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.

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.

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.

Diet and cancers of the larynx and hypopharynx: the IARC multi-center study in southwestern Europe

The main causes of cancer of the larynx and hypopharynx are smoking cigarettes and drinking alcohol. However, for these as well as for other cancers of the upper aerodigestive tract, some dietary components, mainly low consumption of fruit and vegetables, have been observed to be associated with increased cancer risk. We report results from a multicenter case-control study carried out in six regions of Europe located in northern Spain, northern Italy, Switzerland, and France. A total of 1,147 males with cancer (cases) and 3,057 population controls were interviewed on usual diet, lifelong drinking and smoking habits, and occupational history. Cancer cases had histologically verified epidermoid carcinomas. The cancers were classified in two anatomic sub-entities: the epilarynx (hypopharynx and upper part of the larynx), which enters into contact with the bolus and the air; and the endolarynx, through which air and tobacco smoke pass, but not the bolus. A previous report from this study found that alcohol drinking presents a greater risk factor for cancer of the epilarynx than for cancer of the endolarynx. The main results regarding diet indicate that high intake of fruit, vegetables, vegetable oil, fish, and low intake of butter and preserved meats were associated with reduced risk of both epilaryngeal and endolaryngeal cancers, after adjustment for alcohol, tobacco, socioeconomic status, and non-alcohol energy intake. Among nutrients, a reduced risk was found for high intake of vitamins C and E and for a high polyunsaturated/saturated fatty acids (P/S) ratio. While these variables are relevant in scoring nutritional behaviour, it remains unresolved whether the biologic properties of these nutrients play a role in the apparent protective effect.

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.

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.

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.

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.

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.

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).

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.

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.

Consumption of meat, animal products, protein, and fat and risk of breast cancer: a prospective cohort study in New York

Epidemiologic studies have focused on the association between diet and breast cancer with conflicting results. Whereas a majority of case-control studies indicate a role for the intake of total fat and saturated fat, most prospective cohort studies either are negative or indicate very modest associations. Only a few authors have examined the role of meat intake in relation to breast cancer risk. The aim of this study was to examine the relation between risk of breast cancer and dietary intake of meat, animal products, fat, and protein. Between 1985 and 1991, we recruited 14,291 New York City women in a prospective cohort study of endogenous hormones, diet, and cancer in which they reported on their recent diet using a food frequency questionnaire self-administered at enrollment. From the cohort, 180 invasive breast cancer cases diagnosed before December 1990 and five times as many controls, individually matched by age, calendar time at enrollment, menopausal status, and, if premenopausal, phase of menstrual cycle, were included in a nested case-control study. There was an evident increase in the relative risk (RR) of breast cancer for increasing consumption of meat. Women in the upper quintile of meat consumption, as compared with the lowest quintile, had an energy-adjusted RR of 1.87 (95% confidence interval = 1.09-3.21). There was a modest RR increase in the upper quintile of total and saturated fat and no apparent association for other types of fat, protein, dairy products, poultry, or fish.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficient use of biological banks for biochemical epidemiology: exploratory hypothesis testing by means of a sequential t-test

In view of recent advances in molecular and biochemical epidemiology, there is growing interest in the creation of biological banks of blood, urine, tissue, or other biological specimens collected from participants in prospective cohort studies. The existence of biological banks may make it possible to study a multitude of etiologic hypotheses, by comparing biochemical parameters measured in the biological specimens of subjects who will eventually develop the disease of interest ("cases") and of control subjects, using a nested case-control or a case-cohort design. In practice, however, the amount of biological material available per subject (in particular, that of cases) will limit the number of hypotheses that can be tested. The present paper discusses the use of a sequential t-test which, compared with an analogous fixed sample procedure, will on average require fewer biological specimens before a given study hypothesis can be accepted or rejected. The sequential test should thus facilitate an early decision on whether a new hypothesis is worth further investigation, while avoiding wasting too much biological material on testing hypotheses that may eventually prove unfruitful. If the test reveals an exposure difference of interest, the study may be extended so that relevant epidemiologic effect measures can be estimated more accurately.

