GEE model adjusted percentages in awareness of smoking-related health messages among Canadian smokers, 2002–2013
| Median survey date (wave #) | Added in 2012 | Removed in 2012 | Continuously displayed | |||
| Smoking causes blindness (%) | Smoking causes bladder cancer (%) | Nicotine causes addiction (%) | Smoking causes impotence (%) | Cigarette smoke contains carbon monoxide (%) | Smoking causes stroke (%) | |
| November 2002 (Wave 1) | N/A | N/A | N/A | 60.7 (57.8–63.5) | 90.9 (89.1–92.4) | 84.6 (82.4–86.6) |
| June 2003 (Wave 2) | N/A | N/A | N/A | 59.7 (56.8–62.4) | 90.8 (89.1–92.2) | 84.3 (82.0–86.3) |
| July 2004 (Wave 3) | 11.7 (10.0–13.5) | N/A | N/A | 61.3 (58.6–62.4) | 92.8 (91.3–94.0) | 86.6 (84.6–88.3) |
| November 2005 (Wave 4) | 15.1 (13.2–17.2) | N/A | N/A | 63.5 (61.0–66.0) | 90.3 (88.6–91.7) | 87.1 (85.2–88.8) |
| November 2006 (Wave 5) | 16.0 (14.1–18.1) | N/A | N/A | 65.7 (63.2–68.2) | 91.2 (89.4–92.6) | 86.9 (85.0–88.6) |
|
December 2007
(Wave 6) | 18.5 (16.4–20.8) | N/A | 90.1 (88.2–91.7) | 67.5 (65.0–69.9) | N/A | 87.6 (85.6–89.3) |
| January 2009 (Wave 7) | 15.9 (13.9–18.1) | N/A | 89.0 (86.9–90.8) | 66.2 (63.3–68.9) | N/A | 87.3 (85.2–89.1) |
| August 2010 (Wave 8) | 14.7 (12.5–17.1) | 26.8 (23.7–30.1) | 90.6 (88.2–92.5) | 67.8 (64.3–71.1) | 92.4 (90.1–94.2) | 87.5 (84.7–89.8) |
| May 2012 | Revision of warning labels | |||||
| October 2013 (Wave 9) | 36.7*† (32.6–40.9) | 44.0* (40.4–47.5) | 89.6 (86.9–91.8) | 66.2† (62.3–69.9) | 86.7*† (83.7–89.2) | 88.7 (86.1–90.8) |
Percentages are weighted.
*Significant difference (p<0.05) from 2010 to 2013 (GEE contrast of the means).
†Significant difference (p<0.05) in slopes before and after 2012 HWL revisions (segmented regression analysis).
GEE, generalised estimating equation; HWL, health warning label.