Monica Ferraroni

VALIDATION OF A FOOD-FREQUENCY QUESTIONNAIRE TO ASSESS DIETARY INTAKES IN CANCER STUDIES IN ITALY RESULTS FOR SPECIFIC NUTRIENTS

The validity of a 77-item food-frequency questionnaire (FFQ) developed for a multicenter case-control study on diet and cancer in Italy was assessed. Trained interviewers administered the same FFQ to 452 volunteers from three Italian provinces (Pordenone, Genoa, and Forli) completed in two different seasons, at an interval of 3 to 10 months. For 395 (130 males, 265 females; median age = 52 years; range = 35 to 69 years) volunteers, two 7-day dietary (7-DD) records were available. Average intake obtained by means of the FFQ was overestimated by approximately 18% in comparison with the corresponding values based on the two 7-DD records (reference method). Pearson partial correlation coefficients, adjusted for total energy intake between the nutrient intakes assessed by the FFQ and reference method, ranged from 0.19 for vegetable fat to 0.64 for sugar (median value r = 0.46). The unadjusted deattenuated coefficients, which took into account the interindividual variability of consumption, estimated by means of the two 7-DD records, ranged from 0.29 for vegetable fat to 0.72 for starch (median value r = 0.54). The proportion of subjects correctly classified within the lowest two quintiles ranged between 59% for vegetable fat and vitamin E, and 96% for alcohol, and those correctly classified within the highest two quintiles ranged between 44% for vegetable fat and 94% for alcohol. The average proportion of subjects correctly classified within one quintile was 73%. These data indicate that this FFQ provides valid estimates of intakes for major nutrients, comparable to those reported from other studies in North America and other European countries.

Selected micronutrient intake and the risk of colorectal cancer.

The relationship between estimated intake of selected micronutrients and the risk of colorectal cancer was analysed using data from a case-control study conducted in northern Italy. The study was based on 828 patients with colon cancer, 498 with rectal cancer and 2,024 controls in hospital for acute, non-neoplastic, non-digestive tract diseases. Relative risks (RRs) of intake quintiles were computed after allowance for age, sex and other major potential confounding factors, including an estimate of total energy intake. No apparent trend in risk across intake quintiles was evident for retinol, vitamin D, methionine and calcium. For beta-carotene, ascorbic acid, vitamin E and folate there was a trend of a protective effect with increasing consumption: the RR for the highest versus the lowest quintile was 0.32 for beta-carotene, 0.40 for ascorbic acid, 0.60 for vitamin E and 0.52 for folate. These inverse associations were similar for colon and rectal cancer, and consistent across strata of sex and age. When simultaneous allowance was made for all these micronutrients, besides other covariates, the only persistent protective effects were for beta-carotene (RR = 0.38 for the highest quintile) and ascorbic acid (RR = 0.52). Whether this reflects a specific, or stronger, effect of these micronutrients, rather than problems of collinearity between micronutrients or other limitations of the data, remains open to discussion. Still, this study suggests that specific micronutrients may exert an independent protective effect against colorectal carcinogenesis.

Reproducibility of an Italian food frequency questionnaire for cancer studies. Results for specific nutrients

The reproducibility of measures of the intake of total energy and 27 selected nutrients from a quantitative food frequency questionnaire (FFQ) used in a case-control study on cancer of the breast, ovary, and digestive tract was evaluated. The results of two FFQ administrations at an interval of 3 to 10 months (median = 5.4 months) to 452 volunteers (144 males and 308 females; median age = 50 years) from three Italian provinces (Pordenone, Genoa, and Forì) were compared. Pearson correlation coefficients (r) between crude nutrient intake (unadjusted for energy) ranged from 0.50 for vegetable fat to 0.80 for alcohol, with most values falling between 0.60 and 0.70 (median r = 0.67). Adjustment of nutrient intakes for total energy slightly decreased most coefficients (median r = 0.60). The agreement between the two measurements did not differ substantially by sex, age, education, and interval between interviews. The contribution of specific FFQ components (i.e., frequency-only questions, open questions, portion size, and fat intake pattern) was also assessed separately with respect to the performance and reproducibility of nutrient measures, yielding, in general, very similar results. The seven questions concerning individual fat intake pattern, which were used to modulate the composition of various recipes, led, however, to a significant increase in mean daily intake of vegetable fat, oleic acid, and vitamin E, but a reduction of estimated daily intake of linoleic acid and polyunsaturated fatty acids.(ABSTRACT TRUNCATED AT 250 WORDS)

