Adjusted Odds of Past-Year Infections Among 6-Year-Old US Children According to Breastfeeding Practices, IFPS II (2005–2007) and Y6FU (2012); N = 1281

VariableCold or Upper Respiratory Tract InfectionEar InfectionThroat InfectionSinus InfectionPneumonia or Lung InfectionUrinary Tract Infection
aORa95% CIaOR95% CIaOR95% CIaOR95% CIaOR95% CIaOR95% CI
Ever breastfed (n = 1281)
Duration of any breastfeeding (n = 1106)
 >0 to <3 moRefRefRefRefRefRef
 3 to <6 mo0.680.45––1.641.000.62–1.610.710.41–1.230.810.31–2.150.550.17–1.81
 6 to <9 mo1.020.65–1.610.840.51–1.370.870.52–1.440.610.33–1.100.370.10–1.390.730.23–2.37
 ≥9 mo0.980.70–1.360.69b0.48–0.98b0.68b0.47–0.98b0.47b0.30–0.72b0.770.37–1.600.540.23–1.25
Duration of exclusive breastfeeding (n = 1106)
 >0 to <4 moRefRefRefRefRefRef
 4 to <6 mo0.880.62–1.250.690.46–1.030.770.51–1.160.710.43–1.180.670.30–1.521.290.57–2.92
 ≥6 mo1.320.64–2.730.37b0.14–0.98b0.23b0.07–0.76b0.13b0.02–0.97b0.340.04–2.610.460.06–3.65
Formula supplementation (n = 1106)
 Breastfed <6 mo with formula before 6 moRefRefRefRefRefRef
 Breastfed ≥6 mo with formula before 6 mo1.080.77–1.500.810.56–1.160.860.59–1.240.650.42–1.010.920.44–1.900.830.35–1.94
 Breastfed ≥6 mo without formula before 6 mo1.070.78–1.480.66b0.46–0.94b0.63b0.44–0.92b0.50b0.32–0.78b0.610.29–1.290.570.25–1.32
Breast milk intensity (% milk feedings being breast milk) during the first 6 mo (n = 1106)
 Low (>0 to < 33.3%)RefRefRefRefRefRef
 Medium (33.3% to 66.6%)0.840.54–1.320.980.60–1.611.060.64–1.740.730.41–1.310.830.30–2.290.920.31–2.76
 High (>66.6%)1.030.75–1.410.770.54–1.080.730.51–1.030.53b0.35–0.79b0.620.31–1.260.510.23–1.14
  • a aOR obtained after controlling for maternal age; race/ethnicity; education; household income; marital status; parity; Special Supplemental Nutrition Program for Women, Infants, and Children participation; prepregnancy BMI; infant gender and birth weight; infant cared for by someone other than parent at 3 months old; infant attending after-school child care at 6 years of age; and the type of school child attended. Reference group comprised children who had no maternal report of past-year infection.

  • b If 95% CI does not include 1, the findings are considered statistically significant.