Fruit and vegetable intake and incidence of bladder cancer in a male prospective cohort

BACKGROUND: Previous epidemiologic studies of fruit and vegetable intake and bladder cancer risk have yielded inconsistent results, especially with regard to the types of fruits and vegetables consumed. We examined total fruit and vegetable intake, as well as intakes of subtypes of fruits and vegetables, in relation to bladder cancer risk in a large male prospective cohort study. METHODS: Two hundred fifty-two cases of incident bladder cancer were diagnosed from 1986 through January 31, 1996, among 47,909 men enrolled in the Health Professionals Follow-up Study. Each participant in this cohort completed a 131-item food-frequency questionnaire in 1986 and subsequently in 1990 and 1994. We used logistic regression analyses to examine fruit and vegetable intake in relation to bladder cancer risk, after adjusting for age, history of cigarette smoking, current smoking status, geographic region, total fluid intake, and caloric intake. RESULTS: We observed a weak, inverse association that was not statistically significant between total fruit and vegetable intake and bladder cancer risk. Intake of cruciferous vegetables was inversely associated with risk (relative risk = 0.49; 95% confidence interval = 0.32-0.75, for the highest category of cruciferous vegetable intake compared with the lowest), but intakes of yellow or green leafy vegetables or carotenoid-rich vegetables were not associated with risk. Individual cruciferous vegetables, except for coleslaw, were all inversely related to bladder cancer risk, but only the associations for broccoli and cabbage were statistically significant. CONCLUSIONS: Data from this study indicate that high cruciferous vegetable consumption may reduce bladder cancer risk, but other vegetables and fruits may not confer appreciable benefits against this cancer.     

Fruit and vegetable consumption and risk of bladder cancer: a prospective cohort study

Fruit and vegetable consumption has been inconsistently associated with risk of bladder cancer. We used data from a prospective population-based cohort study of 82,002 Swedish women and men to examine the association between fruit and vegetable consumption and bladder cancer incidence. Diet was assessed with a validated food frequency questionnaire. During a mean follow-up of 9.4 years, 485 incident cases of bladder cancer were identified in the Swedish cancer registries. We found no statistically significant association between intakes of total fruits and vegetables, total fruits, or total vegetables and bladder cancer risk after adjustment for age, sex, education, and cigarette smoking. The multivariate rate ratios (95% confidence intervals) comparing the highest with the lowest quartile of intake were 0.80 (0.60-1.05) for total fruits and vegetables, 0.93 (0.69-1.25) for fruits, and 0.89 (0.67-1.19) for vegetables. Likewise, no associations were observed for citrus fruits, cruciferous vegetables, or green leafy vegetables. The associations did not differ by sex or smoking status. In conclusion, findings from this prospective study suggest that fruit and vegetable intakes are not likely to be appreciably associated with the risk of bladder cancer.     

Intake of fruits,vegetables and selected micronutrients in relation to the risk of breast cancer

High fruit and vegetable intake has been linked with a reduced risk of breast cancer, but evidence is not consistent. We investigated the associations of breast cancer risk with vegetables, fruits and related micronutrient intake in a population-based case-control study among Chinese women in Shanghai, where dietary patterns differ substantially from other study populations. Included in the study were 1,459 incident breast cancer cases and 1,556 frequency-matched controls. Usual dietary habits were assessed by in-person interviews. Logistic regression was used to compute adjusted odds ratios (ORs) and 95% confidence intervals (CIs) to measure strength of the associations. There was no association between breast cancer risk and total vegetable intake. The risk of breast cancer declined, however, with increasing intake of dark yellow-orange vegetables (trend test, p = 0.02), Chinese white turnips (trend test, p 相似文献   

Plant foods and colon cancer: an assessment of specific foods and their related nutrients (United States)

