Biomedical subjects
Publications and source records attributed to P Boffetta.
Cancer is a major cause of mortality in developing countries, accounting for 13 percent of the annual deaths in adults. As the population increases and ages, the number of new cases of cancer is expected to increase dramatically. This article presents epidemiologic information on the principal cancers in developing countries and outlines the increasing challenge for the control of cancer in developing countries.
Asbestos causes four diseases in humans: Lung fibrosis (asbestosis) follows heavy exposure and, in industrialized countries, is mainly a relic of past working conditions. The risk of pleural fibrosis and plaques is likely to be linearly dependent from time since first exposure and is present for all types of asbestos fibres. The diagnostic uncertainties regarding pleural plaques and the substantial degree of misclassification make it difficult to precisely estimate the shape of the dose-response relationship. The risk of lung cancer seems to be linearly related to cumulative asbestos exposure, with an estimated increase in risk of 1% for each fibre/ml-year of exposure. All fibre types seem to exert a similar effect on lung cancer risk; a multiplicative interaction with tobacco smoking has been suggested. Pleural mesothelioma is a malignant neoplasm which is specifically associated with asbestos exposure: the risk is linked with the cubic power of time since first exposure, after allowing for a latency period of 10 years, and depends on the fibre type, as the risk is about three times higher for amphiboles as compared to chrysotile. Environmental exposure to asbestos is also associated with mesothelioma risk.
This paper reviews estimates of the proportion of lung cancer attributable to occupational exposures and presents estimates for the City of Turin where a population-based case-control study on lung cancer has been conducted in 1991-1992 among the residents. An analysis of six hundred and five cases (505 males and 100 females) and 859 controls (684 males and 175 females) with histological/cytological confirmed diagnosis of lung cancer and occupational and smoking complete histories has been performed to estimate the proportion of lung cancers attributable to occupation in the city of Turin. The occupational exposure has been assessed with two different classifications: a) classification of a checklist of occupations as obtained from the study questionnaire according to industries and occupations known (List A) and suspected (List B) to be associated with lung cancer; b) translation of ISCO-ISIC codes for industries and occupations according to the same List A and List B. The population attributable risks are comparable when estimated with the two different classifications. In the city of Turin, at the beginning of the Nineties, about 10%-15% of lung cancers in males and 2%-5% in females could be attributed to occupational exposure.
To determine if Kaposi's sarcoma-associated herpesvirus (KSHV) prevalence is correlated with the 9-fold difference in the incidence of classic Kaposi's sarcoma observed among Israeli Jewish populations, we conducted a cross-sectional KSHV seroprevalence survey in a population of 166 HIV-seronegative healthy subjects from the general population (26 women, 140 men). Eight individuals (4.8%) (all men) were seropositive for KSHV; differences between men and women were not statistically significant. If we consider the sensitivity and specificity of the assays, the corrected prevalence would be 6.1% (95% confidence interval 2.0-10.1). We noticed a non-statistically 5.5-fold difference between individuals above and below 40 years of age, but did not find an association with the incidence of classic KS among the Israeli Jewish sub-population, according to their origin. This suggests that KSHV is only necessary, albeit not sufficient, cause of classic Kaposi's sarcoma.
AIMS: This paper reviews the studies, both in vivo and in vitro, carried out for the project on low-dose effects of inorganic mercury, financed by the Italian Ministry of Universities and Scientific and Technological Research. RESULTS, COMMENTS AND PROPOSAL: The results offer both innovative aspects and potential practical applications. Particular attention is drawn to the reliability of biomarkers of exposure [mercury in urine (HgU) and blood (HgB), possibility of speciation] as well as to the availability of guidance values for risk assessment (reference value, action level, biological threshold value). In the general population, HgU and HgB levels are significantly related to the presence of dental amalgams and to fish consumption; nevertheless, such exposure levels do not elicit adverse health effects on renal, immune and nervous functions, according to the markers evaluated in the studies. The present biological threshold values for occupational exposure appear adequate to prevent health effects, considering the immune system, kidney and central nervous system as the target organs. However, possible effects of low doses of mercury on immune and neuroendocrine functions should be further examined; moreover, consideration should be given to the risk of consuming fish species with high Hg content, particularly concerning the renal and central nervous system effects. Finally, further studies should be planned on other potentially important effects, that could not be considered in this study, such as those on prenatal development, the cardiovascular system and the thyroid gland.
