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Biomedical subjects

P Boffetta

Publications and source records attributed to P Boffetta.

At least 109 records · Page 6Linked to original sources
PubMed2000

Vegetables, fruits, related dietary antioxidants, and risk of squamous cell carcinoma of the esophagus: a case-control study in Uruguay.

In 1998-1999, a case-control study on esophageal cancer was conducted in Uruguay. For this purpose, 111 cases with squamous cell carcinoma of the esophagus and 444 controls with conditions unrelated to tobacco smoking, alcohol drinking, or recent changes in the diet were frequency matched on age, gender, residence, and urban/rural status. Vegetables and, more markedly, fruits were associated with strong reductions in risk. On the other hand, 12 of 15 dietary antioxidants displayed significant inverse associations with esophageal cancer risk. The strongest effect was observed for high intake of beta-cryptoxanthin (odds ratio = 0.16, 95% confidence interval = 0.08-0.36). Also, alpha-carotene, lycopene, and beta-sitosterol were associated with significant reductions in risk. Most antioxidants lost their effect when they were further adjusted for a term for all vegetables and fruits. beta-Carotene showed an increased risk with high intakes. On the other hand, vegetables and fruits remained as significant variables after adjustment for each antioxidant, suggesting that other substances or other mechanisms could explain this effect.

Aged↗
PubMed2000

Risk of childhood cancer and adult lung cancer after childhood exposure to passive smoke: A meta-analysis.

We identified more than 30 studies on the association between exposure to maternal tobacco smoke during pregnancy and cancer in childhood. We combined their results in meta-analyses based on a random effects model. The results of the meta-analyses suggest a small increase in risk of all neoplasms [relative risk (RR) 1.10; 95% confidence interval (CI), 1.03-1.19; based on 12 studies], but not of specific neoplasms such as leukemia (RR 1.05; CI, 0.82-1.34; 8 studies) and central nervous system tumors (RR 1.04; CI, 0.92-1. 18; 12 studies). Results for other specific neoplasms were sparse, but the available data did not suggest a strong association for any type of tumor. No clear evidence of dose response was present in the studies that addressed this issue. The results on exposure to maternal tobacco smoke before or after pregnancy are too sparse to allow a conclusion. The results on exposure to paternal tobacco smoke suggest an association with brain tumors (RR 1.22; CI, 1.05-1. 40; based on 10 studies) and lymphomas (RR 2.08; CI, 1.08-3.98; 4 studies). The data are too sparse for the other neoplasms, although the results of a few recent large studies are compatible with a weak carcinogenic effect of paternal smoke. For exposure from either maternal or paternal smoke, bias and confounding cannot yet be ruled out. Further studies are needed to confirm the hypothesis that parental tobacco smoke, from the father in particular, is a risk factor of childhood cancer. Results on the risk of lung cancer in adulthood and childhood passive smoking exposure are available from 11 studies: they do not provide evidence of an increased risk (summary RR 0.91; CI, 0.80-1.05).

Adolescent↗
PubMed2000

Statistical modelling of the determinants of historical exposure to bitumen and polycyclic aromatic hydrocarbons among paving workers.

INTRODUCTION: An industrial hygiene database has been constructed for the exposure assessment in a study of cancer risk among asphalt workers. AIM: To create models of bitumen and polycyclic aromatic hydrocarbons (PAH) exposure intensity among paving workers. METHODS: Individual exposure measurements from pavers (N = 1581) were collected from 8 countries. Correlation patterns between exposure measures were examined and factors affecting exposure were identified using statistical modelling. RESULTS: Inhalable dust appeared to be a good proxy of bitumen fume exposure. Bitumen fume and vapour levels were not correlated. Benzo(a)pyrene level appeared to be a good indicator of PAH exposure. All exposures steadily declined over the last 20 years. Mastic laying, re-paving, surface dressing, oil gravel paving and asphalt temperature were significant determinants of bitumen exposure. Coal tar use dictated PAH exposure levels. DISCUSSION: Bitumen fume, vapour and PAH have different determinants of exposure. For paving workers, exposure intensity can be assessed on the basis of time period and production characteristics.

