Depression, conduct disorder, smoking and alcohol use as predictors of sexual activity in middle adolescence: a longitudinal study

Figures & data

Table 1. Distribution of sexual behaviours, depression, frequent alcohol use and daily smoking at ages 15 and 17, and age at menarche/oigarche as well as mean (s.d.) age at baseline among the participants of the AMHC study (%).

	Girls (n = 1167)	Boys (n = 903)
Has experienced intercourse at age 17
Yes	57.6	42.0
No	39.9	51.9
Missing	2.5	6.1
Has experienced intercourse with five or more partners at age 17
Yes	14.5	11.0
No	83.0	82.9
Missing	2.5	6.1%
Depression at age 15
Yes	11.8	6.0
No	88.0	93.5
Missing	0.5	0.6
Depression at age 17
Yes	10.3	6.3
No	89.5	92.8
Missing	0.2	0.9
Frequent alcohol use at age 15
Yes	9.1	10.9
No	90.6	88.9
Missing	0.3	0.2
Frequent alcohol use at age 17
Yes	15.9	26.0
No	83.7	73.1
Missing	0.4	0.9
Daily smoking at age 15
Yes	20.4	19.7
No	78.7	79.1
Missing	0.9	1.2
Daily smoking at age 17
Yes	25.4	25.6
No	74.1	73.5
Missing	0.4	0.9
Age at menarche/oigarche
11 or less	19.7	17.5
12–13	63.3	57.6
14 or more/not yet	16.7	20.7
Missing	0.3	4.2
Age at baseline (in years) mean (s.d.)	15.5 (0.36)	15.5 (0.36)

Note: As conduct disorder was defined as the 90th percentile of the sum score of CBCL delinquency + aggression scales, its prevalence is always 10%.

Table 2. Experience of intercourse at age 17, and reporting five of more partners for intercourse by age 17, according to depression, daily smoking, frequent alcohol use and conduct disorder at ages 15 and 17 among Finnish girls and boys (%).

	Girls				Boys
	Has experienced intercourse at age 17 years (%)		Five or more partners for intercourse lifetime (%)		Has experienced intercourse at age 17 years (%)		Five or more partners for intercourse lifetime (%)
		p		p		p		p
Depression at age 15		<.001		.001		.156		.227
Yes	76.9		23.9		51.9		14.8
No	56.6		13.2		44.0		10.7
Depression at age 17		.03		.009		.408		.082
Yes	67.2		22.5		42.1		17.5
No	58.1		13.7		44.7		10.5
Daily smoking at 15		<.001		<.001		<.001		<.001
Yes	93.9		39.5		78.9		29.2
No	50.2		8.2		36.4		6.4
Daily smoking at 17		<.001		<.001		<.001		<.001
Yes	89.9		36.0		74.9		25.5
No	42.6		7.2		34.5		6.0
Frequent alcohol use at 15		<.001		<.001		<.001		<.001
Yes	92.1		44.3		76.4		34.7
No	56.0		11.6		41.0		8.1
Frequent alcohol use at 17		<.001		<.001		<.001		<.01
Yes	89.0		38.8		70.8		24.3
No	53.3		10.2		35.5		6.4
Conduct disorder at 15		<.001		<.001		<.001		<.001
Yes	86.5		12.1		63.4		32.6
No	56.1		36.1		42.7		8.5
Conduct disorder at 17		<.001		<.001		<.001		<.001
Yes	72.2		36.1		63.9		24.4
No	57.0		12.1		42.9		9.3

Table 3. Risk (OR, 95% CI) for having experienced intercourse, and for reporting five or more partners for intercourse by age 17 according to depression, conduct disorder, frequent alcohol use and daily smoking at age 15, among Finnish adolescent girls and boys.

	Experience of intercourse by age 17				Intercourse with five or more partners by age 17
	Girls		Boys		Girls		Boys
	OR (95% CI)	p	OR (95% CI)	p	OR (95% CI)	p	OR (95% CI)	p
Age	1.2 (0.8–1.8)	.36	1.9 (1.2–2.9)	.006	0.8 (0.5–1.4)	.5	1.1 (0.6–2.0)	.8
Age at menarche/oigarche		<.001		<.001		<.001		.02
11 or less	2.1 (1.4–3.2)		2.8 (1.7–4.6)		6.6 (2.9–14.7)		2.9 (1.3–6.6)
12–13	2.0 (1.4–2.8)		1.8 (1.2–8.7)		3.2 (1.5–7.0)		1.6 (0.7–3.4)
14 or more	ref		ref		ref		ref
Depression	1.8 (1.1–2.9)	.02	1.0 (0.5–1.9)	.9	1.0 (0.6–1.8)	.9	0.6 (0.2–1.7)	.4
Conduct disorder	2.6 (1.4–2.8)	.002	1.7 (0.7–2.2)	.5	2.4 (1.5–3.9)	.001	2.8 (1.5–5.2)	.001
Frequent alcohol use	3.1 (1.4–6.9)	.005	2.2 (1.2–4.0)	.01	2.4 (1.5–3.9)	.001	2.5 (1.4–4.5)	.003
Daily smoking	10.3 (5.8–18.3)	<.001	4.6 (2.9–7.3)	<.001	4.7 (3.2–7.0)	<.001	3.2 (1.9–5.5)	<.001
Hosmer–Lemeshow goodness of fit	0.837		0.123		0.357		0.027

Note: The independent variables studied were entered into the model simultaneously after controlling for age and age at menarche/oigarche.