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.

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.

Adjustment for bias due to errors in exposure assessments in multicenter cohort studies on diet and cancer: a calibration approach

An advantage of multicenter cohort studies on diet and cancer is that these may include populations over a wide range of dietary exposure. With some simplifying assumptions, the information from such multicenter studies may be divided into 1) estimated relationships within each of the separate cohorts, between individual-level measurements of dietary exposure and disease outcome, and 2) an estimated between-cohort relationship, between the mean intake measurements and mean incidence rates. Errors in the dietary exposure measurements may lead to different amounts of bias in each of these estimated relationships, in particular when dietary questionnaire methods cannot easily be standardized. A calibration approach can be used to adjust for such differences in bias. This will improve the relative weighting of within- and between-cohort components of evidence for a diet-disease association.

Influence of methodologic factors in a pooled analysis of 13 case-control studies of colorectal cancer and dietary fiber

We examined the study design features and data collection methods from 13 case-control studies of colorectal cancer and diet, which had been previously combined and analyzed, to determine whether they influenced the results obtained from a pooled analysis. We assessed the methods used in each study, estimated a quality score, and used random effects models to re-estimate the pooled odds ratio for the association between dietary fiber and colorectal cancer for these data. Key features of the methods used in each study and the quality score were examined in random effects models to determine whether the heterogeneity found between study-specific risk estimates could be explained by these variables. The odds ratio for dietary fiber and colorectal cancer was 0.46 (95% confidence interval = 0.34-0.64) for the 13 case-control studies as estimated with a random effects model. Two factors, whether the diet questionnaire had been validated before use in the case-control study and whether qualitative data on dietary habits and cooking methods had been incorporated into the nutrient estimation, explained some of the heterogeneity found between studies. Risk estimates for dietary fiber and colorectal cancer were closer to the null for the studies that had these two characteristics. Quality score did not explain any between-study heterogeneity. Random effects models, which included fixed effects covariates, explained some between-study heterogeneity in these data and would be useful for future pooled analyses.

Bladder cancer and coffee consumption in smokers and non-smokers in Spain

The association between coffee consumption and bladder cancer was investigated in a multi-centre case-control study conducted in Spain from 1983 to 1986. A total of 497 cases (438 male and 59 female) with histopathologically confirmed bladder cancer were used in the analysis along with 566 hospital controls and 547 population controls. Odds ratios (OR), adjusted for age, province of residence, occupations at risk, consumption of artificial sweeteners and cigarette smoking, did not show any association between coffee consumption and bladder cancer for either sex. However, in non-smokers and mainly in males, for current coffee drinkers the OR was 2.78 (95% [Cl]: 0.78-9.87), while for drinkers of 2-7, 8-14 and > or = 15 cups/week the respective OR were 2.22, 3.11 and 1.87 with a dose-response relationship for lifelong consumption and years of exposure to regular coffee consumption. The OR in male non-smokers and current coffee drinkers were 2.36 (95% Cl: 0.62-9.05) with population controls only and 1.94, 2.58 and 1.48 for the corresponding levels of intensity of consumption (cups/week). The associations observed in non-smokers suggest the existence of a possible association between coffee consumption and bladder cancer, but are based on small numbers and need to be confirmed in larger studies.

Indoor air pollution and lung cancer in Guangzhou, People's Republic of China

A case-control study comprising 224 male and 92 female incident lung cancer cases and the same number of individually matched hospital controls was conducted from June 1983 to June 1984 in Guangzhou, People's Republic of China, to evaluate the association between indoor air pollution and lung cancer risk. Guangzhou residents were exposed to several sources of pollution in their homes, most importantly to cooking fumes. Increased risks were found among subjects living in a house without a separate kitchen (the exposure odds ratio was 2.4 (95% confidence interval (CI) 1.4-4.2) for men and 5.9 (95% CI 2.1-16.0) for women). Similarly, living in a house with poor air circulation was associated with an exposure odds ratio of 2.1 (95% CI 1.2-3.8) for men and 3.6 (95% CI 1.4-9.3) for women. A trend in the association between lung cancer risk and factors pertaining to house and kitchen ventilation was observed, and a decreasing risk of lung cancer was observed for several variables indicating better ventilation, even after adjustment for potential confounders such as education, occupation, living area, smoking, and history of chronic respiratory diseases. No statistically significant differences were found between cases and controls for frequency of cooking at home, presence of a chimney in the kitchen, or type of cooking fuel. Smoking was clearly related to risk of lung cancer in both men and women, and among nonsmoking women, exposure to tobacco smoke from their spouses was also associated with an increased risk. These results suggest that, in addition to smoking, indoor air pollution may be a risk factor for lung cancer.