Databases, Factual↗
PubMed2000

Alpha-linolenic acid and risk of prostate cancer: a case-control study in Uruguay.

In the time period of 1994-1998, a case-control study on diet and prostate cancer was carried out in Uruguay to examine the risk associated with fat intake. Two hundred and seventeen (217) incident cases afflicted with advanced prostate cancer were frequency-matched with 431 controls on age, residence, and urban/rural status. The analysis was carried out using unconditional multiple logistic regression. Alpha-linolenic acid was associated with a strong positive association (fourth quartile of intake odds ratio, 3.91; 95% confidence interval, 1.50-10.1) after controlling for total calorie intake and for the other types of fat. The effect was similar when alpha-linolenic acid was analyzed by its sources of origin (odds ratio for vegetable linolenic acid, 2.03; 95% confidence interval, 1.01-4.07). Including this report, five of six studies that have examined the relationship between alpha-linolenic acid and prostate cancer yielded a positive association, which was significant in four studies. Thus, there appears to be evidence of a role of alpha-linolenic acid in prostate carcinogenesis.

Adult↗
PubMed2000

Levelling-off of the risk of lung and bladder cancer in heavy smokers: an analysis based on multicentric case-control studies and a metabolic interpretation.

The shape of the dose-response relationship between carcinogenic exposure and cancer risk is a key issue, both from a theoretical (models of carcinogenesis) and practical (risk assessment) point of view. Human populations exposed to Polycyclic Aromatic Hydrocarbons (PAH) via air pollution showed a non-linear relationship between levels of exposure and WBC-DNA adducts. Among highly exposed subjects, the DNA adduct level per unit of exposure was significantly lower than measured at environmental exposures. The same exposure-dose non-linearity was observed in lung DNA from rats exposed to PAH. We have analyzed 11 case-control studies on bladder cancer (4584 incident cases and 9360 hospital controls) and eight case-control studies on lung cancer (5092 incident cases and 6083 population controls), conducted in Europe in recent years. All the studies collected detailed information on smoking histories with a similar methodology. We have estimated the relationship between the number of cigarettes smoked and the risk of cancer, with and without adjustment by duration of smoking. We have observed a levelling-off of the relationship between the number of cigarettes smoked and the relative risks for lung and bladder cancer, both in men and women. The levelling-off occurred at an odds ratio of about 5 for bladder cancer, while it occurs at about 20 for lung cancer (in men). A potential explanation for such levelling-off involves metabolic pathways and individual susceptibility. It has been suggested that some metabolic polymorphisms exert an effect that is more important at low levels of exposure.

Adult↗
PubMed2000

Lung cancer risk in nonsmokers and GSTM1 and GSTT1 genetic polymorphism.

Glutathione S-transferase (GST) polymorphism may contribute to the individual variability in detoxifying lung carcinogens. This effect might be particularly relevant at low-level exposure to environmental carcinogens, such as in nonsmokers exposed to environmental tobacco smoke (ETS). We conducted a case-control study among 122 nonsmoking lung cancer cases and 121 nonsmoking controls from eight countries. Information on environmental exposures was obtained through a personal interview. The presence of GSTM1 and GSTT1 genes was determined using multiplex PCR. GSTM1-positive samples were then analyzed for *1A and *1B polymorphism using an allele-specific amplification-PCR method. GSTM1*2 (null) individuals had an odds ratio (OR) of lung cancer of 1.5 [95% confidence interval (CI), 0.9-2.7]; the risk associated with this genotype was higher for cases with squamous and small cell carcinomas (OR, 2.3; 95% CI, 0.9-6.1) than for cases with adenocarcinomas. It was also elevated in individuals with long-term exposure to indoor wood combustion (OR, 3.1; 95% CI, 0.9-9.9), in subjects who mainly lived in a rural setting (OR, 3.6; 95% CI, 1.0-13), and in cases exposed to occupational carcinogens (OR, 10.7; 96% CI, 0.4-260) but not in subjects exposed to ETS. GSTT1*2 subjects did not show a risk of lung cancer. Our study suggests that the effect of GSTM1 polymorphism in nonsmokers is similar to that found in smokers. It does not seem to interact with ETS exposure, although we cannot exclude that it does in association with exposure to other specific environmental carcinogens.

