Maree Brinkman

Use of selenium in chemoprevention of bladder cancer

The anticarcinogenic potential of selenium was first identified nearly 40 years ago in geographical studies that reported lower death rates for cancer in regions with high levels of selenium. Cancer of the bladder was one of the body sites found to share this inverse association. Although many subsequent studies have been done on selenium and cancer, only a few have specifically assessed the relation with bladder cancer. However, the high recurrence rate and ability to monitor bladder urothelial-cell carcinoma make selenium a good candidate for chemoprevention. Evidence suggests that selenium is a biologically plausible, safe, and efficacious potential chemoprevention agent for bladder cancer. Large tertiary chemoprevention trials are needed to further investigate the role of selenium in the prevention of bladder cancer. Future studies should assess the best dose and form of selenium, and whether the protective effect of selenium differs between the sexes.

Nutrition, total fluid and bladder cancer.

Bladder cancer is a major health concern for older males in Western populations. About 30 years ago there was a suggestion that nutrition may have a role in the aetiology of the disease. Although the literature has been accumulating since then, owing to heterogeneity between studies results have often been inconsistent and unclear. The aim of this paper was to present an updated summary of the scientific evidence on the association between nutrition, total fluid intake and bladder cancer. A search of computerized databases, PubMed, ISI, Embase and Cochrane Library, was conducted to identify all epidemiological studies published between 1966 and October 2007. The level of scientific evidence for the various nutritional factors and total fluid intake was ranked according to the number of studies reporting a statistically significant association and the existence of mechanistic evidence. The levels of association were based on a ranking of statistically significant relative risks. Fruit and yellow–orange vegetables, particularly carrots and selenium, are probably associated with a moderately reduced risk of bladder cancer. Citrus fruits and cruciferous vegetables were also identified as having a possible protective effect. Possible risk factors are salted and barbecued meat, pork, total fat, pickled vegetables, salt, soy products, spices and artificial sweeteners. No clear association could be determined for beef, eggs, processed meats and total fluid intake. In conclusion, specific fruit and vegetables may act to reduce the risk of bladder cancer. Future studies on bladder cancer should investigate the effect of food categorization, amount and gender.

Consumption of animal products, olive oil and dietary fat and results from the Belgian case-control study on bladder cancer risk.

AIM The Western diet typically consists of high levels of saturated fat from animal products and has been associated with an increased risk of bladder cancer. Whilst olive oil, the predominant fat in the Mediterranean diet, has been associated with many health benefits its role in bladder cancer aetiology is still unknown. Therefore, we investigated the effect of intake of animal products, olive oil and other major dietary fats on bladder cancer risk. METHODS Dietary data were collected from 200 cases and 386 controls participating in a Belgian case-control study on bladder cancer. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) by comparing the highest with the lowest tertiles of intake between cases and controls using unconditional logistic regression. Adjustment was made for age, sex, smoking characteristics, occupational exposures and calorie intake. RESULTS There was a statistically significant inverse association between olive oil intake and bladder cancer consistent with a linear dose-response relationship: middle versus the lowest tertile (OR: 0.62; 95% CI: 0.39-0.99) and the highest versus the lowest tertile (OR: 0.47; 95% CI: 0.28-0.78; p-trend = 0.002). We also observed borderline statistically significant increased odds of bladder cancer for the highest versus the lowest intake of cheese (OR: 1.53; 95% CI: 0.95-2.46; p-trend = 0.08). No potential associations were detected for any other source or type of dietary fat. CONCLUSION We observed evidence for a protective effect by olive oil and a possible increased risk of bladder cancer associated with a high intake of cheese. Our results require further investigation and confirmation by other studies.

VALIDATION OF THE IMMIDIET FOOD FREQUENCY QUESTIONNAIRE IN AN ADULT BELGIAN POPULATION: A REPORT FROM THE BELGIAN CASE-CONTROL STUDY ON BLADDER CANCER RISK

Abstract We evaluated the performance of the IMMIDIET food frequency questionnaire (FFQ) used to collect dietary data for the Belgian case-control study on bladder cancer. Thirty-seven men and women aged 50 years and older were recruited from the University Hospital in Leuven, Belgium. Participants completed the IMMIDIET FFQ, a 7-day diet diary and a 24-hour diet recall. Median intakes and inter-quartile ranges were calculated for 27 foods and nutrients from each dietary assessment method. All dietary factors were log-transformed and adjusted for energy using the nutrient density method. Pearson correlation coefficients were used to compare the different dietary assessment methods. Bland-Altman plots were also used to assess levels of agreement between the dietary methods. Energy, fruit and vegetable intake estimates were higher from the IMMIDIET FFQ compared with the two reference methods. The highest deattenuated correlations between the FFQ and 7-day diary were meat (0.58), bread (0.44), fruit (0.38) and fish (0.38). The highest deattenuated correlations between the FFQ and 24-hour recall were for fruit (0.72), fat (0.48), alcohol (0.44), cholesterol (0.42), monounsaturated fatty acid (0.42) and polyunsaturated fatty acid (0.41). Generally, correlation was lower for the micro-nutrients except for phosphorus (0.42), vitamin C (0.41) and calcium (0.40). The IMMIDIET FFQ is an appropriate instrument to measure usual dietary intake for the Belgian case-control study on bladder cancer risk. Further investigation of nutritional assessment methods is necessary.