Plant foods have been associated inversely with colon cancer. Since amajor focus of this study was to identify components of plant foods whichmay account for their association with colon cancer, nutrients which arecommonly found in plant foods also were evaluated. A population-basedcase-control study was conducted in Northern California, Utah, and the TwinCities area of Minnesota (United States). Complete data were available frominterviewer-administered questionnaires on 1,993 cases and 2,410 controls.Higher intakes of vegetables (for highest relative to lowest quintile ofintake) were associated inversely with colon cancer risk: the odds ratio(OR) was 0.7 for both men (95 percent [CI] confidence interval = 0.5-0.9)and women (CI = 0.5-1.0). Associations were stronger among those withproximal tumors. Total fruit intake was not associated with colon cancerrisk although, among men, higher levels of whole grain intake wereassociated with a decreased risk (OR = 0.6, CI = 0.4-0.9 for older men);high intakes of refined grains were associated with an increased risk (OR =1.5, CI = 1.1-2.1). Dietary fiber intake was associated with a decreasedrisk of colon cancer: OR = 0.5 (CI = 0.3-0.9) for older men; OR = 0.7 (CI =0.4-1.2) for older women; OR = 0.6 (CI = 0.4-1.0) for men with proximaltumors; OR = 0.5 (CI = 0.3-0.9) for women with proximal tumors. Othernutrients, for which plant foods were the major contributor - such asvitamin B6, thiamin, and niacin (women only) - also were associatedinversely with colon cancer. Neither beta-carotene nor vitamin C wasprotective for colon cancer. Adjustment of plant foods for nutrients foundin plant foods or for supplement use did not appreciably alter the observedassociations between plant foods and colon cancer.     

Fruit and vegetable intakes and risk of colorectal cancer and incident and recurrent adenomas in the PLCO cancer screening trial

The roles of fruits and vegetables in colorectal cancer development are unclear. Few prospective studies have assessed the association with adenoma, a known precursor to colorectal cancer. Our aim was to evaluate the association between fruit and vegetable intake and colorectal cancer development by evaluating the risk of incident and recurrent colorectal adenoma and colorectal cancer. Study participants were identified from the intervention arm of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Fruit and vegetable intake was measured using a self‐reported dietary questionnaire. Total fruit and vegetable intake was not associated with reduced incident or recurrent adenoma risk overall, but a protective association was observed for multiple adenomas (Odds ratio _{3rd tertile vs. 1st tertile} = 0.61, 95% confidence interval (CI): 0.38, 1.00). Higher fruit and vegetable intakes were associated with a borderline reduced risk of colorectal cancer (Hazard ratio (HR) _{3rd tertile vs. 1st tertile} = 0.82, 95% CI: 0.67, 1.01), which reached significance amongst individuals with high processed meat intakes (HR = 0.74, 95% CI: 0.55, 0.99). Our results suggest that increased fruit and vegetable intake may protect against multiple adenoma development and may reduce the detrimental effects of high processed meat intakes on colorectal cancer risk.     

Fruit and vegetable intakes and prostate cancer risk

BACKGROUND: There is extensive and consistent evidence that high fruit and vegetable intakes are associated with decreased risks of many cancers, but results for prostate cancer risk have been inconsistent. We studied the associations of fruit and vegetable intakes with prostate cancer risk in a population-based, case-control study of men under 65 years of age. METHODS: Case participants were 628 men from King County (Seattle area), WA, who were newly diagnosed with prostate cancer. Control participants were 602 men recruited from the same underlying population and frequency matched to case participants by age. Self-administered food-frequency questionnaires were used to assess diet over the 3- to 5-year period before diagnosis or recruitment. Daily nutrient intakes were calculated by use of a nutrient database with recently updated analytic values for carotenoids. Odds ratios for prostate cancer risk associated with foods and nutrients were calculated by use of unconditional logistic regression. RESULTS: No associations were found between fruit intake and prostate cancer risk. The adjusted odds ratio (ORs) for the comparison of 28 or more servings of vegetables per week with fewer than 14 servings per week was 0.65 (95% confidence interval [CI] = 0.45-0.94), with a two-sided P for trend =.01. For cruciferous vegetable consumption, adjusted for covariates and total vegetable intake, the OR for comparison of three or more servings per week with less than one serving per week was 0.59 (95% CI = 0.39-0.90), with a two-sided P for trend =.02. The OR for daily intake of 2000 microg or more lutein plus zeaxanthin compared with an intake of less than 800 microg was 0.68 (95% CI = 0.45-1.00). CONCLUSION: These results suggest that high consumption of vegetables, particularly cruciferous vegetables, is associated with a reduced risk of prostate cancer.     

