Epidemiological study (observational study)

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

By: Qiu C, Fratiglioni L, Karp A, Winblad B, Bellander T

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

neurodegenerative diseases: Alzheimer's disease and dementia

Type of risk estimation:

incidence

(relative risk (RR))

Exposure

- 50/60 Hz
- magnetic field
- occupational

Assessment

interview: lifespan work activity
job exposure matrix
measurement: spot measurements for seamstresses and switchboard operators

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

Group:
- men
- women
Age: ≥ 75 years
Characteristics: registered inhabitants
Observation period: 1987 - 1989, 1991 - 1993, 1994 - 1996
Study location: Sweden (Kungsholmen district of Stockholm)

Study size

Type	Value
Total	1,810
Participants	931

Other:

second follow-up : 626 participants

Statistical analysis method:

Cox proportional regressions analysis

(adjustment:

age
sex
education
vasuclar disease, apolipoprotein E genotype, alcohol use, cigarette smoking, mental and social activity

)

Results (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

Gun and Bertil Stohnes Foundation, Sweden
Insamlingsstiftelsen för Alzheimers- och Demensforskning (SADF), Sweden
Stiftelse för Gamla Tjänarinnor, Sweden
Swedish Council for Working Life and Social Research (FAS)
Swedish Research Council (VR)

Huang LY et al. (2020): Association of Occupational Factors and Dementia or Cognitive Impairment: A Systematic Review and Meta-Analysis
Touitou Y et al. (2020): Evaluation in humans of ELF-EMF exposure on chromogranin A, a marker of neuroendocrine tumors and stress
Jalilian H et al. (2018): Occupational exposure to extremely low frequency magnetic fields and risk of Alzheimer disease: A systematic review and meta-analysis
Pedersen C et al. (2017): Occupational exposure to extremely low-frequency magnetic fields and risk for central nervous system disease: an update of a Danish cohort study among utility workers
Koeman T et al. (2015): Occupational exposures and risk of dementia-related mortality in the prospective Netherlands Cohort Study
Huss A et al. (2015): Occupational exposure to magnetic fields and electric shocks and risk of ALS: The Swiss National Cohort
Capozzella A et al. (2014): Work related etiology of amyotrophic lateral sclerosis (ALS): a meta-analysis
Sorahan T et al. (2014): Neurodegenerative disease and magnetic field exposure in UK electricity supply workers
Davanipour Z et al. (2014): Severe cognitive dysfunction and occupational extremely low frequency magnetic field exposure among elderly Mexican Americans
Vergara X et al. (2013): Occupational exposure to extremely low-frequency magnetic fields and neurodegenerative disease: a meta-analysis
Frei P et al. (2013): Residential Distance to High-voltage Power Lines and Risk of Neurodegenerative Diseases: a Danish Population-based Case-Control Study
Zhang C et al. (2013): Extremely low-frequency magnetic exposure appears to have no effect on pathogenesis of Alzheimer's disease in aluminum-overloaded rat
Andel R et al. (2010): Work-related exposure to extremely low-frequency magnetic fields and dementia: results from the population-based study of dementia in Swedish twins
Röösli M et al. (2007): Mortality from neurodegenerative disease and exposure to extremely low-frequency magnetic fields: 31 years of observations on Swiss railway employees
Hakansson N et al. (2003): Neurodegenerative diseases in welders and other workers exposed to high levels of magnetic fields
Feychting M et al. (2003): Occupational Magnetic Field Exposure and Neurodegenerative Disease
Noonan CW et al. (2002): Occupational exposure to magnetic fields in case-referent studies of neurodegenerative diseases
Deadman JE et al. (2002): Individual estimation of exposures to extremely low frequency magnetic fields in jobs commonly held by women
Johansen C (2000): Exposure to electromagnetic fields and risk of central nervous system disease in utility workers
Graves AB et al. (1999): Occupational exposure to electromagnetic fields and Alzheimer disease
Savitz DA et al. (1998): Electrical occupations and neurodegenerative disease: analysis of U.S. mortality data
Feychting M et al. (1998): Dementia and occupational exposure to magnetic fields
Savitz DA et al. (1998): Magnetic field exposure and neurodegenerative disease mortality among electric utility workers
Davanipour Z et al. (1997): Amyotrophic lateral sclerosis and occupational exposure to electromagnetic fields
Schulte PA et al. (1996): Neurodegenerative diseases: occupational occurrence and potential risk factors, 1982 through 1991
Sobel E et al. (1995): Occupations with exposure to electromagnetic fields: a possible risk factor for Alzheimer's disease