Exposure to occupational carcinogens and lung cancer risk : evolution of epidemiological estimates of attributable fraction

Background and aim of the work: Lung cancer is the leading cause of cancer death world-wide. Among the possible causes, occupational risk factors play a major role and are potentially preventable. We reviewed the scientific evidence about lung cancer burden due to occupation. Methods:We reviewed the literature and selected population case-control and cohort studies which provided estimates of the proportion of lung cancers attributable to occupational carcinogens (population attributable fraction, PAF). Different methods were used to evaluate occupational exposure to suspected/known lung carcinogens: lists of high-risk occupations, job-exposure matrix ( JEM), expert assessment. Only studies which adjusted for tobacco smoking were included. Results: The PAFs reported by the 32 selected Italian and international studies among men vary greatly in time and space: they ranged between 0 to 40% according to different geographical prevalence of hazardous industries (e.g., basic metal industries, shipbuilding and railroad equipment manufacturing). The PAFs estimated using JEM and expert assessment were on average higher. Data for women were usually few and insufficient to calculate stable estimates. Conclusions: A significant proportion of lung cancers is attributable to occupational carcinogens. The estimates are extremely variable in time and place and mainly depend on the industrial setting of the area under study; caution is therefore required in generalizing these results to the whole country. Alternative approaches to evaluate occupational lung cancer burden among women are necessary. (www.actabiomedica.it

The association between air pollution and the incidence of idiopathic pulmonary fibrosis in Northern Italy

Acute exacerbations and worsening of idiopathic pulmonary fibrosis (IPF) have been associated with exposure to ozone (O3), nitrogen dioxide (NO2) and particulate matter, but chronic exposure to air pollution might also affect the incidence of IPF. We investigated the association between chronic exposure to NO2, O3 and particulate matter with an aerodynamic diameter <10 \u3bcm (PM10) and IPF incidence in Northern Italy between 2005 and 2010. Daily predictions of PM10 concentrations were obtained from spatiotemporal models, and NO2 and O3 hourly concentrations from fixed monitoring stations. We identified areas with homogenous exposure to each pollutant. We built negative binomial models to assess the association between area-specific IPF incidence rate, estimated through administrative databases, and average overall and seasonal PM10, NO2, and 8-hour maximum O3 concentrations. Using unadjusted models, an increment of 10 \u3bcg\ub7m-3 in NO2 concentration was associated with an increase between 7.93% (95% CI 0.36-16.08%) and 8.41% (95% CI -0.23-17.80%) in IPF incidence rate, depending on the season. After adjustment for potential confounders, estimated effects were similar in magnitude, but with larger confidence intervals. Although confirmatory studies are needed, our results trace a potential association between exposure to traffic pollution and the development of IPF

Mortality in a population exposed to dioxin after the Seveso, Italy, accident in 1976 : 25 years of follow-up

The Seveso accident in 1976 caused a large, populated area north of Milan, Italy, to be contaminated by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In this study, the authors followed up the exposed population for chronic effects; this paper reports the results of the mortality follow-up extension for 1997-2001. The study cohort includes 278,108 subjects resident at the time of the accident or immigrating/born in the 10 years thereafter in three contaminated zones with decreasing TCDD soil levels (zone A, very high; zone B, high; zone R, low) and in a reference territory comprising surrounding, noncontaminated municipalities. Vital status and cause-of-death ascertainment were 99% complete. Adjusted rate ratios and 95% confidence intervals were calculated by using Poisson regression. Results confirmed previous findings of excesses of lymphatic and hematopoietic tissue neoplasms in zones A (six deaths; rate ratio = 2.23, 95% confidence interval: 1.00, 4.97) and B (28 deaths; rate ratio = 1.59, 95% confidence interval: 1.09, 2.33). These zones also showed increased mortality from circulatory diseases in the first years after the accident, from chronic obstructive pulmonary disease, and from diabetes mellitus among females. A toxic and carcinogenic risk to humans after high TCDD exposure is supported by the results of this study

t(14;18) translocations in lymphocytes of healthy dioxin-exposed individuals from Seveso, Italy

