Centre international de Recherche sur le Cancer Lyon, France
IARC Evaluation of the
Carcinogenicity of Outdoor Air Pollution
Dana Loomis, PhD
IARC Monograph 109, Outdoor Air Pollution Lyon, 7-18 October 2013
Evaluation
•Outdoor air pollution is carcinogenic to humans (Group 1)
•Particulate matter in outdoor air pollution is carcinogenic to humans (Group 1)
Summary: http://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(13)70487-X/fulltext
The IARC Monographs
(http://monographs.iarc.fr/indexfr.php)
• Evaluate factors capable of causing cancer in humans
• Environmental & occupational exposures
• Physical, chemical & biologic agents
• Lifestyle factors
• “The Encyclopedia of Carcinogens”
• More than 900 agents evaluated since 1971
• >100 carcinogenic to humans
• >300 probably or possibly carcinogenic
• National & international health agencies use the Monographs
• To identify carcinogens
• To support prevention or regulation
Evaluation in the IARC Monographs
Review of all relevant
studies Review of all relevant
studies
• Cancer in humans
• Cancer in animals
Weight of the Evidence Weight of
the Evidence
• Working Group:
discussion & debate
Final Evaluation
Final
Evaluation • Consensus
Review of Mechanisms
of Cancer
Review of Exposure
Data
Weight of the Evidence Evaluation
Cancer in humans
• Sufficient evidence
• Limited evidence
• Inadequate evidence
• Evidence suggesting lack of carcinogenicity
Cancer in animals
• Sufficient evidence
• Limited evidence
• Inadequate evidence
• Evidence suggesting lack of carcinogenicity
Mechanisms
• Strong, moderate or weak mechanistic data
• Mechanism likely to operate in humans?
Overall Evaluation
1. Carcinogenic to humans 2A. Probably carcinogenic 2B. Possibly carcinogenic
3. Not classifiable as to carcinogenicity
4. Probably not carcinogenic
Vol. 109: 24 invited experts from 11 countries
Working Group members
IARC and representatives
Source: Brauer et al. (2012). Environ Sci Technol 46:652-60
Outdoor Air Pollution is Global and Highly
Variable
Estimated PM2.5 concentrations, western Europe 2001-2006
Source: van Donkelaar et al. (2010) Environ Health Perspect 118:847–855
Sources of Principal Air Pollutants, Europe
Epidemiologic Studies
• All available studies of air pollution and cancer were reviewed (100s of studies)
• 14 studies of lung cancer were most informative
• Cohorts from the the general population in Europe, North America & Asia: millions of people and 1000s of cancer cases observed
• Quantitative exposure information
• Control of important confounders (smoking)
Lung Cancer and PM-2.5 (RR per 10µg/m 3 )
Lung Cancer and PM-10 (RR per 10µg/m 3)
Meta-Analysis of Lung Cancer and Particulate Matter
• Statistical analysis combining results from 14 studies in Europe, Asia & North America
• Random effects model
• Meta-RR 1,09 (1,04-1,14) per 10 µg/m -3 PM 2.5
• Meta-RR 1,08 (1,00-1,17) per 10 µg/m -3 PM 10
• RR not substantially affected by gender, smoking status, or social class
(Hamra et al., EHP, 2014)
Lung Cancer and NO 2 (RR per 10µg/m 3)
Lung Cancer and Indicators of Exposure to Traffic (RR)
Lung cancer and SO2 (RR per 10 µg/m 3 )
RRs for Lung Cancer and Air Pollution: Non Smokers
Heterogeneity between groups: p = 0.298 Overall (I-squared = 32.3%, p = 0.023) Burns&Swanson 1991 police
