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

John.Cherrie@iom-world.org