INSTITUTE OF OCCUPATIONAL MEDICINE . Edinburgh . UK www.iom-world.org
What should we be doing to prevent occupational diseases
from hazardous substances?
John Cherrie
Summary…
• Workplace disease• The case of workplace cancers• Two key observations that help us plan
our approach• Two examples:• Vinyl chloride monomer• Respirable crystalline silica
• Let’s be bold in our commitment for the future
Accidents and disease around the world
WHO regions
AFRO
AMRO
EURO
SEARO
WPRO
EMRO
Fatal workplace disease/accident rates
Hämäläinen P, Saarela KL, Takala J. Global trend according to estimated number of occupational accidents and fatal work-related diseases at region and country level. Journal of Safety Research 2009;40:125–39.
Ratio disease to accidents
Workplace diseases and their causes…Chemicals Diseases Deaths DALYsChemicals involved in acute poisonings
Unintentional poisonings
30,000 650,000
Asbestos Mesothelioma and other cancers
110,000 1,500,000
Occupational lung carcinogens, e.g. arsenic, silica, chromium
Lung cancer 110,000 1,000,000
Occupational leukaemogens, e.g. benzene
Leukaemia 7,500 110,000
Dust and fumes COPD, asthma 375,000 3,800,000
Prüss-Ustün A, Vickers C, Haefliger P, et al. Knowns and unknowns on burden of disease due to chemicals: a systematic review. Environmental Health 2011;10:9.
Let’s get specific: workplace cancers• In 1981 Richard Doll and
Richard Peto were commissioned by the US government to assess the relative importance of the “environment” in causing cancer
• Their aim was to identify the proportion of cancer that is preventable
Sir Richard Doll
Sir Richard Peto
Attributable fractions…
About 4% (2 – 8%)
Cancer burden in the UK…• Designed to update Doll and Peto’s estimate for
occupational cancer burden• Current burden (2010) • Future burden (to 2060)
• Method based on:• Risk of Disease (relative risk from published literature)• Proportion of Population Exposed
• Estimation for IARC groups 1 (definite) and 2A (probable) carcinogens and occupational circumstances
Rushton L, Hutchings SJ, Fortunato L, et al. Occupational cancer burden in Great Britain. Br J Cancer 2012;107:S3–S7.
Attributable fraction…
5.3% (4.6 – 6.6%)
Men = blueWomen = red
Not all carcinogens are equally important
85% of the cancer cases come from the top ten chemical agents
Some good news…
Creely KS et al. (2007) Trends in inhalation exposure--a review of the data in the published scientific literature. Ann Occup Hyg.; 51(8): 665-678.
Aerosols
Some good news…
Creely KS et al. (2007) Trends in inhalation exposure--a review of the data in the published scientific literature. Ann Occup Hyg.; 51(8): 665-678.
Gases and vapours
14
1973 1974 19751
10
100
1000
f(x) = INF exp( − 2.00333226615499 x )R² = 0.740621920392391
VCM
con
cent
ratio
n (p
pm)
VCM levels in a English PVC plant
Burden should be decreasing…
• If exposure is decreasing then it seems likely that the future burden will also be lower
• Assumes • Risk is related to exposure• Prevalence of exposure is not increasing• The aging population is not
distorting the picture
So what does the future hold?• We have estimated current and future cancer
burden in Europe and socioeconomic costs of interventions for a number of workplace carcinogens• Exposure levels reliant on stakeholder data or
when unavailable published sources• Risk assessment reliant on epidemiological
studies or analogy• Health impact carried out using carefully
reviewed methodology developed for British cancer burden study
• Socioeconomic assessment based on EC guidance
Hutchings S, Cherrie JW, van Tongeren M, et al. Intervening to Reduce the Future Burden of Occupational Cancer in Britain: What Could Work? Cancer Prevention Research Published Online First: 7 September 2012.
Future burden estimates for VCM…• Increased risks angiosarcoma of liver and
possible hepatocellular carcinomas• 19,000 people exposed in Europe• Geometric mean exposure level 0.05 ppm, 5%
exposed above 3 ppm• Current burden - 14 liver cancers• By 2060 we expect there to be
no cancer deaths due to workplace VCM exposure
Risk already eliminated for some substances• In our assessment of current burden in Europe we
estimate <20 cancers/year from past exposure for:• Vinyl chloride monomer 14 cases• 1, 3 Butadiene 2 cases• Beryllium 7 cases• Acrylamide 7 cases• MbOCA 8 cases• Ethylene oxide 0 cases• Refractory ceramic fibre 2 cases• 1, 2-Epoxypropane 0 cases• Bromoethylene 0 cases 1,100,000
Estimates of future burden for silica…• Crystalline silica in Europe:
• 720,000 people exposed• About 40% exposed above 0.05 mg/m3 • Current burden 7,600 lung cancers• 460,000 cases between 2010 and 2069• Cost of inaction between
€190,000m to €490,000m
Lung cancer registrations - baseline
Lung cancer registrations - intervention
The cost and benefits of intervention…• Total net health benefits by 2069 from
setting an OEL at 0.05 mg/m3 are €28,000m to €74,000m
• Costs of compliance estimated to be €34,000m• About half of these costs arise in
construction• Most costs fall on small companies
However, we could just wait…
We could “eliminate” workplace cancer• Elimination of the disease as a public health
problem (i.e. reduction of cases below what is considered to be a public health risk)
• What might be “a public health risk” for occupational cancer?
• Reduction of incidence to <<1% of all cancers?
A challenge…• Focus on the top ten causes of the occupational
cancer burden (and/or COPD)• Ensure that exposures continue to fall by about
10% per annum• We have eliminated the problem when an
assessment of future burden from current exposure is <1% of all cancers
Acknowledgements…• The work was in part funded by the British
Health and Safety Executive (HSE) and the European Commission (EC)
• However, the views presented here are my own
• Collaborators include:• M Gorman Ng, A Shafrir, M van Tongeren, A Searl, J Crawford,
A Sanchez-Jimenez, J Lamb (IOM) • R Mistry, M Sobey, C Corden, O Warwick and M-H Bouhier (AMEC
UK) • L Rushton and S Hutchings (Imperial College)• T Kaupinnen and P Heikkila (Finnish Institute of Occupational
Health),H Kromhout (IRAS, University of Utrecht), L Levy (IEH, Cranfield University)
Questions…• You can contribute to the discussion at
www.OH-world.org