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Biomedical subjects

P Boffetta

Publications and source records attributed to P Boffetta.

At least 37 records · Page 2Linked to original sources
PubMed2005

Effect of different approaches to treatment of smoking as a potential confounder in a case-control study on occupational exposures.

AIM: To evaluate the effect of different approaches to treatment of smoking as a potential confounder in an occupational study of lung cancer. METHODS: Data were used from a case-control study on 956 men with lung cancer and 1253 population controls recruited in two northern Italian areas during 1990-1992. The risk of lung cancer associated with 11 selected job titles and eight selected industrial activities was estimated using seven different methods to treat smoking history. To evaluate the confounding effect of smoking, odds ratios obtained using the first six models were compared with estimates from the seventh and most complex model, in which cumulative tobacco consumption and time since cessation were considered. RESULTS: Although crude odds ratios for some of the occupational categories were biased by up to 25%, such bias decreased to less than 10% when a simple model including smoking status (never, ex-, current) was used. CONCLUSIONS: In occupational studies on lung cancer risk, information on smoking status may allow satisfactory control of the potential confounding effect of the habit.

Case-Control Studies↗
PubMed2004

The cumulative risk of lung cancer among current, ex- and never-smokers in European men.

Recent analyses based on UK data indicate that people who stop smoking, even well into middle age, avoid most of their subsequent risk of lung cancer. We investigated whether similar absolute risks of lung cancer in men are found in other European countries with different smoking patterns and at different stages of their lung cancer epidemic. Using data for men from a multicentre case-control study of lung cancer in the UK, Germany, Italy and Sweden, and including 6523 lung cancer cases and 9468 controls, we combined odds ratio estimates with estimates of national lung cancer incidence rates to calculate the cumulative risk of lung cancer among men by age 75. Lung cancer cumulative risks by age 75 among continuing smokers were similar for the UK, Germany and Italy at 15.7, 14.3 and 13.8% respectively, whereas the cumulative risk among Swedish male smokers was 6.6%. The proportion of the risk of lung cancer avoided by quitting smoking before the age of 40 was comparable between the four countries, at 80% in Italy and 91% in the UK, Germany and Sweden. Similarly, the proportion of the excess risk avoided by quitting before the age of 50 ranged from 57% in Italy to 69% in Germany. Our results support the important conclusion that for long-term smokers, giving up smoking in middle age avoids most of the subsequent risk of lung cancer, and that lung cancer mortality in European men over the next three decades will be determined by the extent to which current smokers can successfully quit smoking.

Adult↗
PubMed2004

Occupational exposure to chemical agents in the paper industry.

As part of an International Agency for Research on Cancer (IARC) international epidemiological study of workers in the pulp and paper industry, previously unpublished exposure measurements were assembled in a database. This article summarizes the results of 3,873 measurements carried out in the production departments of paper and paperboard mills and recycling plants in 12 countries. In the paper and paperboard mills, most of the agents were measured in the pulping and refining departments and in on-machine coating and winding of paper/paperboard. Exposures to asbestos, carbon monoxide, formaldehyde, fungal spores, bacteria, nitrogen dioxide, minerals dusts, paper dust, sulphuric acid and different solvents sometimes exceeded exposure limit values. In the re-pulping and de-inking departments of recycling plants high exposures to formaldehyde, fungal spores, bacteria and paper dust were observed. High exposures to asbestos, bioaerosols, carbon monoxide and paper dust were found in many departments; ammonia, formaldehyde, mineral and paper dust and solvents were found in coating machines; and diphenyl and polychlorobiphenyls (PCBs) were found in some special circumstances. Measurements in the newsprint and uncoated paper machine departments revealed only a few elevated exposures. In nearly all departments, measurements of epichlorohydrin, PCBs, sulphur dioxide, hydrogen sulphide and mercaptans tended to be low, often even below their detection limits. In spite of some uncertainties in the measurement data, the study provides new insights into the level and variation of occupational exposures of production workers in the paper and paperboard industry.

Europe↗
PubMed2004

Risk of fatal industrial accidents and death from other external causes among asphalt workers.

The hypothesis that asphalt workers are at increased risk of mortality from industrial accidents and other external causes was tested. Mortality rates for external and violent causes of death in a cohort of asphalt industry employees from seven European countries and Israel were compared to that of the general population. There was no evidence that mortality from external causes was increased among long term employees in asphalt application and mixing. There was an increased risk for mortality due to external causes among short term workers. However, none of the fatal accidents among short term workers appear to have occurred during employment in the studied asphalt companies. Overall, no evidence was found supporting the hypothesis that asphalt workers are at increased risk of fatal industrial or road accidents. Mortality from other external causes did not increase in this population as a whole, but increased risks among short term workers deserve further attention.

