D. Baris et al., A CASE COHORT STUDY OF SUICIDE IN RELATION TO EXPOSURE TO ELECTRIC AND MAGNETIC-FIELDS AMONG ELECTRICAL UTILITY WORKERS, Occupational and environmental medicine, 53(1), 1996, pp. 17-24
Objectives-This case cohort study examines whether there is an associa
tion between exposure to electric and magnetic fields and suicide in a
population of 21 744 male electrical utility workers from the Canadia
n Province of Quebec. Methods-49 deaths from suicide were identified b
etween 1970 and 1988 and a subcohort was selected comprising a 1% rand
om sample from this cohort as a basis for risk estimation. Cumulative
and current exposures to electric fields, magnetic fields, and pulsed
electromagnetic fields (as recorded by the POSITRON meter) were estima
ted for the subcohort and cases through a job exposure matrix. Two ver
sions of each of these six indices were calculated, one based on the a
rithmetic mean (AM), and one on the geometric mean (GM) of field stren
gths. Results-For cumulative exposure, rate ratios (RR) for all three
fields showed mostly small non-significant increases in the medium and
high exposure groups. The most increased risk was found in the medium
exposure group for the GM of the electric field (RR = 2.76, 95% CI 1.
15-6.62). The results did not differ after adjustment for socioeconomi
c state, alcohol use, marital state, and mental disorders. There was a
little evidence for an association of risk with exposure immediately
before the suicide. Conclusion-Some evidence for an association betwee
n suicide and cumulative exposure to the GM of the electric fields was
found. This specific index was not initally identified as the most re
levant index, but rather emerged afterwards as showing the most positi
ve association with suicide among the 10 indices studied. Thus the evi
dence from this study for a causal association between exposure to ele
ctric fields and suicide is weak. Small sample size (deaths fi om suic
ide) and inability to control for all potential confounding factors we
re the main limitations of this study.