In order to verify both usefulness and reliability of cytologic grading evaluated on urinary sediment, we designed a study to test the ability to distinguish consistently between different degrees of neoplastic abnormalities of urothelial cells from voided urine, in relation to the histologic findings of bladder biopsies performed after cytologic reading. Kappa measures were calculated in 112 cytohistologic pairs representative of first disease detection (A) and in 35 pairs representative of disease recurrence (B). Cytology was able to correctly identify a cancer in 70.5% and 80.0% of group A and group B lesions, respectively. Unweighted kappa values of both groups A and B were poor (0.298 and 0.324 respectively). When we considered the weighted kappa, values suggesting fair agreement were obtained (0.576 and 0.500). Our data confirm that urinary cytology shows a good sensitivity in detecting bladder cancer, but it does not seem to give reliable results for the assessment of the tumor grading.
A begun started Italian multicentric hospital-based case-control study aimed at detecting carcinogenic risk associated with pesticides exposure is presented. During a 2 year period, incident cases of cancer of various sites in adults of both sexes will be identified in five hospitals used by residents of five Italian rural areas (Asti, Imola, Pescia, Pistoia, Grosseto). Selected sites include the following: lip, oral cavity and oropharynx, oesophagus, stomach, colon-rectum, liver, biliary ducts, pancreas, larynx, lung, soft tissue, skin melanoma, skin other than melanoma, breast, uterus, ovary, prostate, bladder, kidney, thyroid, and lymphoid tissue. Trained personnel will interview patients about their total work experience, with special emphasis on activities in agriculture. Other relevant information to be collected includes pathological anamnesis and smoking habits. A team of coders will analyse the occupational histories using an a priori job-exposures matrix (JEM). The JEM will be specific with respect to type of agricultural production, calendar years, geographic location and pesticides. Each cancer site will be compared with a selected pool of the other sites. This investigation is expected to provide information on a range of associations between cancer of various sites and individual pesticides or mixed exposures. The study can be seen as a pilot study which could be replicated in other areas.
In 1987 researchers from Berkeley (CA), proposed an index (HERP) for ranking human carcinogens. The index was derived from human exposure data and rodent carcinogen potency. They concluded that the risks for the US population from man-made industrial carcinogens are trivial compared with the risks from naturally occurring carcinogens in the diet. Analysis of the assumptions and data upon which the HERPs were based revealed major limitations and we concluded that such a simplified approach is inappropriate given the underlying uncertainties. However, when we made a comparison consistently based on estimates of average daily exposure to common carcinogens, the HERP scores of man-made pollutants were comparable to those of naturally occurring carcinogens.
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The contribution of epidemiological research to the definition of cancer risk from the occupational environment is reviewed and evaluated on the basis of the systematic approach adopted by the Monograph Program of the International Agency for Research on Cancer. The importance of cancer risk from industrial environments and its historical pattern are discussed along with the presentation of an updating on the available knowledge in this field.
Exposure to environmental tobacco smoke (ETS) is an established cause of lung cancer, ischaemic heart disease and chronic respiratory disease in adults and of asthma in children. A meta-analysis of 48 risk estimates from 39 published studies in non smokers gave a relative risk of 1.24 (95% Confidence Interval: 1.15-1.34), 1.14 (95% CI: 0.98-1.33) and 1.15 (95% CI: 0.92-1.43) for spousal, working environment and childhood ETS exposures. Misclassification of active smokers, exposure to ETS in reference groups, dietary confounding and publication bias have little effect on the association with spousal exposure. Estimates of the number of lung cancer deaths attributable to ETS from spousal exposure gave 1146 and 200 yearly deaths in the European Union (EU) and Italy respectively. Review of the available evidence confirms that exposure to ETS increases the risk for lung cancer and other diseases and is an important public health problem in the EU and Italy.