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Biomedical subjects

E Riboli

Publications and source records attributed to E Riboli.

At least 127 records · Page 7Linked to original sources
PubMed1996

Nutrition and laryngeal cancer.

The main etiologic factors of cancers of the larynx and hypopharynx are alcohol and tobacco, and their prevalence in different populations explains, to a large extent, the wide variations in incidence observed around the world. Besides these two main risk factors, however, diet also seems to play a role in determining the risk of these cancers. There is consistent evidence that low consumption of fruit and vegetables is associated with higher risk, after statistical adjustment for alcohol and tobacco. Consumption of vegetable oils and fish and a moderately high polyunsaturated/saturated fatty acid ratio (P/S ratio) were reported to be associated with reduced risk. Low intake of vitamin C, beta-carotene and vitamin E were reported consistently to be associated with higher laryngeal cancer risk, but there was no clear evidence that these micronutrients are better predictors of cancer risk than the principal food groups from which their intake levels were estimated, i.e., fruits, vegetables, vegetable oils, and fish. Given the overwhelming role of tobacco and alcohol in the etiology of these cancers and the extremely low incidence among nonsmokers/nondrinkers, the available studies provide no estimate of the role of diet in subjects not exposed to these factors. The evidence indicates, however, that, in the presence of tobacco and/or alcohol, low intake of fruit and vegetables may account for 25 to 50 percent of the cases among men.

Alcohol Drinking↗
PubMed1996

Epithelial, possibly precancerous, lesions of the lung in relation to smoking, passive smoking, and socio-demographic variables.

We have undertaken an autopsy-based study to evaluate the etiologic importance of active and passive smoking, as well as socio-demographic variables, in the development of pathologic precursors of lung cancer. Lung specimens were taken at autopsy from 531 persons who had died within four hours from a cause other than respiratory or cancer in Athens (Greece) or the surrounding area. Specimens were examined blindly for basal cell hyperplasia, squamous cell metaplasia, cell atypia and mucous cell metaplasia, i.e., pathological entities considered as epithelial, possibly precancerous, lesions (EPPL). Interviews were conducted with next of kin of the deceased. Suitable autopsy specimens as well as completed interviews were eventually available for 275 subjects. EPPL score was regressed on the available independent variables. EPPL score was higher among active smokers than among nonsmokers, while ex-smokers occupied an intermediate position. Conditional on smoking habits, EPPL score was higher among women than among men and higher among manual than among non-manual workers, in agreement with the corresponding patterns with respect to lung cancer. Nonsmoking women married to ever smokers had significantly higher EPPL score than those married to never smokers. The overall findings of this study suggest that EPPL is a valuable indicator of lung cancer risk and that exposure to environmental tobacco smoke is associated with higher EPPL levels and therefore with higher lung cancer risk.

Adult↗
PubMed1996

The Malmö Food Study: the reproducibility of a novel diet history method and an extensive food frequency questionnaire.

OBJECTIVE: To assess the reproducibility of two diet assessment methods, an extensive quantitative food frequency questionnaire (method A) and a novel shorter quantitative food frequency questionnaire with a 14 day food record (method B). DESIGN: A randomized prospective cohort study. SETTING: General community. SUBJECTS: 241 residents of the town of Malmö, aged between 50-69 years, 126 men and 115 women who completed the methods one year apart. METHODS: Both diet methods were designed to cover the whole diet and portion sizes were estimated using a booklet with 120 photographs; method A comprised 250 items and method B combined a two-week food record measuring lunch and dinner meals and a shorter 130 item quantitative food frequency questionnaire for average consumption of foods, snacks and beverages during the past year; RESULTS: The percent difference between estimated energy intake one year apart were for men 10.7% for method A and 0.2% for method B, corresponding values for women 13.7% and 1.1%. Method B showed a good agreement between measurements for energy-providing nutrients, micronutrients and major food groups, i.e. meat products, edible fats, milk, fish, fruits and vegetables with correlation coefficients between 0.70-0.90 for women. The percent difference of average intake of edible fat was about 10%. Average energy-adjusted Pearson's correlation coefficients were of the order of 0.50-0.80 for most nutrients including 14 fatty acids. The correlation for the ratio between polyunsaturated and saturated fatty acids were about 0.70 for men and 0.80 for women; CONCLUSION: A modified diet history method combining a food record and a food frequency questionnaire shows good reproducibility.

Aged↗
PubMed1996

The Malmö Food Study: the relative validity of a modified diet history method and an extensive food frequency questionnaire for measuring food intake.

