Radiofrequency fields are now ubiquitous, and several studies have assessed their potential health effects,1 with predominantly negative results. The two main areas of research are exposure associated with the use of mobile phones—for example, the recently published INTERPHONE study2—and risks associated with transmitters, including mobile phone masts.

The linked case-control study by Elliott and colleagues (doi:10.1136/bmj.c3077), assesses whether proximity to masts during pregnancy raises the risk of children developing leukaemia or a tumour in the brain or central nervous system.3 The study identified 1397 British children registered with leukaemia or a tumour in the brain or central nervous system between 1999 and 2001, and it compared each of these children with four controls sampled from the national birth registers who were matched for sex and date of birth. The study found no association between the risk of cancer in early childhood and exposure to a mobile phone base station during pregnancy.

The levels of individual …