The potential impact on women from environmental exposures: observations from the Centers for Disease Control and Prevention.

The Agency for Toxic Substances and Disease Registry (ATSDR) has established the National Exposure Registry (NER) for the purpose of assessing the potential long-term health impact on the general population of exposures to environmental hazards such as those at Superfund sites. Using published policies and procedures, ATSDR has established four chemical-specific subregistries - trichloroethane (TCA), trichloroethylene (TCE), benzene, and dioxin - and is following approximately 10,000 registrants longitudinally (1-6). The NER collects, at baseline and at ongoing biennial follow-ups, information on demographics; smoking, occupational, and reproductive histories; and 25 general health conditions. The rates of reported health conditions are compared with national norms. The comparison results are viewed as interim or hypothesis generating. ATSDR might conduct a more in-depth study based on the findings.

There is very little available information on the potential health effects of low-level exposures of long duration - the type of exposures commonly experienced at waste sites - in a general population. Most information on the health effects of exposure to hazardous substances comes from occupational studies of healthy males and toxicologic studies in which such low-level, long-term environmental exposures cannot be duplicated. Of particular concern is the lack of information about the impact on sensitive subpopulations, such as children, the elderly, those who are sick, and pregnant women. When environmental exposures occur, usually in the home, these sensitive subpopulations experience the greatest exposure because of the nature of their activities and the time spent in the home. The NER is addressing this paucity of relevant health information on environmentally exposed general populations, including sensitive subpopulations and all women, by amassing information. To date, the NER has longitudinal data on approximately 5,000 female registrants, ranging in age from infants to the elderly, who have documented exposure to a specific hazardous substance in the environment. In addition to the baseline data collection, the NER data collection is a longitudinal effort (biennial updates) because the expected outcome for a general population - should there be one - is not known, and, therefore, the expected latency is not known. Some subregistry populations have been followed since 1988.

To determine if there is excess reporting of adverse health outcomes, the registrants' reporting rates for 25 general health outcomes and symptoms were compared (adjusted for sex and age) with national norms provided by the National Health Interview Survey. Statistically significant increases in reports of several health outcomes, that is, anemia and other blood disorders, skin rashes, and stroke, by select age and sex groups were found for registrants of at least one of the active subregistries. For other health outcomes, that is, diabetes, kidney problems, liver problems, and urinary tract disorders, increased reports were found predominantly in women (Table 1).

This information, supplemented with additional information from analyses of the follow-up data, indicates that there is excess reporting of health problems by environmentally exposed women that might be associated with exposure to low-level hazardous substances over extended periods. A more definitive assessment of this association will be made using the additional information and study results being compiled. In some cases, ATSDR decided to carry out additional studies to explore the hypotheses suggested by these baseline data results.

ATSDR is very interested in sharing this information. Baseline information for the TCE subregistry is currently available from ATSDR (without personal identifiers) on CD-ROM. For additional information on these and other data from the NER, contact Je Anne R. Burg, Ph.D., Chief, Exposure and Disease Registry Branch, ATSDR, 1600 Clifton Road, E-31, Atlanta, GA 30333.

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REFERENCES

1. Agency for Toxic Substances and Disease Registry (1994), National Exposure Registry: Policies and Procedures (Revised), Atlanta: U.S. Department of Health and Human Services, Public Health Service, 1994.

2. Burg, J.R., G. Gist, S.A. Allred, T.M. Radtke, L.L. Pallos, and C.D. Cusack (1994), National Exposure Registry Trichloroethylene (TCE) Subregistry Baseline Technical Report (Revised), Atlanta: U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry, NTIS Publication No. PB95-154589.

3. Burg, J.R., G.L. Gist, and T.M. Radtke (1995), National Exposure Registry Benzene Subregistry Baseline Technical Report, Atlanta: U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry, NTIS Publication No. PB95-255766.

4. Burg, J.R., L.L. Pallos, G.L. Gist, T.M. Radtke, and C.D. Cusack (1996), National Exposure Registry Trichloroethylene (TCE) Subregistry Follow-Up 1 Technical Report, Atlanta: U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry, NTIS Publication No. PB96-157573.

5. Burg, J.R., and G.L. Gist (1996), National Exposure Registry, 1,1,1-Trichloroethane (TCA) Subregistry Baseline and Follow-Up 1 Technical Report, Atlanta: U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry, NTIS Publication No. PB96-172101.

6. Burg, J.R., G.L. Gist, B. Kieke, and T.M. Radtke (1996), National Exposure Registry Dioxin Subregistry Baseline and Follow-Ups 1 and 2 Technical Report, Atlanta: U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry, NTIS Publication No. PB96-196693.