Table 4.

Prevalence odds ratio (POR) for cigarette smoking and 95% confidence interval (CI) among 11–15-year-old adolescents by study year, HBSC survey 1994–2006

Study year	POR (95% CI)
	Age groups
	11-year-olds	13-year-olds	15-year-olds
	Boys
1994	1	1	1
1998	1.64 (0.82–3.29)	1.45 (0.97–2.17)	1.09 (0.79–1.51)
2002	1.96 (1.16–3.31)	2.20 (1.57–3.07)	1.42 (1.11–1.81)
2006	1.19 (0.67–2.09)	1.60 (1.13–2.25)	1.16 (0.92–1.47)
	Girls
1994	1	1	1
1998	3.36 (0.75–15.10)	1.49 (0.77–2.86)	2.24 (1.53–3.29)
2002	5.92 (1.72–20.29)	6.15 (3.69–10.25)	3.30 (2.39–4.54)
2006	3.44 (0.97–12.24)	4.38 (2.60–7.38)	3.26 (2.38–4.46)