Epidemiological study (observational study)

Occupational exposures and Parkinson's disease mortality in a prospective Dutch cohort epidem.

By: Brouwer M, Koeman T, van den Brandt PA, Kromhout H, Schouten LJ, Peters S, Huss A, Vermeulen R

Published in: Occup Environ Med 2015; 72 (6): 448-455

Aim of study (acc. to author)

The association between the occupational exposure to extremely low-frequency magnetic fields, electrical shocks as well as other risk factors and the risk of Parkinson disease mortality was investigated in the Netherlands Cohort Study. Furthermore, the effects of combined exposure to these occupational risk factors were studied.

Further details

Following a case-cohort approach, a randomly selected subcohort (n=5000) was drawn.

Endpoint/type of risk estimation

neurodegenerative diseases: Parkinson disease

Type of risk estimation:

mortality

(hazard ratio)

Exposure

- 50/60 Hz
- magnetic field
- touch current
- also other exposures without EMF
- electric injuries/electrocution
- occupational

Assessment

questionnaire: job history
job exposure matrix
calculation: cumulative exposure calculated by weights of exposure level per job, multiplied by duration of that job and summed over the entire job history

Exposure groups

Group	Description
Reference group 1	magnetic field exposure: background
Group 2	magnetic field exposure: low
Group 3	magnetic field exposure: high
Reference group 4	cumulative exposure: background
Group 5	cumulative exposure: 1st terzile
Group 6	cumulative exposure: 2nd terzile
Group 7	cumulative exposure: 3rd terzile
Reference group 8	electric shock risk: background
Group 9	electric shock risk: low
Group 10	electric shock risk: high
Reference group 11	electric shock; cumulative exposure: 1st terzile
Group 12	electric shock; cumulative exposure: 2nd terzile
Group 13	electric shock; cumulative exposure: 3rd terzile

Population

Group:
- men
- women
Age: ≥ 55 years
Characteristics: participants of the Netherlands Cohort Study on diet and cancer
Observation period: 1986 - 2003
Study location: Netherlands
Data source: Dutch Bureau of Genealogy, Dutch population registry, Statistics Netherlands Dutch Bureau of Genealogy, the Municipal, Personal Records Database, Sta

Study size

Type	Value
Total	120,852

Other:

17.3 years of follow-up

Statistical analysis method:

Cox proportional regressions analysis

(adjustment:

age
education
smoking status, BMI and non-occupational physical

)

Results (acc. to author)

Among men, an elevated hazard ratio was observed for high exposure to occupational extremely low-frequency magnetic fields (HR 1.54, CI 1.00-2.36) but neither association with exposure duration nor a trend in cumulative exposure were observed. No association between Parkinson disease mortality and occupational exposure to electric shocks was found. No significant associations between Parkinson disease mortality and occupational exposure to extremely low-frequency magnetic fields as well as electric shocks were observed among women.
When the analysis of exposure to extremely low-frequency magnetic fields was adjusted for risk of electric shocks, the association between high exposure to extremely low-frequency magnetic fields and Parkinson disease mortality became stronger (HR 1.81, CI 1.15-2.85). This suggests that, if the observed association between high exposure to extremely low-frequency magnetic fields and Parkinson disease risk is true, this is likely not driven by electric shocks.
The authors conclude that there are some suggestions for an association between Parkinson disease mortality and occupational exposure to extremely low-frequency magnetic fields. However, the weight given to these findings is limited by the absence of a monotonic trend with duration of exposure or cumulative exposure. No evidence for association between Parkinson disease mortality and occupational exposure to the risk of electric shocks was found.

Study funded by

ZonMw, The Netherlands

Touitou Y et al. (2020): Evaluation in humans of ELF-EMF exposure on chromogranin A, a marker of neuroendocrine tumors and stress
Gervasi F et al. (2019): Residential distance from high-voltage overhead power lines and risk of Alzheimer's dementia and Parkinson's disease: a population-based case-control study in a metropolitan area of Northern Italy
Checkoway H et al. (2018): Occupational exposures and parkinsonism among Shanghai women textile workers
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
Huss A et al. (2015): Extremely Low Frequency Magnetic Field Exposure and Parkinson's Disease-A Systematic Review and Meta-Analysis of the Data
Huss A et al. (2015): Occupational exposure to magnetic fields and electric shocks and risk of ALS: The Swiss National Cohort
van der Mark M et al. (2015): Extremely low-frequency magnetic field exposure, electrical shocks and risk of Parkinson's disease
Vergara X et al. (2015): Case-control study of occupational exposure to electric shocks and magnetic fields and mortality from amyotrophic lateral sclerosis in the US, 1991-1999
Sorahan T et al. (2014): Neurodegenerative disease and magnetic field exposure in UK electricity supply workers
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
Huss A et al. (2013): Electric shocks at work in Europe: development of a job exposure matrix
Grell K et al. (2012): Risk of neurological diseases among survivors of electric shocks: A nationwide cohort study, Denmark, 1968-2008
Huss A et al. (2009): Residence near power lines and mortality from neurodegenerative diseases: longitudinal study of the Swiss population
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
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
Hug K et al. (2006): Magnetic field exposure and neurodegenerative diseases--recent epidemiological studies
Park RM et al. (2005): Potential occupational risks for neurodegenerative diseases
Hakansson N et al. (2003): Neurodegenerative diseases in welders and other workers exposed to high levels of magnetic fields
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
Savitz DA et al. (1998): Electrical occupations and neurodegenerative disease: analysis of U.S. mortality data
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