OBJECTIVE: To assess the relative validity of two diet assessment methods, an extensive quantitative food frequency questionnaire (method A) and a novel shorter quantitative food frequency questionnaire with a 14 day food record (method B). DESIGN: A randomized prospective cohort study. SETTING: General community. SUBJECTS: 206 residents of the town of Malmö, aged between 50-69 years, 101 men and 105 women who completed the methods during one year. METHODS: Both diet methods were designed to cover the whole diet and portion sizes were estimated using a booklet with 120 photographs; method A comprised 250 items and method B combined a two-week food record measuring lunch and dinner meals and a shorter 130 item quantitative food frequency questionnaire for average consumption of foods, snacks and beverages during the past year. An 18 day dietary record comprising six 3-day weighed records evenly distributed over one year served as a reference method. RESULTS: Pearson's correlation coefficients varied from 0.25 for fat intake to 0.84 for milk products for method A and from 0.32 for fish to 0.88 for meat for method B. Correlations for most food groups ranged between 0.50-0.80, and were higher for method B. Only small changes were noted after adjustment for energy intake. On average for most food groups categorization of subjects into quartiles, 55% of subjects belonging to the lowest quartile, and 57-59% of those belonging to the highest quartile for method A and B were correctly classified. CONCLUSION: A combined food record with a quantitative food frequency questionnaire is a better tool for food assessment than an extensive food frequency questionnaire.

Aged↗
PubMed1996

Identifiability of food components for cancer chemoprevention.

Epidemiological studies have consistently reported a reduction in risk for several cancer sites in relation to high consumption of vegetables and fruit. These findings stimulated further research aimed at identifying which compounds in fruit and vegetables are responsible for the reduction in cancer risk. Epidemiological and laboratory studies suggested that some micronutrients, particularly vitamin C, vitamin E, beta-carotene, selenium, magnesium and zinc, could reduce the risk of cancers of the oral cavity, lung, oesophagus and stomach, while dietary fibre was more specifically related to a reduced risk of colorectal cancer. However, the results of large randomized trials on various combinations of vitamins and minerals at supranutritional doses have so far failed to confirm this hypothesis or have found very weak effects. These results should stimulate profound re-thinking of the methods that led to the selection of specific molecules with potential chemopreventive action. From a methodological point of view, little attention has so far been given to four main limitations of nutritional epidemiology, which have direct bearing on the extrapolation of results from foods to food components. Measurements of micronutrient intakes through simple dietary questionnaires and current food composition tables lack precision and specificity. Micronutrient intakes are often highly correlated in nature because micronutrients tend to share the same food sources. Attribution of cancer risk to a single food constituent can be misleading if multicollinearity of dietary variables is not recognized. The etiological meaning of nutritional biomarkers is not straightforward because circulating levels of nutrients reflect not only dietary intake but also complex metabolic regulations. Studies have not considered the physical characteristics of foods, which are important determinants of physiological responses. Understanding the multidimensional nature of diet and of its relationship with different cancers is a major scientific challenge. Epidemiological studies combining detailed dietary questionnaires, appropriate food composition tables, multiple biomarkers, and appropriate statistical methods may provide better measurements of the relationships between cancer risk and specific dietary patterns and therefore contribute to the identification of food components with hitherto unforeseen potential interest for cancer prevention.

Anticarcinogenic Agents↗
PubMed1995

Calibration of dietary intake measurements in prospective cohort studies.

To evaluate the accuracy of dietary intake measurements in prospective cohort studies on diet, it is generally proposed that substudies be conducted to 1) correct relative risk estimates for biases due to measurement error, and 2) account for statistical power losses when estimating the sample size requirements of the cohort. Usually the substudy takes the form of a "validity" study, based on a small group of volunteers and using repeated daily food consumption records as reference measurements. In this methodological review, the authors conclude that when relative risks are estimated for scaled, absolute intake differences rather than for quantile categories, a "calibration" study based on only a single day's food intake record (but generally on a larger number of subjects) can provide sufficient reference information to meet objectives 1 and 2. A major advantage of calibration studies based on this single-day-per-subject design is that they can be conducted on a representative sample of cohort participants more easily than validity studies in which reference measurements are repeated.

Bias↗
PubMed1995

Sample size requirements for calibration studies of dietary intake measurements in prospective cohort investigations.