Adenocarcinoma↗
PubMed2000

Empirical Bayes adjustments for multiple results in hypothesis-generating or surveillance studies.

Traditional methods of adjustment for multiple comparisons (e.g., Bonferroni adjustments) have fallen into disuse in epidemiological studies. However, alternative kinds of adjustment for data with multiple comparisons may sometimes be advisable. When a large number of comparisons are made, and when there is a high cost to investigating false positive leads, empirical or semi-Bayes adjustments may help in the selection of the most promising leads. Here we offer an example of such adjustments in a large surveillance data set of occupation and cancer in Nordic countries, in which we used empirical Bayes (EB) adjustments to evaluate standardized incidence ratios (SIRs) for cancer and occupation among craftsmen and laborers. For men, there were 642 SIRs, of which 138 (21%) had a P < 0.05 (13% positive with SIR > 1.0 and 8% negative with SIR < or = 1.0) when testing the null hypothesis of no cancer/occupation association; some of these were probably due to confounding by nonoccupational risk factors (e.g., smoking). After EB adjustments, there were 95 (15%) SIRs with P < 0.05 (10% positive and 5% negative). For women, there were 373 SIRs, of which 37 (10%) had P < 0.05 before adjustment (6% positive and 4% negative) and 13 (3%) had P < 0.05 after adjustment (2% positive and 1% negative). Several known associations were confirmed after EB adjustment (e.g., pleural cancer among plumbers, original SIR 3.2 (95% confidence interval, 2.5-4.1), adjusted SIR 2.0 (95% confidence interval, 1.6-2.4). EB can produce more accurate estimates of relative risk by shrinking imprecise outliers toward the mean, which may reduce the number of false positives otherwise flagged for further investigation. For example, liver cancer among chimney sweepers was reduced from an original SIR of 2.2 (range, 1.1-4.4) to an adjusted SIR of 1.1 (range, 0.9-1.4). A potentially important future application for EB is studies of gene-environment-disease interactions, in which hundreds of polymorphisms may be evaluated with dozens of environmental risk factors in large cohort studies, producing thousands of associations.

Analysis of Variance↗
PubMed1999

Exposure to environmental tobacco smoke and risk of adenocarcinoma of the lung.

We conducted a case-control study of adenocarcinoma of the lung and exposure to environmental tobacco smoke (ETS) in 7 countries. We interviewed 70 cases of adenocarcinoma of the lung and 178 population or hospital controls. All subjects had smoked fewer than 400 cigarettes in their lifetimes. Ever exposure to ETS from the parents during childhood was associated with a decreased risk [odds ratio (OR) 0.6, 95% confidence interval (CI) 0.3-1.2], and there was a suggestion of a decreasing trend in risk with increasing duration of exposure. Ever exposure to ETS from the spouse was not associated with an increased risk (OR 1.0, 95% CI 0.5-1.8), while the OR of ever exposure to ETS at the workplace was 1.5 (95% CI 0.8-3.0). For both exposure sources, an increased risk was observed among the highly exposed, and the OR among those with the highest duration of exposure to ETS from the spouse or at the workplace was 1.8 (95% CI 0.5-6.2). A similar risk was estimated for current exposure to ETS from either source. Our results confirm previous reports of a weak effect of adult ETS exposure on risk of adenocarcinoma of the lung. Bias and confounding cannot be excluded as explanations for the apparent decrease in risk from childhood exposure.