Intake of macronutrients and risk of breast cancer

BACKGROUND The association between risk of breast cancer and dietary fat and intakes of other energy sources remains controversial. The Italian population offers special opportunities to assess the influence of high intakes of unsaturated fat and starch and, because the population has low awareness of diet and cancer issues, there is less scope for recall bias. We have assessed the relations of various macronutrient intakes with risk of breast cancer. METHODS In this case-control study, 2569 women with incident breast cancer (median age 55 years) and 2588 control women (median age 56 years) in hospital with acute, non-neoplastic diseases, were interviewed in six different areas of Italy between 1991 and 1994. A validated food-frequency questionnaire was used. It included questions on 78 foods and recipes grouped into six sections, as well as specific questions on individual fat intake pattern. FINDINGS The risk of breast cancer decreased with increasing total fat intake (trend p 0.01) whereas the risk increased with increasing intake of available carbohydrates (trend p = 0.002). The odds ratios for women in the highest compared with the lowest quintile of energy-adjusted intake were 0.81 for total fat and 1.30 for available carbohydrates. Starch was the chief contributor to the positive association with available carbohydrates. High intakes of polyunsaturated and unsaturated fatty acids (i.e., polyunsaturated fatty acids plus oleic acid) were associated with a decreased risk of breast cancer (odds ratios for highest vs lowest quintile 0.70 and 0.74, respectively). Conversely, the intakes of saturated fatty acids, protein, and fibre were not significantly associated with breast-cancer risk. INTERPRETATION This case-controls study shows that unsaturated fatty acids protect against breast cancer, possibly because intake of these nutrients is closely correlated with a high intake of raw vegetables. The findings also suggest a possible risk in southern European populations, of reliance on a diet largely based on starch.

Intake of selected micronutrients and the risk of breast cancer

To investigate the relation between selected micronutrients and breast cancer risk, we conducted a case‐control study of breast cancer between June 1991 and April 1994 in 6 Italian areas. The study included 2569 women admitted to the major teaching and general hospitals of the study areas with histologically confirmed incident breast cancer and 2588 control women with no history of cancer, who were admitted to hospitals in the same catchment areas for acute, non‐neoplastic, nongynecological conditions unrelated to hormonal or digestive tract diseases or to long‐term modifications of the diet. Dietary habits, including alcoholic beverage consumption, were investigated using a validated food frequency questionnaire, including 78 foods or food groups, several types of alcoholic beverages, some “fat intake pattern” questions and some open sections for foods consumed frequently by the subject and not reported in the questionnaire. To control for potential confounding factors, several multiple logistic regression models were used. When major correlates, energy intake and the mutual confounding effect of the various micronutrients were taken into account, beta‐carotene, vitamin E and calcium showed a significant inverse association with breast cancer risk. The estimated odds ratios of the 5th quintile compared to the lowest one were 0.84 for beta‐carotene, 0.75 for vitamin E and 0.81 for calcium. No significant association emerged for retinol, vitamin C, thiamin, riboflavin, iron and potassium. Our results suggest that a diet rich in several micronutrients, particularly beta‐carotene, vitamin E and calcium, may be protective against breast cancer.

Medical history, diet and pancreatic cancer.

The relation between various aspects of medical history, selected indicator foods and the risk of pancreatic cancer was analyzed in a hospital-based case-control study conducted in Northern Italy on 247 patients with cancer of the pancreas, and 1,089 controls in hospitals for acute, nonneoplastic or digestive conditions. There was a significant association with history of pancreatitis (relative risk, RR 3.2, 95% confidence interval = 1.3-7.9), which was however reduced when the condition was first diagnosed at least 5 years previously. The point estimates were slightly, but not significantly, above unity for diabetes (RR = 1.5), gastrectomy (RR = 1.1) and cholelithiasis (RR = 1.3), and no association was found with liver disease or drug allergy. In relation to diet, there was some tendency for the risk to decrease with more frequent fruit consumption, but the results were largely inconsistent in relation to various indicators of meat, animal protein or fat intake. Although no important associations were found in this study with various aspects of medical history or diet indicators and pancreatic cancer risk, on account of the size of the dataset and the statistical power, this study contributes usefully to the debate on a common cancer whose causes are still largely undefined.

Resveratrol and breast cancer risk.

