TABLE 4

Unadjusted and Adjusted ORs of Low Birth Weight Children Being Fully Immunized Against Influenza During Their FEW (N = 45 012)

CharacteristicUnadjusted ORa (95% CI)Adjusted ORa,b (95% CI)
Birth wt category
 <1000 g2.24 (1.96–2.57)1.44 (1.17–1.76)
 1000–1499 g1.74 (1.57–1.93)1.34 (1.18–1.51)
 1500–1999 g1.29 (1.19–1.40)1.16 (1.05–1.27)
 2000–2499 g1 (referent)1 (referent)
Gender
 Female1 (referent)1 (referent)
 Male1.06 (0.98–1.13)1.01 (0.94–1.09)
Multiple birth
 No1 (referent)1 (referent)
 Yes1.28 (1.20–1.38)1.36 (1.26–1.48)
Quarter of discharge
 11.23 (1.12–1.35)1.50 (1.31–1.72)
 20.92 (0.84–1.01)1.06 (0.93–1.22)
 30.93 (0.85–1.03)0.90 (0.81–1.00)
 41 (referent)1 (referent)
Age at FEW
 6–8 mo1 (referent)1 (referent)
 9–11 mo1.21 (1.10–1.33)0.98 (0.85–1.12)
 ≥12 months1.09 (1.00–1.18)1.19 (1.04–1.36)
No. of primary care visits 1 year after birth
 3–6 visits1 (referent)1 (referent)
 7–11 visits2.57 (2.20–3.00)2.34 (1.98–2.76)
 ≥12 visits4.51 (3.88–5.26)4.15 (3.51–4.91)
PCP
 FP: low volume1 (referent)1 (referent)
 FP: high volume1.11 (1.01–1.23)1.06 (0.93–1.20)
 Pediatrician2.06 (1.89–2.25)1.80 (1.55–2.09)
Continuity of care
 Very low (<50%)1 (referent)1 (referent)
 Low (50%–67%)0.99 (0.86–1.13)0.99 (0.85–1.15)
 Medium (67%–86%)1.25 (1.11–1.41)1.17 (1.02–1.34)
 High (86%–100%)1.26 (1.13–1.42)1.33 (1.17–1.52)
Neighborhood income quintile
 Quintile 1 (lowest)1 (referent)1 (referent)
 Quintile 21.05 (0.94–1.17)1.02 (0.90–1.15)
 Quintile 31.19 (1.07–1.33)1.12 (1.00–1.26)
 Quintile 41.35 (1.22–1.50)1.25 (1.11–1.41)
 Quintile 5 (highest)1.60 (1.44–1.78)1.47 (1.30–1.67)
Rural residence
 No1 (referent)1 (referent)
 Yes0.80 (0.71–0.92)1.06 (0.91–1.25)
Mother vaccinated for influenza in year after delivery
 No1 (referent)1 (referent)
 Yes3.59 (3.33–3.87)3.37 (3.10–3.67)
Mom aged <20 y at first childbirth
 No1 (referent)1 (referent)
 Yes0.56 (0.49–0.64)0.77 (0.66–0.90)
Neuromuscular, metabolic, or congenital chronic condition
 No1 (referent)1 (referent)
 Yes1.32 (1.13–1.54)1.07 (0.90–1.27)
Cardiovascular chronic condition
 No1 (referent)1 (referent)
 Yes1.87 (1.62–2.15)1.20 (0.98–1.47)
Respiratory chronic condition
 No1 (referent)1 (referent)
 Yes0.95 (0.77–1.18)0.88 (0.69–1.12)
Other chronic condition
 No1 (referent)1 (referent)
 Yes1.32 (1.15–1.51)1.25 (1.08–1.46)
  • a ORs comparing full vaccination to partial or no vaccination and accounting for variation between physicians.

  • b ORs adjusted for all other variables.