Authors
Carpenter, D.O., Shen, Y., Nguyen, T., Le, L., & Lininger, L.L.

Title
Incidence of endocrine disease among residents of New York areas of concern.

Journal
Environmental Health Perspectives. Suppl. 6: 845-851. 2001.

Summary
The International Joint Commission (IJC) was created by the United States and Canada to allow for cooperation in the management of the waterways that reside on the Canada/US border. The majority of the work of the IJC has been in assisting governments to clean up the Great Lakes and prevent further pollution. In 1987, a protocol was signed between the US and Canada which called on the Commission to review “Remedial Action Plans” in 43 “Areas of Concern”. These plans were prepared by communities and governments and contained strategies to clean up the problem areas and promote sustainable development of the Great Lakes region. The authors in this study were approached by the IJC to compare the incidence of endocrine diseases in the New York Areas of Concern compared to other regions.

The study focused on 3 of the 6 Areas of Concern (Niagara River, 18 Mile Creek, Buffalo River) in New York state. This was established on the basis that these areas are neighboring Areas of Concern and they have similar contaminants including PCBs, dioxins, furans, and persistent pesticides. Data on disease incidence was collected from the New York Statewide Planning and Research Cooperative System (SPARCS) database. The SPARCS database contains records of all diagnoses upon hospital discharge for all hospitals covered by Article 28 of New York State law and does not include patients admitted to federal or Veterans Administration hospitals or patients who seek medical attention outside of New York. Endocrine disorders were selected from the database using International Classification of Disease Code, 9th edition codes (ICD-9). The frequency of the ICD-9 codes for disorders of the thyroid gland (ICD 240-246), ovarian dysfunction (ICD 255), testicular dysfunction (ICD 257), diseases of the female genital tract (ICD 617-629) as well as endometriosis (ICD 617) and infertility (ICD 628) were used in the analysis. ZIP code data within 15 miles of the Areas of Concern was utilized to establish exposure. Three different comparison populations were used in the study in order to control for confounding factors. First, the authors compared the diagnosis of endocrine disease in the 3 Areas of Concern (n=1 102 158) compared to New York State, excluding New York City (n=16 224 726). New York City was excluded from all the analyses because it differs significantly from the rest of New York State. The second comparison group was based on Superfund sites. The New York Department of Environmental Conservation has identified 865 state Superfund sites. The authors reviewed the list and identified ZIP codes containing a state or federal Superfund site and further identified those with PCBs, dioxins, furans, or persistent pesticides listed as major contaminants. Those ZIP codes that did not contain or adjoin any Superfund site (n=1 258 ZIP codes or 4 641 170 persons) were used as the second comparison group. The final comparison group was composed of people that resided in ZIP codes that contained or adjoined with a Superfund site but did not list PCBs, dioxins, furans, or persistent pesticides. These areas had mostly metals or volatile organics as the major contaminants. The health effects are unlikely to be similar and the per capita income in these areas is expected to be parallel (n=1 499 ZIP codes; 7 772 250 persons).

Carpenter et al. found significantly higher incidences of infertility, disorders of the female reproductive tract, endometriosis, and thyroid disorders in women living in the three Areas of Concern. Specifically, using summarized age standardized morbidity ratios, female thyroid disorders and other disorders of the female genital tract were significantly elevated (p<0.01) for all age groups (25-44, 45-74 and = 75) compared to all three comparison groups.

Using ZIP codes as the measurement of exposure has clearly limited this study. There are several factors that could have contributed to the differences in disease incidence including: socioeconomic status, diet, exercise, genetics, and access to health care. Nevertheless, this study is an important first step in the identification of disease trends in areas exposed to suspected endocrine disruptors. Furthermore, this study provides consistency to other study findings. If environmental contaminants are acting on the endocrine system, scientists should find similar results independent of one another. Canadian studies have found an increased incidence of thyroid disease in women from the Detroit River, St. Clair River, St. Mary’s River, Collingwood, Jackfish and Metro Toronto Areas of Concern. Further research with enhanced exposure measurements would help to further assess the impact that PCBs and other organochlorine compounds have on the endocrine function of human populations.