Scientific Reports 7: Article number: 44808; published online: 07 April 2017; updated: 06 April 2018.

In this Article, Abhijit Sen and Lars J. Vatten are incorrectly listed with ‘Department of Epidemiology and Biostatistics, Imperial College, London, UK’. The correct affiliation for these authors is listed below:

Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.