Albert J. Tuyns

Colorectal cancer and the consumption of foods: A case‐control study in Belgium

A case-control study on 453 cases with colon cancer, 365 with rectal cancer, and 2,851 population controls was carried out in two Belgian provinces known to differ in certain dietary habits, particularly with regard to the use of butter. All raw vegetables had a clear protective effect for both colon and rectal cancer; bread was also protective for colon cancer. Starchy foods and foods rich in oligosaccharides (sugar) caused an increased risk for both colon and rectal cancer. No other foods were found to have a systematic effect in both sexes and in both provinces, either in one direction or in the other, except for maize, soybean, and sunflower oils, which were clearly protective in all cases. Among the foods contributing to the intake of fats, there was no effect either for butter, margarine, or fatty meats; the only clear-cut protective effect was that of the oils having a high polyunsaturated-to-saturated ratio. These findings are consistent with our previous findings on the role nutrients play in the relationship with colon and rectal cancers.

The relationship between dietary fat intake and risk of colorectal cancer: evidence from the combined analysis of 13 case-control studies

The objective of this study was to examine the effects of the intakeof dietary fat upon colorectal cancer risk in a combined analysis of datafrom 13 case-control studies previously conducted in populations withdiffering colorectal cancer rates and dietary practices. Original datarecords for 5,287 cases of colorectal cancer and 10,470 controls werecombined. Logistic regression analysis was used to estimate odds ratios (OR)for intakes of total energy, total fat and its components, and cholesterol.Positive associations with energy intake were observed for 11 of the 13studies. However, there was little, if any, evidence of anyenergy-independent effect of either total fat with ORs of 1.00, 0.95, 1.01,1.02, and 0.92 for quintiles of residuals of total fat intake (P trend =0.67) or for saturated fat with ORs of 1.00, 1.08, 1.06, 1.21, and 1.06 (Ptrend = 0.39). The analysis suggests that, among these case-control studies,there is no energy-independent association between dietary fat intake andrisk of colorectal cancer. It also suggests that simple substitution of fatby other sources of calories is unlikely to reduce meaningfully the risk ofcolorectal cancer.

Colorectal Cancer and the Intake of nutrients: Oligosaccharides are a risk factor, fats are not. a case-control study in belgium

A case-control study was carried out in the populations of two Belgian provinces that differed in food consumption habits, particularly fat intake. There were 453 colonic and 365 rectal cancer cases and 2,851 population controls. There were no significant differences in the average intake of the major nutrients, with the exception of carbohydrates; patients had a larger intake, limited to oligosaccharides. In both provinces, in males and females having cancer of the colon or the rectum, the intake of linoleic acid was lower than among controls; for dietary fibers, a smaller intake was observed among patients in one province. The relative risks were computed for four levels of daily intake of each nutrient. A positive trend was found for oligosaccharides in all subgroups, and a negative trend was found for polysaccharides, the latter for colon cancer patients only. There was a constant and significant negative trend for linoleic acid, with a similar negative trend for dietary fiber. None of these trends were affected by further adjustment for total calorie intake. For several vitamins and minerals, less marked, less constant effects were observed. They tended to be negative for vitamin B1, vitamin B6, and iron; they were positive for retinol and vitamin B2.

Diet and esophageal cancer in calvados (France)

The role of nutrients and food factors in relation to esophageal cancer was observed in a large case-control study in a region having a high incidence of the disease. Several factors that increased or decreased the risk were identified. After adjusting for other covariates, we found that animal proteins and polyunsaturated fats had a significant protective effect. Separating the effects of specific nutrients was difficult because of the intercorrelation between individual intakes of most nutrients. Foods were not so highly intercorrelated. Fresh meat, citrus fruits, and oil were found to be protective. A dietary index combining these foods was used; between the lowest and the highest levels of intake, a nine-fold difference in risk was observed. This effect is added to that of alcohol, which remains the major risk factor. The adequacy of the concepts of nutrients and foods in epidemiological studies is discussed in addition to the theoretical and practical implications of the findings.

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.

Nutrient intake patterns and gastric cancer risk: a case-control study in Belgium.

A case‐control study on gastric cancer risk in relation to nutrient composition of diet was conducted in the 2 Belgian provinces of Oost‐Vlaanderen and Liège as part of a large epidemiological study on cancers of the digestive tract, also including colorectal cancer. The statistical analysis was carried out on a total of 301 men and women aged 35–74 years with histologically confirmed stomach tumors and 2,851 population controls. Dietary intake assessments were obtained by interview, using a dietary history questionnaire. Gastric cancer risk was increased for diets rich in mono‐ and disaccharides, according to statistical models based on energy‐adjusted residuals [odds ratio (OR) = 1.88 for upper vs. lower quartiles of energy‐adjusted intakes] or energy decomposition models, but showed no increase for high intake of polysaccharides. Intake of polyunsaturated fats, particularly linoleic acid, was inversely associated with gastric cancer risk. High intake of vitamin C, beta carotene and vitamins B1 (thiamine), B3 (nicotinic acid) or B6 (pyridoxine) was also associated with decreased risk, whereas increased risk was observed for high intake of vitamin A (retinol) or vitamin B2 (riboflavin). Many of these associations between gastric cancer risk and nutrient composition were similar to those found in the analysis of a parallel study on cancers of the colon and rectum. Int. J. Cancer 78:415–420, 1998.