Dioxin exposure has been associated with non-Hodgkin's lymphoma (NHL) in epidemiological investigations. The NHL-related t(14;18) translocations can be detected at a low copy number in lymphocytes from healthy subjects. Exposure to NHL-associated carcinogens, such as dioxin or pesticides, may cause expansion of t(14;18)-positive clones. We investigated prevalence and frequency of circulating t(14;18)-positive lymphocytes in 144 healthy subjects from a population exposed to dioxin [plasma TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) range: or =16 years (mean = 12.6; 95% CI, 7.4-21.3; P = 0.01). Higher t(14;18) prevalence was found among individuals with fair hair color (P = 0.01) and light eye color (P = 0.04). No significant association between t(14;18)-and age was found. Our results show that dioxin exposure is associated with increased number of circulating t(14;18) positive cells. Whether this change in t(14;18) frequency is an indicator of elevated lymphoma risk remains speculative and needs further investigation for its potential impact on public health

Early and late de novo tumors after liver transplantation in adults: the late onset of bladder tumors in men

BACKGROUND: De novo tumors (DNT) after liver transplantation (LT) represent a growing concern. PATIENTS AND METHODS: We analyzed the incidence of DNT, type, time of onset, risk factors and mortality (as of 2010) in 494 adult patients transplanted in the last 26 years (1983-2009). RESULTS: DNT occurred in 41 (8.3%) of the patients. The Standardized Incidence Ratio (SIR) compared with the Italian population was 1.8. There was a higher incidence in males (SIR 2.0), an expected extremely high rate of Kaposi's sarcoma (SIR 127.95) and unexpected higher rates of tumors of the bladder in males (SIR 3.3). The incidence of DNT was higher within the first two years of LT (SIR 2.7) for Kaposi's sarcoma (SIR 393.3) and after 10 years (SIR 1.7) for bladder tumors (SIR 10.6). Multivariate analysis identified alcoholic cirrhosis (HR\u200a=\u200a3.0, 95% CI\u200a=\u200a1.2-7.8) and sclerosing cholangitis (HR\u200a=\u200a3.5, 95% CI\u200a=\u200a1.1-11.3) in the recipient as main risk factors for the occurrence of DNT. CONCLUSIONS: Surveillance protocols for DNT must be specifically oriented to patients transplanted for alcoholic cirrhosis and sclerosing cholangitis. They should focus on early detection of Kaposi's sarcomas, and more remarkably, on late development bladder tumors in men after LT

Influence of quercetin-rich food intake on microRNA expression in lung cancer tissues

BACKGROUND: Epidemiologic studies have reported that frequent consumption of quercetin-rich foods is inversely associated with lung cancer incidence. A quercetin-rich diet might modulate microRNA (miR) expression; however, this mechanism has not been fully examined. METHODS: miR expression data were measured by a custom-made array in formalin-fixed paraffin-embedded tissue samples from 264 lung cancer cases (144 adenocarcinomas and 120 squamous cell carcinomas). Intake of quercetin-rich foods was derived from a food-frequency questionnaire. In individual-miR-based analyses, we compared the expression of miRs (n=198) between lung cancer cases consuming high-versus-low quercetin-rich food intake using multivariate ANOVA tests. In family-miR-based analyses, we used Functional Class Scoring (FCS) to assess differential effect on biologically functional miRs families. We accounted for multiple testing using 10,000 global permutations (significance at p-value(global) <0.10). All multivariate analyses were conducted separately by histology and by smoking status (former and current smokers). RESULTS: Family-based analyses showed that a quercetin-rich diet differentiated miR expression profiles of the tumor suppressor let-7 family among adenocarcinomas (p-value(FCS)<0.001). Other significantly differentiated miR families included carcinogenesis-related miR-146, miR-26, and miR-17 (p-values(FCS)<0.05). In individual-based analyses, we found that among former and current smokers with adenocarcinoma, 33 miRs were observed to be differentiated between highest-and-lowest quercetin-rich food consumers (23 expected by chance; p-value(global) = 0.047). CONCLUSIONS: We observed differential expression of key biologically functional miRNAs between high-versus-low consumers of quercetin-rich foods in adenocarcinoma cases. Impact: Our findings provide preliminary evidence on the mechanism underlying quercetin-related lung carcinogenesis