A. Decarli

The European mesothelioma epidemic.

SummaryProjections for the period 1995–2029 suggest that the number of men dying from mesothelioma in Western Europe each year will almost double over the next 20 years, from 5000 in 1998 to about 9000 around 2018, and then decline, with a total of about a quarter of a million deaths over the next 35 years. The highest risk will be suffered by men born around 1945–50, of whom about 1 in 150 will die of mesothelioma. Asbestos use in Western Europe remained high until 1980, and substantial quantities are still used in several European countries. These projections are based on the fit of a simple age and birth cohort model to male pleural cancer mortality from 1970 to 1989 for six countries (Britain, France, Germany, Italy, The Netherlands and Switzerland) which together account for three-quarters of the population of Western Europe. The model was tested by comparing observed and predicted numbers of deaths for the period 1990–94. The ratio of mesothelioma to recorded pleural cancer mortality has been 1.6:1 in Britain but was assumed to be 1:1 in other countries.

Selected micronutrient intake and the risk of colorectal cancer.

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

Nutrition, social factors and prostatic cancer in a Northern Italian population

The relationship between prostate cancer and indicators of nutrition, diet and social factors was evaluated in a case-control study of 166 patients with histologically confirmed prostatic carcinoma and 202 control subjects hospitalized for acute diseases other than malignant, hormonal or urogenital. The relative risk increased with increasing body mass index, men being moderately overweight showing a 2.3 elevated risk, and those grossly overweight an over four-fold higher risk of prostate cancer, when allowance was made for several identified potential confounding factors. Cases also reported more frequent consumption of milk and other dairy products and meat, but no significant difference was noted for vegetable intake. The risk of prostate cancer was unrelated to marital status or indicators of social class based on occupation.

Short term increase in risk of breast cancer after full term pregnancy.

To determine whether there is a short term increase in the risk of breast cancer after a full term birth data from two hospital based, case-control studies in Italy were pooled. Analysis was restricted to women aged under 50 with two or more children (573 women with cancer and 570 controls). A relative risk for breast cancer of 2.66 was seen in women who had given birth during the three years preceding the interview compared with women whose last birth had occurred 10 or more years before, after adjustment for age, age at first birth, and parity. The relative risk slowly decreased for women who had last given birth three to 10 years before. Multivariate analyses confirmed the protective effect of an early age at first birth and the age dependent effect of parity on the risk of breast cancer--that is, a direct relation below age 40 and an inverse one in older women. These data provide epidemiological evidence that a full term birth is followed by a transient increase in the risk of breast cancer, which for some time contrasts with and overcomes the long term protection of pregnancy at an early age. They therefore confirm predictions from animal studies and theoretical models that pregnancy prevents the early stages of breast carcinogenesis but promotes the late stages of the process.

Dietary factors and the risk of breast cancer

We evaluated the risk of breast cancer in relation to the frequency of consumption of a few selected dietary items. Data were used from a case-control study of 1,108 histologically confirmed breast cancer patients and 1,281 control subjects who were in the hospital for acute conditions unrelated to any of the established or suspected risk factors for breast cancer. Moderately elevated risk estimates were associated with higher levels of fat consumption in seasonings [butter, margarine, and oil, relative risk (RR) = 1.34, 95% confidence interval (CI) = 1.06-1.71] and meat (RR = 1.36, 95% CI = 1.12-1.65), whereas a reduced risk (RR = 0.42, 95% CI = 0.34-0.51) was associated with a more frequent green vegetable consumption. It was not possible to show that these associations were incidental, because allowance for several identified potential confounding factors, including the major identified or potential risk factors for breast cancer, did not materially modify the risk estimates. Further, no appreciable interaction emerged with age or menopausal status, because the diet-related risk estimates were similar in pre- or postmenopausal women. However, the implications of these findings in terms of specific micronutrients (e.g., retinol or beta-carotene) and biological correlates are still unclear. Alcohol consumption was significantly greater among breast cancer cases, with a multivariate risk estimate of 2.92 for the highest level. Thus, the present findings confirm that various aspects of diet may influence the risk of breast cancer, although the small amount of available knowledge does introduce serious uncertainties in any discussion of the potential implications in terms of prevention on a public health scale.

Social factors, diet and breast cancer in a northern Italian population.

The relation of breast cancer to social and dietary variables was evaluated in a case-control study of 368 women with breast cancer admitted to the General Hospital of Pordenone (a town in the eastern side of Northern Italy) and 373 age-matched controls. Occupation was related to the risk of breast cancer, housewives and non-manual workers (teachers and other professionals, clerical workers, etc.) showing relative risks of 1.7 and 2.4 respectively when compared to women occupied in agriculture. The role of education was apparently less important, and not statistically significant. The risk was higher in women who were obese, the trend of increasing risk with increasing body mass index being confined to post-menopausal women. When indicators of dietary fat intake were analysed, a significantly increased risk was found with more frequent consumption of milk and dairy products but the risk estimates were only slightly above unity with reference to meat consumption. Women who drank alcoholic beverages showed a relative risk of 2.5 compared to women who had never drunk, when allowance was made for all identified potential confounding factors. The association between alcohol and breast cancer was not explained by the other dietary variables considered, and the risk estimates were higher for women who drank more wine, or more than one type of alcoholic beverage. Thus, the findings of the present study give evidence in favour of the hypothesis that alcohol consumption is related to the risk of breast cancer.

