Exposure to emissions from Mount Etna (Sicily, Italy) and incidence of thyroid cancer: a geographic analysis

Paolo Boffetta,Margherita Ferrante,Dario Giuffrida,Lorenzo Memeo,Salvatore Sciacca

doi:10.1038/s41598-020-77027-9

Abstract

An increased incidence of thyroid cancer has been reported in the area close to Mount Etna, the largest volcano in Europe located in Northeastern Sicily. We tested the hypothesis that exposure to the emissions from the volcano is associated with thyroid cancer in 186 municipalities from three provinces surrounding the volcano (1.9 million inhabitants). We measured the angle between the bearing of the municipalities and each direction, with special focus on South-East, the prevalent direction of the plume, and conducted a regression analysis on 2003–2016 incidence rates of thyroid cancer, adjusting for distance from Mount Etna, population size, and income. A 10-degree increase in the angle with South-East was associated with a decrease in thyroid cancer rates in the whole population (− 0.67 cases/100,000, p = 0.002) and in women (− 1.54/100,000, p < 0.001), and were robust to several sensitivity analyses. Similar results were obtained for East-South-East direction. These results support the hypothesis of a potential role of exposure to the plume from Mount Etna in determining the high rates of thyroid cancer. The results need to be confirmed in analytical studies, in which information of exposure to chemicals originating from the volcano, as well as other possible causes, should be carefully measured, molecular characteristics of the tumors and taken into account.

Highlights

Mount Etna is the largest active volcano in Europe, located in the province of Catania in Northeastern Sicily
The incidence rate of thyroid cancer in the study population was higher than those reported in other areas of Sicily, and comparable to other high-incidence areas in other Italian regions (Table 1)
Our results show a decrease in the incidence of thyroid cancer of 0.67 cases/100,000 for a 10 degree increase in the angle between bearing of the place of residence from Mount Etna and either East-South-East or South-East, and of 1.00 case/100,000 for a 10-km increase in the distance from Mount Etna

Summary

Introduction

Mount Etna is the largest active volcano in Europe, located in the province of Catania in Northeastern Sicily. An analysis of 2002–2004 incidence of thyroid cancer in Sicily identified a higher rate in Catania province, which was attributed to papillary cancer and was not explained by mild iodine deficiency or industrial activities[10]. These and other a uthors[11,12,13] hypothesized a role of the volcanic environment, possibly related the presence of heavy metals and other carcinogens in the aquifer used for drinking water in the surrounding area. We aimed at testing the hypothesis that exposure to the emissions from Mount Etna is an additional route of exposure to carcinogens of volcanic origin that can explain the increased incidence of thyroid cancer, by analyzing the correlation between the incidence of the disease and the angle between the bearing of the municipalities and each direction, with special focus on South-East, the prevalent direction of the plume

Methods

Results

Conclusion