Table 2

Results of multiple logistic regression analyses examining the impact of risk factors on the trend in regular smoking in adolescents

YearModel 1:
OR for year
partially adjusted
(95% CI)		Model 1+best friend smokes
(95% CI)		Model 1 +exposure to smoking in home
(95% CI)		Model 1+parental
 smoking		Model 1+ sibling 
smoking		Model 1+all risk factors
20031
20060.62 (0.59 to 0.64)0.83* (0.78 to 0.87)0.58 (0.55 to 0.61)0.60 (0.57 to 0.63)0.61(0.58 to 0.64)0.75* (0.71 to 0.79)
20070.56 (0.53 to 0.59)0.78* (0.74 to 0.83)0.54 (0.52 to 0.57)0.55 (0.52 to 0.58)0.56 (0.54 to 0.59)0.72* (0.68 to 0.76)
20080.51 (0.48 to 0.53)0.74* (0.70 to 0.79)0.49 (0.47 to 0.52)0.50 (0.48 to 0.53)0.51 (0.48 to 0.53)0.68* (0.64 to 0.72)
20090.47 (0.44 to 0.49)0.69*(0.65 to 0.73)0.46 (0.43 to 0.49)0.46 (0.44 to 0.49)0.47 (0.45 to 0.50)0.63* (0.59 to 0.67)
20100.40 (0.38 to 0.42)0.58*(0.54 to 0.61)0.40 (0.38 to 0.42)0.39 (0.37 to 0.41)0.40 (0.38 to 0.42)0.53* (0.50 to 0.57)
20110.36 (0.34 to 0.38)0.55* (0.51 to 0.58)0.33 (0.31 to 0.35)0.36 (0.34 to 0.38)0.37 (0.35 to 0.39)0.47* (0.44 to 0.51)
20120.28 (0.27 to 0.30)0.42* (0.39 to 0.45)0.26 (0.25 to 0.28)0.29 (0.27 to 0.30)0.29 (0.27 to 0.31)0.37* (0.35 to 0.40)
20130.27 (0.25 to 0.28)0.41* (0.39 to 0.44)0.28 (0.26 to 0.29)0.27 (0.26 to 0.29)0.28 (0.26 to 0.30)0.39* (0.37 to 0.42)
20140.24 (0.22 to 0.25)0.36* (0.34 to 0.39)0.23 (0.22 to 0.25)0.24 (0.23 to 0.26)0.25 (0.24 to 0.27)0.34* (0.32 to 0.36)
20150.21 (0.19 to 0.22)0.34* (0.32 to 0.37)0.20 (0.19 to 0.22)0.21 (0.20to 0.23)0.22 (0.21 to 0.24)0.31* (0.29 to 0.34)
All years combined, using year as a continuous variable
 Linear trend (2003–2015)0.88 (0.88 to 0.88)0.91* (0.91 to 0.92)0.88 (0.88 to 0.88)0.88 (0.88 to 0.89)0.88(0.88 to 0.89)0.91* (0.90 to 0.91)

  • Model 1 is adjusted for age, gender, ethnicity and school decile.

  • ↵*OR >model 1 OR (p<0.05).