Severe Cognitive Dysfunction and Occupational Extremely Low Frequency Magnetic Field Exposure among Elderly Mexican Americans.
OBJECTIVE
This report is the first study of the possible relationship between extremely low frequency (50-60 Hz, ELF) magnetic field (MF) exposure and severe cognitive dysfunction. Earlier studies investigated the relationships between MF occupational exposure and Alzheimer's disease (AD) or dementia. These studies had mixed results, depending upon whether the diagnosis of AD or dementia was performed by experts and upon the methodology used to classify MF exposure.


METHODS
Population-based case-control.


METHODS
Neurology and Preventive Medicine, Keck School of Medicine, University of Southern California, 2 years.


METHODS
The study population consisted of 3050 Mexican Americans, aged 65+, enrolled in Phase 1 of the Hispanic Established Population for the Epidemiologic Study of the Elderly (H-EPESE) study. Mini-Mental State Exam (MMSE) results, primary occupational history, and other data were collected. Severe cognitive dysfunction was defined as an MMSE score below 10. The MF exposure methodology developed and used in earlier studies was used.


RESULTS
Univariate odds ratios (OR) were 3.4 (P< .03; 95% CI: 1.3-8.9) for high and 1.7 (P=.27; 95% CI: 0.7-4.1) for medium or high (M/H) MF occupations. In multivariate main effects models, the results were similar. When interaction terms were allowed in the models, the interactions between M/H or high occupational MF exposure and smoking history or age group were statistically significant, depending upon whether two (65-74, 75+) or three (65-74, 75-84, 85+) age groups were considered, respectively. When the analyses were limited to subjects aged 75+, the interactions between M/H or high MF occupations and a positive smoking history were statistically significant.


CONCLUSIONS
The results of this study indicate that working in an occupation with high or M/H MF exposure may increase the risk of severe cognitive dysfunction. Smoking and older age may increase the deleterious effect of MF exposure.
Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
Zoreh
Z
Davanipour
Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
Chiu-Chen
CC
Tseng
Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
Pey-Jiuan
PJ
Lee
Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, Texas 77555-1153, USA.
Kyriakos S
KS
Markides
Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA ; Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
Eugene
E
Sobel
Dementia; Elderly Mexican Americans; Extremely Low Frequency Magnetic Fields; Hispanic Established Population for the Epidemiologic Study of the Elderly (H-EPESE); Mini-Mental State Exam; Occupational Exposure; Severe Cognitive Dysfunction