Accidents, Occupational↗
PubMed2003

Food groups and risk of squamous cell carcinoma of the oesophagus: a case-control study in Uruguay.

In the time period January 1998-December 2000, a case-control study on squamous cell cancer of the oesophagus was conducted in Montevideo, Uruguay. The main objective of the study was to estimate the odds ratios (ORs) associated with main food groups. For this purpose, 166 patients afflicted with squamous cell oesophageal cancer and 664 hospitalised controls were frequency matched on age and sex. Both series of patients were administered with a structured questionnaire. Aside from queries related with tobacco smoking, alcohol drinking and maté drinking, patients were interviewed with a food-frequency questionnaire (FFQ) on 64 items, representative of the usual Uruguayan diet. Red meat, salted meat and boiled meat displayed strong direct associations (OR for red meat 2.4, 95% CI 1.4-4.2). On the other hand, fish and total white meat showed moderate protective effect (OR for total white meat 0.5, 95% CI 0.3-0.9). Total fruit intake displayed a strong inverse association (OR 0.2, 95% CI 0.1-0.4), whereas total vegetable consumption presented a weak inverse association (OR for total vegetable intake 0.7, 95% CI 0.4-1.2). These results suggest that vegetables, mainly cooked vegetables, are rich in thermolabile protective substances. On the other hand, boiled (stewed) meat, which is ingested at high temperature could be, like maté, a risk factor for squamous cell cancer of the oesophagus.

Adult↗
PubMed2003

Polymorphisms in CYP1A1, GSTM1, GSTT1 and lung cancer below the age of 45 years.

BACKGROUND: A genetic component of early-onset lung cancer has been suggested. The role of metabolic gene polymorphisms has never been studied in young lung cancer cases. Phase 1 and Phase 2 gene polymorphisms are involved in tobacco carcinogens' metabolism and therefore in lung cancer risk. METHODS: The effect of metabolic gene polymorphisms on lung cancer at young ages was studied by pooling data from the Genetic Susceptibility to Environmental Carcinogens (GSEC) database. All primary lung cancer cases of both sexes who were Caucasian and </=45 years of age at diagnosis, and the corresponding controls were selected. We obtained 261 cases and 1452 controls. RESULTS: There was a marginally significant association between lung cancer and GSTT1 null genotype (OR=1.2; 95% CI:1.0-1.6), and a significant association between lung cancer and the homozygous CYP1A1 Msp1 variant allele (CYP1A1*2A and *2B) genotype (OR=4.7 95% CI:1.2-19.0). When data were stratified by smoking status, the association between CYP1A1 genotype and lung cancer was confined to never smokers. CONCLUSIONS: These results suggest that metabolic genetic factors play a role in lung cancer developing at young ages.

Adult↗
PubMed2002

Alcohol and hepatocellular carcinoma: the effect of lifetime intake and hepatitis virus infections in men and women.

The authors investigated the dose-effect relation between alcohol drinking and hepatocellular carcinoma (HCC) in men and women separately, also considering hepatitis B and hepatitis C virus infections. They enrolled 464 subjects (380 men) with a first diagnosis of HCC as cases and 824 subjects (686 men) unaffected by hepatic diseases as controls; all were hospitalized in Brescia, northern Italy, in 1995-2000. Spline regression models showed a steady linear increase in the odds ratio of HCC for increasing alcohol intake, for values of >60 g of ethanol per day, with no substantial differences between men and women. Duration of drinking and age at start had no effect on the odds ratio when alcohol intake was considered. Former drinkers who had stopped 1-10 years previously had a higher risk of HCC than current drinkers did. The effect of alcohol drinking was evident even in the absence of hepatitis B or hepatitis C virus infection. In addition, a synergism between alcohol drinking and either infection was found, with approximately a twofold increase in the odds ratio for each hepatitis virus infection for drinkers of >60 g per day.

Adult↗
PubMed2002

Tobacco use, cancer causation and public health impact.

This review describes global patterns of tobacco use and the mechanisms by which tobacco use is involved in carcinogenesis. A second part will discuss the association between tobacco use and risk of specific cancer types. Tobacco use has traditionally been a practice of high-income countries, but it has recently been taken up in low-income countries and it is particularly common in men. A wide variety of tobacco products exist, of which cigarettes are most frequently consumed. Tobacco products contain more than 50 established or identified carcinogens and these may increase risk of cancer by causing mutations that disrupt cell cycle regulation, or through their effect on the immune or endocrine systems. Certain factors such as genes, diet and environmental exposures may alter susceptibility to cancer in tobacco users. Today at least 15% of all cancers are estimated to be attributable to smoking, but this figure is expected to increase because of the uptake of tobacco use in low-income countries.

Adult↗
PubMed2002

Tobacco use and cancer causation: association by tumour type.