Dietary assessment methods evaluated in the Malmö food study

A study to evaluate the relative validity of two dietary assessment methods, to be used in a prospective cohort study on diet and cancer, was conducted in a random sample of the Malmö population during 1984-1985. The study compared (i) a long, self-administered 'food-use questionnaire' (about 250 food items), asking for frequency of consumption of food and beverages and for usual portion size estimated with the help of a booklet of food pictures, and (ii) a combined method involving a shorter food frequency questionnaire (about 130 food items) and a 2-week diet diary, with (iii) a reference method requiring 18 days of weighed food records. The results indicated that subject compliance was quite good for both methods and, in particular, that the diet diary was well accepted. Both methods produced fairly good correlations with the reference method, of the order of 0.40 to 0.60 for most nutrients after adjustment for energy. Both methods tended to overestimate intake of fat, protein and carbohydrates as well as of vitamins and minerals.

Nutrition and cancer: background and rationale of the European Prospective Investigation into Cancer and Nutrition (EPIC)

The development of epidemiological research on diet and cancer during the last decades is discussed. Apart from some consistent data on the protection against several cancers conferred by a diet rich in fruits and vegetables, the results provided by retrospective case-control studies on diet and cancer remain contradictory on many important issues, and primarily on the relation between diet and breast cancer. The rationale is presented for setting up large prospective cohort studies combining epidemiological and laboratory methods in order to expand the presently limited knowledge of the role of nutrition and related factors in cancer etiology. The main features of the European Prospective Investigation into Cancer and Nutrition are outlined. The study is being carried out in seven European countries and it will collect data on diet, other lifestyle and environmental factors, anthropometry as well as biological samples in a cohort of about 400,000 healthy European adults. The subjects will be followed up to investigate the incidence of and mortality from cancer in relation to epidemiological data and biochemical markers.

Active and passive smoking and pathological indicators of lung cancer risk in an autopsy study

OBJECTIVE

The association between involuntary smoking and lung cancer has been supported by most epidemiologic studies, but a number of authors and interest groups claim that the possibility of bias has not been excluded. Few autopsy-based studies have explored the role of active smoking and other exposures in lung carcinogenesis, and none has been previously done to examine the role of passive smoking. We have undertaken such an autopsy-based study in Athens, Greece.

DESIGN

Lung specimens were taken at autopsy from 400 persons 35 years of age or older, of both genders, who had died within 4 hours from a cause other than respiratory or cancer in Athens or the surrounding area. For each person at least seven tissue blocks were taken from the main and lobar bronchi and at least five blocks from the parenchyma, including an average of about 20 smaller cartilaginous bronchi and membranous bronchioles. The specimens were examined without knowledge of the exposures of the particular subject in Turin, Italy. For 283 (71%) of the subjects the preservation of the bronchial epithelium was satisfactory for pathological examination, and for 206 among them (73%) an interview could be arranged with their next of kin, focusing on smoking habits of the deceased and their spouses, as well as other variables. The interviewers were not aware of the results of the pathological examinations.

MAIN OUTCOME MEASURE

Specimens were examined for basal cell hyperplasia, squamous cell metaplasia, cell atypia, and (in membranous bronchioles and bronchiolo-alveolar airways) mucous cell metaplasia, ie, pathological entities that may be lung cancer risk indicators or epithelial, possibly precancerous, lesions (EPPL). The gland and wall thicknesses were also measured and their ratio calculated (Reid Index).

