Table 1.

Unadjusted and adjusted analysis of the association between individual, maternal, and pregnancy-related variables and conviction for violent delinquency up to age 25 years among males from the 1982 Pelotas Birth Cohort

		Lifetime conviction for violent delinquency
		Unadjusted			Adjusteda
Level	Independent variables	n	CI%	CIR [95% CI]	Pb	CIR [95% CI]	Pb
1	Mother's skin colour				0.01		0.01
	White	2228	2.6%	1.0 Reference		1.0 Reference
	Black or mixed	489	4.7%	1.8 [1.1, 2.9]		1.8 [1.1, 2.9]
2	Mother's age (years)				0.2		0.5
	<20	399	4.0%	1.4 [0.8, 2.5]		1.2 [0.7, 2.1]
	≥20	2320	2.8%	1.0 Reference		1.0 Reference
	Mother's marital status				0.7		0.9
	With husband or partner	2516	2.9%	1.0 Reference		1.0 Reference
	Without husband or partner	201	3.5%	1.2 [0.6, 2.5]		0.9 [0.4, 2.1]
	Family income (no. of minimum wages)				P < 0.001c		P < 0.001c
	≤1	542	3.9%	12.2 [1.6, 90.0]		10.6 [1.4, 78.8]
	1.1–3	1337	3.7%	11.5 [1.6, 83.1]		10.7 [1.5, 77.2]
	3.1–6	515	1.9%	6.1 [0.8, 47.4]		5.9 [0.8, 46.1]
	>6	314	0.3%	1.0 Reference		1.0 Reference
	Smoking during pregnancy				0.3		0.6
	No	1761	2.7%	1.0 Reference		1.0 Reference
	Yes	958	3.4%	1.3 [0.8, 2.0]		1.1 [0.7, 1.8]
3	Obstetric complications				0.8		0.9d
	No	2506	3.0%	1.0 Reference		1.0 Reference
	Yes	213	3.3%	1.1 [0.5, 2.4]		1.1 [0.5, 2.4]
	Low birthweight				0.7		0.5d
	No	2546	3.0%	1.0 Reference		1.0 Reference
	Yes	172	3.5%	1.2 [0.5, 2.7]		1.3 [0.6, 3.1]
	Number of younger siblings				0.005c		0.01c,d
	0	1649	2.3%	1.0 Reference		1.0 Reference
	1	627	4.3%	1.9 [1.2, 3.0]		1.9 [1.2, 3.0]
	≥2	79	5.1%	2.2 [0.80, 6.0]		1.9 [0.7, 5.4]
	Number of older siblings				0.6c		0.8c,d
	0	1044	2.8%	1.0 Reference		1.0 Reference
	1	653	2.9%	1.1 [0.6, 1.9]		1.1 [0.6, 2.0]
	≥2	658	3.2%	1.2 [0.7, 2.0]		1.1 [0.6, 1.9]
4A	Duration of partial breast feeding (months)				0.2c		0.1c,d,e
	<1	585	1.5%	1.0 Reference		1.0 Reference
	1–2.9	670	4.2%	2.7 [1.3, 5.7]		2.6 [1.2, 5.7]
	3–5.9	580	2.9%	1.9 [0.9, 4.2]		2.0 [0.9, 4.8]
	6–8.9	249	2.0%	1.3 [0.4, 3.9]		1.3 [0.4, 4.2]
	9–11.9	108	0.9%	0.6 [0.1, 4.7]		0.9 [0.1, 7.4]
	≥12	382	4.4%	2.9 [1.3, 6.4]		2.9 [1.3, 6.6]
4B	Duration of predominant breast feeding (months)				0.1c		0.06c,d,f
	<1	656	1.8%	1.0 Reference		1.0 Reference
	1–1.9	383	4.2%	2.3 [1.1, 4.8]		1.6 [0.7, 3.5]
	2–2.9	448	2.0%	1.1 [0.5, 2.6]		1.1 [0.5, 2.6]
	3–3.9	658	3.3%	1.8 [0.9, 3.7]		1.7 [0.9, 3.5]
	≥4	294	4.1%	2.2 [1.0, 4.9]		2.2 [1.0, 4.6]
	Total	2719	3.0%

^aAdjusted for all variables in the same level or in higher levels with P < 0.2.

^bWald test for heterogeneity.

^cWald test for linear trend.

^dAlso adjusted for maternal schooling in 1982.

^eModel fitted with partial breast feeding as dependent variable.

^fModel fitted with predominant breast feeding as dependent variable.

CI, confidence interval; CI%, cumulative incidence; CIR, cumulative incidence ratio.