Incidence of mesothelioma in Lombardy, Italy: exposure to asbestos, time patterns and future projections

Abstract

Objectives: In Italy, asbestos has been extensively used from 1945 to 1992. We evaluated the impact of exposure to asbestos on occurrence of malignant mesothelioma (MM) in the Lombardy Region, Northwest Italy, the most populated and industrialised Italian region.

Methods: From the Lombardy Mesothelioma Registry, we selected all incident cases of MM diagnosed between 2000 and 2012. We described sources of exposure to asbestos and examined time trends of MM rates. Using Poisson age-cohort models, we derived projections of burden of MM in the Lombardy population for the period 2013-2029.

Results: In 2000-2012, we recorded 4442 cases of MM (2850 men, 1592 women). Occupational exposure to asbestos was more frequent in men (73.6%) than in women (38.2%). Non-occupational exposure was found for 13.6% of women and 3.6% of men. The average number of cases of MM per year was still increasing (+3.6% in men, +3.3% in women). Incidence rates were still increasing in individuals aged 65+ years and declining in younger people. A maximum of 417 cases of MM (267 men, 150 women) are expected in 2019. We forecast there will be 6832 more cases (4397 in men, 2435 in women) in the period 2013-2029, for a total of 11 274 cases of MM (7247 in men, 4027 in women) in 30 years.

Conclusions: This study documented a high burden of MM in both genders in the Lombardy Region, reflecting extensive occupational (mainly in men) and non-occupational (mainly in women) exposure to asbestos in the past. Incidence rates are still increasing; a downturn in occurrence of MM is expected to occur after 2019.

Keywords: Age-cohort model; Asbestos exposure; Cancer registry; Mesothelioma incidence; Mesothelioma projections.

Figure 1

Incidence rates (per 100 000 person-years) of malignant mesothelioma (20–99 years of age) (no cases were recorded in persons <20 years of age. Owing to small number of cases, ages 20–24, 25–29, and 30–34 and birth cohorts 1900–1904, 1905–1909, 1970–1974, 1975–1979, 1980–1984, and 1985–1989 were combined) by birth cohort for different categories of age at diagnosis, Lombardy Region Mesothelioma Registry, 2000–2012.

Figure 2

Incidence rates (per 100 000 person-years) of malignant mesothelioma by age at diagnosis (20–99 years) (no cases were recorded in persons <20 years of age. Owing to small number of cases, ages 20–24, 25–29, and 30–34 and birth cohorts 1900–1904, 1905–1909, 1970–1974, 1975–1979, 1980–1984, and 1985–1989 were combined) for different birth cohorts, Lombardy Region Mesothelioma Registry, 2000–2012.

Figure 3

Observed (2000–2012), model predicted and projected (2013–2029, based on Poisson age-cohort models) numbers of malignant mesothelioma cases per year, by gender, Lombardy Region Mesothelioma Registry.