DEMENTIA AND OCCUPATIONAL EXPOSURE TO MAGNETIC-FIELDS

Objectives The purpose of the present report was to assess whether occ upational magnetic field exposure is a risk factor for dementia, in pa rticular for Alzheimer's disease. Methods Case-control analyses were a pplied to 77 dementia cases, 55 of whom had Alzheimer's disease, ascer tained from the population-based Swedish twin register. Two reference groups were derived, with 228 and 238 persons, respectively. Occupatio ns were linked to a job-exposure matrix based on magnetic field measur ements. Primary occupation, last occupation before reference date, and the occupation with the highest magnetic field exposure during the su bject's lifetime were evaluated. Results For primary occupation, all r elative risk estimates were close to unity. For last occupation, at th e exposure level greater than or equal to 0.2 mu T, a relative risk wa s found for dementia estimated at 3.3 [95% confidence interval (95% CI ) 1.3-8.6] and 3.8 (95% CI 1.4-10.2) for reference groups 1 and 2, res pectively. The relative risk for Alzheimer's disease was estimated at 2.4 (95% CI 0.8-6.9) and 2.7 (95% CI 0.9-7.8), respectively. For the o ccupation with the highest magnetic field exposure, the relative risk estimates were close to unity for reference group 1 and slightly eleva ted for reference group 2. The relative risk estimates were greater fo r the subjects who were younger at onset (less than or equal to 75 yea rs). Conclusions These results only partially support previous finding s, but they indicate that occupational magnetic field exposure may pos sibly influence the development of dementia.