Fruit and Vegetable Intake in Relation to Prostate Cancer in Iranian Men: A Case-Control Study

Background: Findings of epidemiologic studies on the relationship between fruit and vegetable consumption and prostate cancer (PCa) risk have been inconclusive. We therefore examined the association between intake of fruits and vegetables and PCa risk in Iran. Materials and Methods: In this hospital based, case-control study, a total of 50 patients with PCa and 100 controls underwent face-to-face interviews. Regression analysis was used to examine the relation between fruit and vegetable intake and PCa risk. Results: A protective independent effect was observed for the highest tertile of total fruit and vegetable (OR: 0.33, CI: 0.04-0.30, p value<0.001), total fruit (OR: 0.30, CI: 0.06-0.4, p value=0.03) and total vegetable (OR: 0.31, CI: 0.02-0.21, p value<0.001) consumption. Within the group of fruits, a significant inverse association was observed for apple and pomegranate (p trends were 0.01 and 0.016, respectively). In the vegetable group, a significant inverse association was observed for tomatoes (p trend<0.001) and cabbage (p trend=0.021). Conclusions: The results of the present study suggestedthat fruits and vegetable intake might be negatively associated with PCa risk.     

A prospective study of whole grains, fruits, vegetables and colon cancer risk

OBJECTIVE: We examined the relation between whole grains, fruit, vegetables and dietary fiber and colon cancer risk in the prospective Cancer Prevention Study II Nutrition Cohort. METHODS: In 1992-1993, 62,609 men and 70,554 women completed questionnaires on medical history, diet and lifestyle behaviors. After exclusions, we confirmed 298 cases of incident colon cancer among men and 210 among women through August 31, 1997. RESULTS: Multivariate rate ratios (RR) and 95% confidence intervals (CI) for all dietary factors were null. However, a statistically non-significant 30% reduction in risk was observed for men with the highest vegetable intakes (RR = 0.69, CI = 0.47-1.03, top versus bottom quintile, p trend = 0.10). Men with very low (lowest tertile within the lowest quintile) intakes of vegetables and dietary fiber were at increased risk compared to those in the highest four quintiles of intake (vegetables RR = 1.79, CI = 1.22-2.61, p trend = 0.04, and fiber RR = 1.96, CI = 1.24-3.10, p trend = 0.006). Women with very low intakes of fruit were also at increased risk (RR = 1.86, CI = 1.18-2.94, p trend = 0.06). CONCLUSIONS: Higher intakes of plant foods or fiber were not related to lower risk of colon cancer. However, our data suggest that very low intakes of plant foods may increase risk, and that certain phytochemical subgroups may decrease risk.     

Consumption of fruits,vegetables and fruit juices and differentiated thyroid carcinoma risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study

