A population-based case-control study was conducted in Taiwan to investigate the association of radiofrequency exposure from mobile phone base stations and risks of all neoplasms, leukemia, and brain neoplasms in children.
The annual summarized power (in watt-year (WY)) was calculated for each mobile phone base station annually from 1998 to 2007 from the product of duration of operation (in year) and real emitted power (in watt). The annual power density (WY/km²) in each of the 367 townships in Taiwan was computed as ratio of total annual summarized power from all base stations in a township to the area of that particular township. For each child, the exposure metric was estimated from the averaged annual power density for the five-year period (induction period) prior to the neoplasm diagnosis in the township where the child lived at the time of diagnosis.
|Reference group 1||exposure density < median: < 167.02 WYs/km²|
|Group 2||exposure density ≥ median: ≥ 167.02 WYs/km²|
|Reference group 3||exposure density < 1st tertile: 91.65 WYs/km²|
|Group 4||exposure density ≥ 1st terzile - < 2nd tertile: 91.65 - 392.86 WYs/km²|
|Group 5||exposure density ≥ 2nd tertile: ≥ 392.86 WYs/km²|
A higher than median averaged annual power density (approximately 168 WYs/km²) was significantly associated with an increased adjusted odds ratio for all neoplasms (OR 1.13; CI 1.01-1.28), but not for leukemia (OR 1.23; CI 0.99-1.52) or brain tumor (OR 1.14, CI 0.83 to 1.55).
The authors conclude that the study does not indicate a significant association of exposure to mobile phone base stations at levels typically encountered in people's everyday environment with risks of brain tumor and leukemia in children. Although risk of overall neoplasm is elevated in children with higher-than-median radiofrequency exposure, the magnitude of risk estimate was small. These results may occur due to several methodological limitations.