TABLE 4

Mutually Adjusted Cox Proportional Hazard Ratios for Noninitiation and Cessation of Breastfeeding in the 2012–2013-SPATZ Cohort

Risk FactorHazard Ratio (95% Confidence Interval)
Predominant BreastfeedingAny Breastfeeding
NoninitiationCessation at 6 WeeksCessation at 4 MonthsNoninitiationCessation at 6 WeeksCessation at 6 Months
Education
 ≥12 yrefrefrefrefrefref
 <12 y1.18 (0.75–1.87)1.44 (1.00–2.09)1.50 (1.10–2.05)1.74 (0.83; 3.66)1.87 (1.18–2.97)1.66 (1.25–2.21)
Alcohol status
 Never drinkerReferenceReferenceReferenceReferenceReferenceReference
 Abstinent drinker0.42 (0.19–0.94)0.44 (0.23–0.84)0.46 (0.27–0.78)0.35 (0.07–1.74)0.35 (0.13–0.96)0.36 (0.21–0.63)
 Resumed at 6 wk to 6 mo0.76 (0.39–1.52)0.96 (0.56–1.66)1.14 (0.73–1.77)0.77 (0.25–2.40)0.86 (0.40–1.86)1.63 (1.10–2.40)
 Resumed by 6 wk1.02 (0.58–1.78)1.61 (1.00–2.57)1.52 (1.01–2.30)1.62 (0.68–3.87)3.08 (1.71–5.55)2.13 (1.46–3.12)
 Undetermined0.56 (0.28–1.13)0.81 (0.43–1.50)0.88 (0.51–1.52)0.55 (0.17–1.74)1.18 (0.55–2.54)1.08 (0.65–1.80)
Smoking status
 Never smokerReferenceReferenceReferenceReferenceReferenceReference
 Abstinent smoker1.41 (0.74–2.67)1.05 (0.63–1.77)1.11 (0.71–1.73)2.26 (0.90–5.68)1.41 (0.76–2.60)1.22 (0.82–1.80)
 Resumed smoking1.48 (0.57–3.87)1.18 (0.53–2.62)2.11 (1.20–3.70)0.67 (0.09–5.35)1.13 (0.43–2.95)2.03 (1.21–3.38)
 Continuous smoker2.23 (1.18–4.19)1.69 (0.99–2.88)1.78 (1.12–2.82)1.14 (0.41–3.21)1.02 (0.51–2.04)1.54 (0.99–2.39)
 Undetermined2.25 (1.10–4.58)1.63 (0.89–2.98)1.28 (0.75–2.18)1.04 (0.34–3.25)1.08 (0.54–2.16)1.11 (0.67–1.84)
Prepregnancy BMI
 Normal (≤18.5 to <25)ReferenceReferenceReferenceReferenceReferenceReference
 Underweight (<18.5)4.22 (1.85–9.61)3.35 (1.60–7.01)2.64 (1.30–5.37)4.92 (1.59–15.23)3.93 (1.59–9.72)2.60 (1.25–5.43)
 Overweight (≤25 to <30)2.30 (1.43–3.71)1.87 (1.28–2.73)1.51 (1.09–2.09)1.65 (0.76–3.61)1.67 (1.04–2.67)1.34 (0.99–1.81)
 Obese (BMI ≥30)2.85 (1.68–4.85)2.37 (1.54–3.64)1.98 (1.37–2.87)2.05 (0.87–4.85)2.09 (1.23–3.57)1.76 (1.25–2.47)
Delivery mode
 Vaginal spontaneousReferenceReferenceReferenceReferenceReferenceReference
 Elective cesarean1.73 (1.08–2.77)1.81 (1.21–2.72)1.60 (1.11–2.31)2.29 (1.11–4.73)1.68 (1.02–2.77)1.90 (1.36–2.66)
 Emergency cesarean1.55 (0.91–2.65)1.87 (1.21–2.89)1.96 (1.35–2.85)1.83 (0.77–4.36)1.54 (0.88–2.68)1.66 (1.16–2.37)
 Vaginal assisted0.70 (0.24–1.97)1.10 (0.55–2.17)1.08 (0.62–1.88)0.51 (0.07–3.96)0.79 (0.31–2.05)1.16 (0.72–1.88)
Returned to work after delivery
 Did not workReferenceReferenceReferenceReferenceReferenceReference
 Month 1–30.92 (0.33–2.57)0.54 (0.20–1.49)0.72 (0.35–1.49)1.58 (0.45–5.59)0.93 (0.33–2.60)1.24 (0.73–2.10)
 Month 4–60.80 (0.28–2.29)0.78 (0.33–1.82)0.87 (0.42–1.81)1.51 (0.41–5.51)1.19 (0.50–2.84)1.36 (0.80–2.30)
 Month 7–120.46 (0.14–1.48)0.72 (0.35–1.51)0.83 (0.46–1.47)NA1.08 (0.46–2.57)1.12 (0.67–1.87)
 Undetermined1.88 (1.03–3.43)1.59 (0.94–2.70)1.98 (1.23–3.18)3.16 (1.24–8.01)2.43 (1.28–4.61)2.57 (1.64–4.04)
  • NA signifies not applicable (eg, no participants in the numerator).