Fruit and vegetable (F&V) intake is considered as probably protective against overall cancer risk, but results in previous studies are not consistent for thyroid cancer (TC). The purpose of this study is to examine the association between the consumption of fruits, vegetables, fruit juices and differentiated thyroid cancer risk within the European Prospective Investigation into Cancer and Nutrition (EPIC) study. The EPIC study is a cohort including over half a million participants, recruited between 1991 and 2000. During a mean follow‐up of 14 years, 748 incident first primary differentiated TC cases were identified. F&V and fruit juice intakes were assessed through validated country‐specific dietary questionnaires. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox regression models adjusted for potential confounding factors. Comparing the highest versus lowest quartile of intake, differentiated TC risk was not associated with intakes of total F&V (HR: 0.89; 95% CI: 0.68–1.15; p‐trend = 0.44), vegetables (HR: 0.89; 95% CI: 0.69–1.14; p‐trend = 0.56), or fruit (HR: 1.00; 95% CI: 0.79–1.26; p‐trend = 0.64). No significant association was observed with any individual type of vegetable or fruit. However, there was a positive borderline trend with fruit juice intake (HR: 1.23; 95% CI: 0.98–1.53; p‐trend = 0.06). This study did not find any significant association between F&V intakes and differentiated TC risk; however a positive trend with fruit juice intake was observed, possibly related to its high sugar content.     

Intakes of fruits and vegetables,carotenoids and vitamins A,E, C in relation to the risk of bladder cancer in the ATBC cohort study

We examined the relation between dietary fruit and vegetables, carotenoids and vitamin intakes and the risk of bladder cancer among male smokers in a prospective cohort study. Over a median of 11 years, we followed 27 111 male smokers aged 50-69 years who were initially enrolled in the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study. During this period, 344 men developed bladder cancer. All of these men had completed a 276-food item dietary questionnaire at baseline. Cox proportional hazards models were used to estimate the relative risks and 95% confidence intervals and to simultaneously adjust for age, smoking history, energy intake and intervention group. Consumption of fruits and vegetables was not associated with the risk of bladder cancer (relative risk=1.28; 95% confidence intervals CI: 0.89-1.84, for highest vs lowest quintile). Similarly, no associations were observed for groups of fruits or vegetables (berries and cruciferous vegetables), or for specific fruits and vegetables. Dietary intakes of alpha-carotene, beta-carotene, lycopene, lutein/zeaxanthin, beta-cryptoxanthin, vitamins A, E, and C, and folate were not related to the risk of bladder cancer. These findings suggest that fruit and vegetable intakes are not likely to be associated with bladder cancer risk. However, these results may not be generalisable to non-smokers.     

Intake of Fruits and Vegetables,Carotenoids, Folate,and Vitamins A,C, E and Risk of Bladder Cancer Among Women (United States)

Objective: To examine the relation between fruits and vegetables, carotenoids, folate, and vitamins A, C, E and the risk of bladder cancer in a prospective study of women Methods: A total of 237 incident bladder cancer cases were documented during 20 years of follow-up among 88,796 women enrolled in the Nurses’ Health Study. Dietary intake was assessed by food-frequency questionnaires every two to four years and incident diagnosis of bladder cancer was ascertained every two years. Cox proportional hazard models were used to estimate incidence rate ratios (RR) and 95% confidence intervals (CI) for bladder cancer risk, adjusting for age, pack-years of smoking, current smoking, and total caloric intake. Results: Consumption of total fruits and vegetables was not associated with bladder cancer risk (RR = 1.08, 95% CI = 0.70–1.65, for > 5.5 compared to < 2.5 servings per day). Similarly, dietary intakes of carotenoids, folate, and vitamins A, C, E, were not related to bladder cancer risk. No association was observed between supplemental intake of multivitamins, vitamins A, C, E and bladder cancer risk. Conclusions: We did not observe any association for fruit and vegetable consumption or vitamin intake and bladder cancer risk among women.     

