Table 2 Change in mean BMI (kg m−2) among parous women by parity and total duration of breastfeeding in models variously standardised

From: Persistent effects of women’s parity and breastfeeding patterns on their body mass index: results from the Million Women Study

 

Number of women

Unadjusted results

Model A—standardised by age and region only

Model A + additionally standardised by breastfeeding (when looking at parity), and for parity (when looking at breastfeeding)

Model A + additionally standardised by breastfeeding, parity, socioeconomic group, smoking and physical activity

Parity (mean)

1

100 639

Reference

Reference

Reference

Reference

2

310 841

−0.02 (−0.05 to 0.01)

−0.01 (−0.04 to 0.02)

0.11 (0.08 to 0.14)

0.13 (0.09 to 0.16)

3

159 100

0.45 (0.41 to 0.48)

0.45 (0.41 to 0.48)

0.63 (0.60 to 0.67)

0.58 (0.55 to 0.62)

4 (4.4)

80 600

1.31 (1.27 to 1.36)

1.30 (1.26 to 1.34)

1.53 (1.49 to 1.58)

1.33 (1.28 to 1.37)

Total duration of breastfeeding (mean in months)

 Did not breastfeed

201 688

Reference

Reference

Reference

Reference

 <6 months (2.3)

239 836

−0.27 (−0.24 to −0.30)

−0.26 (−0.24 to −0.29)

−0.32 (−0.29 to −0.35)

−0.24 (−0.21 to −0.26)

 6–9 months (7.3)

82 198

−0.43 (−0.40 to −0.47)

−0.42 (−0.38 to −0.46)

−0.52 (−0.48 to −0.56)

−0.36 (−0.32 to −0.40)

10 months (18.5)

127 458

−0.44 (−0.41 to −0.48)

−0.43 (−0.40 to −0.46)

−0.75 (−0.71 to −0.78)

−0.53 (−0.50 to −0.57)

 Change in mean BMI per 6 months breastfeedinga

 

−0.12 (−0.11 to −0.13)

−0.11 (−0.10 to 0.12)

−0.17 (−0.16 to −0.18)

−0.13 (−0.11 to −0.13)

  1. Abbreviation: BMI, body mass index.
  2. Trend fitted through category mid-points and multiplied as appropriate.