Asbestos Exposure and Smoking Together Increase Lung Cancer Risk more than Separately

by | Apr 22, 2016 | 2015, Cancer, Lung Cancer, Pollution, Tobacco

Written by Greg Arnold, DC, CSCS. Exposure to asbestos increases the risk of lung cancer in smokers by 700% compared to a 70% risk of lung cancer in non-smokers.

Lung cancer is responsible for 1 in 5 global cancer deaths, with a latency period of 20 years and a 10% survival rate (1). 70–90% of all cases of lung cancer are “directly attributed” to cigarette smoking (2), with even secondhand smoke shown to increase lung cancer risk by as much 25% (3). Asbestos is a group of naturally occurring silicate mineral fibers widely used in building materials, vehicle brakes and thermal insulators since the 1900s. There are many well-documented cases of lung disease in asbestos factory workers and miners after 1900 (4, 5, 6).

Now a new study (7) suggests that exposure to both asbestos and cigarette smoking further increases lung cancer risk. Researchers analyzed data on 17 studies, 10 of which were case-control studies comparing 4,327 lung cancer cases with 5,896 controls, and 7 cohort studies comparing 3,316 lung cancer cases to 61, 608 controls. All asbestos exposure cases that occurred in this analysis were job-related.

The researchers noted “a significant difference” in lung cancer risk among workers exposed to asbestos and/or smoking compared to controls. Specifically, compared to the control group (those who have never smoked and have never been exposed to asbestos), they observed:

  • A 70% increased risk of lung cancer in non-smokers exposed to asbestos
  • A 465% increased risk of lung cancer in smokers never exposed to asbestos
  • A 700% increased risk of lung cancer in smokers exposed to asbestos

While the researchers did not provide data on asbestos exposure duration and lung cancer risk, they stated that data in the 17 studies was obtained from lung cell structure, postal questionnaires, and methods like “counting fibers trapped by midget impingers or membrane filters” (8, 9) and “a long-duration personal konimeter” (10) or postal questionnaires (11). Regarding smoking amounts with asbestos exposure, the only group that experienced significant increases in risk were those smoking 10-19 cigarettes per day (p = 0.019) compared to 0-9 cigarettes per day (p = 0.964) and more than 20 cigarettes per day (p = 0.119).

For the researchers, “Our results point to an additive synergism for lung cancer with co-exposure of asbestos and cigarette smoking” and that “Assessments of industrial health risks should take smoking and other airborne health risks when setting occupational asbestos exposure limits.”

When looking for ways to help maintain lung health despite exposure to asbestos and/or smoking, research (12) has shown that taking multivitamins provides protective benefits. Specifically, current daily use of a multivitamin reduced lung cancer risk 43% and past daily use of a multivitamin reduced lung cancer risk by 32%. This suggests possible future recommendations of multivitamin use for overall lung health for those exposed to asbestos and/or smoking.

Source: Ngamwong Y, Tangamornsuksan W, Lohitnavy O, Chaiyakunapruk N, Scholfield CN, Reisfeld B, et al. (2015) Additive Synergism between Asbestos and Smoking in Lung Cancer Risk: A Systematic Review and Meta-Analysis. PLoS ONE 10(8): e0135798. doi:10.1371/journal.pone.0135798

© 2015 Ngamwong et al. Creative Commons Attribution License 

Click here to read the full text study.

Posted October 5, 2015.

Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY.  You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com

References:

  1. Siegel R, Naishadham D, Jemal A. Cancer statistics, 2012. CA: A Cancer Journal for Clinicians. 2012; 62: 10–29
  2. IARC. Tobacco Smoke and Involuntary Smoking. IARC momographs on the evaluation of carcinogenic risks to humans. 2004; 83: 1–1438.
  3. (US) Office on Smoking and Health. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Atlanta (GA): Centers for Disease Control and Prevention (US), 2006
  4. Rake C, Gilham C, Hatch J, Darnton A, Hodgson J, Peto J. Occupational, domestic and environmental mesothelioma risks in the British population: a case-control study. British Journal of Cancer 2009; 100: 1175–1183
  5. Olsen NJ, Franklin PJ, Reid A, de Klerk NH, Threlfall TJ, Shilkin K, et al. Increasing incidence of malignant mesothelioma after exposure to asbestos during home maintenance and renovation. Medical Journal of Australia. 2011; 195: 271–274
  6. Yano E, Wang X, Wang M, Qiu H, Wang Z. Lung cancer mortality from exposure to chrysotile asbestos and smoking: a case-control study within a cohort in China. Occupational and Environmental Medicine 2010; 67: 867–871.
  7. Ngamwong Y. Additive Synergism between Asbestos and Smoking in Lung Cancer Risk: A Systematic Review and Meta-Analysis. PLoS One 2015 Aug 14;10(8):e0135798. doi: 10.1371/journal.pone.0135798. eCollection 2015
  8. Liddell FD, Thomas DC, Gibbs GW, McDonald JC. Fibre exposure and mortality from pneumoconiosis, respiratory and abdominal malignancies in chrysotile production in Quebec, 1926–75. Annals of the Academy of Medicine, Singapore. 1984; 13: 340–344
  9. Rubino GF, Piolatto G, Newhouse ML, Scansetti G, Aresini GA, Murray R. Mortality of chrysotile asbestos workers at the Balangero Mine, Northern Italy. British Journal of Industrial Medicine. 1979; 36: 187–194
  10. Villeneuve PJ, Parent MÉ, Harris SA, Johnson KC, The Canadian Cancer Registries Epidemiology Research Group. Occupational exposure to asbestos and lung cancer in men: evidence from a population-based case-control study in eight Canadian provinces. BMC Cancer. 2012; 12
  11. Berry G, Newhouse ML, Antonis P. Combined effect of asbestos and smoking on mortality from lung cancer and mesothelioma in factory workers. British Journal of Industrial Medicine. 1985; 42: 12–18
  12. Flores FG.  Multi-Vitamins, Folate, and Green Vegetables Protect Against Gene Promoter Methylation in the Aerodigestive Tract of Smokers.  Cancer Research 2010. Published online ahead of print, doi: 10.1158/0008-5472.CAN-09-3410