SERUM LEVELS AND MALIGNANT PLEURAL MESOTHELIOMA (MPM) IN A HIGHLY IN PIEDMONT, ITALY:

Transcription

1 25-OH-VITAMIN D (vd) SERUM LEVELS AND MALIGNANT PLEURAL MESOTHELIOMA (MPM) IN A HIGHLY ASBESTOS-POLLUTED AREA IN PIEDMONT, ITALY: A CASE-CONTROL STUDY

2 Grosso F 1, Bianchi V 1, Bertolotti M 1, Orecchia S 1, Libener R 1, Roveta A 1, Mazzucco L 1, Guaschino R 1, Degiovanni D 2, Botta M 2, Mirabelli D 3, Bonelli F 4, Magnani C 5 Correspondence to: Federica Grosso Corrado Magnani fgrosso@ospedale.al.it magnani@med.unipmn.it

3 1 SS Antonio e Biagio General Hospital, Alessandria, Italy 2 S Spirito General Hospital, Casale Monferrato, Italy 3 SCDU Epidemiologia dei Tumori Città della Salute e della Scienza General Hospital Torino, Italy 4 Diasorin, Minnesota, USA 5 CDU Epidemiologia dei Tumori Maggiore della Carità General Hospital, Novara, Italy

4 Epidemiological rational The past presence of an asbestos cement factory using highly polluting industrial processes (Eternit) has greatly increased the cancer incidence of malignant mesothelioma in the area of Casale Monferrato. Eternit Casale Monferrato

5 A significant number of new cases in people not employed in the factory (environmental exposure) is reported. Non-occupational exposure (environmental and domestic) causes more than 2/3 of cases of mesothelioma in this area (Maule et al. EHP 2007).

6 Scientific rational Exposure to asbestos is the only known cause of MM. About the mechanisms of action of asbestos fibers, there is still a lot of uncertainty but it seems obvious a role of pro-inflammatory mechanisms caused by exposure to fibers. Vitamin D has an anti-tumorigenic role (Deeb et al.2007, Nature Reviews Cancer 7, ), Holick M. (Prog Biophysics Mol Biol 2006; 92) and Giovannucci E. (Cancer Causes and Control 2005, 16), have speculated that the inverse correlation between the rate of death for cancer and latitude (ie exposure to sunlight), that is observed in epidemiological studies, is due to the different availability of vitamin D. It can therefore be hypothesized interaction between vitamin D and asbestos in the genesis of MM (Tschopp et al).

7 Objective In this study, we intend to compare serum levels of vitamin D in cases of MM and healthy controls drawn from the same population. This study includes serum samples from 91 cases and 195 controls. Statistical analysis The statistical analysis has been conducted as follows: Preliminary analysis of data quality assessment and normalizing transformations; Comparison of vitamin D concentration in cases and controls using multiple regression models to account for the effect of potential confounders (age, sex, time of year of sampling, storage time) and exposure to asbestos; Analysis with logistic models of the risk of MM for asbestos exposure and vitamin D levels, and their possible interaction, controlling for potential confounders (age, sex, time of year of sampling, storage time).

8 Background Low serum vd levels are a known risk factor for several diseases, including many types of human cancer. Furthermore in vitro and in vivo studies have demonstrated vd anti-tumor effects. The aim of this study is to identify a potential association between vd serum levels and MPM in a case-control study in the highly asbestos polluted area of Casale Monferrato, in Italy. Methods Ninety-one subjects diagnosed with MPM since June 2002 to June 2006 constituted the case group. Two controls per patient (196), matched for age and gender, were randomly selected from the local population. A standard questionnaire was administered to collect information about demographics, life-style, occupational history and asbestos exposure. Serum samples were collected after interview and stored at -20 C until vd measurements were performed with a chemiolumiscence immunoassay (LIAISON, DiaSorin, Minnesota, USA). After evaluation of factors influencing vd in controls, the association of vd levels with case/control status was assessed, adjusting for the detected variables. Unconditional multivariate logistic regression analysis was mainly used but exploratory analyses using multivariate linear regression (GLM) were also conducted. ORs and 95%CIs were calculated for unit increase of the logarithm of vd and for quartiles of the distribution.

9 Results Factors associated with vd level in controls were age, gender and season; no data were available on nutrition. Median vd concentrations (ng/ml) in cases and controls were (IQR: ) and ( ), respectively. In both groups vd distribution was skewed and therefore analyses were conducted after logarithm transformation. In GLM multivariate analyses cases presented a lower level of ln(vd) (p<0.0001). In logistic regression analyses adjusted by age, gender, season and occupational exposure, the OR for a unit increase of ln(or) was (95% CI: ), showing a statistically significant protective effect of vd. Conclusions In this cohort low vd levels strongly associate with MPM case status. Further investigations are ongoing to elucidate whether this striking difference between cases and controls could be involved in the pathogenesis of MPM as it is in other cancers.

10 Patients characteristics Cases Controls Sex M/F 61/30 137/59 Age ẋ ± SD ± ± Year of collection Season of collection Jan-Mar Apr-Jun Jul-Sep Oct-Dec Exposure to asbesto High occupational Environmental / Low occupational Missing for 5 cases

11 Descritive analysis of Vit D levels Median IQR P [median test] Age 61 > P = 0.15 Sex M F P = 0.28 Season of collection Jan-Mar Apr-Jun P < Jul-Sep Oct-Dec Asbestos Exposure High (occupational) Intermediate or Environmental P = 0.73 Missing

12 Distribution of Vitamin D in cases and controls) Median IQR P [median test] Cases P < Controls

13 Is Vit D associated with risk of MM? Logistic regression model OR 95 % CI P value Vit D ( for 10 Units ) P < Model adjusted for age, gender, asbestos exposure, season Logistic regression model OR 95 % CI Vit D ( for 10 Units ) Exposure High occupational Middle Environmental , Model adjusted for age, gender and season

14 How case/control status and other variables of interest predict Vit D levels? Ln (Vit D concentration) P value Intercept Cases (vs controls) P < Men (vs women) P < Season (ref. to Oct-Dec) Jan-Mar Apr-Jun Jul-Sep R 2 =

15 Prospects Path forward is to conduct a prospective study aimed to confirm these preliminary findings that, if confirmed, will prompt additional studies finalized to establish a cause effect relationship.

16 Bibliography Maule MM, Magnani C, Dalmasso P, Mirabelli D, Merletti F, Biggeri A. Modelling mesothelioma risk associated with environmental asbestos exposure. Environ Health Perspect 2007; 115: Deeb KK, Trump DL, Johnson CS.Vitamin D signalling pathways in cancer: potential for anticancer therapeutics. Nat Rev Cancer 2007; 7: Holick MF. Vitamin D: its role in cancer prevention and treatment. Prog Biophysics Mol Biol 2006; 92: Giovannucci E. The epidemiology of vitamin D and cancer incidence and mortality: a review (United States). Cancer Causes Control 2005;16: Tschopp J, Schroder K. NLRP3 inflammasome activation: The Convergence of multiple signalling pathways on ROS production? Nature Reviews Immunology 2010; 10(3):