Are coffee, tea, and total fluid consumption associated with bladder cancer risk? Results from the Netherlands Cohort Study.

OBJECTIVES: Coffee, tea, and fluid consumption have been thought to influence bladder cancer incidence. In a large prospective study, these associations were investigated. METHODS: In 1986, cohort members (55-69 years) completed a questionnaire on cancer risk factors. Follow-up was established by linkage to cancer registries until 1992. The multivariable case-cohort analysis was based on 569 bladder cancer cases and 3,123 subcohort members. RESULTS: The incidence rate ratios (RR) for men consuming <2 cups of coffee/day was 0.89 (95% CI 0.51-1.5) using the median consumption category (4-<5 cups/day) as reference. This RR increased to 1.3 (95% CI 0.94-1.9) for men consuming >7 cups/day, although no clear dose response association was found. The RRs decreased from 1.2 (95% CI 0.56-2.7) for women consuming <2 cups of coffee/day to 0.36 (95% CI 0.18-0.72) for women consuming >5 cups/day compared to the median consumption category (3-<4 cups/day). Men and women who abstained from drinking tea had a RR of 1.3 (95% Cl 0.97-1.8) compared to those consuming 2-<3 cups of tea per day (median consumption category). The RR for men and women comparing highest to lowest quintile of total fluid consumption was 0.87 (95% CI 0.63 1.2). CONCLUSION: The data suggest a possible positive association between coffee consumption and bladder cancer risk in men and a probable inverse association in women. Tea consumption was inversely associated with bladder cancer. Total fluid consumption did not appear to be associated with bladder cancer.

Folate intake of the Dutch population according to newly established liquid chromatography data for foods.

BACKGROUND: Determining folate intake is difficult because existing folate data in food-composition tables are scarce and unreliable. OBJECTIVE: The purposes of this study were first to analyze 125 of the most important foods that contribute to folate intake in the Netherlands and second to estimate the folate intake of a representative sample of the population. DESIGN: We analyzed the folate content of foods by using a newly developed HPLC trienzyme method combined with an affinity chromatography cleanup step. These results were then used to estimate the folate intake of persons aged 1-92 y who participated in the second Dutch National Food Consumption Survey (DNFCS) in 1992 (n = 6218). RESULTS: For 35 important folate-containing foods, the mean relative folate contents measured by HPLC were 66%, 80%, and 77% of values for comparable foods included in the British food-composition table; the Ministry of Agriculture, Fisheries and Food table; and the US Department of Agriculture database, respectively. P values for comparison of relative values with 100% were 0.001, 0.171, and 0.144, respectively. The mean dietary folate intake of the DNFCS participants was 182 +/- 119 microg/d. Intake of supplement users (n = 86) was 344 microg/d, with 147 microg/d from supplements. On the basis of these findings, 42% of men and 54% of women do not meet current Dutch recommendations of 60 microg/d for children and 200 microg/d for adults. CONCLUSIONS: Total folate quantities in foods, analyzed by HPLC, are approximately 25% lower than amounts listed in recent food-composition tables estimated by use of the microbiological method. On the basis of these new data, approximately 50% of a representative Dutch population sample does not meet the current recommendations for folate intake.

Factors associated with the intention to use vitamin D supplements: quantitative study among a sample of elderly people in a medium-sized town in the Netherlands.

The objective of this study was to assess which factors are related to the intention of elderly people to use vitamin D supplements.A questionnaire that was based on several theories, feedback of experts, and personal interviews with members of the target group was distributed among a random sample of 497 elderly people in a medium-sized town in the Netherlands (response 46%). Variables measured included perceived susceptibility, severity and control with respect to developing a vitamin D deficiency or getting a bone fracture, and beliefs, perceived social norms, modeling, self-efficacy, and intention with respect to the use of vitamin D supplements. Univariate analyses of variance, chi-square tests, stepwise multiple regression, and stepwise logistic regression analysis were performed. Respondents reporting a high intention had more positive attitudes and normative beliefs, higher self-efficacy expectations with respect to using vitamin D supplements, and more often used other supplements than respondents with a low intention. Subjects who already used vitamin D supplements were more often female and already familiar with the advice and had more positive attitudes and normative beliefs than nonusers. It was concluded that many elderly people have high intentions to start using vitamin D supplements as soon as they hear about the advice. A health promotion campaign to promote the use of vitamin D supplements should aim at making elderly people familiar with the Health Council of the Netherlands' advice. Furthermore, the campaign should place emphasis on changing attitudes, perceived social norms, and self-efficacy expectations toward vitamin D supplement use.