Pooling data from multiple cohort studies on diet and cancer has the advantage that it allows detailed cross-validation of relative risk estimates between different study populations. If there is reasonable agreement between cohort-specific relative risk estimates, a more powerful pooled summary estimate can be obtained. A complication, however, is that in different cohorts, relative risk estimates may be biased to a different degree as a result of errors in the baseline assessments of habitual dietary intake levels. Such divergent biases can be adjusted for by means of "calibration" studies, using standardized reference measurements obtained in a subgroup of each cohort. These adjustments entail a cost, however, in terms of an increase in the confidence interval of relative risk estimates within each cohort separately. In this paper, the authors evaluate the possible magnitude of such intracohort losses in precision and discuss the approximate sample size required to have a sufficient level of accuracy in dietary calibration studies to adjust for bias.

Calibration↗
PubMed1995

A case-control study of gastric cancer and nutritional factors in Marseille, France.

A case-control study was conducted in Marseille (France) to investigate the relationship between usual diet and risk of gastric cancer. Patients with histologically confirmed gastric adenocarcinoma were identified in 8 major centres for gastric surgery. Controls were selected in specialized medical centres from patients undergoing functional reeducation for injuries or trauma, according to the age and sex distributions of the cases. The study involved 92 cases and 128 controls who were interviewed with a dietary history questionnaire on their usual diet during the year preceding first symptoms for cases, or preceding interview for controls. Odds ratios for specific foods were calculated after adjustment for age, sex, occupation and energy intake. A reduced risk was observed for consumption of raw vegetables (OR2: 0.55; OR3: 0.41 for the second and third tertiles, respectively), fresh fruit (OR2: 0.63; OR3: 0.50), vegetable oil (OR2: 0.60; OR3: 0.52), pasta and rice (OR2: 1.06; OR3: 0.50) whereas consumption of cakes and pastries (OR2: 1.02; OR3: 2.96), sugar and confectionery (OR2: 0.96; OR3: 1.68) was associated with an increased risk. An increased risk was found for intake of saturated fat (OR2: 1.49; OR3: 1.67), simple sugars (OR2: 1.18; OR3: 1.78) and calcium (OR2: 1.84; OR3: 2.57). A decreased risk was observed with intake of fiber (OR2: 0.49; OR3: 0.59), fibre from vegetables and fruit (OR2: 0.83; OR3: 0.53) and iron (OR2: 0.70; OR3: 0.41).

Adenocarcinoma↗
PubMed1995

Nitrosamine, nitrate and nitrite in relation to gastric cancer: a case-control study in Marseille, France.

A case-control study on gastric cancer and diet was conducted in Marseille (France). Ninety-two patients with histologically confirmed adenocarcinoma and 128 controls undergoing functional reeducation for injuries or trauma were interviewed by a trained dietician using a dietary history questionnaire on their usual diet during the year preceding the first symptoms for cases, or preceding interview for controls. Intake of nitrite, nitrate and pre-formed N-nitrosodimethylamine (NDMA) from food was estimated using a food composition table compiled ad hoc. Odds ratios (ORs) were calculated after adjustment for age, sex, occupation and calorie intake. The results indicated that high intake of NDMA was associated with increased risk for gastric cancer. The ORs for the second and third tertile of NDMA intake were: OR2 = 4.13 (95% CI = 0.93 18.27) and OR3 = 7.00 (95% CI = 1.85 to 26.46). Intake of nitrate and nitrite was not associated with increased risk of stomach cancer. Consumption of vegetables was protective in general and independent of their estimated nitrate content.

Adenocarcinoma↗
PubMed1995

Validity of urinary biomarkers of exposure to tobacco smoke following prolonged storage.

BACKGROUND: The utility of using biomarkers of smoking in epidemiological studies depends not only on the validity and precision of the laboratory procedure but often on the long-term stability of the analytes of interest in stored biological samples. METHODS: We retrieved urine samples collected in 1976-1977 from women included in a cohort study in Utrecht and for whom information on smoking status was available. Creatinine and thiocyanate were measured in 1976-1977 on fresh samples. Cotinine and creatinine were analysed in 1988 on urine stored at -20 degrees C. RESULTS: Measurements of creatinine more than 10 years apart showed a correlation of 0.95 and equal means. Cotinine measurements made in 1988 allowed a clear separation of smokers and non-smokers (sensitivity 92%, specificity 100%), suggesting that concentrations retained their discriminant value even after 10 years of storage. CONCLUSION: These results emphasize the possibilities offered by long-term storage, under proper conditions, of biological samples for subsequent determination of analytes which may emerge as the study progresses.

Biomarkers↗
PubMed1995

Misclassification of smoking status among women in relation to exposure to environmental tobacco smoke.

