Temporal evolution of the risk factors associated with low birth weight rates in Brazilian capitals (1996-2011)

Viviane Costa de Souza Buriol; Vânia Hirakata; Marcelo Zubaran Goldani; Clécio Homrich da Silva

doi:10.1186/s12963-016-0086-0

Population Health Metrics

Table 2 Distribution of maternal characteristics in the first and last years of the series and AAPC^a of low birth weight among single newborns for each stratum of the variables studied, Brazil and its regions according to the 26 state capitals and Brazil’s capital, Brasília, between 1996 and 2011

From: Temporal evolution of the risk factors associated with low birth weight rates in Brazilian capitals (1996-2011)

Variables	1996	2011	AAPC (95 % CI)	P	1996	2011	AAPC (95 % CI)	P	1996	2011	AAPC (95 % CI)	P
	North				Northeast				Southeast
Maternal age (years)
10–17 years	14.9	11.3	-	-	11.4	9.0	-	-	8.0	7.0	-	-
≥35 years	4.7	8.6	-	-	6.4	10.9	-	-	9.7	15.3	-	-
18-34	80.3	80.0	-	-	82.2	80.2	-	-	82.2	77.7	-	-
LBW 10–17 years	10.2	10.6	0.1 (−0.9;1.2)	<0.001	9.9	10.7	0.2 (−0.5;0.9)	0.037	11.9	10.9	−0.5 (−1.5;0.4)	0.227
LBW ≥35 years	6.6	8.6	1.8 (1.0;2.6)^a	<0.001	7.7	9.0	0.6 (0.2;1.1)^a	<0.001	11.0	9.3	−0.9 (−1.1;−0.6)^a	<0.001
LBW 18–34	6.0	7.0	1.1 (0.5;1.8)^a	<0.001	6.6	7.4	0.8 (0.5;1.1)^a	<0.001	8.3	7.6	−0.4 (−1.2;0.4)	0.001
Educational level (years)
<8 years	64.2	28.3	-	-	62.3	26.2	-	-	48.9	19.5	-	-
≥12	3.0	16.4	-	-	5.5	19.5	-	-	10.4	24.5	-	-
8–11	32.7	55.3	-	-	32.2	54.3	-	-	40.7	56.0	-	-
LBW <8 years	7.1	8.3	1.2 (0.6;1.9)^a	<0.001	7.7	9.0	1.1 (0.7;1.5)^a	<0.001	10.0	9.7	−0.2 (−1.1;0.7)	<0.001
LBW ≥12	5.4	7.5	3.2 (1.3;5.0)^a	<0.001	5.1	7.3	1.3 (0.6;2)^a	<0.001	5.7	7.2	1.5 (1.0;2.1)^a	<0.001
LBW 8-11	5.7	7.2	1.6 (1.3;2.0)^a	<0.001	6.2	7.5	1.4 (0.7;2.2)^a	<0.001	7.9	8.0	0.1 (−1.3;1.5)	<0.001
Prenatal care (no. of visits)
None	11.1	4.1	-	-	9.7	4.7	-	-	6.6	1.7	-	-
≤6 or	35.5	49.9	-	-	37.5	46.9	-	-	35.1	24.2	-	-
≥7	53.4	46.0	-	-	52.8	48.4	-	-	58.3	74.1	-	-
LBW None	10.1	13.9	2.7 (−0.2;5.6)	<0.001	11.3	13.2	1.5 (−0.5;3.6)	<0.001	16.9	24.2	3.7 (2.7;4.7)^a	<0.001
LBW ≤6 or	7.5	9.3	1.3 (0.9;1.8)^a	<0.001	8.4	9.8	1 (0.1;1.8)^a	<0.001	11.7	14.0	1.4 (0.4;2.3)^a	<0.001
LBW ≥7	5.4	5.0	−0.4 (−0.8;0.1)	0.002	5.1	5.2	0.4 (−0.2;0.9)	<0.001	6.1	5.8	−0.3 (−0.5;0.0)^a	<0.001
Gestational age (weeks)
<37	4.9	10.8	-	-	4.9	11.0	-	-	6.5	8.7	-	-
≥37	95.1	89.2	-	-	95.1	89.0	-	-	93.5	91.3	-	-
LBW <37	45.1	34.9	1.2 (−1.6;4)	<0.001	48.1	39.4	−1.2 (−3.7;1.3)	<0.001	59.3	52.5	−0.1 (−0.6;0.4)	<0.001
LBW ≥37	4.6	4.2	0.1 (−0.7;0.8)	0.937	4.8	3.7	−1.3 (−2.2;0.4)^a	<0.001	5.2	3.9	−2 (−2.7;1.3)^a	<0.001
Mode of delivery
