Table 2.

Odds ratios for clinic based testing in multivariable logistic regression models

		Girls			Boys			All participants1
Characteristic	OR	95% CI	p2	OR	95% CI	p2	OR	95% CI	p2
Gender: girls vs boys3
Norwegian	NA			NA			7.96	5.26–12.04	< 0.001
Sami/Sami-Norwegian	NA			NA			3.62	1.92–6.82	< 0.001
Other	NA			NA			1.89	0.66–5.45	0.24
Age
OR per year	1.47	1.20–1.81	< 0.001	1.73	1.28–2.32	< 0.001	1.54	1.30–1.83	< 0.001
Family and culture
Ethnicity girls4
Norwegian	ns			NA			1.00		0.37
Sami/Sami-Norwegian	ns			NA			1.30	0.82–2.08
Other	ns			NA			0.78	0.38–1.60
Ethnicity boys5
Norwegian	NA			1.00		< 0.001	1.00		< 0.001
Sami/Sami-Norwegian	NA			2.83	1.56–5.13		2.86	1.59–5.14
Other	NA			3.53	1.44–8.64		3.28	1.37–7.84
Sexual behaviour
Age at first intercourse
≥15 years	1.00		0.006	1.00		0.003	1.00		< 0.001
≤14 years	1.78	1.18–2.67		2.56	1.39–4.71		2.02	1.43–2.85
Condom use first intercourse
Yes	ns			ns			1.00		0.013
No6	ns			ns			1.48	1.09–2.01
Currently in a relationship
Yes	ns			ns			1.00		0.009
No	ns			ns			0.66	0.49–0.90
Lifetime no of sex partners
1-2	1.00		< 0.001	1.00		< 0.001	1.00		< 0.001
3-5	2.42	1.59–3.71		4.22	1.95–9.12		3.07	2.11–4.46
≥6	6.31	3.85–10.34		8.57	3.91–18.79		7.63	5.03–11.55
Condom use last intercourse
Yes	1.00		0.011	ns			ns
No7	1.93	1.16–3.20		ns			ns

The significant variables from stepwise selection, age and gender (if applicable) were included in the models.

OR, odds ratio; CI, confidence interval; NA, not applicable; ns, non-significant; ¹Interaction term between gender and ethnicity included in the model (p 0.012); ²p-value for equality between categories; ³Reference group: boys; ⁴Odds ratios in girls; ⁵Odds ratios in boys; ⁶Includes the response: ‘Uncertain if any contraception was used’ (girls n = 3, boys n = 10); ⁷Includes the response: ‘Uncertain if any contraception was used’ (girls n = 3, boys n = 8).