Relationship between distance to overhead power lines and calculated fields in two studies

Abstract

There is some evidence that both distance from transmission lines and measured or calculated magnetic fields are associated with childhood leukemia. Because distance is a key component when calculating the magnetic field generated by power lines, distance from lines and calculated fields based on lines tend to be highly correlated. Socioeconomic status (SES) and dwelling type are also associated with magnetic field exposure. We used exposure data from two large studies of childhood leukemia and other cancers, in the US and the UK, to describe a relationship between distance and magnetic fields across the population within 100 meters (m) of power lines as a whole and evaluate potential modifiers such as SES and type of dwelling. There were 387 subjects living within 100 m of an overhead power line. There was no significant difference in mean calculated fields nor distance to 200+ kV lines within 100 m by study. Within the range where the power line field is expected to be significant compared to other sources, which we take as 100 m, distance to high voltage lines predicted MF variation in both studies better than other functions of distance tested in both linear and logistic regression. There were no differences between high and low SES nor dwelling types (single-family home vs other). In conclusion, we found that calculated fields do appear to diminish linearly with increasing distance from overhead power lines, up to 100 m, particularly those 200+ kV and above. These results are stronger in the UK study. Within 100 m, distance to high voltage lines continues to be highly correlated with calculated magnetic fields and each can be a proxy for the other.