Table 3

Odds ratios of linear and quadratic models for ever drunk alcohol and ever cannabis use between 1998–2015 for England, Scotland and Wales

		Ever drunk alcohol				Ever used cannabis
		Linear	P value	Quadratic	P value	Linear	P value	Quadratic	P value
Whole sample (n=239 190; 239 457)	Year	0.91 (0.90 to 0.91)	<0.001	1.10 (1.08 to 1.12)	<0.001	0.92 (0.92 to 0.92)	<0.001	1.08 (1.07 to 1.10)	<0.001
	Year²	–	–	0.99 (0.99 to 0.99)	<0.001	–	–	0.99 (0.99 to 0.99)	<0.001
	Level	0.90 (0.85 to 0.95)	<0.001	0.85 (0.81 to 0.90)	<0.001	0.98 (0.90 to 1.07)	0.661	1.01 (0.93 to 1.10)	0.761
	Post-slope	0.96 (0.94 to 0.97)	<0.001	1.17 (1.14 to 1.19)	<0.001	1.00 (0.98 to 1.03)	0.667	1.21 (1.18 to 1.25)	<0.001
Male only subgroup (n=119 989; 120 025)	Year	0.91 (0.90 to 0.91)	<0.001	1.06 (1.03 to 1.09)	<0.001	0.93 (0.92 to 0.93)	<0.001	1.06 (1.04 to 1.09)	<0.001
	Year²	–	–	0.99 (0.99 to 0.99)	<0.001	–	–	0.99 (0.99 to 0.99)	<0.001
	Level	0.89 (0.82 to 0.96)	0.004	0.85 (0.79 to 0.92)	<0.001	0.92 (0.82 to 1.04)	0.185	0.94 (0.84 to 1.06)	0.337
	Post–slope	0.96 (0.94 to 0.98)	<0.001	1.12 (1.09 to 1.16)	<0.001	1.02 (0.99 to 1.05)	0.175	1.20 (1.15 to 1.24)	<0.001
Female only subgroup (n=119 201; 119 432)	Year	0.90 (0.90 to 0.91)	<0.001	1.15 (1.12 to 1.18)	<0.001	0.92 (0.91 to 0.92)	<0.001	1.11 (1.08 to 1.14)	<0.001
	Year²	–	–	0.99 (0.98 to 0.99)	<0.001	–	–	0.99 (0.99 to 0.99)	<0.001
	Level	0.91 (0.84 to 0.98)	0.016	0.85 (0.79 to 0.92)	<0.001	1.06 (0.93 to 1.20)	0.396	1.11 (0.98 to 1.26)	0.110
	Post–slope	0.96 (0.94 to 0.97)	<0.001	1.22 (1.18 to 1.26)	<0.001	0.99 (0.95 to 1.02)	0.359	1.23 (1.17 to 1.28)	<0.001
13 year olds only (n=124 842; 123 608)	Year	0.90 (0.90 to 0.90)	<0.001	1.11 (1.08 to 1.13)	<0.001	0.90 (0.89 to 0.90)	<0.001	1.16 (1.12 to 1.21)	<0.001
	Year²	–	–	0.99 (0.99 to 0.99)	<0.001	–	–	0.98 (0.98 to 0.99)	<0.001
	Level	0.88 (0.82 to 0.95)	0.001	0.84 (0.78 to 0.91)	<0.001	1.07 (0.89 to 1.28)	0.480	1.14 (0.95 to 1.37)	0.165
	Post–slope	0.95 (0.93 to 0.97)	<0.001	1.17 (1.14 to 1.21)	<0.001	0.99 (0.95 to 1.04)	0.746	1.34 (1.26 to 1.42)	<0.001
15 year olds only (n=114 348; 115 849)	Year	0.92 (0.91 to 0.92)	<0.001	1.08 (1.05 to 1.11)	<0.001	0.93 (0.92 to 0.93)	<0.001	1.06 (1.04 to 1.08)	<0.001
	Year²	–	–	0.99 (0.99 to 0.99)	<0.001	–	–	0.99 (0.99 to 0.99)	<0.001
	Level	0.92 (0.84 to 1.00)	0.049	0.87 (0.80 to 0.95)	0.002	0.96 (0.87 to 1.06)	0.432	0.99 (0.90 to 1.09)	0.776
	Post–slope	0.96 (0.94 to 0.98)	<0.001	1.13 (1.09 to 1.17)	<0.001	1.01 (0.98 to 1.03)	0.645	1.17 (1.13 to 1.20)	<0.001