RESULTS

In comparison with nonsmokers, EPPL values were significantly higher among current smokers and higher, but not significantly so, among former smokers. Furthermore, EPPL values were significantly higher among deceased nonsmoking women married to smokers rather than to nonsmokers. In this set of data neither occupation nor residence was associated with EPPL, but this could be due to the poor correlation of residential history with exposure to air pollution and the lack of adequate standardization of contemporary Greek occupations. The Reid Index was higher among smokers and former smokers in comparison with nonsmokers, among subjects with mainly urban residence in comparison with those with mainly rural residence, and among nonsmoking women married to smokers in comparison with those married to nonsmokers, but none of these differences was statistically significant.

CONCLUSION

These results provide support to the body of evidence linking passive smoking to lung cancer, even though they are based on a study methodologically different from those that have previously examined this association.

Validation of a method for the estimation of food portion size

In the context of the planning phase of a large cohort study on dietary habits and cancer, we have developed a food frequency questionnaire on usual food intake, which includes a set of pictures to estimate the portion size of 23 different dishes. The validity of the estimation of portion size of recently consumed foods has been questioned by other researchers. To validate the use of pictures, we organized a field trial with 103 volunteers. They were invited to a dinner where standard Italian dishes were offered (total 17 foods); all of the portions they chose were recorded and weighed. The following day, we interviewed the volunteers on what they consumed during the dinner, and we compared the weight of the food actually eaten with the weight of the food represented in the pictures. The volunteers overestimated the portion size by more than 20% for six foods and underestimated the portion size by more than 20% for four foods. In addition, we found a tendency toward overestimation of portion size by those who ate smaller portions and underestimation, by those who ate larger portions ("flat slope syndrome").

Diet and gastric cancer. A case-control study in Belgium

A case-control study was carried out in 2 Belgian provinces with contrasting gastric-cancer mortality. The results were analyzed for the total study group and also separately in each of the 4 sub-groups: men and women in each province. Only risks which appeared consistently in at least 3 of these 4 sub-groups were retained in the discussion. Consumption of most vegetables, either cooked or raw, and of fresh fruit was found to be protective. There was an increased risk associated with meal and flour products, including white bread. Added sugar also increased the risk of gastric cancer. Consumption of lean meat was associated with a decreased risk. There was no clear effect for most sources of fat, but for oils with a high P/S ratio there was a decreased risk. Together with our earlier finding on salt, these results are to a large extent similar to those of other recent studies on gastric cancer.

Dietary factors and stomach cancer in Spain: a multi-centre case-control study

A multi-centre case-control study of diet and gastric cancer was carried out in 4 regions of Spain (Aragon, Castile, Catalonia and Galicia). We selected 354 cases of pathologically confirmed gastric adenocarcinoma from 15 hospitals, representative of nearly all those in the study areas. A control for each case, matched by age, sex and area of residence, was selected from the same hospital as the case. Habitual diet was investigated by the dietary history method, and past diet by means of a frequency questionnaire. The results regarding consumption of food items are presented here. With respect to habitual diet, an increase in risk was associated with consumption of preserved fish, cold cuts and oleaginous fruits. A high intake of cooked green vegetables, fresh noncitrus fruit and dried fruit showed an inverse association with the risk of gastric cancer. Simultaneous intake of 2 groups of food which increase or decrease the risk of cancer strengthens the respective individual effect. The intake of protective food items seems to neutralize the effects of food items which increase risk. With reference to past diet, a possible protective effect was observed for daily consumption of fresh fruit and green vegetables.

