“…Using the Newcastle–Ottawa Scale for risk of bias, 6 studies received a score of 5 (moderate quality), 25 , 26 , 28 , 32 , 33 , 35 4 studies received a score of 6 (moderate quality), 24 , 31 , 34 , 39 5 studies received a score of 7 (high quality) 23 , 27 , 29 , 30 , 38 and 3 studies received a score of 8 (high quality) (Appendix 4, available at www.cmajopen.ca/content/10/2/E500/suppl/DC1 ). 36 , 37 , 40 Using criteria from the Guide to Community Preventive Services , a score of 3 (good quality) was assigned to 9 studies, 23 , 27 , 34 – 40 and a score of 1 (poor quality) was assigned to 9 studies (Appendix 5, available at www.cmajopen.ca/content/10/2/E500/suppl/DC1 ).…”