TABLE 5.
Unadjusted and adjusted models for the association of maternal prepregnancy BMI and PSFs with intention to breastfeed, ever breastfed, and duration of EBF and ABF in all participants1
| Outcome |
||||
| Predictor | Intention to breastfeed (n = 2824)23 | Ever breastfed (n = 2824)24 | Duration of EBF (n = 1258)56 | Duration of ABF (n = 2423)57 |
| BMI category | ||||
| Unadjusted model8 | ||||
| P | 0.07 | 0.04 | 0.0009 | 0.03 |
| Underweight/normal weight | Reference | Reference | Reference | Reference |
| Overweight | 1.05 (0.80, 1.37) | 1.08 (0.83, 1.41) | 1.12 (0.97, 1.29) | 1.14 (1.01, 1.28) |
| Obese | 0.77 (0.59, 1.00) | 0.76 (0.60, 0.98) | 1.32 (1.14, 1.52) | 1.16 (1.02, 1.31) |
| n | 2824 | 2824 | 1258 | 2423 |
| Model adjusted for all PSFs9 | ||||
| P | 0.26 | 0.17 | 0.02 | 0.79 |
| Underweight/normal weight | Reference | Reference | Reference | Reference |
| Overweight | 1.32 (0.92, 1.90) | 1.32 (0.95, 1.84) | 1.06 (0.92, 1.23) | 1.00 (0.88, 1.13) |
| Obese | 0.98 (0.69, 1.41) | 0.95 (0.69, 1.32) | 1.25 (1.07, 1.46) | 1.04 (0.91, 1.19) |
| n | 2801 | 2801 | 1176 | 2225 |
| Final adjusted model10 | ||||
| P | 0.74 | 0.64 | 0.01 | 0.31 |
| Underweight/normal weight | Reference | Reference | Reference | Reference |
| Overweight | 1.03 (0.66, 1.59) | 1.07 (0.63, 1.84) | 1.09 (0.93, 1.27) | 1.00 (0.87, 1.15) |
| Obese | 0.87 (0.57, 1.33) | 0.82 (0.49, 1.38) | 1.29 (1.09, 1.53) | 1.11 (0.96, 1.29) |
| n | 2487 | 2466 | 1000 | 1785 |
| Social knowledge | ||||
| Unadjusted model8 | ||||
| P | <0.0001 | <0.0001 | <0.0001 | <0.0001 |
| >5 people | Reference | Reference | Reference | Reference |
| 3–5 people | 0.29 (0.20, 0.42) | 0.36 (0.25, 0.51) | 1.48 (1.28, 1.70) | 1.64 (1.45, 1.86) |
| 1–2 people | 0.14 (0.10, 0.21) | 0.18 (0.13, 0.25) | 1.64 (1.39, 1.93) | 1.88 (1.64, 2.15) |
| 0 people/do not know | 0.12 (0.08, 0.17) | 0.13 (0.09, 0.19) | 1.86 (1.52, 2.27) | 2.16 (1.84, 2.54) |
| n | 2801 | 2801 | 1247 | 2400 |
| Model adjusted for BMI and all PSFs9 | ||||
| P | <0.0001 | <0.0001 | <0.0001 | <0.0001 |
| >5 people | Reference | Reference | Reference | Reference |
| 3–5 people | 0.42 (0.27, 0.67) | 0.55 (0.37, 0.82) | 1.45 (1.25, 1.69) | 1.49 (1.30, 1.69) |
| 1–2 people | 0.24 (0.15, 0.38) | 0.31 (0.21, 0.46) | 1.64 (1.38, 1.94) | 1.63 (1.41, 1.88) |
| 0 people/do not know | 0.28 (0.17, 0.45) | 0.30 (0.19, 0.45) | 1.61 (1.30, 1.99) | 1.63 (1.37, 1.94) |
| n | 2801 | 2801 | 1176 | 2225 |
| Final adjusted model10 | ||||
| P | 0.02 | 0.55 | 0.001 | 0.0003 |
| >5 people | Reference | Reference | Reference | Reference |
| 3–5 people | 0.54 (0.32, 0.92) | 0.97 (0.53, 1.78) | 1.31 (1.11, 1.54) | 1.35 (1.17, 1.56) |
| 1–2 people | 0.44 (0.26, 0.74) | 0.73 (0.39, 1.35) | 1.36 (1.13, 1.64) | 1.22 (1.04, 1.44) |
| 0 people/do not know | 0.50 (0.28, 0.88) | 0.68 (0.34, 1.36) | 1.20 (0.95, 1.53) | 1.37 (1.12, 1.67) |
| n | 2487 | 2466 | 1000 | 1785 |
| Social influence | ||||
| Unadjusted model8 | ||||
| P | <0.0001 | <0.0001 | <0.0001 | <0.0001 |
| High | Reference | Reference | Reference | Reference |
| Medium | 0.10 (0.05, 0.23) | 0.25 (0.16, 0.42) | 1.27 (1.12, 1.44) | 1.19 (1.06, 1.34) |
| Low | 0.01 (0.01, 0.02) | 0.03 (0.02, 0.05) | 1.52 (1.29, 1.79) | 1.56 (1.37, 1.78) |
| n | 2824 | 2824 | 1258 | 2423 |
| Model adjusted for BMI and all PSFs9 | ||||
| P | <0.0001 | <0.0001 | 0.12 | 0.53 |
| High | Reference | Reference | Reference | Reference |
| Medium | 0.18 (0.08, 0.40) | 0.42 (0.25, 0.70) | 1.12 (0.98, 1.28) | 0.96 (0.85, 1.08) |
| Low | 0.03 (0.01, 0.06) | 0.09 (0.05, 0.14) | 1.16 (0.98, 1.40) | 1.03 (0.89, 1.20) |
| n | 2801 | 2801 | 1176 | 2225 |
| Final adjusted model10 | ||||
| P | <0.0001 | 0.02 | 0.04 | 0.99 |
| High | Reference | Reference | Reference | Reference |