Tobacco smoke inhalation pattern, tobacco type, and bladder cancer in Spain

The association between tobacco smoking and bladder cancer was investigated in a multicenter case-control study conducted in five provinces of Spain between 1983 and 1986. A matched analysis was carried out in males, based on 430 histologically confirmed cases, 405 hospital controls, and 386 population controls, matched by age and place of residence. An increased risk was found for smokers as compared with nonsmokers (odds ratio (OR) = 3.79, 95% confidence intervals (CI) 2.41-5.97), and this increase was significantly associated with the intensity of smoking. Smokers of filter-tipped cigarettes had a reduced risk as compared with smokers of non-filter-tipped cigarettes (OR = 0.57, 95% CI 0.32-1.02). A diminution of risk was also observed for smokers of low-tar and low-nicotine ("light") cigarettes. Depth of inhalation was strongly associated with illness. No difference was shown in the logistic regression model between smokers of black tobacco and smokers of blond tobacco after controlling for depth of inhalation. Although the number of persons who smoked blond tobacco exclusively was small, the results suggest that it is important to consider inhalation patterns when studying risk variations between smokers of black tobacco and smokers of blond tobacco. The age at which a person started to smoke did not appear to affect risk. An analysis of the decrease in risk associated with years since quitting smoking suggested that different components of cigarette smoke may play a role at different stages of the carcinogenic process.

Diet and bladder cancer in Spain: a multi-centre case-control study

A multi-centre case-control study on bladder cancer and diet was carried out in 5 regions of Spain. We report results on 432 male cases and 792 matched controls. Usual dietary habits were investigated by means of an interview-based dietary history questionnaire. Bladder-cancer cases were selected from the registers of 12 hospitals located in the study areas. Each case was matched by sex, age and area of residence to 2 controls, one identified in the same hospital and one drawn from population lists. Descriptive analyses indicated that the average dietary pattern was typical of Mediterranean populations: a high P/S ratio, high intake of fish, fruits and vegetables and moderate or low intake of meat and dairy products. Relative risks for specific foods and nutrients were adjusted for tobacco smoking and energy intake. Subjects in the highest quarter of intake of saturated fat had a significantly increased risk of bladder cancer (RR for highest quarter = 2.25; 95% CI = 1.42 to 3.55). Moderate increases in risk for high intake of mono-unsaturated fats and calcium, and a slight decrease for iron were also found, but these disappeared after adjustment for saturated fat. Intake of vitamin E was related to slightly reduced risk (RR for highest quarter = 0.72; 95% CI = 0.48 to 1.09) which was not modified by adjustment for fat. No association was found with intake of retinol or carotene. These results, along with those of previous studies, suggest that saturated fat intake may influence the occurrence of bladder cancer.

A community study of alcohol consumption and dietary habits in middle-aged Italian women

This population-based study examines whether dietary intake in middle-aged Italian women is influenced by alcohol drinking habits. The 499 participants were interviewed using a dietary history questionnaire designed to investigate alcohol consumption. Mean intake of total and non-alcohol energy increased progressively within categories of increasing alcohol consumption (less than 5, 5-19, 20-39, 40+ g/day). Mean body weight and Quetelet index (kg/m2), however, decreased with increasing alcohol consumption. Once the disparities in energy intake were reduced by computing intake densities, the data suggest that moderate and heavy drinkers have dietary habits similar to those of abstainers or light drinkers. These findings were confirmed by multiple linear regression analyses in which the confounding effects of age, place of residence, occupation, and Quetelet index were taken into account. Increasing alcohol consumption appeared associated only with a modest decrease in the intake of fibre, beta-carotene, and vitamin C. These findings do not support the hypothesis that the observed protection from coronary artery disease among moderate drinkers is related to a chronic reduction in the intake of carbohydrates and fat, at least in middle-aged women.

Cancer and polyps of the colorectum and lifetime consumption of beer and other alcoholic beverages

