To study the possible effects of occupational extremely low frequency magnetic field exposure on natural killer cell cytotoxic activity in peripheral blood cells of workers engaged in different occupational activities not involving any exposure to chemical/physical factors.
The study was performed to confirm previous results with a larger study group (see Gobba et al. 2009).
Individual extremely low frequency magnetic field exposure of all participants (121 workers; 65 men and 56 women) was measured during two consecutive work-shifts using personal dosimeters and environmental, non-occupational exposure was also monitored. Workers were classified as low exposed (62 subjects, TWA ≤ 0,2 µT), medium exposed (35 subjects; 0.21-0.99 µT) and higher exposed workers (24 subjects; TWA ≥ 1 µT).
|magnetic flux density||0.2 µT||average over time||measured and calculated||-||maximum value for the low exposure group|
|magnetic flux density||0.21 µT||average over time||measured and calculated||-||minimum value for the medium exposure group|
|magnetic flux density||0.99 µT||average over time||measured and calculated||-||maximum value for the medium exposure group|
|magnetic flux density||1 µT||average over time||measured and calculated||-||minimum value for the higher exposure group|
In higher exposed workers (exceeding 1 µT) natural killer cell activity was significantly reduced compared to low exposure group. In the medium exposure group a decrease was also observed, but the difference was not significant.
In conclusion, the data suggest that occupational exposure to extremely low frequency magnetic fields, at least at TWA levels exceeding 1 µT, may induce a decrease in natural killer cell activity in peripheral blood lymphocytes.