Can pictorial warning labels on cigarette packages address smoking-related health disparities? Field experiments in Mexico to assess pictorial warning label content

We investigated the association between diet and head and neck cancer (HNC) risk using data from the International Head and Neck Cancer Epidemiology (INHANCE) consortium. The INHANCE pooled data included 22 case-control studies with 14,520 cases and 22,737 controls. Center-specific quartiles among the controls were used for food groups, and frequencies per week were used for single food items. A dietary pattern score combining high fruit and vegetable intake and low red meat intake was created. Odds ratios (OR) and 95% confidence intervals (CI) for the dietary items on the risk of HNC were estimated with a two-stage random-effects logistic regression model. An inverse association was observed for higher-frequency intake of fruit (4th vs. 1st quartile OR = 0.52, 95% CI = 0.43-0.62, p (trend) < 0.01) and vegetables (OR = 0.66, 95% CI = 0.49-0.90, p (trend) = 0.01). Intake of red meat (OR = 1.40, 95% CI = 1.13-1.74, p (trend) = 0.13) and processed meat (OR = 1.37, 95% CI = 1.14-1.65, p (trend) < 0.01) was positively associated with HNC risk. Higher dietary pattern scores, reflecting high fruit/vegetable and low red meat intake, were associated with reduced HNC risk (per score increment OR = 0.90, 95% CI = 0.84-0.97).     

Consumption of raw cruciferous vegetables is inversely associated with bladder cancer risk.

Cruciferous vegetables contain isothiocyanates, which show potent chemopreventive activity against bladder cancer in both in vitro and in vivo studies. However, previous epidemiologic studies investigating cruciferous vegetable intake and bladder cancer risk have been inconsistent. Cooking can substantially reduce or destroy isothiocyanates, and could account for study inconsistencies. In this hospital-based case-control study involving 275 individuals with incident, primary bladder cancer and 825 individuals without cancer, we examined the usual prediagnostic intake of raw and cooked cruciferous vegetables in relation to bladder cancer risk. Odds ratios (OR) and 95% confidence intervals (CI) were estimated with unconditional logistic regression, adjusting for smoking and other bladder cancer risk factors. We observed a strong and statistically significant inverse association between bladder cancer risk and raw cruciferous vegetable intake (adjusted OR for highest versus lowest category = 0.64; 95% CI, 0.42-0.97), with a significant trend (P = 0.003); there were no significant associations for fruit, total vegetables, or total cruciferous vegetables. The associations observed for total raw crucifers were also observed for individual raw crucifers. The inverse association remained significant among current and heavy smokers with three or more servings per month of raw cruciferous vegetables (adjusted ORs, 0.46 and 0.60; 95% CI, 0.23-0.93 and 0.38-0.93, respectively). These data suggest that cruciferous vegetables, when consumed raw, may reduce the risk of bladder cancer, an effect consistent with the role of dietary isothiocyanates as chemopreventive agents against bladder 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.     

Prospective study of fruit and vegetable consumption and risk of lung cancer among men and women

BACKGROUND: Diets high in fruits and vegetables have been shown to be associated with a lower risk of lung cancer. beta-Carotene was hypothesized to be largely responsible for the apparent protective effect, but this hypothesis was not supported by clinical trials. METHODS: We examined the association between lung cancer risk and fruit and vegetable consumption in 77 283 women in the Nurses' Health Study and 47 778 men in the Health Professionals' Follow-up Study. Diet was assessed with the use of a food-frequency questionnaire that included 15 fruits and 23 vegetables. We used logistic regression models to estimate relative risks (RRs) of lung cancer within each cohort. All statistical tests were two-sided. RESULTS: We documented 519 lung cancer cases among the women and 274 among the men. Total fruit and vegetable consumption was associated with a modestly lower risk of lung cancer among the women but not among the men. The RR for the highest versus lowest quintile of intake was 0.79 (95% confidence interval [CI] = 0.59-1.06) among the women and 1.12 (95% CI = 0.74-1.69) among the men after adjustment for smoking status, quantity of cigarettes smoked per day, time since quitting smoking, and age at initiation of smoking. However, total fruit and vegetable consumption was associated with a lower risk of lung cancer among never smokers in the combined cohorts, although the reduction was not statistically significant (RR = 0.63; 95% CI = 0.35-1.12 in the highest tertile). CONCLUSION: Higher fruit and vegetable intakes were associated with lower risks of lung cancer in women but not in men. It is possible that the inverse association among the women remained confounded by unmeasured smoking characteristics, although fruits and vegetables were protective in both men and women who never smoked.     