Two parallel case-control studies were conducted in the Marseilles metropolitan area of France from 1979 to 1985 on cancers and adenomatous polyps of the colorectum. All cases of cancer (n = 389) and polyps (n = 252) were incident and histologically confirmed. Controls (n = 641) matched for sex and age were selected among patients undergoing functional reeducation for injury or trauma in one of five hospital centers. Intake of alcoholic beverages was investigated by questions on daily or weekly intake of wine, beer, apéritifs, and distillates during different life periods. Questions on alcoholic beverages were integrated in a detailed diet history interview questionnaire. The risk of rectal cancer was elevated in male beer drinkers (relative risk = 1.73, 95% confidence interval 1.01-2.95) and in men and women combined (relative risk = 1.71), while beer consumption was not associated with colon cancer. Total ethanol intake and consumption of wine and distillates were not associated with the risk of cancer of the colon or rectum, nor with risk of polyps. Adjustment in the statistical analysis for energy intake and for other dietary variables (fiber from fruits and fiber from vegetables), which were found to be risk factors in the study, did not substantially change the results found for beer and other alcoholic beverages. Etiologic hypotheses related to nitrosamine content of beer are discussed in the light of growing epidemiologic evidence that beer consumption specifically increases the risk of rectal cancer.

The association between alcohol and breast cancer risk: evidence from the combined analysis of six dietary case-control studies

Data from 1,575 cases and 1,974 controls enrolled in 6 previously conducted case-control studies of diet and breast cancer have been analysed with respect to alcohol intake. There appears to be an absence of any association between consumption of up to 40 g of alcohol per day and risk of breast cancer, and a highly statistically significant and consistent elevated risk of breast cancer for drinkers of 40 g or more of alcohol per day, for whom the relative risk, as compared with that of non-drinkers, is 1.69 (95% confidence interval 1.19 to 2.40). This association is not due to confounding by a number of diet-related factors, including total calories, fat, fibre and vitamin C.

A case-control study of air pollution and tobacco smoking in lung cancer among women in Athens

BACKGROUND

A case-control study exploring the role of smoking and outdoor air pollution in the causation of lung cancer, by histologic type, in nonsmoking women, was undertaken in Athens between 1987 and 1989.

METHODS

One hundred one women with lung cancer and 89 comparison women with fractures or other orthopedic conditions, all permanent residents of Greater Athens, were included in the study. Smoking habits were ascertained through interviews, whereas lifetime exposure to air pollution was assessed by linking blindly lifelong residential and employment addresses of all subjects with objectively estimated or presumed air pollution levels.

RESULTS

The age-adjusted relative risk and 95% confidence intervals for lung cancer among current smokers compared with nonsmokers was 3.40 (1.75-6.61); it was 7.43 (2.88-19.13) among those smoking for more than 30 years and 7.46 (2.40-23.17) among those smoking more than 20 cigarettes per day. The age-adjusted relative risk was 1.70 (0.75-3.89) for adenocarcinoma and 6.45 (2.73-15.25) for other histologic types of lung cancer; statistically significant dose-response trends were evident for both histologic groups. Air pollution levels were associated with increased risk for lung cancer but the relative risk was small and statistically not significant. However, when both air pollution and duration (or quantity) of tobacco smoking, as well as their interaction, were introduced in a multiple logistic regression model, the interaction term was significant at the suggestive level of 0.10.

CONCLUSION

Whereas there is no effect of air pollution among nonsmokers, the relative risk contrasting extreme quartiles of air pollution among smokers of 30 years duration was 2.23. The interaction was almost exclusively accounted for by the nonadenocarcinoma lung tumors.

Urinary infection, renal lithiasis and bladder cancer in Spain

A case-control study on bladder cancer was carried out in 12 hospitals located in 4 regions of Spain. The study included 497 cases and 530 population controls, matched by sex, age and residence. The present paper reports the results regarding the risk for bladder cancer in relation to history of infections and lithiasis of the urinary tract. Increased risk was found for infections starting 4 years or less before diagnosis (OR = 15.00; 95% CL: 6.07-51.66) but no statistically significant increase in risk was observed for infections starting 5 or more years before (OR = 1.44; 95% CL: 0.86-2.47). Our data suggest that the association of urinary infections with bladder cancer is probably not causal and is more likely to be a consequence of cancer, although a weak causal association cannot be excluded. A small but not statistically significant increase in risk was found to be associated with a history of renal lithiasis.

