Risks Not Assessed for Use “Considerably Greater Than” 30 Minutes Or More A Week – UK Million Woman Study

1. You stated to Medscape News that “These results support the accumulating evidence that mobile phone use under usual conditions does not increase brain tumor risk,” Can you please tell me what you mean. What is “usual conditions?” How many hours a day? Please define “usual.” 

The participants in this study were not particularly heavy users of mobile phones, as only 18% of phone-users reported talking on a mobile phone for 30 minutes or more each week. As such, we were unable to assess the risks associated with considerably greater levels of exposure.

2. You said “Questions on cellular telephone use were first asked in median year 2001 and again in median year 2011 ” Were women asked to complete the questionnaire  each year like 2009, 2010, 2011, 2012, 2013? or just once in that time period? After that survey, were they ever asked again?

Study participants are resurveyed approximately every 3-5 years, but questions on mobile phone use were only included on two of these questionnaires (ie, the questionnaires completed in median years 2001 and 2011). The questionnaire in median year 2001 was completed just once per woman, at some point between 1999 and 2005 (as it can take a long time to post out and process questionnaires for over 1 million women). Similarly, women who completed the questionnaire in median year 2011 did so just once, between 2009 and 2013.

 I hope that this helps. Best wishes, Kirstin

Kirstin Pirie

Oxford Population Health (Nuffield Department of Population Health, University of Oxford)

E: kirstin.pirie@ndph.ox.ac.uk  | W: www.ndph.ox.ac.uk