Vegetables,fruit and risk of gastric cancer in Japan: a 10-year follow-up of the JPHC Study Cohort I

The association between vegetables and fruit consumption and gastric cancer risk was investigated in a population-based prospective study in 4 public health center areas in Japan. Dietary and other exposure data were obtained in 1990 from a cohort of 19,304 men and 20,689 women with a self-administered questionnaire. After 10 years of follow-up, a total of 404 cases of gastric cancer were documented among them. After adjustment for age, gender, areas and other potential confounding factors and after exclusion of the cases diagnosed in first and second follow-up years, the relative risk associated with intake 1 or more days per week compared to less than 1 day per week was 0.64 (95% CI 0.45-0.92) for yellow vegetable, 0.48 (95% CI 0.25-0.89) for white vegetable and 0.70 (95% CI 0.49-1.00) for fruit. Relative risks associated with quintile of total vegetable consumption were 1.00, 0.86, 0.75, 0.90 and 0.75 (p for trend = 0.17). In the differentiated type of gastric cancer, the association became clearer: 1.00, 0.96, 0.78, 0.88 and 0.53 (p for trend = 0.03). This prospective study suggests that vegetable and fruit intake, even in low amounts, is associated with a lower risk of gastric cancer. Although no striking differences in the association were seen between cardia and noncardia cancer, an inverse association was higher in differentiated rather than in undifferentiated types of gastric cancer.     

Fruit and vegetables and cancer risk

The possibility that fruit and vegetables may help to reduce the risk of cancer has been studied for over 30 years, but no protective effects have been firmly established. For cancers of the upper gastrointestinal tract, epidemiological studies have generally observed that people with a relatively high intake of fruit and vegetables have a moderately reduced risk, but these observations must be interpreted cautiously because of potential confounding by smoking and alcohol. For lung cancer, recent large prospective analyses with detailed adjustment for smoking have not shown a convincing association between fruit and vegetable intake and reduced risk. For other common cancers, including colorectal, breast and prostate cancer, epidemiological studies suggest little or no association between total fruit and vegetable consumption and risk. It is still possible that there are benefits to be identified: there could be benefits in populations with low average intakes of fruit and vegetables, such that those eating moderate amounts have a lower cancer risk than those eating very low amounts, and there could also be effects of particular nutrients in certain fruits and vegetables, as fruit and vegetables have very varied composition. Nutritional principles indicate that healthy diets should include at least moderate amounts of fruit and vegetables, but the available data suggest that general increases in fruit and vegetable intake would not have much effect on cancer rates, at least in well-nourished populations. Current advice in relation to diet and cancer should include the recommendation to consume adequate amounts of fruit and vegetables, but should put most emphasis on the well-established adverse effects of obesity and high alcohol intakes.     

A prospective analysis of the association between dietary fiber intake and prostate cancer risk in EPIC

Few studies have examined the association between dietary fiber intake and prostate cancer risk. We evaluated the association between dietary fiber intake and the risk of prostate cancer among 142,590 men in the European Prospective Investigation into Cancer and Nutrition (EPIC). Consumption of dietary fiber (total, cereal, fruit and vegetable fiber) was estimated by validated dietary questionnaires and calibrated using 24-hr dietary recalls. Incidence rate ratios were estimated using Cox regression and adjusted for potential confounding factors. During an average of 8.7 years follow-up, prostate cancer was diagnosed in 2,747 men. Overall, there was no association between dietary fiber intake (total, cereal, fruit or vegetable fiber) and prostate cancer risk, although calibrated intakes of total fiber and fruit fiber were associated with nonstatistically significant reductions in risk. There was no association between fiber derived from cereals or vegetables and risk and no evidence for heterogeneity in any of the risk estimates by stage or grade of disease. Our results suggest that dietary fiber intake is not associated with prostate cancer risk.     