Adenocarcinoma↗
PubMed1999

Gender differences in the healthy worker effect among synthetic vitreous fiber workers.

The aim of this study was to determine whether the healthy worker effect and its component parts operate similarly for women and men. A cohort of workers from 14 synthetic vitreous fiber factories in seven countries, employed for at least 1 year between 1933 and 1977 and followed up to the early 1990s, included 375 deaths and 53,608 person-years among females and 2,568 deaths and 210,073 person-years among males. Standardized mortality ratios for all-cause and circulatory diseases were adjusted for country, age, calendar time, and gender. In addition, internal comparisons were adjusted for time since hire and employment status. The analyses addressed the following: 1) the healthy hire effect, 2) the time since hire effect, and 3) the healthy worker survivor effect. In this cohort, an overall healthy worker effect was not present in either gender. The healthy hire effect, based on standardized mortality ratios for years 1-4 since hire, was observed in males (standardized mortality ratio (SMR) = 0.8; 95% confidence interval (CI): 0.7, 1.0) but was less in females (SMR = 0.9; 95% CI: 0.5, 1.6). The relative risks increased slightly with time since hire in males but not in females. Higher mortality ratios were seen among those leaving employment than among those who remained actively employed; however, this effect was substantially greater for women (relative risk (RR) = 3.4; 95% CI: 1.8, 6.3) than men (RR = 1.8; 95% CI: 1.5, 2.1). The gender difference for active versus inactive status was stronger up to age 60 (men: RR = 1.7; 95% CI: 1.4, 2.0; women: RR = 3.6; 95% CI: 1.8, 7.1) than above that age. In conclusion, it appears that there is a stronger selection of healthy men than women into the workforce, while health-related selection out of the workforce is stronger for women than men.

Adult↗
PubMed1999

Meat intake and risk of squamous cell esophageal cancer: a case-control study in Uruguay.

In order to examine the relationship between different types of meat and squamous cell cancer of the esophagus, a case-control study was carried out in Uruguay. Eighty-two cases and 248 hospitalized controls were frequency-matched on age, sex, residence and urban/rural status. All patients responded to a detailed questionnaire, which included a food-frequency form for 64 food items representative of the usual Uruguayan diet. Whereas increases in risk were observed for high intake of salted meat [odds ratio (OR) 2.5, 95% confidence interval (CI) 1.1-5.4] and lamb (OR 2.1, 95% CI 1.1-4.2), beef from cow was inversely associated with the risk of esophageal cancer (OR 0.4, 95% CI 0.2-0.9). Also, polyunsaturated fat from meat was associated with an increased risk (OR 3.2, 95% CI 1.0-9.8). Finally, total meat intake was not associated with squamous cell cancer of the esophagus.

Adult↗
PubMed1999

Case-control study on hepatitis C virus (HCV) as a risk factor for hepatocellular carcinoma: the role of HCV genotypes and the synergism with hepatitis B virus and alcohol. Brescia HCC Study.

We performed a case-control study to evaluate the risk of hepatocellular carcinoma (HCC) for hepatitis C virus (HCV) infection. A total of 305 newly diagnosed HCC cases (80% males) and 610 subjects (81% males) unaffected by clinically evident hepatic disease admitted to the 2 main hospitals in Brescia, North Italy, were recruited as cases and controls, respectively. Among the 122 HCC cases positive for HCV RNA, genotype 1b was found in 83 patients (68%), genotype 2 in 36 (29.5%) and genotype 1a in 3 (2.5%). Among the controls, 15 were infected with genotype 1b and 15 with type 2. Analysis of HCV envelope 1 nucleotide sequence among 25 cases and 8 controls infected with genotype 2 showed subtype 2c in 96% of cases and in all controls, and subtype 2a in 1 HCC case. The odds ratio (OR) for HCV RNA positivity adjusted for hepatitis B virus (HBV) markers and alcohol intake was 26.3 [95% confidence interval (CI): 15.8-44], and it was higher for genotype 1b (OR = 34.2) than type 2 (OR = 14.4). The OR for HCV RNA was 35.6 (95% CI: 14.5-87.1) when the HBV markers were all negative and 132 (15.3-890) when HBsAg positivity was present; the OR was 26.1 (95% CI: 12.6-54.0) among subjects with alcohol intake of 0-40 g/day and increased to 62.6 (23.3-168) and 126 (42.8-373) with an alcohol intake of 41-80 and >80 g/day, respectively. In conclusion, synergism was found between HCV infection and HBV infection and alcohol intake in causing HCC.

