Elsevier

The Lancet Oncology

Volume 14, Issue 9, August 2013, Pages 813-822
The Lancet Oncology

Articles
Air pollution and lung cancer incidence in 17 European cohorts: prospective analyses from the European Study of Cohorts for Air Pollution Effects (ESCAPE)

https://doi.org/10.1016/S1470-2045(13)70279-1Get rights and content

Summary

Background

Ambient air pollution is suspected to cause lung cancer. We aimed to assess the association between long-term exposure to ambient air pollution and lung cancer incidence in European populations.

Methods

This prospective analysis of data obtained by the European Study of Cohorts for Air Pollution Effects used data from 17 cohort studies based in nine European countries. Baseline addresses were geocoded and we assessed air pollution by land-use regression models for particulate matter (PM) with diameter of less than 10 μm (PM10), less than 2·5 μm (PM2·5), and between 2·5 and 10 μm (PMcoarse), soot (PM2·5absorbance), nitrogen oxides, and two traffic indicators. We used Cox regression models with adjustment for potential confounders for cohort-specific analyses and random effects models for meta-analyses.

Findings

The 312 944 cohort members contributed 4 013 131 person-years at risk. During follow-up (mean 12·8 years), 2095 incident lung cancer cases were diagnosed. The meta-analyses showed a statistically significant association between risk for lung cancer and PM10 (hazard ratio [HR] 1·22 [95% CI 1·03–1·45] per 10 μg/m3). For PM2·5 the HR was 1·18 (0·96–1·46) per 5 μg/m3. The same increments of PM10 and PM2·5 were associated with HRs for adenocarcinomas of the lung of 1·51 (1·10–2·08) and 1·55 (1·05–2·29), respectively. An increase in road traffic of 4000 vehicle-km per day within 100 m of the residence was associated with an HR for lung cancer of 1·09 (0·99–1·21). The results showed no association between lung cancer and nitrogen oxides concentration (HR 1·01 [0·95–1·07] per 20 μg/m3) or traffic intensity on the nearest street (HR 1·00 [0·97–1·04] per 5000 vehicles per day).

Interpretation

Particulate matter air pollution contributes to lung cancer incidence in Europe.

Funding

European Community's Seventh Framework Programme.

Introduction

Lung cancer is one of the most common cancers and has a poor prognosis. Active smoking is the main cause, but occupational exposures, residential radon, and environmental tobacco smoke are also established risk factors. Furthermore, lower socioeconomic position has been associated with a higher risk for lung cancer.1 Ambient air pollution, specifically particulate matter with absorbed polycyclic aromatic hydrocarbons and other genotoxic chemicals, is suspected to increase the risk for lung cancer. Results of several epidemiological studies have shown higher risks for lung cancer in association with various measures of air pollution2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and suggested an association mainly in non-smokers4, 12 and never-smokers13, 14 and in individuals with low fruit consumption.4, 13 In developed countries, overall lung cancer incidence rates have stabilised during the past few decades, but major shifts have been recorded in the frequencies of different histological types of lung cancer, with substantial relative increases in adenocarcinomas and decreases in squamous-cell carcinomas.15 Changes in tobacco blends15 and ambient air pollution16, 17 might have contributed to these shifts.

Within the European Study of Cohorts for Air Pollution Effects (ESCAPE), we aimed to analyse data from 17 European cohort studies with a wide range of exposure levels to investigate the following hypotheses: that ambient air pollution at the residence (specifically particulate matter) is associated with risk for lung cancer; that the association between air pollution and risk for lung cancer is stronger for non-smokers and people with low fruit intake; and that the association with air pollution is stronger for adenocarcinomas and squamous-cell carcinomas than for all lung cancers combined.

Section snippets

Study design and participants

This study is a prospective analysis of data obtained by ESCAPE—an investigation into the long-term effects of exposure to air pollution on human health in Europe—which included 36 European areas in which air pollution was measured, land-use regression models were developed, and cohort studies were located. The present study included 17 cohort studies, located in 12 areas, from which information about incident lung cancer cases and the most important potential confounders could be obtained, and

Results

The 17 cohorts in nine European countries that contributed to this study contained 312 944 cohort members and contributed 4 013 131 person-years at risk and 2095 incident lung cancer cases that developed during follow-up (average follow-up was 12·8 years). More details of each cohort, including characteristics of the participants, available variables, and their distribution are provided in the appendix (pp 2–18). Most of the cohort studies recruited participants in the 1990s (appendix, pp 2–18

Discussion

This analysis of 17 European cohort studies shows associations between residential exposure to particulate matter air pollution at enrolment and the risk for lung cancer. The associations were stronger for adenocarcinomas of the lung and in participants who lived at their enrolment address throughout follow-up.

The strengths of our study include the use of 17 cohort studies in several locations in Europe with very different air pollution exposure levels and also the use of standardised protocols

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