Social inequalities and their impact on exposures to carcinogens and occupational cancer Elsebeth Lynge University of Copenhagen WORKSHOP ON CARCINOGENS AND WORK-RELATED CANCER Berlin, 3 September 2012

Occupational cancer Traditional study approaches Exposure to cancer approach: Estimation of cancer incidence from exposures to known work-place carcinogens Cancer to ”exposure” approach: Observed cancer incidence of occupational groups controlled for social class / life-style carcinogens EXPOSURECANCER

Exposure to cancer approach – the famous debate Bridbord et al. (OSHA-report), 1978: Estimates of the fraction of cancer in the United States related to occupational factors Asbestos: number exposed, percent who died from various cancers Arsenic, benzene, chromium, nickel, and petroleum products: Exposed (N), Relative risk RR), Incidence (I) Conclusion: ”In our view there is nothing in the gross cancer statistics for the U. S. population which is inconsistent with the hypothesis that up to 20-40% of all cancers are … attributable to occupational factors”

Exposure to cancer approach – the famous debate Doll and Peto, 1981: Estimates of the fraction of cancer in the United States related to occupational factors Cancers: 1) not known to be produced by occupational hazards; 2) that possible may be produced by occupational hazards; 3) that definitely can be produced by occupational hazards Conclusion: ”The proportion of cancer deaths that we have tentatively attributed to occupational causes is … about 4% of all US cancer deaths”

Exposure to cancer approach – recent estimate Rushton et al., 2012: Occupational cancer burden in Great Britain Attributable fraction, AF: proportion of cancer cases that would not have occurred in the absence of exposure Exposures: IARC Gruup 1 or 2A carcinogens Risk estimates: Key studies, meta-analysis, pool studies Number exposed: CARcinogen EXposure (CAREX), UK Labour Force Survey, Census of Employment Cancer incidence: 2004

Etc. Rushton et al, 2012

Exposure to cancer approach – recent estimate Rushton et al., 2012: Occupational cancer burden in Great Britain Attributable fraction, AF: proportion of cancer cases that would not have occurred in the absence of exposure Exposures: IARC Gruup 1 or 2A carcinogens Risk estimates: Key studies, meta-analysis, pool studies Number exposed: CARcinogen EXposure (CAREX), UK Labour Force Survey, Census of Employment Cancer incidence: 2004 AF: men 5.7% ; women 2.1% ; all 4.0% AF: men lung cancer 21.1%

Cancer to ”exposure” approach - controlled for social class Fox & Adelstein, 1978: Occupational mortality: work or way of life? Variation in cancer mortality between occupational orders associated with work: 12% OccupationClassSMRAdj SMR Stevedores/dock lab.V Bun conductorsIV PaintersIIIM ClerksIIIN TeachersII6682 DoctorsI81105

Cancer to ”exposure” approach - controlled for life-style carcinogens Haldorsen et al., 2005: Smoking-adjusted incidence of lung cancer by occupation among Norwegian men Across 42 occupational groups: observed cases 12,250, expected cases taking smoking into account 8893, excess for all 21%, excess for econ. active 17% OccupationSIRAdj SIR95% CI Farmer Physician Glass/chemamics Waiter

So, what can we conclude from the traditional approaches From exposure to cancer: 4% of cancers From cancer to ”exposure”: 12% of cancers Point to existence of unidentified work-place carcinogens Men: Exposure to lung cancer: 21% of cancers Men: Lung cancer to ”exposure”:21% of cancers Strength of Exposure to lung cancer approach is direct use for prevention, e.g. for British HSE: asbestos, respiratory crystalline silica, diesel engine exhaust, [shift work and breast cancer], construction industry, Chen & Osman, 2012

What is an occupational cancer? ”We have to decide how to classify cancers such as the: lip and skin cancers produced by exposure to UV light associated with work in the open air, cancers of the upper respiratory and digestive tract due to the consumption of alcohol associated with work in bars, restaurents, and … manufacture of alcoholic drinks, cancer of the cervix uteri in prostitutes due to intercourse with many men, and cancer of the breast in nuns due to the avoidance of pregnancy. As these are not the sort of cancers that are commonly termed ”occupational”, we should perhaps omit them, although we do so reluctantly.” Doll & Peto, 1981

What is an occupational risk factor? During the tobacco smoking epidemia, smoking was predominantly considered a personal life-style habit, a confounder not caused by occupation Obesity new epidemic causally associated with cancer of the colon, breast, endometrium, oesophagus, and kidney, IARC, 2002 During the obesity epidemia, the personal life-style habit concept is increasingly questionned Obesogenic environment, geographical concentrations of fast-food outlets, Poston & Foreyt, 1999 Obesity as response to stress invoked by economic insecurity, Offer et al, 2010

A work-related approach to occupational cancer NOCCA Nordic Occupational Cancer Study NOCCA I, Andersen et al., 1999 Cohort study of 1970-census population 10 million people 1 million cancers NOCCA II, Pukkala et al., 2009 Cohort study of 1960, 1970, 1980 and 1990-census populations 15 million people 2.8 million cancers

NOCCA I, 1999

The cancer you get reflects the life you have lived and this is closely linked to your occupation

Socially discriminating cancers NOCCA II, 2009

Traditional occupational cancers, all the rest traditional life-style cancers NOCCA II, 2009

So, what can we conclude from the work-related approach Variation across occupational groups in cancer incidence is much wider than the variation traditionally termed ”occupational cancers” Obesity, tobacco smoking, alcohol use, etc. are not soleby personal life-style habits These exposures are also determined by the living environment and the experience of subordination and economic insecurity which may come with the occupation

Conclusion Social inequalities and their impact on exposures to carcinogens and occupational cancer In the social inequality perspective a two-tier strategy is needed for prevention of occupational cancer First, the British HSE- approach: asbestos, respiratory crystalline silica, diesel engine exhaust, shift work and breast cancer, construction industry, Chen & Osman, 2012 Second, the broader political approach: liberal market economies (e.g. USA, Britain) versus coordinated market economies (e.g. Germany, Nordic), Offer et al, 2010

Conclusion Social inequalities and their impact on exposures to carcinogens and occupational cancer In the social inequality perspective a two-tier strategy is needed for prevention of occupational cancer First, the British HSE- approach: asbestos, respiratory crystalline silica, diesel engine exhaust, shift work and breast cancer, construction industry, Chen & Osman, 2012 Second, the broader political approach: liberal market economies (e.g. USA, Britain) versus coordinated market economies (e.g. Germany, Nordic), Offer et al, 2010 Useful tools, but only part of the solution

Thank you for your attention Copenhagen Old Municipality Hospital, now part of University of Copenhagen