PT - JOURNAL ARTICLE ED - , TI - Correction AID - 10.1136/bmjopen-2014-006946corr1 DP - 2015 Jul 01 TA - BMJ Open PG - e006946corr1 VI - 5 IP - 7 4099 - http://bmjopen.bmj.com/content/5/7/e006946corr1.short 4100 - http://bmjopen.bmj.com/content/5/7/e006946corr1.full SO - BMJ Open2015 Jul 01; 5