Cancer, Reproductive, and Cardiovascular Diseases: Occupational Risks

Input: Occupational Safety and Health Risks

Burden of Occupational Disease

Deaths due to occupational disease are an important source of human suffering and economic cost. It has been estimated that between 26,000 and 72,000 deaths due to occupational disease occur yearly in the United States,¹ while the Bureau of Labor Statistics has estimated that nearly 300,000 occupational illnesses occurred in 2002.²

Costs of occupational illness in the United States have been estimated to be more than 14 billion dollars yearly.³ Occupational cancers and occupational heart disease are important components of the total burden of occupational disease. Estimates of the range of deaths in the United States due to occupationally-related cancer and heart disease are 12,000–26,000 deaths and 6,000–18,000 deaths per year, respectively,¹ with costs being estimated at 9 billion dollars for those two groups of illnesses.³

Worldwide, occupational carcinogens were estimated to cause 152,000 deaths and nearly 1.6 million disability adjusted life years in 2000.⁴

Occupational Cancer

Many sources of data exist on occupational carcinogens, including data concerning single agents and complex mixtures as preventable causes of occupational cancer and occupational groups at high risk for cancer.⁵ Many epidemiologic studies, within specific industries and/or addressing specific exposures, have identified elevated cancer risks among workers. These studies are too numerous to detail here. Among recent examples, a published update of the mortality status of 7,800 workers exposed to solvents in the manufacture of shoes revealed an excess of lung cancer deaths (standardized mortality ration=1.36, 95% confidence interval=1.19-1.54).⁶ This study supports a possible association between lung cancer mortality and exposure to chronic, low levels of organic solvents, a finding supported by other studies. One of the goals of CRC research is to followup on cohorts such as this to continue to increase our knowledge about exposures, interventions, and health effects with the goal of preventing occupational cancer.

Surveillance systems are available that provide data addressing potentially occupationally related cancer. The NIOSH National Occupational Mortality Surveillance System is a database of death certificate data with coded occupation and industry information. Investigators can use these data to survey association of cause-specific mortality and occupation and/or industry. The measure of association used most often in this system is the proportionate mortality ratio. For example, this database can be used to survey associations of cancer (or other health outcomes such as heart disease) mortality among persons from different occupations. Regarding lung cancer specifically, surveillance information is available from sources including the Work-Related Lung Disease Surveillance Report, 2002. This surveillance activity has identified a number of industries in which workers have elevated lung cancer mortality pdf icon[PDF – 115 KB].

Cardiovascular Disease

Heart disease is the major single cause of mortality in the United States, accounting for 29% of deaths in 2002 pdf icon[ PDF – 1.26 MB]. Little is known about occupational risks for heart disease. A few specific toxins encountered occupationally are known to affect the heart, including carbon disulfide, nitroglycerin, carbon monoxide and environmental tobacco smoke. For example, concerning environmental tobacco smoke, a large prospective epidemiologic study by NIOSH CRC investigators and others found approximately 20% higher coronary heart disease death rates among never smokers exposed to environmental tobacco smoke. (Environmental tobacco smoke and coronary heart disease in the ACS CPS-II cohort. Circulation 1996. 94:622-628). A risk assessment addressing occupational settings has determined that exposure to environmental tobacco smoke is associated with increased risk of death from ischemic heart disease among nonsmoking U.S. workers.⁷ Increased epidemiologic research into occupational heart disease has been called for;⁸ among the goals of CRC research is improved understanding and prevention of occupational cardiovascular disease.

Reproductive Health

There is significant public health concern about potential effects of occupational exposures on reproductive outcomes. Examples of substances with reported reproductive or developmental effects still in regular commercial use include heavy metals (such as lead), solvents, and pesticides. Estimates of adverse reproductive outcomes demonstrate widespread impact—for example, it is estimated that 10% to 20% of recognized pregnancies end in spontaneous abortion, and that 3% of all live births have major malformations.⁹ Others have estimated that 3% of major malformations are due to toxicant exposure, 23% are due to multifactorial causes, and 40% are due to unknown causes.¹⁰ Despite the public health concern and the widespread impact, progress has been limited in identifying occupational reproductive hazards and in separating the contributions of potential occupational hazards from other etiologic factors. One of the goals of the NIOSH CRC program, in collaboration with many partners, is to take advantage of recent technologic and methodologic advances in reproductive health research to improve health and reduce adverse reproductive health outcomes.

References

1. Dying for work: The magnitude of U.S. mortality from selected causes of death associated with occupation.
   AJIM 2003; 43:461-482
2. Characterizing the burden of occupational injury and disease.
   JOEM 2005; 47(6):607-622
3. Medical costs of fourteen occupational illnesses in the United States in 1999.
   Scand J Work Environ Health 2003; 29(4):304-313
4. The global burden of disease due to occupational carcinogens.
   AJIM 2005; 48:419-431
5. Overview of preventable industrial causes of occupational cancer.
   Environ Health Perspect 1995; 103:197-203
6. Mortality of workers employed in shoe manufacturing: An update.
   AJIM 2006; 49:535-546.
7. Risk assessment for heart disease and workplace ETS exposure among nonsmokers.
   Env Health Persp 1999; 107(S6):859-863.
8. Epidemiology of occupation and coronary heart disease: research agenda.
   AJIM 1996; 30:495-499
9. An occupational reproductive research agenda for the third millennium.
   Env Health Perspectives 2003; 111(4):584-592
10. Impact of the detection and prevention of developmental abnormalities in human studies.
    Reprod Toxicol 1997; 11:267-269;
    Introduction to the symposium. Reprod Toxicol 1997; 11:261-263.;
    Frequency of human congenital malformations. Clin Perinatol 1986; 13(3):545-554

Other Relevant Peer-Reviewed Literature

Other examples of peer-reviewed literature that may be sources of information on which to guide future work of the CRC include the following:

Prioritization of NTP reproductive toxicants for field studies
Reprod Toxicol 2000; 14(4):293-301.
This article describes a systematic method for prioritizing chemicals that may need human reproductive health field studies.

Priorities for development of research methods in occupational cancer
Env Health Perspectives 2003; 111(1):1-12.
This article identifies needs and gaps in occupational cancer research methods in four broad areas: identification of occupational carcinogens, design of epidemiologic studies, risk assessment, and primary and secondary intervention.