of kaempferol intake (RR = 0.60, 95% CI = 0.42-0.87; p-trend = 0.002), and a significant 34% decrease in incidence for the highest versus lowest quintile of luteolin intake (RR = 0.66, 95% CI = 0.49-0.91; p-trend = 0.01). There was evidence of an inverse association with consumption of tea (nonherbal) and broccoli, the primary contributors to kaempferol intake in our population. These data suggest that dietary intake of certain flavonoids may reduce ovarian cancer risk, although additional prospective studies are needed to further evaluate this association. If confirmed, these results would provide an important target for ovarian cancer prevention.

Intake of specific carotenoids and the risk of epithelial ovarian cancer

There has been considerable interest in the role of carotenoids in the chemoprevention of cancer. However, few studies have examined the association between intake of specific carotenoids and the risk of epithelial ovarian cancer and the results for carotenoids have been inconclusive. To investigate whether the intake of α-carotene, β-carotene, β-cryptoxanthin, lutein and zeaxanthin, and lycopene is inversely associated with ovarian cancer risk, a case–control study was conducted in China during 1999–2000. The cases were 254 patients with histologically confirmed epithelial ovarian cancer and 652 age-matched controls were randomly recruited during the same period. Habitual dietary intake and lifestyle were collected by face-to-face interview using a validated and reliable FFQ. The US Department of Agriculture nutrient composition database was used to calculate the intake of specific carotenoids. Unconditional logistic regression analyses were used to estimate OR and 95 % CI, accounting for age, locality, education, BMI, smoking, tea drinking, parity, oral contraceptive use, hormone replacement therapy, menopausal status, family history of ovarian cancer, physical activity and energy intake. Compared with the highest v. the lowest quartile of intake, the adjusted OR were 0·39 (95 % CI 0·23, 0·66) for α-carotene, 0·51 (95 % CI 0·31, 0·84) for β-carotene, 0·51 (95 % CI 0·31, 0·83) for β-cryptoxanthin, 0·45 (0·27, 0·76) for lutein and zeaxanthin, and 0·33 (95 % CI 0·20, 0·56) for total carotenoids, with statistically significant tests for trend. It is concluded that a higher intake of carotenoids can reduce the risk of epithelial ovarian cancer.

[Vegetarian nutrition: Preventive potential and possible risks. Part 1: Plant foods]

Today vegetarian nutrition is more accepted and widespread in Europe than in former years. For a long time scientific research on vegetarian diets has focused mostly on malnutrition, whereas nowadays research centers increasingly on the preventive potential of plant-based diets. We followed a nutritive and a metabolic-epidemiological approach to obtain dietary recommendations. A MEDLINE research was performed for all plant food groups relevant for a vegetarian diet (key words: all relevant food groups, "vegetarian diet", "chronic disease", "cancer", "cardiovascular disease", "diabetes mellitus", "osteoporosis"). All relevant food groups were characterized regarding their nutrient content and rated with respect to the available metabolic-epidemiological evidence. Based on the evidence criteria of the WHO/FAO, cancer risk reduction by a high intake of vegetables and fruits is assessed as probable or possible, while a lowered risk of cardiovascular disease is convincing and a lowered risk of osteoporosis is probable. The evidence of a risk reducing effect of whole grain relating to colorectal cancer is assessed as possible, whereas it is probable relating to cardiovascular disease and diabetes mellitus type 2. There is an insufficient risk-reducing effect of legumes like soja relating to epithelial tumours and cardiovascular disease. The evidence of a risk-reducing effect of nuts to cardiovascular disease is assessed as probable, and in relation to cholelithiasis and diabetes mellitus type 2 as possible and insufficient, respectively. In conclusion, high consumption of fruits, vegetables, whole grains and nuts can lower the risk for several chronic diseases.

