Reply to ‘Comment on ‘Domestic light at night and breast
cancer risk: a prospective analysis of 105 000 UK women in the
British Journal of Cancer (2018) 118:1537; https://doi.org/10.1038/
We thank Mortazi for the comment
on our recent paper
published in British Journal of Cancer
. We indeed did not collect
exposure data in this cohort, starting in 2003, to test Mortazavi
and Mortazavi’s hypothesis
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.
Note: This work is published under the standard license to publish agreement. After
12 months the work will become freely available and the license terms will switch to
a Creative Commons Attribution 4.0 International (CC BY 4.0).
Louise E Johns
, Michael E Jones
, Minouk J Schoemaker
, Alan Ashworth
Anthony J Swerdlow
Division of Genetics and Epidemiology, The Institute of Cancer
Research, London SM2 5NG, UK.;
Division of Breast Cancer Research,
The Institute of Cancer Research, London SW3 6JB, UK.;
Cancer Now Research Centre at The Institute of Cancer Research,
London SW3 6JB, UK and
Division of Molecular Pathology, The
Institute of Cancer Research, London SW7 3RP, UK.
Correspondence: Louise E Johns (firstname.lastname@example.org)
1. Mortazavi, S. M. J. Comment on 'Domestic light at night and breast cancer risk: a
prospective analysis of 105 000 UK women in the Generations Study’. Br J Cancer
2. Johns, L. E., Jones, M. E., Schoemaker, M. J., McFadden, E., Ashworth, A., Swerdlow,
A. J. Domestic light at night and breast cancer risk: a prospective analysis of 105
000 UK women in the Generations Study. Br J Cancer 118: 600–606 (2018).
3. Mortazavi, S. A. R. & Mortazavi, S. M. J. Women with hereditary breast cancer
predispositions should avoid using their smartphones, tablets and laptops at
night. Iran. J. Basic Med Sci. 21, 112–5 (2018).
Received: 22 February 2018 Revised: 26 March 2018 Accepted: 26 March 2018
Published online: 17 May 2018
Present address: Nufﬁeld Department of Primary Care Health Sciences, University of Oxford, Oxford OX2 6GG, UK.
Present address: UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, CA 94158, USA.
© Cancer Research UK 2018