[ EMF-Link Home
| Online Store
| Comments
| Up One Level ]
| TITLE: | Magnetic Fields and Breast Cancer Risk | ||
| Principal Investigator |
John M. Peters, M.D. | University of Southern California | |
| Health Relevance |
Cancer | ||
| Research Categories |
Studies Involving People | Epidemiological Research | Breast Cancer |
| FY95 Funds | R01ES06921 $ 146,904 | Start Date 9/8/94 | End Date 8/31/98 |
| Rationale and Summary |
In developing countries, increases in breast cancer incidence occur simultaneously with increases in
industrialization. Increased exposure to magnetic fields has been offered as one possible
explanation of this occurrence. Therefore, we are conducting a nested case-control study of the
possible association between magnetic field and breast cancer risk in African-American and Latino
women in Los Angeles County. The research questions being addressed are as follows:
Primary: 1. Is residential exposure to magnetic fields, as assessed by wiring configuration coding in homes occupied over the past 10 years before diagnosis, associated with the risk of breast cancer. Wiring configuration coding is a method that uses data on the types and distances to nearby outdoor electrical wiring to impute magnetic field levels in homes. 2. Do higher exposures to alternating current (AC) magnetic fields, as assessed by 7 days of measurements, increase a woman’s risk of breast cancer. Secondary 1. Do particular combinations of the alternating current (AC) magnetic field and the direct current (DC) magnetic field, increase the risk of breast cancer. The AC field results from our use of the 60 Hz electric power supplied by the utilities; the DC (or static) field results from the earth’s magnetic field but is altered by the environment within residences. This hypothesis was prompted by observations of biologic effects at particular combinations of the AC and DC fields in several experimental systems. |
||
| Experimental Design and Exposure Conditions |
The study population is composed of African-American and Latino women in Los Angeles County
who responded to a mailed questionnaire on a variety of diet and lifestyle factors related to cancer
risk. Women who did not report breast cancer on this questionnaire but who develop it during the
4.5 years of the study will be included. Controls will be randomly sampled from women who do
not have breast cancer in the cohort.
Magnetic field assessments are performed using wiring configuration coding of all homes occupied in Los Angeles County for at least 6 months during the 10 years prior to the reference date. The reference date for cases is 6 months prior to diagnosis; for controls an equivalent date is generated. AC magnetic fields measurements are performed with an EMDEX LITE (Enertech Consultants, Campbell CA) for 7 days - 1 day of personal monitoring, 6 days of measurements in the bedroom. The home occupied at the reference date will be measured. We are also conducting static field spot measurements on day 7 of the measurement period using a fluxgate magnetometer (Walker Scientific, Worcester MA). The home occupied at the reference date will be measured. A questionnaire will be used to collect information on light at night (a potential confounder) and employment in occupations with potential exposure to EMF. Information on known risk factors for breast cancer will be obtained from the previously completed cohort study questionnaire. Standard methods for the analysis of data from case-control studies will be used. |
||
| Quality Assurance Measures |
Wire mapping and coding are done bind to case-control status.
Emdex meters are calibrated in the office weekly using a calibration system designed by Dr. William Kaune and then factory calibrated every 6 months. Magnetometers are calibrated in the office using a device designed by Dr. Kaune. In the event of malfunction they will be returned for repair or replaced. |
||
| Results and Discussion |
This is a 5 year epidemiologic study. The first year was devoted to setting up all study protocols and pilot testing and then finalizing the protocols in the field. This has been successfully accomplished and we began enrolling real study subjects in the spring. Data entry screens have recently been completed and questionnaire and spot measurement data are currently being entered into the computer. Data reduction software is being written to generate summary statistics from the large volume of data generated by the Emdex 7 day recordings. Because of the long term nature of this project, we are not able to present results at this time. We have enrolled 56 cases and 74 controls. There have been essentially no changes in the methods originally proposed. Participation rates are at the level we had predicted in the original submission which is substantially better than standard population based case-control studies in these ethnic groups. | ||
| Recent Publications |
None. | ||