Subtotal (I-squared = 31.8%, p = 0.086) Gaertner 2004 men vehicle drivers
Coggon (1986)
Cassidy (2009)
Burns&Swanson 1991 drivers
bus
Guo 2004 SIR Iyer (1990)
Gaertner (2004)
Colt (2011)a tractor-trailer: men Silverman (1986)
Colt 2004 truck/bus/taxi men
Petersen 2010 SIR other job
Colt (2011)c light
Samanic (2008) Colt (2004)
Jensen 1987 >10 yrs bus/taxi/truck driver
Silverman (1989b) Dolin (1992)
Hoar & Hoover (1985) ID
Guo 2004 SIR
Subtotal (I-squared = 0.0%, p = 0.806) Dryson (2008)
Colt (2004)a tractor-trailer: men
Colt (2011)b heavy Dryson (2008) Brownson (1987)
Band (2005)
Colt (2011) Gaertner (2004) Risch 1988 Men
Samanic (2008)
Dryson (2008)
Pesch 2000 high exhaust exposure men
Subtotal (I-squared = 56.7%, p = 0.014)
Colt (2004)b heavy Siemiatycki (1994) truck
Cordier 1993 street vendors
Reulen 2007 motor vehicle driver
Colt (2004) Guo 2004 SIR Risch 1988 Women
Schifflers (1987)
Colt (2004)c light
taxi
Samanic (2008)
Subtotal (I-squared = 32.5%, p = 0.192) Silverman (1986)
Band (2005) Study
1.18 (1.11, 1.25) 1.00 (0.53, 1.90)
1.16 (1.07, 1.27) 1.08 (0.79, 1.48)
1.60 (1.03, 2.48)
1.43 (0.81, 2.53) 0.70 (0.49, 0.99)
1.29 (1.02, 1.63) 0.48 (0.15, 1.55)
1.23 (0.87, 1.73)
0.90 (0.61, 1.32) 1.50 (1.11, 2.02) 1.20 (0.82, 1.75)
1.60 (1.24, 2.07) 0.80 (0.52, 1.24)
1.14 (0.69, 1.89) 0.80 (0.29, 2.22) 1.29 (1.05, 1.59)
1.30 (0.51, 3.29) 1.24 (0.91, 1.69) 1.50 (0.88, 2.55) RR (95% CI)
1.01 (0.85, 1.20)
1.13 (0.96, 1.34) 0.73 (0.33, 1.61) 2.40 (1.40, 4.11)
1.30 (0.87, 1.94) 1.36 (0.47, 3.96) 1.20 (0.69, 2.08)
1.21 (0.92, 1.60)
1.10 (0.60, 2.01) 1.23 (0.87, 1.73) 1.53 (1.17, 2.00)
0.91 (0.67, 1.24)
1.69 (0.55, 5.23) 1.00 (0.78, 1.27)
1.14 (1.02, 1.27)
0.80 (0.19, 3.35) 1.20 (0.78, 1.85) 3.60 (1.15, 11.26)
0.90 (0.36, 2.25)
0.50 (0.18, 1.41) 1.06 (0.81, 1.39) 0.62 (0.24, 1.62)
2.15 (0.88, 5.27)
1.30 (0.72, 2.36)
0.75 (0.32, 1.74)
1.36 (1.16, 1.60) 1.50 (0.59, 3.82) 1.82 (0.85, 3.90)
100.00 0.83
45.93 3.38
1.77
1.05 2.83
6.35 0.25
2.88
2.27 3.80 2.39
5.21 1.77
1.33 0.33 7.90
0.39 3.51 1.21 Weight
12.01
12.20 0.55 1.18
2.13 0.30 1.13
4.44
0.94 2.88 4.73
3.50
0.27 5.77
28.86
0.17 1.82 0.26
0.40
0.31 4.57 0.37
0.42
0.96
0.48
13.01 0.39 0.59
%
1.18 (1.11, 1.25) 1.00 (0.53, 1.90)
1.16 (1.07, 1.27) 1.08 (0.79, 1.48)
1.60 (1.03, 2.48)
1.43 (0.81, 2.53) 0.70 (0.49, 0.99)
1.29 (1.02, 1.63) 0.48 (0.15, 1.55)
1.23 (0.87, 1.73)
0.90 (0.61, 1.32) 1.50 (1.11, 2.02) 1.20 (0.82, 1.75)
1.60 (1.24, 2.07) 0.80 (0.52, 1.24)
1.14 (0.69, 1.89) 0.80 (0.29, 2.22) 1.29 (1.05, 1.59)
1.30 (0.51, 3.29) 1.24 (0.91, 1.69) 1.50 (0.88, 2.55) RR (95% CI)
1.01 (0.85, 1.20)
1.13 (0.96, 1.34) 0.73 (0.33, 1.61) 2.40 (1.40, 4.11)
1.30 (0.87, 1.94) 1.36 (0.47, 3.96) 1.20 (0.69, 2.08)
1.21 (0.92, 1.60)
1.10 (0.60, 2.01) 1.23 (0.87, 1.73) 1.53 (1.17, 2.00)
0.91 (0.67, 1.24)
1.69 (0.55, 5.23) 1.00 (0.78, 1.27)
1.14 (1.02, 1.27)
0.80 (0.19, 3.35) 1.20 (0.78, 1.85) 3.60 (1.15, 11.26)
0.90 (0.36, 2.25)
0.50 (0.18, 1.41) 1.06 (0.81, 1.39) 0.62 (0.24, 1.62)
2.15 (0.88, 5.27)
1.30 (0.72, 2.36)
0.75 (0.32, 1.74)
1.36 (1.16, 1.60) 1.50 (0.59, 3.82) 1.82 (0.85, 3.90)
100.00 0.83
45.93 3.38
1.77
1.05 2.83
6.35 0.25
2.88
2.27 3.80 2.39
5.21 1.77
1.33 0.33 7.90
0.39 3.51 1.21 Weight
12.01
12.20 0.55 1.18
2.13 0.30 1.13
4.44
0.94 2.88 4.73
3.50
0.27 5.77
28.86
0.17 1.82 0.26
0.40
0.31 4.57 0.37
0.42
0.96
0.48
13.01 0.39 0.59
%
1
.2 .5 1 2 5