Environmental and Genetic Factors Associated With AOM in the First 6 Months (n = 70 Infants)

FactornHR (95% CI)P
Cigarette exposurea540.74 (0.48–1.14).17
Day care attendanceb671.19 (0.79–1.80).41
One or more sibling(s) in the homec861.07 (0.97–1.18).20
Breastfeeding exclusively at least 3 mod2450.40 (0.18–0.90).028
Length of breastfeeding, moe950.85 (0.78–0.93).0003
Length of time to exclusive formula feeding, mo2680.76 (0.69–0.83)<.0001
Length of time to other feeding, mof2710.89 (0.70–1.00).051
Born after February 2010g2200.89 (0.71–1.11).31
TNFα−308 polymorphismh810.71 (0.49–1.03).069
IL-6–174 polymorphismh1270.79 (0.55–1.15).23
  • CI, confidence interval

  • a Any smoking in the household.

  • b Yes/no, any length of time.

  • c Linear function, taking into account the number of siblings.

  • d The length 3 mo was chosen because it optimized the model fit to the data (ie, maximized the likelihood).

  • e Length of breastfeeding, not necessarily exclusively.

  • f Other food than breast milk or formula.

  • g Heptavalent PCV (7) was given before February 2010; all subjects received PCV13 thereafter. Of the subjects completing the study, 73% had received 4 doses of PCV vaccines, 18% received 3 doses, 5% received 2 doses, and 3% received only 1 dose.

  • h Homozygous and heterozygous.