Diet and risk of ovarian cancer in the California Teachers Study cohort

Dietary phytochemical compounds, including isoflavones and isothiocyanates, may inhibit cancer development but have not yet been examined in prospective epidemiologic studies of ovarian cancer. The authors have investigated the association between consumption of these and other nutrients and ovarian cancer risk in a prospective cohort study. Among 97,275 eligible women in the California Teachers Study cohort who completed the baseline dietary assessment in 1995-1996, 280 women developed invasive or borderline ovarian cancer by December 31, 2003. Multivariable Cox proportional hazards regression, with age as the timescale, was used to estimate relative risks and 95% confidence intervals; all statistical tests were two sided. Intake of isoflavones was associated with lower risk of ovarian cancer. Compared with the risk for women who consumed less than 1 mg of total isoflavones per day, the relative risk of ovarian cancer associated with consumption of more than 3 mg/day was 0.56 (95% confidence interval: 0.33, 0.96). Intake of isothiocyanates or foods high in isothiocyanates was not associated with ovarian cancer risk, nor was intake of macronutrients, antioxidant vitamins, or other micronutrients. Although dietary consumption of isoflavones may be associated with decreased ovarian cancer risk, most dietary factors are unlikely to play a major role in ovarian cancer development.

Intake of the major carotenoids and the risk of epithelial ovarian cancer in a pooled analysis of 10 cohort studies

Carotenoids, found in fruits and vegetables, have the potential to protect against cancer because of their properties, including their functions as precursors to vitamin A and as antioxidants. We examined the associations between intakes of alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein/zeaxanthin and lycopene and the risk of invasive epithelial ovarian cancer. The primary data from 10 prospective cohort studies in North America and Europe were analyzed and then pooled. Carotenoid intakes were estimated from a validated food frequency questionnaire administered at baseline in each study. Study-specific relative risks (RR) were estimated using the Cox proportional hazards model and then combined using a random-effects model. Among 521,911 women, 2,012 cases of ovarian cancer occurred during a follow-up of 7-22 years across studies. The major carotenoids were not significantly associated with the risk of ovarian cancer. The pooled multivariate RRs (95% confidence intervals) were 1.00 (0.95-1.05) for a 600 microg/day increase in alpha-carotene intake, 0.96 (0.93-1.03) for a 2,500 microg/day increase in beta-carotene intake, 0.99 (0.97-1.02) for a 100 microg/day increase in beta-cryptoxanthin intake, 0.98 (0.94-1.03) for a 2,500 microg/day increase in lutein/zeaxanthin intake and 1.01 (0.97-1.05) for a 4,000 microg/day increase in lycopene intake. These associations did not appreciably differ by study (p-values, tests for between-studies heterogeneity >0.17). Also, the observed associations did not vary substantially by subgroups of the population or by histological type of ovarian cancer. These results suggest that consumption of the major carotenoids during adulthood does not play a major role in the incidence of ovarian cancer.

Fruits and Vegetables and Ovarian Cancer Risk in a Pooled Analysis of 12 Cohort Studies

Because fruits and vegetables are rich in bioactive compounds with potential cancer-preventive actions, increased consumption may reduce the risk of ovarian cancer. Evidence on the association between fruit and vegetable intake and ovarian cancer risk has not been consistent. We analyzed and pooled the primary data from 12 prospective studies in North America and Europe. Fruit and vegetable intake was measured at baseline in each study using a validated food-frequency questionnaire. To summarize the association between fruit and vegetable intake and ovarian cancer, study-specific relative risks (RR) were estimated using the Cox proportional hazards model, and then combined using a random-effects model. Among 560,441 women, 2,130 cases of invasive epithelial ovarian cancer occurred during a maximum follow-up of 7 to 22 years across studies. Total fruit intake was not associated with ovarian cancer risk-the pooled multivariate RR for the highest versus the lowest quartile of intake was 1.06 [95% confidence interval (95% CI), 0.92-1.21; P value, test for trend = 0.73; P value, test for between-studies heterogeneity = 0.74]. Similarly, results for total vegetable intake indicated no significant association (pooled multivariate RR, 0.90; 95% CI, 0.78-1.04, for the highest versus the lowest quartile; P value, test for trend = 0.06; P value, test for between-studies heterogeneity = 0.31). Intakes of botanically defined fruit and vegetable groups and individual fruits and vegetables were also not associated with ovarian cancer risk. Associations for total fruits and vegetables were similar for different histologic types. These results suggest that fruit and vegetable consumption in adulthood has no important association with the risk of ovarian cancer.