Dietary intakes of fruit,vegetables, and fiber,and risk of colorectal cancer in a prospective cohort of women (United States)

Objective: Although animal studies suggest an inverse association between consumption of plant foods and risk of colorectal cancer, many observational data have failed to support such an association. We prospectively examined the association between dietary intakes of fruit, vegetables, and fiber and colorectal cancer risk in a large female cohort from the Womens Health Study.Methods: Among 39,876 healthy women aged 45 years at baseline, 36,976 with baseline self-reported information on dietary intakes and other risk factors for colorectal cancer were included in the analyses. During an average follow-up of 10 years, 223 women were diagnosed with colorectal cancer. Intakes of fruit, vegetables, and fiber were assessed by a baseline food-frequency questionnaire. The analyses were carried out using the Cox proportional hazards regression and all tests were two-sided.Results: Intakes of fruit, vegetables, and the specific subgroups were not found to be associated with colorectal cancer risk. Multivariate relative risks (RRs) comparing the highest with lowest quintile were 0.79 (95% CI = 0.49–1.27,pfor trend = 0.30) for fruit intake, and 0.88 (95% CI=0.56–1.38,pfor trend=0.30) for vegetables intake. Similarly, intake of total fiber was not associated with colorectal cancer risk; the RR for the highest relative to lowest quintile was 0.75 (95% CI=0.48–1.17,pfor trend=0.12). However, higher intake of legume fiber was associated with a lower risk of colorectal cancer; the RR for the highestversuslowest quintile was 0.60 (95% CI=0.40–0.91,pfor trend=0.02).Conclusions: Our data offer little support for associations between intakes of fruit, vegetables, and fiber, and colorectal cancer risk. However, our data suggest that legume fiber and/or other related sources may reduce risk of colorectal cancer.     

Colorectal cancer and diet in an Asian population--a case-control study among Singapore Chinese

A hospital-based case-control study of diet and colorectal cancer was conducted among Chinese in Singapore (who constitute 77% of the population). A total of 203 cases and 425 controls were included. A history of the usual dietary intake one year prior to interview was taken using a quantitative food frequency questionnaire. Daily intakes of nutrients and selected food items were computed and stratified by tertiles of the control range, to assess risk in low-, medium- and high-intake categories. Effects were adjusted in analysis for age, sex, Chinese dialect group and occupation. For cancers of colon and rectum combined, significant observations were a protective effect of high cruciferous vegetable intake (OR = 0.50, p less than 0.01) and a predisposing effect of a high meat/vegetable consumption ratio (OR = 1.77, p less than 0.05). Similar results were observed for colon cancer alone. For rectal cancer alone (only 71 cases), significant (p less than 0.05) protective effects were observed for high intakes of protein (OR = 0.61), fibre (OR = 0.46), beta-carotene (OR = 0.54), cruciferous vegetables (OR = 0.51) and total vegetables (OR = 0.51). When further assessed by multiple logistic regression, tests for trend and assessment of risk in the extreme highest and lowest quintiles of the control range, the factors consistently significant were cruciferous vegetable intake and the meat/vegetable ratio. A particularly high relative risk was also noted in association with low coffee consumption (OR = 1.59, with p less than 0.05 for trend). No consistent trends were noted for fat or fibre intakes. For non-dietary variables investigated, a history of cholecystectomy increased the risk of both cancers combined (OR = 3.43, p less than 0.05) and colon cancer alone (OR = 4.39, p less than 0.01). This study in an Asian population of countries of Southern and Eastern Asia newly undergoing industrialization and in which rapid economic change is reflected in changing cancer patterns, suggests that the protective effects of certain dietary constituents, notably the cruciferous vegetables, may be more important than the hitherto stressed carcinogenic potential of fat and protein.