Exposure of nonsmoking women to environmental tobacco smoke: a 10-country collaborative study

The interpretation and interpretability of epidemiologic studies of environmental tobacco smoke (ETS) depend largely on the validity of self-reported exposure. To investigate to what extent questionnaires can indicate exposure levels to ETS, an international study was conducted in 13 centers located in 10 countries, and 1,369 nonsmoking women were interviewed. The present paper describes the results of the analysis of self-reported recent exposure to ETS from any source in relation to urinary concentrations of cotinine. Of the total, 19.7 percent of the subjects had nondetectable cotinine levels, the median value was 6 ng/mg, and the cut-point of the highest decile was 24 ng/mg. The proportion of subjects misreporting their active smoking habit was estimated at between 1.9 and 3.4 percent, depending on whether cut-points of 50 or 100 ng/mg creatinine were used. Large and statistically significant differences were observed between centers, with the lowest values in Honolulu, Shanghai, and Chandigarh, and the highest in Trieste, Los Angeles, and Athens. Mean cotinine/creatinine levels showed a clear linear increase from the group of women not exposed either at home or at work, to the group of those exposed both at home and at work. Values were significantly higher for women exposed to ETS from the husband but not at work, than for those exposed at work but not from the husband. The results of linear regression analysis indicated that duration of exposure and number of cigarettes to which the subject reported being exposed were strongly related to urinary cotinine. ETS exposure from the husband was best measured by the number of cigarettes, while exposure at work was more strongly related to duration of exposure. After adjustment of number of cigarettes for volume of indoor places, a similar increase in cotinine (5 ng/mg) was predicted by the exposure to 7.2 cigarettes/8 h/40 m3 from the husband and 17.9 cigarettes/8 h/40 m3 at work. The results indicate that, when appropriately questioned, nonsmoking women can provide a reasonably accurate description of ETS exposure. Assessment of individual exposure to ETS should focus on daily duration and volume of indoor places where exposure occurred.

Hospital versus neighbourhood controls in the assessment of dietary risk factors

The selection of the best control group is a major concern in the design of any case-control study, because of its enormous implications on both interval validity and cost. We compare the dietary habits of hospital and neighbourhood control groups which had both been used in a case-control study on bladder cancer. The analysis is based on 485 matched sets. No differences were observed between the two groups in terms of nutrient consumption nor in consumption of specific foods or food groups. Alcohol consumption represents an exception. This may be attributed to the use of incorrect exclusion criteria given that alcohol consumption was not one of the major determinants of the original study. We conclude that, provided correct exclusion criteria are used, hospital controls may be a suitable as neighbourhood controls in the assessment of dietary risk factors in case-control studies in Spain.

Breast cancer and alcohol consumption: a case-control study in northern Italy

From 1983 to 1986, a population-based case-control study of alcohol and breast cancer (250 cases and 499 controls) was conducted in a grape-farming area of northern Italy, where wine consumption is widespread. In the study population, 30% of women were abstainers and 15% reported alcohol intakes of 30 g/day or more. After adjustment for potential confounders, no appreciable association was evident for alcohol consumptions as high as 40 g/day. Women reporting intakes of more than 40 g/day showed approximately a 2-fold increase in the risk of breast cancer (relative risk, 1.9; 95% confidence interval, 1.1-3.3). A 2-fold increase in risk was observed for consumptions of more than 40 g/day of alcohol from wine, the most common alcoholic beverage in this population. These findings suggest that an association between alcohol intake and breast cancer may exist. However, the moderate risk observed seems to be limited to the relatively small group of women consuming daily amounts of alcohol in excess of 40 g, the equivalent of about half a bottle of wine or more.

Occupation and bladder cancer in Spain: a multi-centre case-control study

A case-control study on bladder cancer was carried out in four regions of Spain. The study included 497 cases (438 males and 59 females), 583 hospital controls and 530 population controls matched by sex, age and residence. The present paper reports the results of the analyses on occupational history. Among men, an increased risk of bladder cancer was found for textile workers (OR = 1.97, 95% CL 1.2-3.3), mechanics and maintenance workers (OR = 1.86, 95% CL 1.2-2.8), workers in the printing industry (OR = 2.06, 95% CL 1.0-4.3) and for managers (OR = 2.03, 95% CL 1.2-3.5). The risk was highest among those first employed in the textile industry before the age of 25 and prior to 1960. Among mechanics the risk was highest for those who started after the age of 25 and later than 1960. The OR for smokers who had also been employed in one of the high risk occupations was 7.82 (95% CL 4.4-14.0) which is compatible with a multiplicative effect of joint exposure to tobacco and occupational hazards.