Adult↗
PubMed1999

Cigar and pipe smoking and lung cancer risk: a multicenter study from Europe.

BACKGROUND: Because limited information is available on the quantitative association between consumption of tobacco products other than cigarettes and lung cancer risk, we undertook a case-control study of this relationship. METHODS: We investigated lung cancer risk among smokers of cigars and/or cigarillos only and of pipes only and compared these risks with the risk of smokers of cigarettes only in a case-control study conducted in seven European areas. Our study population consisted of 5621 male case patients with lung cancer and 7255 male control subjects. Each subject or his proxy was interviewed with respect to the subject's smoking history and other risk factors for lung cancer. RESULTS: The odds ratio (OR) for smoking cigars and cigarillos only was 9.0 (95% confidence interval [CI] = 5.8-14.1), based on 43 exposed case patients and 77 exposed control subjects, and the OR for smoking a pipe only was 7.9 (95% CI = 5.3-11.8), representing 61 case patients and 129 control subjects. The OR for smoking cigarettes only was 14.9 (95% CI = 12.3-18.1), based on 4204 case patients and 3930 control subjects. A dose-response relationship was present for duration of use and cumulative consumption both for cigars and cigarillos and for pipe tobacco. An effect was also suggested for inhalation of cigar and cigarillo smoke. The dose-response relationships between lung cancer risk and either duration of smoking or average and cumulative consumption were similar for cigar and cigarillo smoking, pipe smoking, and cigarette smoking. CONCLUSION: Our results suggest that smoking of European cigars, cigarillos, and pipe tobacco might exert a carcinogenic effect on the lung comparable to that of cigarettes.

Age Factors↗
PubMed1999

Cancer incidence and mortality in a cohort of chloroprene workers from Armenia.

We evaluated the risk of cancer among 1897 men and 417 women exposed to chloroprene (2-chloro-1,3-butadiene, CP) at a production plant in Yerevan, Armenia, between 1940 and 1988. The cohort was followed up for cancer incidence for the years 1979-1990 and for cancer mortality for 1979-1988. In the cohort, incidence and mortality from all cancers were below expectation, but increased incidence (standardized incidence ratio 3.27, 95% confidence interval [CI] 1.47-7.27), and mortality (standardized mortality ratio 3.39, 95% CI 1.09-10.5) from liver cancer were noticed. A dose-response relationship was suggested between liver cancer and indices of CP exposure, such as duration of employment, duration of high CP exposure and cumulative exposure to CP. The risk of other neoplasms was not increased.

Armenia↗
PubMed1999

Classic Kaposi's sarcoma as a first primary neoplasm.

Patients with a diagnosis of primary classic Kaposi's sarcoma (CKS) appear to be at a higher risk of multiple neoplasms. We analyzed a nation-wide series of 1,016 patients with a primary CKS occurring between 1961 and 1992 in the Jewish Israeli population to evaluate the risk of secondary neoplasms. The primary CKS and subsequent neoplasms were identified from the Israel Cancer Registry. All HIV-seropositive Kaposi's sarcoma cases were excluded. The expected number of second primary neoplasms was calculated after stratifying by age, origin and gender. Of the CKS patients, 61 developed a second neoplasm by the end of the study, similar to the expected number of 60.33 [standardized incidence ratio (SIR) of 1.01]. However, there was an excess of non-Hodgkin's lymphoma (NHL) (SIR = 3.94) and cutaneous malignant melanoma (SIR = 5.81), balanced by a deficit of lung cancers (none observed, 7 expected). We found high risk for migrants from Eastern Europe when compared with other migrants for both solid tumors [rate ratio (RR) = 3.01] and NHL (RR = 4.10). Patients with a diagnosis of primary CKS do not have an overall increased risk of new neoplasms later in life. However, an increased risk of NHL implies the presence of common risk factors for both NHL and CKS.

