Pleural malignant mesothelioma epidemic: incidence, modalities of asbestos exposure and occupations involved from the Italian National Register.

Due to the large scale use of asbestos (more than 3.5 million tons produced or imported until its definitive banning in 1992), a specific national surveillance system of mesothelioma incident cases is active in Italy, with direct and individual anamnestic etiological investigation. In the period between 1993 and 2004, a case-list of 8,868 pleural MM was recorded by the Italian National Register (ReNaM) and the modalities of exposure to asbestos fibres have been investigated for 6,603 of them. Standardized incidence rates are 3.49 (per 100,000 inhabitants) for men and 1.25 for women, with a wide regional variability. Occupational asbestos exposure was in 69.3% of interviewed subjects (N = 4,577 cases), while 4.4% was due to cohabitation with someone (generally, the husband) occupationally exposed, 4.7% by environmental exposure from living near a contamination source and 1.6% during a leisure activity. In the male group, 81.5% of interviewed subjects exhibit an occupational exposure. In the exposed workers, the median year of first exposure was 1957, and mean latency was 43.7 years. The analysis of exposures by industrial sector focuses on a decreasing trend for those traditionally signaled as "at risk" (asbestos-cement industry, shipbuilding and repair and railway carriages maintenance) and an increasing trend for the building construction sector. The systematic mesothelioma surveillance system is relevant for the prevention of the disease and for supporting an efficient compensation system. The existing experience on all-too-predictable asbestos effects should be transferred to developing countries where asbestos use is spreading.

Analysis of latency time and its determinants in asbestos related malignant mesothelioma cases of the Italian register.

Italy was an important producer of raw asbestos until 1992 (when it was banned) and it is now experiencing severe public health consequences due to large-scale industrial use of asbestos in shipbuilding and repair, asbestos-cement production, railways, buildings, chemicals and many other industrial sectors. Latency of malignant mesothelioma generally shows a large variability and the relationship with the modality of asbestos exposure is still not fully clarified. We present an analysis of latency period among the case list collected by the Italian mesothelioma register (ReNaM) in the period of diagnosis 1993-2001 (2544 malignant mesothelioma (MM) cases with asbestos exposure history). Exposure is assessed retrospectively by interview. Statistical univariate analyses were performed to estimate median and variability measures of latency time by anatomical site, gender and diagnosis period. The role of diagnostic confidence level, the morphology of the tumour and the modalities of asbestos exposure were verified in a regression multivariate model. We found a median latency period of 44.6 years increasing in recent years with a linear trend. Anatomical site, gender and morphology were not relevant for MM latency time whereas a shorter latency period was documented among occupationally exposed subjects (43 years) with respect to environmentally and household exposed ones (48 years).