[Design and implementation of a multicenter case-control study on bladder cancer in Spain]

The aim of a case-control design is to make a measurement of the highest possible accuracy, reducing to a minimum the possible selection, information and confusion biases. The design, methods and procedures of a multicentric study carried out in 14 hospitals from 4 autonomous communities in Spain are discussed. Overall 254 incident cases, 243 prevalent cases, 583 hospital controls and 530 population controls were included. The proportion of nonresponders was somewhat higher in population controls, particularly in large cities. Statistically significant differences between cases and controls were not found for socioeconomic levels, educational level, number of jobs, degree of response, duration of the interview, and errors of transcription and codification of information. Also, significant differences were not found between the population and hospital controls regarding diet habits and cigarette smoking. It is considered that a non-biased measurement of the association can be obtained from cases and hospital controls. The collected information was satisfactory. In spite of the lack of adequate facilities for research in hospitals, the development of multicentric etiologic studies is feasible.

Calorie-providing nutrients and risk of breast cancer

A case-control study was conducted in Italy to investigate the role of diet in breast cancer. Cases were 250 women with breast cancer, and controls were a stratified random sample of 499 women from the general population. A dietary history questionnaire was used to measure the intake of total fat, saturated fat, animal proteins, and other macronutrients. In multivariate analyses, the relative risks of breast cancer for women in the highest quintile of consumption of saturated fat and animal proteins were 3.0 (95% confidence interval, 1.9-4.7) and 2.9 (1.8-4.6), respectively. A reduced risk was found for women who derived less than 28% of calories from fat versus greater than 36%. A similarly reduced risk was found for women who derived less than 9.6% of calories from saturated fat or less than 5.9% from animal proteins. These data suggest that during adult life, a reduction in dietary intake of fat and proteins of animal origin may contribute to a substantial reduction in the incidence of breast cancer in population subgroups with high intake of animal products.

Passive smoking and lung cancer: current evidence and ongoing studies at the International Agency for Research on Cancer

The evidence available from 3 cohort and 11 case-control studies investigating the relationship between exposure to environmental tobacco smoke (ETS) and lung cancer in non-smokers is reviewed. While it appears most likely that a causal relationship exists, the size of the effect, under different circumstances of exposures, remains to be accurately estimated. This requires studies using valid instruments (e.g., questionnaires) to quantitate exposures, and free as far as possible from biases. An investigation addressing this point is in progress under the coordination of the International Agency for Research on Cancer.

Bladder cancer among workers in the textile industry: results of a Spanish case-control study

This paper presents results from a case-control study carried out in the county of Mataro, Spain. The study was designed to investigate the possible causes of an unusually high mortality rate from bladder cancer in Mataro county as compared to Spain as a whole, and this report focuses on occupational exposures. The study is based on 57 cases who were hospitalized for or died from bladder cancer between 1978 and 1981. Two controls per case were matched for sex, age, residence, and date of either hospitalization or death. Information was collected on smoking, coffee drinking, and occupation. Occupational histories were then evaluated and coded blind by a group of occupational health physicians. Analyses were carried out by means of conditional logistic regression. Among a group of common occupational sectors, an increased risk for past employment in the textile industry (OR = 2.2; p = .038) was found. Further analyses indicated that the risk is particularly elevated (OR = 4.41; 95% confidence limits; 1.15-16.84) for subjects who worked in dyeing or printing and who were most probably exposed to azo-dyes. Exposure in the textile industry may be responsible for 16% of the bladder cancers in the Mataro area. A list of dyes commonly used in the Mataro textile industries was compiled and cross-checked with lists of substances tested or evaluated for carcinogenesis.