Aged↗
PubMed1999

Classic Kaposi's sarcoma as a second primary neoplasm.

Although the incidence of classic Kaposi's sarcoma (CKS) has been investigated, its occurrence following a primary neoplasm and its association with this first neoplasm need to be determined. We analyzed a series of 124 patients with a secondary CKS (8.4% of a total of 1485 incident cases) which occurred between 1961 and 1992 in the Jewish Israeli population. Data on first neoplasms and subsequent Kaposi's sarcoma were retrieved from the Israel Cancer Registry. Acquired-immune-deficiency-syndrome-related Kaposi's sarcomas were excluded from the case series. Four controls were randomly selected for each CKS case among all Cancer Registry cases free from a second neoplasm at the time of diagnosis of the CKS in the case, and matched on gender, year of birth and year of diagnosis of the first neoplasm. The average time lapse between first neoplasm and secondary CKS was 4.5 years, being shorter for prostate cancer and for hematopoietic malignancies. As compared with Israel-born Jews, the risk of a subsequent CKS was significantly increased in immigrants [odds ratio (OR) 3.0]; this risk was particularly high in immigrants from the former Soviet Union (OR 9.4) and Poland (OR 7.0). There was no clear trend with age at immigration; however, low age at immigration and a short length of stay in Israel endowed a higher risk of developing a secondary CKS, markedly among patients suffering from solid tumors as the first primary. There was an excess of secondary CKS following a non-Hodgkin's lymphoma (OR 5.3), a Hodgkin's lymphoma (OR 7.5), a leukemia (OR 5.3) or a breast cancer (OR 2.2). Cancer patients with a first primary in the lung, colon, stomach, larynx, liver, pancreas or kidney showed secondary CKS less frequently. Despite the lack of control of therapy for the first neoplasm, development of secondary CKS seems to be mediated by mechanisms similar to those for hematopoietic neoplasms and selected nonhematopoietic neoplasms, such as breast cancer. The trend toward increased risk after a short time lapse and the difference in risk among immigrants indicate that genetic susceptibility is part of the complex interplay between cellular proliferation and control systems.

Aged↗
PubMed1999

Tobacco, occupation and non-transitional-cell carcinoma of the bladder: an international case-control study.

Transitional-cell carcinoma is the dominant histological type of malignant tumors of the urinary bladder. There is limited information on risk factors for non-transitional-cell carcinoma (NTCC) of the bladder. We used data from 9 case-control studies on bladder cancer from 6 European countries to examine the association between NTCC, tobacco smoking and occupation. Information on 146 cases diagnosed with NTCC were matched by age, gender and study center to 727 non-cancer population or hospital controls and also with 722 transitional-cell-bladder-cancer controls. Lifetime smoking and occupational history were evaluated. A statistically significant excess risk for NTCC was observed for current smoking [odds ratio (OR) = 3.61, 95% confidence interval (CI) 2.08-6.28]. The risk increased with higher tobacco consumption (OR for highest tertile of pack-years = 7.01, 95% CI 3.60-13.66). The risks were higher for squamous-cell carcinomas than for other types of NTCC. Among major occupational groups, a significant excess risk was seen for field-crop and vegetable-farm workers (OR = 2.06, 95% CI 1.03-4.10). These results indicate that NTCC of the bladder is associated with smoking and specific occupations. The risk pattern seems to differ, in part, from that observed for transitional-cell carcinoma of the bladder.

Carcinoma, Squamous Cell↗