Salt and gastrointestinal cancer

This study reports on the taste for salt among patients with gastric, colon, or rectal cancers and among population controls, within the scope of an investigation on those cancers in two Belgian provinces. Among people who systematically added salt to their food, the relative risks observed were as follows: 1.78 for gastric cancer, 1.53 for colon cancer, and 1.74 for rectal cancer. Even though all three were statistically significant, these increases are moderate and may be due to interaction with other, as yet unknown casual factors.

Occupation and larynx and hypopharynx cancer: a job-exposure matrix approach in an international case-control study in France, Italy, Spain and Switzerland

Objective: To investigate the effect of exposure to occupational agents on the risk of hypopharyngeal/laryngeal cancer. Methods: Case-control study conducted during 1979–1982 in six centres in South Europe. An occupational history and information on exposure to non-occupational factors were collected for 1010 male cases of hypopharyngeal/laryngeal cancer as well as for 2176 population controls. The exposure to 10 occupational agents was assessed through a job-exposure matrix. As occupational histories had been collected since 1945 major analyses were restricted to subjects aged less than 55 years (315 cases and 819 controls). Results: Significant elevated risks adjusted for non-occupational variables (smoking, alcohol consumption and diet) and other occupational exposures were consistently found for organic solvents (odds ratio (OR) for ever-exposure: 1.7, 95% confidence interval: 1.1–2.5) and asbestos (OR: 1.6, 1.0–2.5). A significant positive trend for both probability of exposure and duration was found for exposure to solvents. A positive association between exposure to formaldehyde and laryngeal cancer was also suggested. No association was found for exposure to arsenic and compounds, chromium and compounds, and polycyclic aromatic hydrocarbons. Analyses restricted to subjects aged 55 or more did not show elevated risks, with the exception of wood dust (OR: 1.8, 1.3-2.7). Conclusions: In our study occupational exposure to solvents was associated with an increased risk of hypopharyngeal/laryngeal cancer. Results also provide additional evidence of an excess of risk for exposure to asbestos.

Occupation and larynx and hypopharynx cancer: an international case–control study in France, Italy, Spain, and Switzerland

Objective: To estimate risks for laryngeal/hypopharyngeal cancer associated with occupational titles and industrial activities. Methods: A multicentre population-based case-control study was conducted in the early 1980s in six southern European areas. Analyses included 1010 male cases and 2176 controls. Odds ratios (ORs) (adjusted for age, study area, tobacco consumption, and alcohol consumption) were estimated for 156 occupations and 70 industrial activities. Results: An excess risk has been confirmed for categories of construction workers, potters (OR: 5.91, 95% confidence intervals 1.46-24.0), butchers (2.53, 1.22–5.22), barbers (2.33, 1.00–5.40), laborers not otherwise specified (1.52, 1.12–2.06), as well as for men who had been employed in railway transport (1.52, 0.97–2.39), shipbuilding (2.05, 0.89–4.94), and hotels (2.06, 0.89–4.75). An association was also found for shoe finishers (3.23, 0.75–13.9), loggers (2.07, 0.87–4.90), and some groups of metal workers. ORs for loggers, butchers, railway transport workers, laborers, and reinforced concreters increased with duration of employment. The suggestion of a risk for machine operators among woodworkers (3.10, 0.92–10.5) conflicts with previous findings. No significant excess of risk was found for categories previously reported to be associated with laryngeal and hypopharyngeal cancer, such as drivers, mechanics, welders, machinists, and painters. Conclusions: The present study provides additional evidence to the hypothesis of a risk of cancer of the larynx/hypopharynx for workers engaged in jobs in the construction, metal, textile, ceramic, and food industries and in railway transport. Loggers were also found at risk; a previously unreported finding.

Cancer risks derived from alcohol.

Most cancers of the upper aero-digestive tract are related to alcohol consumption. For the mouth, oesophagus and larynx a positive dose-response relationship has been observed, as well as a combination effect with tobacco smoking—according to a multiplicative model in the case of the oesophagus. Nutritional factors also play a role. For other cancer sites, the role of alcohol is controversial, except for primary liver cancer which often develops on a cirrhotic liver. The mechanisms by which alcohol increases cancer risk are still obscure. It is not considered to be a carcinogen by itself but rather as a co-carcinogen, facilitating or enhancing the role of other carcinogens. Another mechanism might be the induction of microsomal enzymes activating pro-carcinogens. As in the case for smoking, prevention can be achieved by abstention or reduction of consumption. This has to be considered seriously in countries where alcohol consumption is increasing.