Table 3

Multivariate association of socioeconomic factors with CZS in Northeast Brazil 2015–2018

Demographic variables	Model 1*		Model 2†		Model 3‡
Demographic variables	OR (95% CI)	P value	OR (95% CI)	P value	OR (95% CI)	P value
Year of birth
2015	1		1		1
2016	0.71 (0.65 to 0.79)	<0.001	0.70 (0.63 to 0.78)	<0.001	0.68 (0.62 to 0.76)	<0.001
2017	0.14 (0.12 to 0.17)	<0.001	0.14 (0.11 to 0.16)	<0.001	0.13 (0.11 to 0.16)	<0.001
2018	0.09 (0.07 to 0.11)	<0.001	0.09 (0.07 to 0.11)	<0.001	0.08 (0.06 to 0.10)	<0.001
Sex of the newborn
Male	1		1		1
Female	1.22 (1.11 to 1.33)	<0.001	1.23 (1.12 to 1.34)	<0.001	1.20 (1.10 to 1.32)	<0.001
Maternal ethnicity
White			1		1
Black			1.72 (1.39 to 2.12)	<0.001	1.56 (1.25 to 1.94)	<0.001
Mixed Brown			1.12 (0.97 to 1.30)	0.130	1.04 (0.89 to 1.21)	0.639
Asian			0.39 (0.10 to 1.59)	0.190	0.39 (0.10 to 1.59)	0.190
Indigenous			1.01 (0.50 to 2.05)	0.979	0.89 (0.42 to 1.90)	0.749
Maternal education (years)
0–3					1.19 (0.92 to 1.54)	0.198
4–7					1.16 (0.97 to 1.40)	0.130
12–8					1.27 (1.08 to 1.51)	0.005
>12					1
Maternal marital status
Married/union					1
Single					1.30 (1.18 to 1.43)	<0.001
Widow					0.70 (0.17 to 2.79)	0.609
Divorced					1.10 (0.57 to 2.12)	0.782
No of prenatal appointments
None					1.24 (0.68 to 2.25)	0.476
1–3					1.08 (0.90 to 1.27)	0.350
4–6					1.00 (0.88 to 1.14)	0.894
7+					1
Maternal age (years)
<20					1.05 (0.88 to 1.25)	0.621
20–34					0.91 (0.78 to 1.06)	0.218
35+					1

*Model 1 is a minimally adjusted model—adjusted for year of birth, region and sex of the newborn.
†Model 2 year of birth, region and sex and race.
‡Model 3—year of birth, region and sex, race, maternal education, marital status, maternal age, number of prenatal appointments.
CZS, congenital Zika syndrome.