In the second part of our review we describe the association between tobacco use and risk of specific cancer types. There is evidence for an established association of tobacco use with cancer of the lung and larynx, head and neck, bladder, oesophagus, pancreas, stomach and kidney. In contrast, endometrial cancer is less common in women who smoke cigarettes. There are some data suggesting that tobacco use increases the risk for myeloid leukaemia, squamous cell sinonasal cancer, liver cancer, cervical cancer, colorectal cancer after an extended latency, childhood cancers and cancer of the gall bladder, adrenal gland and small intestine. Other forms of cancer, including breast, ovarian and prostate cancer, are unlikely to be linked to tobacco use.

Case-Control Studies↗
PubMed2002

Plant foods and differences between colon and rectal cancers.

A case-control study on plant food intake and its role in the risk of colon and rectal cancers was carried out in Montevideo, Uruguay. Four hundred and eighty-four (484) cases of colorectal cancer and 1452 controls were frequency matched on age, sex, residence and urban/rural status. Among cases, 260 patients had colon cancer whereas 224 had rectal tumours. Controls had non-neoplastic conditions. Both cases and controls were interviewed in the four major hospitals in Montevideo shortly after admittance for diagnosis or treatment. The questionnaire included a section on frequency of foods, which included 64 items, in particular, queries on 18 vegetables, 10 fruits and 6 cereal dishes were included. Thus, the amount of plant foods consumed was complete and included the main plant foods in the Uruguayan diet. The analysis showed that rectal cancer displayed inverse associations with total plant foods, total vegetables, cooked vegetables, potatoes and legumes. When data were stratified by tumour site and sex, only men showed a protective effect of plant foods (odds ratio (OR) of rectal cancer for men 0.4, 95% confidence interval (CI) 0.2-0.7). In contrast, women with rectal carcinoma were not associated with plant food intake. It can be concluded that plant foods are protective factors for men afflicted with colorectal cancer but that plant food intake is not associated with risk in women. This is, at least in part, due to the high risk associated with bread intake in this gender.

Adult↗
PubMed2002

Exposure-response analysis and risk assessment for silica and silicosis mortality in a pooled analysis of six cohorts.

AIMS: To study the relation between exposure to crystalline silica and silicosis mortality. Although mortality is an important endpoint for regulators, there have been no exposure-response studies for silicosis mortality, because of the relative rareness of silicosis as an underlying cause of death, and the limited availability of quantitative exposure estimates. METHODS: Data from six occupational cohorts were pooled with good retrospective exposure data in which 170 deaths from silicosis were reported. Standard life table analyses, nested case-control analyses, and risk assessment were performed. RESULTS: The rate of silicosis mortality in the combined data was 28/100 000 py, increasing in nearly monotonic fashion from 4.7/100 000 for exposure of 0-0.99 mg/m(3)-years to 233/100 000 for exposure of >28.1 mg/m(3)-years. The estimated risk of death up to age 65 from silicosis after 45 years of exposure at 0.1 mg/m(3) silica (the current standard in many countries) was 13 per 1000, while the estimated risk at an exposure of 0.05 mg/m(3) was 6 per 1000. Both of these risks are above the risk of 1 per 1000 typically deemed acceptable by the US OSHA. CONCLUSION: The findings from this pooled analysis add further support to the need to control silica exposure and to lower the occupational standards. Our estimates of lifetime silicosis mortality risk are probably underestimates as, in addition to exposure misclassification, our study might have suffered from outcome misclassification in that silicosis deaths might have been coded to other related causes, such as tuberculosis or chronic obstructive pulmonary disease.

Adult↗
PubMed2002

Validity of empirical models of exposure in asphalt paving.

AIMS: To investigate the validity of empirical models of exposure to bitumen fume and benzo(a)pyrene, developed for a historical cohort study of asphalt paving in Western Europe. METHODS: Validity was evaluated using data from the USA, Italy, and Germany not used to develop the original models. Correlation between observed and predicted exposures was examined. Bias and precision were estimated. RESULTS: Models were imprecise. Furthermore, predicted bitumen fume exposures tended to be lower (-70%) than concentrations found during paving in the USA. This apparent bias might be attributed to differences between Western European and USA paving practices. Evaluation of the validity of the benzo(a)pyrene exposure model revealed a similar to expected effect of re-paving and a larger than expected effect of tar use. Overall, benzo(a)pyrene models underestimated exposures by 51%. CONCLUSIONS: Possible bias as a result of underestimation of the impact of coal tar on benzo(a)pyrene exposure levels must be explored in sensitivity analysis of the exposure-response relation. Validation of the models, albeit limited, increased our confidence in their applicability to exposure assessment in the historical cohort study of cancer risk among asphalt workers.

Air Pollutants, Occupational↗
PubMed2002

Lung cancer risk in a population-based cohort of patients hospitalized for asthma in Sweden.

