Epidemiological study (observational study)

Occupational exposure to extremely low-frequency magnetic fields and cardiovascular disease mortality in a prospective cohort study epidem.

By: Koeman T, Slottje P, Kromhout H, Schouten LJ, Goldbohm RA, van den Brandt PA, Vermeulen R

Published in: Occup Environ Med 2013; 70 (6): 402-407

The association between occupational extremely low-frequency magnetic fields exposure and cardiovascular disease (CVD) mortality was investigated within a community-based prospective cohort study in The Netherlands.

Type of risk estimation:

(hazard rate)

questionnaire: occupational history up to baseline (job title, company name and type of industry, products manufactured and time period for each job ever performed)
job exposure matrix: intensity of time-weighted average exposure to magnetic fields by job based on available measurement data and probability of exposure
calculation: cumulative exposure (given in units-years) by multiplying the duration with exposure level using arbitrary weights (0 for background, 1 for low and 4 for high exposure) for each job and adding across all jobs in the job history

Group	Description
Reference group 1	background exposure
Group 2	low or high exposure
Reference group 3	cumulative exposure: 0 unit-years
Group 4	cumulative exposure, 1st tertile: 0.5 - 9 unit-years
Group 5	cumulative exposure, 2nd tertile: 9.5 -28 unit-years
Group 6	cumulative exposure, 3rd tertile: 28.5 - 208 unit-years

Group:
- men
- women
Age: 55–69 years
Characteristics: residents of 204 municipalities throughout The Netherlands
Observation period: 1986, followed-up until 1996
Study location: The Netherlands
Data source: The Netherlands Cohort Study on diet and cancer, Dutch Bureau of Genealogy, Central Bureau of Statistics

Type	Value
Total	120,852

Statistical analysis method:

(adjustment:

)

In this prospective population-based cohort study, 120,852 men and women were followed-up for cardiovascular disease mortality over a period of 10 years, resulting in 8200 deaths caused cardiovascular diseases.
Ever low or high exposure to extremely low-frequency magnetic fields showed no association with total cardiovascular disease mortality (HR 1.02, CI 0.99-1.06), nor with any cause-specific subtypes of cardiovascular disease mortality. Other exposure metrics showed no increased risks either.
The authors concluded that they found no indication of an association between occupational extremely low-frequency magnetic fields exposure and risk of cardiovascular disease mortality.

McNamee DA et al. (2011): The response of the human circulatory system to an acute 200-muT, 60-Hz magnetic field exposure
McNamee DA et al. (2010): The cardiovascular response to an acute 1800-microT, 60-Hz magnetic field exposure in humans
Cooper AR et al. (2009): A population-based cohort study of occupational exposure to magnetic fields and cardiovascular disease mortality
Röösli M et al. (2008): Cardiovascular mortality and exposure to extremely low frequency magnetic fields: a cohort study of Swiss railway workers
Lednev VV et al. (2008): Modulation of cardiac rhythm in the humans exposed to extremely weak alternating magnetic fields
Kheifets L et al. (2007): Extremely low-frequency magnetic fields and heart disease
Mezei G et al. (2005): Occupational magnetic field exposure, cardiovascular disease mortality, and potential confounding by smoking
Santangelo L et al. (2005): Magnetic field exposure and arrythmic risk: evaluation in railway drivers
Ahlbom A et al. (2004): Occupational Magnetic Field Exposure and Myocardial Infarction Incidence
Hakansson N et al. (2003): Occupational exposure to extremely low frequency magnetic fields and mortality from cardiovascular disease
Sahl J et al. (2002): Occupational magnetic field exposure and cardiovascular mortality in a cohort of electric utility workers
Savitz DA et al. (1999): Magnetic field exposure and cardiovascular disease mortality among electric utility workers