Table 1

Trends in sociodemographic variables, 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	p Value
Number cohort visits	1658	1863	2110	2554	2772	2663
Female (%)	46	41	39	37	35	33	^1-165
Age	29.7	32.0	34.1	35.6	37.1	38.7	^1-165
Nationality							^1-165
Dutch (%)	74	74	76	78	80	81
German (%)	18	16	13	10	8	7
Ethnicity							^1-165
West European (%)	89	90	88	84	82	82
Surinam/Antillean (%)	5	5	6	9	12	12
Left school age <16 (%)	60	56	57	56	56	56	^1-160
HIV seropositive (%)	36	37	36	33	29	26	^1-165
History of injecting (%)	89	89	87	86	82	79	^1-165
Years since onset injecting^1-151	9.4	10.9	12.4	13.6	14.8	16.3	^1-165
Age start injecting^1-151	20.3	21.0	21.7	22.4	22.7	22.7	^1-150
Homelessness (%)^1-152	—	16	17	17	17	18	NS
Prostitution (%)^1-152	29	20	14	14	12	10	^1-165
Daily methadone (%)^1-152	83	73	72	70	70	66	^1-165

↵1-150 , p<0.05;
↵1-160 , p<0.01;
↵1-165 , p<0.001; GEE was used for statistical analysis, using a linear link function.
↵1-151 Only at visits of participants with history of injecting.
↵1-152 Current behaviour—that is, in the preceding six months or since the previous cohort visit.