MAGNETIC-FIELDS OF HIGH-VOLTAGE POWER-LINES AND RISK OF CANCER IN FINNISH ADULTS - NATIONWIDE COHORT STUDY

Objective-To investigate the risk of cancer in association with magnet ic fields in Finnish adults Living close to high voltage power lines. Design-Nationwide cohort study. Subjects-383 700 people who Lived duri ng 1970-89 within 500 metres of overhead power lines of 110-400 kV in a magnetic field calculated to be greater than or equal to 0.01 mu T. Study subjects were identified by record linkages of nationwide regist ers. Main outcome measures-Numbers of observed and expected cases of c ancer, standardised incidence ratios, and incidence rate ratios adjust ed for sex, age, calendar year, and social class-for example, by conti nuous cumulative exposure per 1 mu T year-with 95% confidence interval s from multiplicative models for all cancers combined and 21 selected types. Results-Altogether 8415 cases of cancer were observed (standard ised incidence ratio 0.98; 95% confidence interval 0.96 to 1.00) in ad ults. All incidence rate ratios for both sexes combined were non-signi ficant and between 0.91 and 1.11. Significant excesses were observed i n multiple myeloma in men (incidence rate ratio 1.22) and in colon can cer in women (1.16). Conclusions-Typical residential magnetic fields g enerated by high voltage power lines do not seem to be related to the risk of overall cancer in adults. The previously suggested association s between extremely low frequency magnetic fields and tumours of the n ervous system, lymphoma, and leukaemia in adults and breast cancer in women were not confirmed.