Association of energy and fat intake with prostate carcinoma risk: results from The Netherlands Cohort Study.

BACKGROUND: The roles of energy and fat intake as risk factors for prostate carcinoma are still questionable. Therefore, these factors were evaluated in the Netherlands Cohort Study described in this article. METHODS: The cohort study consisted of 58,279 men ages 55-69 years at baseline in 1986. After 6.3 years of follow-up, 642 incident prostate carcinoma cases were available for analysis. Intake of energy, fat, and separate fatty acids were measured by means of a self-administered questionnaire; fat intake was adjusted for energy by regression analysis. The case-cohort method was used to calculate rate ratios (RRs). Analyses were conducted for all prostate carcinoma cases together as well as for case subgroups (latent vs. nonlatent and localized vs. advanced). RESULTS: No associations were found in multivariate analyses between prostate carcinoma and intake of energy, total fat, total saturated fatty acids, or total trans unsaturated fatty acids (RR highest vs. lowest quintile: 0.99, 1.10, 1.19, and 0.99, respectively). Oleic acid intake showed a nonsignificant positive association (RR = 1.38, 95% CI: 0.88-2.19). Positive associations were also observed for intake of oleic acid in subgroup analyses. Linoleic (RR = 0.78, 95% CI: 0. 56-1.09) and linolenic (RR = 0.76, 95% CI: 0.66-1.04) acid intake were associated with nonsignificantly decreased risks; only for linolenic acid did these associations persist in subgroup analyses. No associations were found for intake of arachidonic acid, eicosapentaenoic acid, or docosahexaenoic acid. CONCLUSIONS: These data suggest that certain fatty acids might be involved in prostate carcinoma occurrence, although the possibility that these were chance findings cannot be ruled out.

Antibacterial effect of garlic and omeprazole on Helicobacter pylori.

The antibacterial effect of a home-made raw garlic extract and commercial garlic tablets alone and in combination with antibiotics or omeprazole was determined against clinical isolates of Helicobacter pylori. MIC values of raw garlic extract and three types of commercial garlic tablets ranged from 10,000 to 17,500 mg/L. When MIC values of the commercial tablets were based on the allicin content, no differences between the three types were observed. The combination of garlic and omeprazole, studied with killing curves, showed a synergic effect which was concentration dependent. Further clinical evaluation of garlic in combination with the conventional agents for H. pylori treatment seems warranted.

Vitamins C and E, retinol, beta-carotene and dietary fibre in relation to breast cancer risk: a prospective cohort study.

Association between breast cancer risk and the intake of vitamins C and E, retinol, beta (beta)-carotene, dietary fibre, vegetables, fruit and potatoes was examined in The Netherlands Cohort Study, for 62,573 women aged 55-69 years. After 4.3 years of follow-up, 650 incident breast cancer cases were identified. After adjusting for traditional risk factors, breast cancer risk was not influenced by the intake of beta-carotene, vitamin E, dietary fibre, supplements with vitamin C, vegetables or potatoes. Fruit consumption showed a non-significant inverse association with breast cancer risk (RR highest/lowest quintile = 0.76, 95% CI 0.54-1.08). A small reduction in risk was also observed with increasing intake of dietary vitamin C (RR highest/lowest quintile = 0.77, 95% CI 0.55-1.08). For retinol, a weak positive association was observed (RR highest/lowest quintile = 1.24, 95% CI 0.83-1.83). Among subjects with a high intake of polyunsaturated fatty acids (PUFAs), both beta-carotene and vitamin C intake showed a non-significant inverse association with breast cancer risk (P-trend = 0.15 and 0.16 respectively). Our findings do not suggest a strong role, if any, for intake of vitamins C and E, beta-carotene, retinol, dietary fibre, vegetables, fruit and potatoes in the aetiology of breast cancer.

A prospective cohort study on the relationship between onion and leek consumption, garlic supplement use and the risk of colorectal carcinoma in The Netherlands.