In studies of the health effects of exposure to environmental tobacco smoke (ETS), misclassification of active smokers has the potential to bias the estimates of disease risk. Biochemical validation of exposure to ETS can provide objective evidence of current smoking status in epidemiological studies. Intrinsic to this effort is the establishment of appropriate cut-off points for the measurements of tobacco biomarkers. Within a collaborative study on ETS co-ordinated by the International Agency for Research on Cancer, questionnaire data and urine samples were collected from 1,369 women at 13 centres in 10 countries. Forty seven of these women had urine cotinine levels above 50 ng.mg-1 creatinine, a level used to discriminate smokers from nonsmokers in previous studies. The distributions of the subjects across cotinine values and self-reported exposure to ETS was consistent with the association, at one extreme, of moderate cotinine levels (50-150 ng.mg-1) with very high exposure to ETS, and, at the other extreme, of very high cotinine levels indicating actual use of nicotine-containing products in women with low ETS exposure. Using the cut-off point of 150 ng.mg-1, only 1.5% of the alleged nonsmokers were reclassified as current light smokers. Potential bias due to smoker misclassification is very unlikely to be responsible for the increased health risks observed in epidemiological studies on ETS.

Bias↗
PubMed1995

Do the nonsmoking daughters of smokers tend to marry smokers? Implications for epidemiological research on environmental tobacco smoke: the IARC collaborative study.

The IARC collaborative study on exposure to environmental tobacco smoke (ETS) involved collecting interview data and biochemical indicators of exposure from 1369 nonsmoking women in 13 centers in 10 countries. Information on childhood and adulthood exposure to other people's smoke and duration of this exposure from both parents and spouse was gathered at the interview. Of the 900 women whose husbands smoked (current or exsmokers), 71.3% had one or both parents who smoked (predominantly the father), whereas among the 277 women married to never-smokers, only 60.3% had at least one parent who smoked. The odds ratio for the daughter of a smoker to marry a smoker was, therefore, 1.64 (95% confidence interval = 1.24-2.17; P > 0.001), and there was an exposure-response relation between the number of years of childhood exposure to ETS from the parents and the likelihood of being married to a smoker. These results show that nonsmoking women married to smokers are more likely to have been exposed to tobacco pollution during their whole life. Because the duration of exposure is known to be important in the genesis of lung cancer, some of the excess risk of lung cancer in nonsmoking women married to smokers may be due exposure to ETS from parents during childhood.

Adolescent↗
PubMed1994

Nutritional factors and gastric cancer in Spain.

A case-control study on diet and gastric cancer, carried out in selected areas of four regions of Spain (Aragon, Castile, Catalonia, and Galicia) in 1988 and 1989, included 354 cases of histologically confirmed gastric adenocarcinoma and 354 controls matched by age, sex, and area of residence. Cases and controls were selected from 15 hospitals, representing most of the hospital facilities in the study areas. Usual diet was estimated by means of a dietary history questionnaire administered by interview. An increased risk of gastric cancer was observed for high consumption of exogenous nitrosamines (odds ratio = 2.1 for the highest quartile of consumption versus the lowest; p for linear trend = 0.007), nitrites, fat, and cholesterol. However, in a multivariate regression model, the effect of fat and cholesterol disappeared. An inverse association with the risk for gastric cancer was seen for high intake of fiber, vitamin C, folate, carotene, and nitrates. High consumption of vitamin C seemed to neutralize the increased risk related to simultaneous consumption of nitrosamines. For histologic type, the authors found no meaningful differences in the effect of most of the nutrients between intestinal and diffuse cancers. Their findings are consistent with previously reported results about the protective effect of fruit and vegetables and the increased risk associated with foods that are important sources of nitrites and preformed nitrosamines.

Adenocarcinoma↗
PubMed1994

Estimating the accuracy of dietary questionnaire assessments: validation in terms of structural equation models.

The validity and precision of questionnaire assessments of the habitual intake of individuals are usually evaluated by comparison with reference measurements that are supposed to provide a best possible substitute for the individuals' true intake values. In the present paper, a measurement error model is presented, defining different types of error--random or systematic, and within or between individuals--that may occur in dietary intake measurements. It is then discussed how simple latent variable models (structural equation models) can be used to estimate the average magnitude of these various types of error. So far, approaches described for the analysis of dietary validity studies have all been based on the assumption that the random errors of repeat reference measurements, taken by the same method on different occasions, are uncorrelated, so that the average of a sufficiently large number of repeat reference measurements will provide an accurate ranking of individuals by true intake level. In the present paper it is described how, by additional comparison with a third type of measurement such as a biochemical marker, the validity of dietary questionnaire measurements can be evaluated even in situations where the random errors of repeat reference measurements can no longer be assumed to be independent.

Ascorbic Acid↗