Body weight and the prevalence of chronic diseases.

The relation between body mass index and prevalence of 17 chronic diseases or groups of diseases was analysed using data from the 1983 Italian National Health Survey, based on a sample of 72,284 individuals aged 15 or over randomly selected within strata of geographical area, size of place of residence and of household in order to be representative of the whole Italian population. The prevalence of diabetes was directly and strongly related to body weight (age-adjusted relative risk estimates being 1.5 for overweight and 2.7 for obese men compared with normal weight individuals; 1.6 and 2.4 for overweight and obese women). Other conditions directly related to self-reported measures of body weight were hypertension (relative risk = 1.7 for obese men and 1.9 for women), myocardial infarction (relative risk = 1.5 for obese men, 1.6 for women), other heart diseases (relative risk = 1.7 for obese men, 1.5 for women), haemorrhoids or varices (relative risk = 1.2 for obese men, 1.5 for women), cholelithiasis (relative risk = 1.2 for obese men, 1.4 for women), urolithiasis and arthritis. Chronic respiratory disorders showed a U-shaped relation to measures of body weight, since their prevalence was elevated in both under- and over-weight individuals. Anaemias and gastroduodenal ulcer showed an inverse relation to body weight, whereas no association was apparent with allergy, liver cirrhosis, and psychiatric or neurological disorders. Allowance for the two major identified covariates (education and smoking) failed to explain the observed variations between measures of body weight and disease, while separate inspection of various strata of age indicated that for most diseases the elevated risks of obesity were higher in younger and decrease steadily with advancing age. Thus, the results of this national survey indicate that overweight has a widespread and substantial impact not only on mortality but also on morbidity from different chronic conditions.

Aspirin and colorectal cancer.

The relationship between aspirin use and colorectal cancer risk was examined by a case-control study in Italy. Regular aspirin use was reported by only 47 (3.5%) cases and 77 (4.1%) control subjects, giving a multivariate odds ratio (OR) of 0.7 (95% CI 0.5-1.0) after allowance for education, physical exercise and selected dietary factors.

A case-control study of cancers of the gastric cardia in Italy

In a case-control study of gastric cancer (GC) in high-risk and low-risk areas in Italy, 923 GCs were reviewed by one pathologist and classified according to anatomic site. There were 68 (7.4%) cancers occurring in the gastric cardia. Compared to other GCs, cardia cancer tended to occur more often in males (sex ratio 2.8 vs 1.7) and as intestinal or unclassified histologic types. Nutritional factors for cardia tumours resembled those of other GCs, showing inverse associations with the consumption of raw vegetables, citrus and other fresh fruit, and ascorbic acid, and positive associations with the intake of traditional soups and meat, protein and cholesterol, and preference for salty foods. Cigarette smoking and wine consumption were unrelated to cardia cancer risk, and there was only a weak association with total alcohol intake. Cardia tumours showed a greater familial occurrence of GC than did other sites, with a 7-fold increase in risk for those reporting two first-degree relatives with GC. The authors discuss these findings in view of the rising incidence of adenocarcinomas of the cardia and lower oesophagus that has been reported in some western countries.

Body mass index and post-menopausal breast cancer: an age-specific analysis.

The relationship between body mass index (BMI, Quetelets index, kg m(-2)) and post-menopausal breast cancer risk was considered in age-specific strata on the basis of a pooled analysis of three Italian case-control studies, including a total of 3108 post-menopausal breast cancer patients aged 50 years or over and 2664 control subjects. Overall, there was a moderate, but significant, association between BMI and post-menopausal breast cancer: the odds ratios (ORs) were around 1.3 for the three intermediate quintiles compared with the lowest one, and 1.4 for the highest one. The association was moderate among women aged 50-59 years and 60-69 years, with ORs around 1.3 for the highest BMI quintiles, but stronger among elderly women, with ORs of 1.6 for the fourth and 2.1 for the fifth quintile. An 8-unit increase in BMI involved an OR of 1.18 at age 50-59 years, of 1.14 at age 60-69 years and of 1.59 above age 70 years. This pattern of risk is similar to that observed for post-menopausal hormone replacement treatment and is consistent with a duration-risk relationship in the exposure to high oestrogen levels and with a greater differential in oestrogen levels in overweight elderly women. In terms of population attributable risk, 19.6% of all post-menopausal breast cancer patients and 27.1% of those in women above age 70 years were attributable to overweight and obesity in this population. This has, therefore, major preventive implications as to reduce breast cancer risk late in life, it is essentially important to control weight gain in elderly women.