The association between onion and leek consumption, garlic supplement use and colon and rectum carcinoma among men and women was evaluated in the Netherlands Cohort Study, a large-scale prospective cohort study on diet and cancer. Onions, leeks, and garlic belong to the Allium genus and contain large amounts of potentially chemopreventive compounds. The Netherlands Cohort Study was started in 1986 among 120 852 men and women, aged 55-69 years. Dietary intake was measured with a 150-item food frequency questionnaire. After 3.3 years of follow-up, 150 and 143 incident male and female cases of colon carcinoma, and 93 and 57 cases of rectum carcinoma, respectively, with complete dietary data were available for analysis. Dietary data were available for 1525 men and 1598 women of a randomly selected subcohort, that was followed up to estimate person-time in the entire cohort. In men, the adjusted rate ratios (RRs) in multivariable analysis for colon and rectum carcinoma in the highest compared to the lowest onion consumption categories were 0.87 (95% confidence interval [CI] = 0.48-1.65), and 0.66 (95% CI = 0.28-1.52), respectively. The RRs for proximal colon carcinoma were lower than for distal colon carcinoma. Leek consumption was not associated with colon and rectum carcinoma incidence in men. None of the RRs were significantly different from unity and no trends in the RRs were detected. A lower risk was found for rectum carcinoma in women consuming less than 0.25 onions per day (RR=0.36, 95% CI = 0.13-0.99), but the trend in the RRs was not statistically significant (P = 0.25). All other RRs for colon and rectum carcinoma associated with onion consumption were slightly higher than one. Leek consumption was not associated with colon and rectum carcinoma incidence. The use of garlic supplements was not associated with colon and rectum carcinoma in men and women combined. This study does not support an inverse association between the consumption of onions and leeks, or the use of garlic supplements and the incidence of male and female colon and rectum carcinoma.

Consumption of onions and a reduced risk of stomach carcinoma.

BACKGROUND & AIMS: Results from case-control studies and laboratory tests indicate that consumption of allium vegetables may considerably reduce the risk of stomach cancer. The association between onion and leek consumption, garlic supplement use, and the incidence of stomach carcinoma was studied. METHODS: The association was investigated in the Netherlands Cohort Study on diet and cancer, which started in 1986 with 120,852 men and women ranging in age from 55 to 69 years. Dietary data were available for 139 stomach carcinoma cases diagnosed during 3.3 years of follow-up and for 3123 subjects of the randomly selected subcohort. RESULTS: The rate ratio for stomach carcinoma in the highest onion consumption category (> or = 0.5 onions/day) was 0.50 (95% confidence interval, 0.26-0.95) compared with the lowest category (0 onions/day) after adjustment for other risk factors. The reduction in risk was restricted to carcinoma in the noncardia part of the stomach (P = 0.002) and was also found among subjects without a history of stomach disorders (P = 0.01). The consumption of leeks and the use of garlic supplements were not associated with stomach carcinoma risk. CONCLUSIONS: The Netherlands Cohort Study provides evidence for a strong inverse association between onion consumption and stomach carcinoma incidence.

Allium vegetable consumption, garlic supplement intake, and female breast carcinoma incidence.

The risk of female breast carcinoma in relation to onion and leek consumption and the use of garlic supplements was evaluated in the Netherlands Cohort Study on diet and cancer. Onions, leeks, and garlic contain specific compounds which might act as antimutagens. Animal experiments also suggest a possible role for these compounds in inhibition of mammary carcinogenesis. The Netherlands Cohort Study was started in 1986 among 120,852 Dutch men and women, aged 55-69 years, with collecting information on usual diet and important lifestyle characteristics. After 3.3 years of follow-up, 469 incident female breast carcinoma cases and 1713 female members of a randomly sampled control subcohort were available for analysis. Intake of onions or leeks was not associated with breast carcinoma risk after controlling for dietary and nondietary risk factors: the rate ratios in the highest intake categories were 0.95 (95% confidence interval 0.61-1.47) and 1.08 (95% confidence interval 0.79-1.48), respectively, compared with the lowest intake categories. The tests for trend in the rate ratios were neither significant. Garlic supplement use was also not associated with breast carcinoma incidence (rate ratio = 0.87, 95% confidence interval 0.58-1.31). In conclusion, we found no association between the consumption of onions or leeks, or garlic supplement use, and the incidence of female breast carcinoma.

A prospective cohort study on Allium vegetable consumption, garlic supplement use, and the risk of lung carcinoma in The Netherlands.

