Table 2

Trends in injecting and non-injecting drug use behaviours, using 13 620 visits of 996 drug users in the Amsterdam Cohort Study

		86–88	89–90	91–92	93–94	95–96	97–98	Yr	Yr^2-150Yr
Injecting status (%)
never		11	11	13	14	18	21
stopped		22	26	28	31	35	42
current		66	64	59	55	47	36	NS	^2-160
Transitions injecting: (%)^2-151
initiation		4.1	5.1	2.8	1.1	1.1	0.7	^2-150	NS
cessation		10.0	10.2	10.1	11.0	13.3	17.1	NS	^2-165
relapse		21.3	20.1	19.3	16.9	13.4	11.8	^2-165	NS
Injecting behaviours: (%)^2-152
Main type:	heroin	20	21	20	17	22	24
	cocaine	9	12	10	15	20	18	^2-160	NS
	speedballs	61	56	60	59	51	45
	other	10	11	10	9	7	13
⩾2 injections/day		39	36	32	31	25	22	^2-165	NS
All needles at exchange		57	65	66	75	73	73	^2-165	^2-165
Non-injecting use: (%)
heroin:	<daily	34	32	33	36	43	42	^2-165	^2-165
	daily	27	19	15	18	20	19
cocaine:	<daily	30	28	19	31	38	48	^2-165	^2-165
	daily	14	10	9	8	10	14
tranquilisers		44	28	33	32	35	43	^2-165	^2-165
>4 units alcohol/day		22	18	19	23	21	20	NS	NS

Yr, p value effect calendar year; Yr^2-150Yr, quadratic effect calendar year;
↵2-150 , p<0.05;
↵2-160 , p<0.01;
↵2-165 , p<0.001; GEE was used for statistical analysis, using a linear link function.
↵2-151 Expressed as percentage per visit at risk, see methods.
↵2-152 Only at visits at which participants reported current injecting.