Caesarean section	34.5	51.2	-	-	38.0	60.3	-	-	47.3	53.1	-	-
Vaginal delivery	65.5	48.8	-	-	62.0	39.7	-	-	52.7	46.9	-	-
Caesarean section LBW	5.3	7.4	2.1 (1.4;2.8)^a	<0.001	5.8	7.1	1.2 (0.7;1.7)^a	<0.001	8.0	8.4	0.5 (−0.1;1.1)	<0.001
Vaginal delivery LBW	7.3	7.7	0.4 (0.0;0.9)	<0.001	7.7	9.0	0.7 (0.4;1.1)^a	<0.001	9.6	7.8	−1.2 (−1.5;−0.9)^a	<0.001
	South				Central West				Brazil
Maternal age (years)
10–17 years	9.4	6.7	-	-	10.6	7.0	-	-	10.1	8.1	-	-
≥35 years	10.5	15.4	-	-	5.9	12.3	-	-	8.0	13.1	-	-
18-34	80.1	77.9	-	-	83.5	80.6	-	-	81.9	78.9	-	-
LBW 10–17 years	10.6	10.0	−0.3 (−1.1;0.5)	0.246	10.2	10.3	0.6 (0.1;1.0)^a	0.001	11.0	10.8	−0.1 (−0.8;0.5)^a	0.008
LBW ≥35 years	9.2	8.8	−0.5 (−1;−0.1)^a	0.010	8.9	8.6	0.3 (−0.3;0.8)	0.175	9.8	9.1	−0.4 (−0.6;−0.2)	<0.001
LBW 18–34	6.8	7.5	0.5 (0.0;1.1)	<0.001	6.7	7.7	0.9 (0.5;1.2)^a	<0.001	7.4	7.5	0.1 (−0.4;0.6)	<0.001
Educational level (years)
<8 years	46.2	20.6	-	-	52.6	18.8	-	-	55.4	22.3	-	-
≥12	10.8	33	-	-	7.4	27.0	-	-	7.2	22.9	-	-
8–11	42.9	46.4	-	-	40.1	54.2	-	-	37.4	54.8	-	-
LBW <8 years	8.6	9.5	1 (0.4;1.6)	<0.001	7.9	9.2	0.7 (0.2;1.2)^a	<0.001	8.4	9.3	0.6 (−1;2.2)	,0.001
LBW ≥	5.2	6.8	1.8 (0.7;2.9)^a	<0.001	5.7	7.8	1.8 (1.2;2.3)^a	<0.001	5.6	7.3	1.5 (1.1;1.9)^a	,0.001
LBW 8-11	6.6	7.8	1.1 (0.1;2.2)^a	<0.001	6.5	7.6	1.2 (0.7;1.6)^a	<0.001	6.9	7.8	0.9 (0.6;1.1)^a	<0.001
Prenatal care (no. of visits)
None	4.4	1.4	-	-	5.5	3.3	-	-	8.3	3.0	-	-
≤6 or UD	32.5	17.7	-	-	40.1	27.6	-	-	35.8	33.5	-	-
≥7	63.2	80.9	-	-	54.5	69.2	-	-	55.9	63.5	-	-
LBW None	16.5	24.6	3.1 (1.4;4.8)^a	<0.001	13.5	16.9	1.3 (−1.4;4.1)	<0.001	12.9	17.4	2.4 (0.6;4.1)^a	<0.001
LBW ≤6 or UD	9.7	15.3	3.2 (2.4;4.0)^a	<0.001	8.2	12.3	2.6 (2.1;3.1)^a	<0.001	9.3	11.5	1.3 (0.2;2.4)^a	<0.001
LBW ≥7	5.5	5.9	0.4 (−0.1;0.8)	0.011	5.9	5.7	0.3 (−0.2;0.8)	0.004	5.8	5.6	−0.1 (−0.3;0.0)	0.002
Gestational age (weeks)
<37	5.5	8.2	-	-	3.9	9.7	-	-	5.2	9.6	-	-
≥37	94.5	91.8	-	-	96.1	90.3	-	-	94.8	90.4	-	-
LBW <37	63.1	57.4	−0.5 (−0.8;−0.2)	<0.001	62.1	44.9	0 (−1.7;1.8)	0.019	56.1	46.1	−1 (−2.3;0.3)	<0.001
LBW ≥37	4.1	3.4	−1.4 (−1.8;−0.9)^a	<0.001	4.9	4.0	−0.7 (−2.7;1.3)	<0.001	4.9	3.9	−1.6 (−2.1;−1.1)^a	<0.001
Mode of delivery
Caesarean section	44.2	56.6	-	-	49.2	59.5	-	-	42.9	55.2	-	-
Vaginal delivery	55.8	43.4	-	-	50.8	40.5	-	-	57.1	44.8	-	-
Caesarean section LBW	7.3	8.4	0.5 (0.0;1.1)^a	<0.001	6.3	8.0	1.6 (1.2;2.0)^a	<0.001	7.1	8.0	1 (0.6;1.4)^a	<0.001
Vaginal delivery LBW	7.5	7.1	−0.2 (−0.6;0.2)	0.078	8.1	8.0	0 (−0.4;0.5)	0.929	8.6	8.0	−0.5 (−1.1;0.2)	<0.001

^aAAPC average annual percentage of change

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