The association between the consumption of onions and leeks (vegetables belonging to the Allium genus), garlic supplements, and the risk of lung carcinoma was investigated in a large-scale prospective cohort study on diet and cancer in the Netherlands. The Netherlands Cohort Study was started in 1986 among 120,852 men and women, ages 55-69 years, by collecting information on usual diet and important life-style characteristics. After 3.3 years of follow-up, 550 incident lung carcinoma cases were observed. Information on Allium vegetable consumption was available for 484 lung carcinoma cases and 3123 members of a randomly sampled subcohort. In stratified analysis, a lower lung carcinoma risk was observed in the highest onion intake category [rate ratio (RR) = 0.65; 95% confidence interval, 0.45-0.95] compared to the lowest consumption category. After including other, dietary and nondietary, determinants of lung carcinoma in the multivariable models and using pack years for past and current smoking, instead of using smoking status categorized as never, ex-, and current smoking, the rate ratio in the highest intake category increased to 0.80 and was no longer significantly different from unity (95% confidence interval, 0.52-1.24). Leek consumption was not associated with risk for lung carcinoma (RR = 1.08; 95% confidence interval 0.80-1.45 in the highest intake category, compared to the lowest). No statistically significant trends in the rate ratios associated with increasing consumption of these vegetables were detected for lung carcinoma or the four histological subtypes. A higher lung carcinoma risk was observed for those subjects who used exclusively garlic supplements (RR = 1.78; 95% confidence interval, 1.08-2.92), compared to those not taking dietary supplements. A lower lung carcinoma risk was seen for those using garlic supplements together with any other supplement (RR = 0.93; 95% confidence interval 0.46-1.86) compared to those using any other supplement. In conclusion, we found no evidence of a relation between the consumption of onions or leeks and the risk of lung carcinoma or any of the histological subtypes. Garlic supplement use seems not associated with a lower risk of lung carcinoma.

Toenail selenium levels and the risk of breast cancer.

The association between toenail selenium and breast cancer was studied in a prospective study on diet and cancer among 62,573 Dutch women aged 55-69 years that started in September 1986. The analysis was based on 355 breast cancer cases, detected during 3.3 years of follow-up (1986-1989), for whom selenium data were available. Selenium levels were significantly lower among cases diagnosed early during follow-up. After exclusion of cases that occurred in the first year of follow-up, multivariable-adjusted rate ratios of breast cancer in increasing quintiles of selenium were 1.00, 0.90, 0.76, 0.86, and 0.91 (trend p = 0.618). The authors found no evidence for an inverse association between selenium status and breast cancer.

Agreement between interview data and a self-administered questionnaire on dietary supplement use.

OBJECTIVE: To study the relative validity of an open-ended question on the consumption of dietary supplements in the preceding five-year period, incorporated in a self-administered questionnaire used in the NLCS, The Netherlands Cohort Study on diet and cancer (120,852 men and women aged 55-69 years). DESIGN: Questionnaire data were compared with reference information from three personal interviews carried out within a period of 10 months. SETTING AND SUBJECTS: A randomly selected subgroup (59 men and 50 women) of the cohort living in 12 municipalities in the eastern and western regions of The Netherlands. RESULTS AND CONCLUSIONS: The overall sensitivity of the questionnaire concerning the use of any dietary supplement was 65.9%, the specificity was 98.5%; kappa as measure of agreement was estimated at 0.69. A high percentage recall was observed among women, users of at least three types of dietary supplements, long-term supplement users and those in the oldest age group. Recall of intake of specific supplements ranged from 77.8% for garlic preparations to 11.8% for 'other' supplements. Estimates of consumption of specific supplements (garlic and vitamin preparations) may provide enough precision to correctly classify individuals as users or non-users of those supplements.

A prospective cohort study on selenium status and the risk of lung cancer.

Selenium has been suggested to be anticarcinogenic and to play a role in the cellular defense against oxidative stress. The association between toenail selenium (a marker of long-term selenium status) and lung cancer was investigated in a cohort study of diet and cancer that started in 1986 among 120,852 Dutch men and women aged 55-69 years. After 3.3 years of follow-up, 550 incident cases of lung carcinoma were detected. Toenail selenium data were available for 370 lung cancer cases and 2459 members of a randomly selected subcohort. The rate ratio of lung cancer for subjects in the highest compared to the lowest quintile of toenail selenium, after controlling for age, gender, smoking, and education, was 0.50 (95% confidence interval, 0.30-0.81), with a significant inverse trend across quintiles (P = 0.006). The protective effect of selenium was concentrated in subjects with a relatively low dietary intake of beta-carotene or vitamin C. The rate ratio in the highest compared to the lowest quintile of selenium was 0.45 in the low beta-carotene group (95% confidence interval, 0.22-0.92; trend P = 0.028) and 0.36 in the low vitamin C group (95% confidence interval, 0.17-0.75; trend P < 0.001). The results of this study support an inverse association between selenium status and lung cancer and suggest a modification of the effect of selenium by the antioxidants beta-carotene and vitamin C.

