Electromagnetic fields do not pose a health hazard to energy workers

December 31, 2015

Exposure to low frequency electromagnetic fields of 50 to 60 Hz has been implicated in an increased risk of leukaemia, brain and breast cancers.

The researchers used the health and employment records of more than 22,000 utility workers at 99 different electrical energy supply companies in Denmark.

All the employees had been employed at the companies for a minimum of three months since 1968, and they were tracked for an average of nearly 23 years or until death..

When the data were linked to the Danish Cancer Registry where all new cases of cancer in the country have been recorded since 1942, the researchers found ,no compelling evidence, for an increased risk of leukaemia, breast or brain cancers.

There were no excess cases of leukaemia among men or of breast cancer among female employees who had been exposed to medium to high frequency magnetic fields.

Women exposed to medium frequency electromagnetic fields were more likely to develop brain cancer than women with background frequency levels.

But this was not true of men who had been exposed to high frequency magnetic fields. They were less likely to develop the disease.

The researchers conclude that their findings agree with those of the International Agency for Research on Cancer in 2002

bmj

Based on the model, clinicians can compute a patient's ordinal risk score and absolute chance a patient has of developing lung cancer within a year. The patient then can be classified into high-, moderate-, or low-risk groups. Examples of key risk factors found in the targeted groups include:

in never smokers: exposure to secondhand smoke and family history of cancer; in both current and former smokers: emphysema; exposure to dust and no history of hay fever; in former smokers: age they stopped smoking and family history of cancer; and in current smokers: asbestos exposure, intensity of smoking and family history of a smoking-related cancer. Spitz and Etzel say that the most striking finding was the strong impact of a prior history of emphysema as a risk factor in both current and former smokers. In contrast, hay fever worked as a protective agent against lung cancer in both groups.

The study is not without limitations. One major drawback is that the model focuses only on Caucasians, due to the fact that there were not enough minority patients in the cohort to build and validate the model. "We are currently working with other institutions to combine our numbers and build a model specifically for Mexican Americans and African Americans. In preliminary testing, already we are finding that while some of the risk factors are common to both groups, there are different levels of risk, so the model for Caucasians would likely not be as predictive for other populations," says Etzel.

Also, cases and controls were paired based on smoking status - perhaps masking the importance of smoking as a risk factor, though adjustment factors were included for this limitation.

Currently, the researchers are developing a Web-based version of this lung cancer assessment model, in hopes of soon making the tool accessible to clinicians.

mdanderson