Increased incidence of cancer in a cohort of office workers exposed to strong magnetic fields.
A small cohort of 410 office workers (263 men and 147 women, ever employed) exposed to strong magnetic fields by three 12 kV transformers located beneath their first-floor office developed eight incident cancers over a 15 year exposure period. Only one cancer was ascertained in the 254 workers employed for less than 2 years, compared to seven cancer cases ascertained in the 156 workers employed for 2 years or more (p = 0.0057; Fisher's exact test). An analysis of linear trend of cancer incidence using average years employed as an exposure score was positive (p = 0.00337) with an odds ratio of 15.1 in workers employed over 5 years. A positive trend of cancer cases with duration of employment is seen for males and females separately and together (p < 0.05). For workers employed more than 2 years, the standardized cancer incidence ratio was 389 (95% confidence interval 156-801). Cumulative magnetic field exposure may be of etiologic importance in explaining the cancer incidence pattern in this cohort.
Milham
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D000328:Adult; D015331:Cohort Studies; D016001:Confidence Intervals; D004574:Electromagnetic Fields / Q000009:adverse effects; D004651:Employment; D005260:Female; D006801:Humans; D015994:Incidence; D016014:Linear Models; D008280:Magnetics / Q000009:adverse effects*; D008297:Male; D009369:Neoplasms / Q000209:etiology*; D009784:Occupational Diseases / Q000209:etiology*; D016273:Occupational Exposure; D016017:Odds Ratio; D013997:Time Factors