Study type: Epidemiological study (observational study)

Occupational exposure to electromagnetic fields and risk of Alzheimer's disease. epidem.

Published in: Epidemiology 2004; 15 (6): 687-694

Aim of study (acc. to author)

The association between occupational exposure to electromagnetic fields and risk of Alzheimer's disease and dementia was investigated in a cohort in Sweden.

Further details

Magnetic field exposure was assessed by job-exposure matrix, measurement at typically female workplaces and estimation for housewives.

Endpoint/type of risk estimation

Type of risk estimation: (relative risk (RR))

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 exposure to magnetic fields in lifetime principal occupation for men: < 0.20 µT
Group 2 exposure to magnetic fields in lifetime principal occupation for men: ≥ 0.20 µT
Reference group 3 exposure to magnetic fields in lifetime principal occupation for women: < 0.20 µT
Group 4 exposure to magnetic fields in lifetime principal occupation for women: ≥ 0.20 µT
Reference group 5 exposure to magnetic fields in lifetime principal occupation: < 0.20 µT
Group 6 exposure to magnetic fields in lifetime principal occupation: ≥ 0.20 µT
Reference group 7 lifetime average occupational exposure to magnetic fields for men: < 0.16 µT
Group 8 lifetime average occupational exposure to magnetic fields for men: 0.16 - 0.21 µT
Group 9 lifetime average occupational exposure to magnetic fields for men: > 0.21 µT
Reference group 10 lifetime average occupational exposure to magnetic fields for women: < 0.14 µT
Group 11 lifetime average occupational exposure to magnetic fields for women: 0.14 - 0.17 µT
Group 12 lifetime average occupational exposure to magnetic fields for women: > 0.17 µT
Reference group 13 lifetime average occupational exposure to magnetic fields: < 0.15 µT
Group 14 lifetime average occupational exposure to magnetic fields: 0.15 - 0.18 µT
Group 15 lifetime average occupational exposure to magnetic fields: > 0.18 µT

Population

Study size

Type Value
Total 1,810
Participants 931
Other:

second follow-up : 626 participants

Statistical analysis method: ( adjustment: )

Conclusion (acc. to author)

During the 4366 person-years of follow up, 265 subjects were diagnosed as having dementia, including 202 with Alzheimer's disease. No association of extremely low frequency magnetic field exposure with the risk of dementia was found for the entire cohort. However, a higher magnetic field exposure (≥ 0.2 µT) in the lifetime principal occupation was associated with the risk of Alzheimer's disease and dementia in men. No association was observed among women. A similar sex-specific pattern was observed for the association of average extremely low frequency magnetic field exposure throughout the work life.
Longterm occupational exposure to a higher magnetic field level may increase the risk of dementia and Alzheimer's disease in men.

Limitations (acc. to author)

The information on job history was retrospectively collected. Exposure misclassification is greater for women because the job exposure matrix has been particularly developed for male jobs.

Study funded by

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