Text and Data Mining valid from 2019-01-22
Received: 7 December 2018
Accepted: 8 December 2018
First Online: 22 January 2019
Compliance with Ethical Standards
: The authors declare that they have no conflict of interest.
: Ethical oversight for the study was obtained from the ALSPAC Law and Ethics Committee and Local Research Ethics Committees.
: All individuals gave consent to be included in ALSPAC.