It has been suggested that asthma increases the risk of lung cancer in males but not in females. However, previous studies may suffer from report bias and are based on a small numbers of cases. The objective of the present study was to assess the incidence of lung cancer in males and females using a nationwide Swedish cohort of asthma patients. Patients (n=92,986) aged > or = 20 yrs with a hospital-discharge diagnosis of asthma and who were alive and free from malignancy I yr after first hospitalization were followed-up, for incidence of lung cancer during the period 1965-1994 (average duration of follow-up, 8.5 yrs). Their incidence of lung cancer was compared with that of the national population. The authors observed 713 lung cancers (standardized incidence ratio (SIR) 1.58, 95% confidence interval (CI) 1.47-1.70). The SIR was 1.51 in males (95% CI 1.38-1.65, 492 cases) and 1.78 in females (95% CI 1.55-2.03, 221 cases). The SIR decreased with duration of follow-up and increased with calendar period and age at first hospitalization. The risk of lung cancer was higher for squamous cell and small cell carcinoma than for adenocarcinoma, and it was higher in patients with other diseases as the main diagnosis and in patients hospitalized in departments other than internal and respiratory medicine. It was confirmed that asthma patients are at increased risk of lung cancer, but there is no heterogeneity in risk between the sexes. Several indirect arguments point towards a noncausal explanation of these findings; in particular, confounding by tobacco smoking is a plausible explanation.

Adenocarcinoma↗
PubMed2001

Primary liver cancer and occupation in men: a case-control study in a high-incidence area in Northern Italy.

The objective of our study was to evaluate the association between occupation and risk of liver cancer. A hospital-based case-control study was carried out during 1997-1999 in the Province of Brescia, a highly industrialized area in Northern Italy with a high incidence of this neoplasm. The cases were 144 male patients with incident liver cancer (96% hepatocellular carcinoma). Controls were 283 male patients, matched to cases on age (+/-5 years), period and hospital of admission. Information on lifetime occupational history and alcohol consumption was obtained via interview. Specific occupational exposures to pesticides, solvents and other suspected hepatocarcinogens were evaluated. A blood sample was collected to detect hepatitis B and C infections. Odds ratios (OR) of occupational exposure and 95% confidence intervals (CI), adjusted for age, residence, education, heavy alcohol intake, hepatitis B surface antigen and hepatitis C virus antibodies positivity were computed. A statistically significant increased OR was observed for employment in repair of motor vehicles (OR 3.7; 95% CI 1.1-12.3; 9 exposed cases, 10 exposed controls). Increased ORs, although not statistically significant, were found for field-crop farm workers, food and beverage processors, blacksmiths and machine-tool operators, electrical fitters, clerical workers, manufacture of industrial machinery and personal and household services. A slightly increased OR was noted in workers exposed to toluene and xylene (OR 1.4; 95% CI 0.7-3.0, 23 cases, 36 controls); the OR was 2.8 (95% CI 1.0-7.6, 11 cases, 12 controls) for 20 or more years of exposure and 2.0 (95% CI 0.9-4.1, 21 cases, 28 controls) for 30 or more years of time since first exposure. The increase in OR seemed to be independent from that of alcohol or viral infections. Our study showed that the role of occupational exposures in liver carcinogenesis is limited. However, prolonged exposure to organic solvents such as toluene and xylene may represent a risk factor for liver cancer.

Adult↗
PubMed2001

Risk of adenocarcinomas of the oesophagus and gastric cardia in patients hospitalized for asthma.

In the first cohort study of the question we followed 92 986 (42 663 men and 50 323 women) adult patients hospitalized for asthma in Sweden from 1965 to 1994 for an average of 8.5 years to evaluate their risk of oesophageal and gastric cardia adenocarcinoma. Standardized incidence ratio (SIR) adjusted for gender, age and calendar year was used to estimate relative risk, using the Swedish nationwide cancer incidence rates as reference. Asthmatic patients overall had a moderately elevated risk for oesophageal adenocarcinoma (SIR = 1.5, 95% confidence interval CI, 0.9-2.5) and gastric cardia cancer (SIR = 1.4, 95% CI, 1.0-1.9). However, the excess risks were largely confined to asthmatic patients who also had a discharge record of gastro-oesophageal reflux (SIR = 7.5, 95% CI, 1.6-22.0 and SIR = 7.1, 95% CI, 3.1-14.0, respectively). No significant excess risk for oesophageal squamous-cell carcinoma or distal stomach cancer was observed. In conclusion, asthma is associated with a moderately elevated risk of developing oesophageal or gastric cardia adenocarcinoma. Special clinical vigilance vis-à-vis gastro-esophageal cancers seems unwarranted in asthmatic patients, but may be appropriate in those with clinically manifest gastro-oesophageal reflux.

Adenocarcinoma↗