Table 2.

Multiple logistic regression model, dependent variable – DTaP-IPV-Hib 1 – age-appropriate vaccination status.^a

Variables	Birthweight – main independent variable Adjusted OR [95% CI]	Gestational age – main independent variable Adjusted OR [95% CI]
Gender
Male	1.06 [1.02–1.10] *	1.06 [1.03–1.10] *
Female	reference	reference
Mother family status
Married	reference	reference
Other	1.54 [1.44–1.65] *	1.54 [1.44–1.65] *
Ethnicity
Jew & others	3.27 [3.07–3.48] *	3.30 [3.10–3.52] *
Arab	reference	reference
Birthweight
$\ge$2500 g	reference	Na
2000–2500 g	0.98 [0.90–1.07]	Na
1500–2000 g	1.56 [1.36–1.78] *	Na
1000–1500 g	3.34 [2.81–3.96] *	Na
$<$1000 g	17.03 [13.58–21.35] *	Na
Gestational age at birth
$\ge$37 weeks	Na	reference
32–36 weeks	Na	1.10 [1.02–1.19] *
28–32 weeks	Na	3.62 [3.08–4.27] *
$<$ 28 weeks	Na	21.77 [16.98–27.91] *
Birth order
First born	reference	reference
Second born	1.75 [1.65–1.85] *	1.77 [1.67–1.87] *
Third born	2.02 [1.90–2.14] *	2.02 [1.91–2.15] *
Fourth born and above	3.22 [3.04–3.40] *	3.25 [3.08–3.44] *
Socioeconomic rank
Rank 1–3	1.30 [1.23–1.37] *	1.31 [1.24–1.39] *
Rank 4–7	0.56 [0.53–0.59] *	0.56 [0.53–0.59] *
Rank 8–10	reference	reference
Month of birth
January–March	reference	reference
April–June	0.91 [0.87–0.96] *	0.91 [0.87–0.96] *
July–September	1.11 [1.06–1.17] *	1.11 [1.06–1.17] *
October–December	0.93 [0.89–0.98] *	0.93 [0.88–0.98] *

*p-value $\le$<0.001.

^aThe OR in the regression is defined as the rate of delayed initiation of the DTaP-IPV-Hib 1 vaccine.