| Medium | 0.16 (0.06, 0.44) | 0.73 (0.37, 1.43) | 1.20 (1.04, 1.38) | 0.99 (0.87, 1.13) |
| Low | 0.03 (0.01, 0.06) | 0.42 (0.21, 0.83) | 1.15 (0.95, 1.39) | 0.99 (0.84, 1.16) |
| n | 2487 | 2466 | 1000 | 1785 |
| Attitude/behavioral beliefs | ||||
| Unadjusted model8 | ||||
| P | <0.0001 | <0.0001 | <0.0001 | <0.0001 |
| Good | Reference | Reference | Reference | Reference |
| Fair | 0.10 (0.07, 0.14) | 0.13 (0.10, 0.17) | 2.04 (1.72, 2.41) | 2.10 (1.86, 2.37) |
| Poor | 0.02 (0.01, 0.03) | 0.03 (0.02, 0.04) | 2.18 (1.56, 3.05) | 2.50 (2.03, 3.07) |
| n | 2824 | 2824 | 1258 | 2423 |
| Model adjusted for BMI and all PSFs9 | ||||
| P | <0.0001 | <0.0001 | <0.0001 | <0.0001 |
| Good | Reference | Reference | Reference | Reference |
| Fair | 0.18 (0.13, 0.26) | 0.22 (0.16, 0.30) | 1.77 (1.47, 2.13) | 1.76 (1.54, 2.01) |
| Poor | 0.04 (0.03, 0.06) | 0.07 (0.05, 0.10) | 2.01 (1.41, 2.86) | 1.75 (1.37, 2.25) |
| n | 2801 | 2801 | 1176 | 2225 |
| Final adjusted model10 | ||||
| P | <0.0001 | 0.002 | 0.002 | 0.07 |
| Good | Reference | Reference | Reference | Reference |
| Fair | 0.22 (0.15, 0.34) | 0.41 (0.25, 0.67) | 1.28 (1.04, 1.58) | 1.17 (1.01, 1.37) |
| Poor | 0.05 (0.03, 0.08) | 0.50 (0.26, 0.97) | 1.81 (1.22, 2.69) | 1.22 (0.91, 1.63) |
| n | 2487 | 2466 | 1000 | 1785 |
| Maternal confidence11 | ||||
| Unadjusted model8 | ||||
| P | — | — | <0.0001 | <0.0001 |
| Confident | — | — | Reference | Reference |
| Neutral | — | — | 1.74 (1.50, 2.02) | 2.08 (1.84, 2.34) |
| Not confident | — | — | 2.02 (1.53, 2.68) | 2.98 (2.48, 3.59) |
| n | — | — | 1186 | 2246 |
| Model adjusted for BMI and all PSFs9 | ||||
| P | — | — | <0.0001 | <0.0001 |
| Confident | — | — | Reference | Reference |
| Neutral | — | — | 1.56 (1.33, 1.82) | 1.81 (1.60, 2.04) |
| Not confident | — | — | 1.66 (1.24, 2.21) | 2.50 (2.07, 3.02) |
| n | — | — | 1176 | 2225 |
| Final adjusted model10 | ||||
| P | — | — | 0.02 | <0.0001 |
| Confident | — | — | Reference | Reference |
| Neutral | — | — | 1.27 (1.07, 1.51) | 1.32 (1.15, 1.52) |
| Not confident | — | — | 1.16 (0.84, 1.61) | 1.68 (1.34, 2.09) |
| n | — | — | 1000 | 1785 |
Values are ORs; 95% CIs in parentheses for intention to breastfeed and ever breastfed; values are HRs; 95% CIs in parentheses for duration of EBF and duration of ABF. ABF, any breastfeeding; EBF, exclusive breastfeeding; PSF, psychosocial factor.
Logistic regression models that predicted the odds of intention to breastfeed and ever breastfed.
All final models were adjusted for education, income, race-ethnicity, smoking status, and past breastfeeding experience.
All final models were adjusted for race-ethnicity, planned return to work, past breastfeeding experience, prenatal infant-feeding intention, and marital status.
Cox proportional hazard models that predicted the hazard of earlier cessation of EBF and ABF.
All final models were adjusted for marital status, education, intended duration of breastfeeding, and actual return time to work.
All final models were adjusted for intended duration of breastfeeding, actual return time to work, education, past breastfeeding experience, gestation duration, and marital and smoking status.
Unadjusted model of the single predictor with each outcome.
Model was adjusted to include BMI and psychosocial variables for each outcome.
Best-fitting model for each outcome was determined by using the Akaike information criterion score. Models included BMI and psychosocial variables as well as particular covariates as described in footnotes 3, 4, 6, and 7.
Maternal confidence was not used as a predictor for outcomes of intention to breastfeed or ever breastfed because only women with a prenatal intention to breastfeed responded to the question about their breastfeeding confidence.