A multisite case-control study on factor analysis and several cancer sites (mouth and pharynx, esophagus, stomach, colon, rectum, larynx, lung, breast, prostate, bladder, kidney) was conducted in Uruguay. The study included 3,528 cases and 2,532 controls. Factor analysis (principal components) was modeled among controls. This patterning method retained 4 factors per sex, labeled as prudent, drinker, traditional and Western. Odds ratios for these cancer sites, stratified by sex, were estimated using polytomous regression. Whereas the prudent pattern was mainly negatively associated with cancers of the upper aerodigestive tract, the Western pattern showed a strong increase in breast, lung and colon cancers. The study allowed for the reproducibility of the prudent, drinker and Western patterns, whereas the traditional pattern appears to be country specific. ' 2008 Wiley-Liss, Inc.Key words: dietary patterns; factor analysis; principal components; polytomous regression Uruguay is a developing country with high rates of cancer, showing age-adjusted incidence rates of 386.0 per 100,000 men and 303.2 per 100,000 women for all sites. 1 The most frequent sites are female breast (age standardized rate 114.9 per 100,000 women) and lung (Age standardized rate 76.5 per 100,000 men). Smoking and alcohol drinking are the major risk factors for frequent cancers like lung cancer and cancers of the upper aerodigestive tract in the Uruguayan population. Also, a diet low in vegetables and fruits and high in beef consumption are risk factors for digestive tract cancers. 2 Since foods are consumed together it could be suggested that the true effect of the diet may only be observed when all components are analyzed simultaneously. In fact, foods could act in synergism or be metabolized jointly. [3][4][5] Patterning methodologies, including factor analysis, may turn the analytical difficulties into an advantage. Factor analysis is used to reduce a large number of foods or nutrients to smaller number of factors for modeling purposes. 6 This analytic method was originated in the pioneer paper of Spearman in 1904. 7 Since then it has grown explosively mainly in psychology and social sciences. In 1992, Randall et al. 8 firstly applied this method in the study of food patterns and colon cancer. Since then, numerous studies on dietary patterns and diverse cancers have been published all over the World.On the basis of a large dataset of cases and controls, we decided to conduct a multisite study using factor analysis in a high-risk country such as Uruguay. The main objective was to estimate odds ratios (ORs) of several cancer sites by means of the application of the principal components method and multinomial regression. Material and methodsA large scale study was designed jointly by the

To generate broad eating patterns, which could explain more adequately the breast cancer etiology, we conducted an exploratory factor analysis in Montevideo, Uruguay. The study included 442 newly diagnosed and microscopically confirmed cases with breast cancer and 442 hospitalized controls, with non-neoplastic diseases. Factor analysis (principal components) was conducted in the control series, and as a result, 6 factors were extracted. These factors were labeled as traditional, healthy, western, stew, high-fat and drinker. The model explained 58.3% of the variance. After scoring the rotated factors, the relations between scores and breast cancer risk factors were analyzed by using Pearson correlation coefficients. After this step, the odds ratios of breast cancer for continuous scores of the rotated factors were carefully analyzed. The highest risk was directly associated with the western diet (OR 1.31, 95% CI 1.13-1.51), whereas the traditional (OR 0.77, 95% CI 0.64-0.93), healthy (OR 0.84, 95% CI 0.73-0.98) and stew (OR 0.83, 95% CI 0.71-0.98) diets were significantly protective. Women who reported a history of breast cancer among mother and sisters displayed strong elevations in risk for western (OR 2.03, 95% CI 1.11-3.72) and high-fat (OR 2.72, 95%CI 1.16-6.37) dietary patterns. This finding could suggest that gene-dietary interaction could play an important role in breast carcinogenesis. ' 2006 Wiley-Liss, Inc.

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Background Previous studies have suggested that a high intake of legumes may decrease the risk of stomach and prostate cancer and some other cancers. However, the evidence is still limited. To further explore the association between legume intake and cancer risk we conducted a case-control study of 11 cancer sites in Uruguay between 1996 and 2004, including 3,539 cancer cases and 2,032 hospital controls. Results The highest versus the lowest tertile of legume intake was associated with a significant decrease in the risk of cancers of the oral cavity and pharynx (OR = 0.48, 95% CI: 0.34-0.68), esophagus (OR = 0.54, 95% CI: 0.38-0.77), larynx (OR = 0.55, 95% CI: 0.40-0.77), upper aerodigestive tract (OR = 0.50, 95% CI: 0.40-0.63), stomach (OR = 0.69, 95% CI: 0.49-0.97), colorectum (OR = 0.43, 95% CI: 0.32-0.59), kidney (OR = 0.41, 95% CI: 0.24-0.71), and all sites combined (OR = 0.68, 95% CI: 0.59-0.78). No significant association was observed between legume intake and cancers of the lung (OR = 1.03, 95% CI: 0.83-1.27), breast (OR = 0.89, 95% CI: 0.65-1.20), prostate (OR = 0.87, 95% CI: 0.64-1.18) or bladder (OR = 0.82, 95% CI: 0.57-1.17). Similar results were found for both beans and lentils.Conclusion Higher intake of legumes was associated with a decreased risk of several cancers including those of the upper aerodigestive tract, stomach, colorectum, and kidney, but not lung, breast, prostate or bladder. Further investigations of these associations in prospective cohort studies are warranted.

