Epidemiological study (observational study)

Severe cognitive dysfunction and occupational extremely low frequency magnetic field exposure among elderly Mexican Americans epidem.

By: Davanipour Z, Tseng CC, Lee PJ, Markides KS, Sobel E

Published in: Br J Med Med Res 2014; 4 (8): 1641-1662

Aim of study (acc. to author)

A population-based cohort study was conducted in the USA to investigate the association between severe cognitive dysfunction and occupational extremely low frequency magnetic field exposure among elderly Mexican Americans.

Further details

A Mini-Mental State Exam score below 10 was used to define cognitive dysfunction.

Endpoint/type of risk estimation

severe cognitive dysfunction

Type of risk estimation:

incidence

(odds ratio (OR))

Exposure

- 50/60 Hz
- magnetic field
- occupational

Assessment

job exposure matrix: job title, type of work, and primary tasks

Exposure groups

Group	Description
Reference group 1	average occupational magnetic field exposure < 0.2 or intermittently < 1 µT: low
Group 2	average occupational magnetic field exposure between 0.2 and 1 µT or intermittently > 1 µT: medium
Group 3	average occupational magnetic field exposure > 1 µT or intermittently > 10 µT: high

Population

Group:
- men
- women
Age: ≥ 65 years
Characteristics: participants of the Hispanic Established Population for Epidemiologic Studies of the Elderly (H-EPESE), a longitudinal study of a representative sample of Mexican Americans age 65 and older
Observation period: 1993 - 1994
Study location: USA (Texas, New Mexico, Colorado, Arizona, and California)

Study size

Type	Value
Participants	3,050
Participation rate	85 %
Evaluable	2,844

Statistical analysis method:

logistic regression

Results (acc. to author)

Overall 91.8% of the study participants hat a low occupational magnetic field exposure, 4.7% a medium exposure and 3.5% a high exposure. About 1.7% of 2873 subjects with a Mini-Mental State Exam had a MMSE score below 10.
Significant increased risks for severe cognitive dysfunction were observed for high (group 2: OR 3.4, CI 1.3-8.9) and for 'medium or high' occupational magnetic field exposure (groups 2 + 3: OR 1.7, CI 0.7-4.1). Interaction between occupational magnetic field exposure and other possible risk factors were investigated. The results showed that the interactions between 'medium or high' 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.
The authors conclude that working in an occupation with high or 'medium or high' magnetic field exposure may increase the risk of severe cognitive dysfunction. Smoking and older age may increase the deleterious effect of occupational magnetic field exposure.

Study funded by

National Institute on Aging (NIA; U.S. National Institutes of Health), Maryland, USA

Huang LY et al. (2020): Association of Occupational Factors and Dementia or Cognitive Impairment: A Systematic Review and Meta-Analysis
Jalilian H et al. (2018): Occupational exposure to extremely low frequency magnetic fields and risk of Alzheimer disease: A systematic review and meta-analysis
Koeman T et al. (2015): Occupational exposures and risk of dementia-related mortality in the prospective Netherlands Cohort Study
Capozzella A et al. (2014): Work related etiology of amyotrophic lateral sclerosis (ALS): a meta-analysis
Vergara X et al. (2013): Occupational exposure to extremely low-frequency magnetic fields and neurodegenerative disease: a meta-analysis
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
Garcia AM et al. (2008): Occupational exposure to extremely low frequency electric and magnetic fields and Alzheimer disease: a meta-analysis
Sorahan T et al. (2007): Mortality from Alzheimer's, motor neurone and Parkinson's disease in relation to magnetic field exposure: findings from the study of UK electricity generation and transmission workers, 1973-2004
Davanipour Z et al. (2007): A case-control study of occupational magnetic field exposure and Alzheimer's disease: results from the California Alzheimer's Disease Diagnosis and Treatment Centers
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
Seidler A et al. (2007): Occupational exposure to low frequency magnetic fields and dementia: a case-control study
Park RM et al. (2005): Potential occupational risks for neurodegenerative diseases
Qiu C et al. (2004): Occupational exposure to electromagnetic fields and risk of Alzheimer's disease
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
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
Schulte PA et al. (1996): Neurodegenerative diseases: occupational occurrence and potential risk factors, 1982 through 1991
Sobel E et al. (1996): Elevated risk of Alzheimer's disease among workers with likely electromagnetic field exposure
Sobel E et al. (1995): Occupations with exposure to electromagnetic fields: a possible risk factor for Alzheimer's disease