Garlic and its significance for the prevention of cancer in humans: a critical view.

Recently published results of epidemiologic case-control studies in China and Italy on gastric carcinoma in relation to diet suggest that consuming garlic may reduce the risk of gastric cancer. Chemical constituents of garlic have been tested for their inhibiting effect on carcinogenesis, using in vitro and in vivo models. In most experiments inhibition of tumour growth was established using fresh garlic extract, garlic compounds or synthetically prepared analogs. In this review the strengths and weaknesses of the experiments are discussed and the outcomes are evaluated to assess the possible significance of garlic or garlic compounds for the prevention of cancer in humans. It is concluded that evidence from laboratory experiments and epidemiologic studies is presently not conclusive as to the preventive activity of garlic. However, the available evidence warrants further research into the possible role of garlic in the prevention of cancer in humans.

A prospective cohort study on toenail selenium levels and risk of gastrointestinal cancer.

BACKGROUND: Various animal studies and ecologic studies suggest an inverse association between low dietary selenium intake and risk of various types of cancer. PURPOSE: The goal of this prospective cohort study was to investigate the association between toenail selenium levels and risks of stomach cancer and colorectal cancer. METHODS: Our cohort study on diet and cancer started in The Netherlands in 1986 with enrollment of 120,852 subjects aged 55-69 years. Of this number, 58,279 were men and 62,573 were women. Following the case-cohort approach for analysis of the data, we randomly selected from the cohort a subcohort of 3500 subjects (1688 men and 1812 women). After 3.3 years of follow-up, 155 incident cases of microscopically confirmed stomach cancer, 313 cases of colon cancer, and 166 cases of rectal cancer had been detected in the cohort. Toenail selenium data were available for 104 patients with stomach cancer, 234 with colon cancer, and 113 with rectal cancer and for 2459 subjects from the subcohort. RESULTS: In a multivariate analysis, the relative rates (RRs) of stomach cancer for subjects in increasing quintiles of toenail selenium level were 1.00, 0.44, 0.59, 0.84, and 0.64 (trend, P = .491). For men, there was some evidence for an inverse association between toenail selenium levels and stomach cancer: The RR for those in the highest compared with the lowest quintile of toenail selenium was 0.40 (95% confidence interval = 0.17-0.96), but the trend was not statistically significant (P = .136). For stomach cancer in women, there was no negative association with toenail selenium levels. Toenail selenium level was not associated with the risk of colon or rectal cancer. After exclusion of cases diagnosed in the 1st year of follow-up, the RRs of colon cancer for increasing quintiles of toenail selenium were 1.00, 1.27, 1.17, 0.75, and 1.07 (trend, P = .544); for rectal cancer, RR estimates were 1.00, 1.73, 0.83, 1.58, and 1.12 (trend, P = .890). CONCLUSIONS: These data support a suggestive but inconsistent inverse association between selenium levels and risk of stomach cancer. Our findings, like those of other studies, do not suggest an inverse association with risk of colorectal cancer.

The use of vitamins, minerals and other dietary supplements in The Netherlands.

By means of a two-day dietary record, information on the use of dietary supplements has been collected in 1987 and 1988 in a representative sample of the Dutch population aged 1-75 years. More than 17 percent of the population had been using at least one dietary supplement on at least one day of the survey. Age, sex, season, social class, alternative food habits, smoking and diet were related to the use of supplements. In young persons mainly fluoride and vitamin AD preparations were used, while a shift towards other supplements, like garlic and brewer's yeast preparations, was observed as age progresses. The use of single vitamin C supplements was not related to the level of mean daily vitamin C intake by food consumption.

[Utilization of food supplements in The Netherlands]. / Gebruik van voedingssupplementen in Nederland.

In 1987 and 1988 a dietary survey was carried out in a representative sample of the Dutch population, under the authority of the Ministries of Welfare, Health and Cultural Affairs, and Agriculture and Fisheries. By means of a two day dietary record data were collected on food consumption and the use of dietary supplements. More than seventeen percent of the Dutch population has been using at least one dietary supplement on at least one day of the survey. Age, sex, season, social class, alternative food habits, smoking and diet are related to the use of supplements. In young persons mainly fluoride and vitamin AD preparations are used, while as age progresses a shift towards other supplements, like garlic and brewer's yeast preparations, is observed. The use of single vitamin C supplements is not related to the level of mean daily vitamin C intake from foods.