CHALLENGING THE IMMUNE SYSTEM

Is cleanliness next to godliness? Not so, according to Professor Harvey Checkoway, quoted in a recent story in New Scientist magazine. Checkoway noted that dairy farmers, who breathe in dust mixed with dried manure and its associated bacteria, are as much as five times less likely to develop lung cancer than nonfarmers.

Kids in daycare may develop healthier immune systems. Photo by Ken Hammond, USDA.

Epidemiologists have also found that children who attend daycare in their first few months are much less likely to develop leukemia than those who stay at home. Checkoway said immune stimulation by bacteria and viruses may prevent some cancers.

In one of the largest occupational epidemiology cohort studies ever conducted, Checkoway and a research team found that a certain type of bacterial toxin might protect Shanghai textile workers from lung and other cancers.

The lung cancer result may have been strongly influenced by cotton dust and endotoxin exposures. Endotoxins are a particular type of toxin bound to gram negative bacterial cells that are released when the cells are disrupted.

The New Scientist piece questions whether the higher incidence of certain cancers in affluent populations—including breast cancer, lymphoma and melanoma—might have something to do with sanitized living. Based on the literature, Checkoway thinks it might.

Further Reading

Astrakianakis G, Seixas NS, Ray R, Camp JE, Gao DL, Feng Z, Wernli K, Fitzgibbons ED, Thomas DB, Checkoway H. Reduced risk of lung cancer among female textile workers exposed to endotoxin. J Natl Cancer Inst 2007; 99(5):357–364.

Marshall, J. Filthy healthy: The cancer hygiene hypothesis. New Scientist, Jan. 12, 2008; 197(2638):34–37.

DISCOVER GRANT

The National Institute of Environmental Health Sciences (NIEHS) has selected the UW as one of the first three research centers in the United States to define the role of environmental agents in human disease.

The three new centers called DISCOVER (Disease Investigation through Specialized Clinically Oriented Ventures in Environmental Research) will receive $6.8 million for the first year of funding to bridge the gap between basic research and clinical diseases caused by the environment.

"The DISCOVER centers will help to define the role of environmental agents in the initiation and progression of human disease and develop new ways to both prevent and treat disease," said Dennis Lang, interim director, NIEHS Division of Extramural Research and Training, as he announced the awards.

Professor Joel Kaufman and colleagues will study the impact of traffic-related air pollution on cardiovascular disease. Specifically, the program will seek to increase understanding of biological pathways related to inflammation and vascular dysfunction from air pollutants and progression of cardiovascular disease.

Eventually, their findings could help prevent cardiovascular disease through educational outreach opportunities to both the medical and public health communities.

The other centers are Johns Hopkins Bloomberg School of Public Health, Baltimore; and Columbia University School of Public Health, New York City

-Justin Reedy