Table 1

Result of the segmented regression model predicting smoking prevalence by sex

	Boys				Girls
	β	95% CI		P value	β	95% CI		P value
	β	Lower	Upper	P value	β	Lower	Upper	P value
Intercept β₀	16.5	15.4	17.5	<0.001	9.5	9.1	9.8	<0.001
Baseline trend β₁	−0.1	−0.3	0.2	0.610	−0.6	−0.6	−0.5
Level change after smoke-free legislation β₂	0.8	−1.1	2.7	0.406	0.4	−0.3	1.0	0.255
Trend change after smoke-free legislation β₃	−1.1	−1.9	−0.2	0.013	−0.4	−0.6	−0.1	0.011
Level change after price increase β₄	−1.3	−3.3	0.7	0.189	−0.8	−1.5	−0.2	0.012
Trend change after price increaseβ₅	−0.1	−1.3	1.0	0.795	0.9	0.5	1.2	<0.001