Table 1.

General characteristics of the women living in Amsterdam participating in the national Chlamydia screenings trial included in this study, at baseline

	Controls N=55	Cases N=60	P-value
Median age (IQR)	22 (19–25)	23 (20–25)	0.41
Median age first sexual contact (IQR)	16 (15–17)	16 (15–17)	0.52
Born in the Netherlands	46 (83.6%)	50 (83.3%)	0.96
Ethnicity			0.98
Dutch	39 (70.9%)	41 (68.3%)
Surinamese/Dutch Antilles	11 (20.0%	13 (21.7%)
Asian	3 (5.4.9%)	3 (5.0%)
Turkish	1 (1.7%)	1 (1.8%)
Education			0.28
Low	2 (3.6%)	-
Middle	23 (41.9%)	22 (36.7%)
High	28 (50.9%)	34 (56.7%)
Sexual partners in the previous six months (IQR)	1 (1–2)	2 (1–3)	0.07
Previous infection with C. trachomatis*	3 (5.5%)	9 (15.0%)	0.09
Sexual health problems**	6 (10.9%)	13 (21.7%)	0.27
Relationship			0.21
Living together	6 (10.9%)	2 (3.3%)
Living apart	17 (30.9%)	14 (23.3%)
Single	25 (45.5%)	31 (51.7%)

^*Self-reported

^**Self-reported complaints like having more vaginal discharge than normal, a burning sensation while urinating, abdominal pain, blood loss between menses or during or after sexual intercourse

IQR: InterQuartile Range

P-value: Probability value