We thank Mortazi for the comment1 on our recent paper published in British Journal of Cancer2. We indeed did not collect exposure data in this cohort, starting in 2003, to test Mortazavi and Mortazavi’s hypothesis3 that using smartphones, tablets and laptops in the night might affect breast cancer risk. We also did not collect information on the spectral characteristics of the light in the bedroom at night; however, in a study dependent on recalled self-reported exposure of > 100,000 women, it is difficult to imagine how one could collect such data.
Competing interests
The authors declare no competing financial interest.
Reference
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