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Extramural Papers of the Month

By Jerry Phelps
November 2007

Safety Oversight among Contract Workers not Equal to DOE Workers

Recent NIEHS-funded research on safety and health programs within the Department of Energy (DOE) found that hiring contractors often provides specialized knowledge in solving a problem, but also can bring “young, inexperienced, inadequately trained workers onto industrial and hazardous waste sites.”

The researchers found that reliable data on subcontractor health and safety programs are limited. They also found that DOE has first-rate safety standards, but that these standards are not always adhered to by contract workers, making for unsafe work conditions in some instances. They point out that DOE is increasing agency efforts toward enhancing contractor protection, but that there are lucrative financial incentives for productivity that are not offset by “disincentives for unsafe work practices.”

The report points out that these findings are probably not unique to DOE because of the increased national and international trends for outsourcing of work traditionally done by direct hires. The research team recommends that “site hosts” such as DOE maintain stringent oversight of safety and health programs for all workers by working with contractors at all levels to value safety of workers above all other considerations and that contracting should not be viewed as a means of lessening the liability of the owners of hazardous waste sites and facilities.

Citation: Gochfeld M, Mohr S Exit NIEHS . Protecting contract workers: case study of the US. 2007. Department of Energy's nuclear and chemical waste management. Am J Public Health 97(9):1607-1613.

High Blood Urate Levels Linked to Lower Risk of Parkinson’s Disease

A large-scale prospective epidemiologic study investigating the link between plasma urate levels and the risk of Parkinson’s disease conducted by NIEHS-funded researchers shows that the higher the urate level, the lower the risk of the progressive neurodegenerative disease.

The researchers used a cohort of more than 18,000 men who were participating in the Harvard-based Health Professionals Follow-up Study, which began in 1986. Blood samples were drawn between 1993 and 1995, and the subjects’ health status has been followed since.

Men with plasma urate concentrations in the top 25 percent exhibited 55 percent lower risk of developing Parkinson’s disease over the course of the study than men in the bottom 25 percent. These results mirror those seen in two previous yet smaller studies.

The research team hypothesizes that the antioxidant properties of urate may be the cause of the decreased risk. Oxidative stress is thought to contribute to the progressive loss of dopamine producing neurons in Parkinson’s cases. To follow-up on this finding, two of the researchers are collaborating on the design of a clinical trial in Parkinson’s disease patients to determine whether elevating levels of urate may slow the progression of the disease.

Citation: Weisskopf MG, O'Reilly E, Chen H, Schwarzschild MA, Ascherio A. 2007. Plasma urate and risk of Parkinson's disease. Am J Epidemiol 166(5):561-567.

Solid Waste Facilities in N.C. Disproportionately Located in Communities of Color

Landfills and other solid waste facilities are twice as likely to be located in communities of color in North Carolina, according to new NIEHS-funded research findings reported in the September 2007 issue of Environmental Health Perspectives.

A research team from the UNC School of Public Health examined records for all solid waste facilities in North Carolina as of 2003 and found that 419 facilities were permitted as of the end of 2003. Facilities were 2.1 times more likely to be found in communities with greater than 10 percent people of color. The research also found that facilities were 1.4 times more likely in communities with average home values less than $100,000.

Newer facilities permitted between 1990 and 2003 were 2.2 times more likely to be found in communities with populations made up of greater than 10 percent minorities. Numbers were similar for private versus public facilities.

The communities that host these facilities are concerned about their health and well being because of truck traffic and traffic-related pollution, odor, noise and water contamination. Other concerns include the effect on property values and the effects these facilities have on the location of schools, medical facilities and cleaner industries.

Citation: Norton JM, Wing S, Lipscomb HJ, Kaufman JS, Marshall SW, Cravey AJ Exit NIEHS. Race, wealth, and solid waste facilities in North Carolina. 2007. Environ Health Perspect 115(9):1344-1350.

Epigenetics vs. Gene Mutations in Colorectal Cancer

A large research team at John’s Hopkins University led by NIEHS grantee Stephen Baylin has developed a new method they term a “transcriptome-wide approach” to identify genes susceptible to hypermethylation and transcriptional silencing in human colorectal cancer.

Using microarray technology, the new approach enables the identification of genes silenced by promoter hypermethylation and identifies candidate cancer genes in single tumors with a high degree of accuracy. The team estimates that nearly 5% of all known genes may be methylated in individual tumors. They found more hypermethylated genes than mutated genes in tumor tissue.

The study data indicate that for any cancer, failing to screen for both genetic and epigenetic changes may result in underestimating the full range of gene alterations and subsequent cellular pathway abnormalities. The overall findings point towards the need for genome-wide cancer gene screening efforts to include studying hypermethylated genes. These genes should be prioritized for sequencing to find mutations as well as prioritizing newly discovered mutations to be analyzed for methylation.

Citation: Schuebel KE, Chen W, Cope L, Glockner SC, Suzuki H, Yi JM, Chan TA, Van Neste L, Van Criekinge W, van den Bosch S, van Engeland M, Ting AH, Jair K, Yu W, Toyota M, Imai K, Ahuja N, Herman JG, Baylin SB. 2007. Comparing the DNA hypermethylome with gene mutations in human colorectal cancer. PLoS Genet 21;3(9):1709-1723.


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