Long‐term exposure to air pollution and liver cancer incidence in six European cohorts
Rina So, Jie Chen, Amar Mehta, Shuo Liu, Maciej Strak, Kathrin Wolf, Ulla Arthur Hvidtfeldt, Sophia Rodopoulou, Massimo Stafoggia, Jochem O. Klompmaker, Evangelia Samoli, Ole Raaschou‐Nielsen, Richard Atkinson, Mariska Bauwelinck, Tom Bellander, Marie‐Christine Boutron‐Ruault, Jørgen Brandt, Bert Brunekreef, Giulia Cesaroni, Hans Concin, Francesco Forastiere, Carla H. van Gils, John Gulliver, Ole Hertel, Barbara Hoffmann, Kees de Hoogh, Nicole Janssen, Youn‐Hee Lim, Rudi G. J. Westendorp, Jeanette T. Jørgensen, Klea Katsouyanni, Matthias Ketzel, Anton Lager, Alois Lang, Petter Ljungman, Patrik K. E. Magnusson, Gabriele Nagel, Mette Kildevæld Simonsen, Göran Pershagen, Raphael S. Peter, Annette Peters, Matteo Renzi, Debora Rizzuto, Torben Sigsgaard, Danielle Vienneau, Gudrun Weinmayr, Gianluca Severi, Daniela Fecht, Anne Tjønneland, Karin Leander, Gerard Hoek, Zorana Jovanovic Andersen
Abstract
Abstract Particulate matter air pollution and diesel engine exhaust have been classified as carcinogenic for lung cancer, yet few studies have explored associations with liver cancer. We used six European adult cohorts which were recruited between 1985 and 2005, pooled within the “Effects of low‐level air pollution: A study in Europe” (ELAPSE) project, and followed for the incidence of liver cancer until 2011 to 2015. The annual average exposure to nitrogen dioxide (NO 2 ), particulate matter with diameter <2.5 μm (PM 2.5 ), black carbon (BC), warm‐season ozone (O 3 ), and eight elemental components of PM 2.5 (copper, iron, zinc, sulfur, nickel, vanadium, silicon, and potassium) were estimated by European‐wide hybrid land‐use regression models at participants' residential addresses. We analyzed the association between air pollution and liver cancer incidence by Cox proportional hazards models adjusting for potential confounders. Of 330 064 cancer‐free adults at baseline, 512 developed liver cancer during a mean follow‐up of 18.1 years. We observed positive linear associations between NO 2 (hazard ratio, 95% confidence interval: 1.17, 1.02‐1.35 per 10 μg/m 3 ), PM 2.5 (1.12, 0.92‐1.36 per 5 μg/m 3 ), and BC (1.15, 1.00‐1.33 per 0.5 10 −5 /m) and liver cancer incidence. Associations with NO 2 and BC persisted in two‐pollutant models with PM 2.5 . Most components of PM 2.5 were associated with the risk of liver cancer, with the strongest associations for sulfur and vanadium, which were robust to adjustment for PM 2.5 or NO 2 . Our study suggests that ambient air pollution may increase the risk of liver cancer, even at concentrations below current EU standards.