Resveratrol is a non-flavonoid polyphenol that has attracted attention as a potential anticancer agent in vitro and in vivo, but scanty epidemiological data are available. We have therefore analysed the relation between dietary intake of resveratrol and breast cancer risk using data from a case–control study conducted between 1993 and 2003 in the Swiss Canton of Vaud on 369 cases and 602 controls. Compared with the lowest tertile of total resveratrol intake, the multivariate odds ratios (OR) were 0.50 for the intermediate and 0.39 for the highest tertile, and the trend in risk was significant. A significant inverse association was observed for resveratrol from grapes (OR = 0.64 and 0.55), but not for wine. The inverse relation between resveratrol and breast cancer risk was not explained by several potential confounding factors, including detailed allowance for alcohol intake, nor attributable to a non-specific favourable effect of fruit on breast cancer risk.

Dietary patterns and the risk of colorectal cancer and adenomas

The association of colorectal cancer risk with select foods has been evaluated by dietary pattern analysis. This review of the literature was conducted to thoroughly examine the available evidence for the association between dietary patterns and colorectal cancers and adenomas. A total of 32 articles based on worldwide epidemiological studies were identified. Pattern identification was achieved by exploratory data analyses (principal component, factor, and cluster analyses) in most articles, and only a few used a priori-defined scores. Dietary patterns named as healthy, prudent, fruit and vegetables, fat-reduced/diet foods, vegetable/fish/poultry, fruit/whole grain/dairy, and healthy eating index-2005, recommended food and Mediterranean diet scores were all associated with reduced risk of colorectal cancer and the risk estimates varied from 0.45 to 0.90. In contrast, diets named Western, pork-processed meat-potatoes, meat-eaters, meat and potatoes, traditional patterns, and dietary risk and life summary scores were associated with increased risk of colorectal cancer with risk estimates varying from 1.18 to 11.7. Dietary patterns for adenomas were consistent with those identified for colorectal cancer.

Nutrient dietary patterns and the risk of breast and ovarian cancers

The issue of diet and breast and ovarian cancers has been considered in terms of foods and nutrients, but rarely in terms of dietary patterns. We examined the associations between dietary patterns and breast and ovarian cancers in 2 Italian multicentric case–control studies. Cases were 2,569 breast cancers and 1,031 ovarian cancers hospitalized in 4 Italian areas between 1991 and 1999. Controls were 3,413 women from the same hospital network. Dietary habits were investigated through a validated food‐frequency questionnaire. Dietary patterns were identified on a selected set of nutrients through principal component factor analysis. Odds ratios (OR) and 95% confidence intervals (CI) for both cancers were estimated using unconditional multiple logistic regression models on quartiles of factor scores and continuous factor scores. We identified 4 major dietary patterns named Animal products, Vitamins and fiber, Unsaturated fats and Starch‐rich. The animal products pattern and the unsaturated fats pattern were inversely associated with breast cancer (OR = 0.74, 95% CI: 0.61–0.91 and OR = 0.83, 95% CI: 0.68–1.00, respectively, for the highest consumption quartile), whereas the starch‐rich pattern was directly associated with it (OR = 1.34, 95% CI: 1.10–1.65). The vitamins and fiber pattern was inversely associated with ovarian cancer (OR = 0.77, 95% CI: 0.61–0.98), whereas the starch‐rich pattern was directly associated with it (OR = 1.85, 95% CI: 1.37–2.48). In conclusion, the starch‐rich pattern is potentially an unfavorable indicator of risk for both breast and ovarian cancers, while the animal products and the vitamins and fiber patterns may be associated with a reduced risk of breast and ovarian cancers, respectively.

Dietary patterns and breast cancer: a review with focus on methodological issues

Available information on dietary patterns (multiple dietary components operationalized as a single exposure) and cancer is still sparse. This review presents papers published to date that have identified dietary patterns according to all the existing approaches and have assessed their association with breast cancer. Nineteen articles published since 1995 were identified based on studies conducted in various populations across many countries. The majority of them identified a posteriori dietary patterns, mainly using principal component factor analysis. Six studies did not find associations between any of the identified dietary patterns and breast cancer. Nine studies identified one dietary pattern significantly associated with breast cancer, and the remaining four identified two to four dietary patterns related to breast cancer. Although the body of literature has recently increased, a meaningful assessment of the association between dietary patterns and breast cancer still calls for extra effort to refine the statistical techniques and to address the issue of reproducibility of dietary patterns.