To examine the protective role of dietary antioxidants (carotenoids, vitamin C, vitamin E, glutathione, and flavonoids) in lung cancer risk, a case-control study involving 541 cases of lung cancer and 540 hospitalized controls was carried out in Uruguay. The relevant variables were energy adjusted using the residuals method and then categorized in quartiles. Adjusted odds ratios (ORs) for antioxidants were calculated through unconditional logistic regression. With the exception of lycopene and vitamin C, the remaining antioxidants were associated with significant reductions in risk of lung cancer. Of particular interest was the inverse association between dietary glutathione and lung cancer [OR of quartile with highest intake compared with lowest quartile = 0.42, 95% confidence interval (CI) = 0.27-0.63]. Also, carotenoids and vitamin E were associated with significant reductions in risk of lung cancer (OR = 0.43, 95% CI = 0.29-0.64 for total carotenoids and OR = 0.50, 95% CI = 0.39-0.85 for vitamin E). A joint effect for high vs. low intakes of beta-carotene and glutathione was associated with a significant reduction in risk (OR = 0.32, 95% CI = 0.22-0.46). It could be concluded that dietary antioxidants are associated with a significant protective effect in lung carcinogenesis and that the inverse association for glutathione persisted after controlling for total vegetables and fruits.

This study displayed consistent results from three different approaches. Concerning different food groups, stewed and processed meat are rich in salt; rice, tubers, and winter squash are sources of starch; and vegetables and fruits are rich in ascorbic acid and carotenoids. All these substances have been strongly related to gastric carcinogenesis. Furthermore, this study suggests that diets rich in vegetables and fruits and with low amounts of salty and starchy foods are recommendable for the prevention of gastric cancer.

To evaluate whether the protective effect associated with vegetables and fruits in breast cancer could be explained by nutrients and bioactive substances present in these plant foods, we carried out a case-control study in Uruguay including 400 cases and 405 controls. The intake of vegetables, fruits, and related nutrients was estimated with a food frequency questionnaire on 64 food items. This questionnaire allowed the calculation of total energy intake, and nutrients were calorie adjusted by the residuals method. Odds ratios for study variables were estimated by unconditional multiple logistic regression. Total vegetable, total fruit, dietary fiber, vitamin C, vitamin E, lycopene, folate, and total phytosterol intakes were inversely associated with breast cancer risk [4th quartile odds ratio for total vegetable intake = 0.41, 95% confidence interval = 0.26-0.65, p (for trend) = 0.004]. The association with total vegetable intake was not independent of lycopene intake. The results related to vegetable and nutrient intakes are consistent with antioxidant and antiestrogenic effects. This could be mediated, among other nutrients, by dietary fiber and lycopene intake. The role of other unmeasured phytochemicals, correlated with dietary fiber and lycopene intakes, cannot be ruled out.

Prostate cancer is the second commonest malignancy among Uruguayan men, with an age-adjusted incidence rate of 32.6 per 100 000 (Parkin et al, 1997). According to a previous study (De Stefani et al, 1994), the mortality rate for prostate cancer has increased by 77% in the period between 1953 and 1991. Also, migrants from Spain and Italy have increased their risk of prostate cancer after arrival in Uruguay, suggesting the importance of environmental factors (De Stefani et al, 1990).In the only previous analytic study conducted in Uruguay (De Stefani et al, 1995), diet was assessed by food groups; both red meat and dairy foods were associated with an increased risk of prostate cancer. Also, fruit intake was associated with a risk increase of 70% (De Stefani et al, 1995). Since these estimates were not energy-adjusted some uncertainty remains about its validity. Therefore, we have decided to carry out a new case-control study on dietary factors and prostate cancer, based on a more detailed food-frequency questionnaire. SUBJECTS AND METHODSSelection of cases. In the period 1994-1997, all incident-and histologically verified prostatic adenocarcinomas occurring in men in the age range 40-89 years, admitted to the four major hospitals in Montevideo, were considered eligible for this study. Of 190 cases identified, 15 patients refused interview, leaving 175 cases of prostate carcinomas (response rate 92.1%). The stage distribution was as follows: localized 25%, regional 72% and disseminated 3%. There were no cases with latent carcinomas, and, therefore, this series is representative of a series of mainly advanced prostate tumours. The stage distribution of our series was compared with the figures drawn from the National Cancer Registry. According to this source, 70% of prostate cancers were locally advanced (regional) or disseminated at the time of the diagnosis. These figures reflect the fact that there are no mass screening programmes for prostate cancer in Uruguay. Controls selectionIn the same period, all patients admitted to the same hospitals as the cases with conditions unrelated to diet were considered eligible as controls if below age 90. A total of 240 patients were hospitalmatched to the cases; from this initial number seven patients refused interview, leaving a total of 233 controls (response rate 97.1%). The distribution of controls by disease category was as follows: eye disorders (87 patients, 37.3%), abdominal hernia (56 patients, 24.0%), acute appendicitis (25 patients, 10.7%), fractures and trauma (23 patients, 9.9%), hydatid cyst (15 patients, 6.4%), skin diseases (14 patients, 6.1%) and varicose veins (13 patients, 5.6%). QuestionnaireBoth cases and controls were specifically called up to the hospital for a face-to-face interview after diagnosis or treatment. The mean time since admission for cases was 62 days, and for controls was 50 days. Both cases and controls completed a detailed questionnaire which covered sociodemographic variables, anthropometric variables, occupational exposures, family hist...