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WORKSHOP ON CARCINOGENS AND WORK-RELATED CANCER Berlin, 3 September 2012. Social inequalities and their impact on exposures to carcinogens and occupational cancer. Elsebeth Lynge University of Copenhagen elsebeth@sund.ku.dk. Occupational cancer Traditional study approaches.
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WORKSHOP ON CARCINOGENS AND WORK-RELATED CANCER Berlin, 3 September 2012 Social inequalities and their impact on exposures to carcinogens and occupational cancer Elsebeth Lynge University of Copenhagen elsebeth@sund.ku.dk
Occupational cancerTraditional 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 EXPOSURE CANCER
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%
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%
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
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
ConclusionSocial 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
ConclusionSocial 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
Thankyou for your attention Copenhagen Old Municipality Hospital, now part of University of Copenhagen