Table 1 Characteristics of study participants included in these analyses by parity and breastfeeding
Population characteristics | By parity | By breastfeeding a | All women | |||||
|---|---|---|---|---|---|---|---|---|
Nulliparous | One | Two | Three | Four or more | Never breastfed | Ever breastfed | ||
n=89 448 | n=100 639 | n=309 841 | n=159 100 | n=80 600 | n=201 688 | n=449 492 | n=740 628 | |
Age in years (mean (s.d.)) | 57 (5) | 57 (5) | 57 (4) | 58 (4) | 58 (4) | 57 (4) | 58 (4) | 58 (4) |
Parity (mean (s.d.)) | 0 | 1 (0) | 2 (0) | 3 (0) | 4.4 (0.8) | 2.1 (0.9) | 2.5 (1.0) | 2.1 (1.2) |
Number of children breastfed (mean (s.d.)) | 0 | 0.5 (0.5) | 1.1 (0.9) | 1.7 (1.2) | 2.5 (1.8) | 0 | 1.9 (1.0) | 1.2 (1.2) |
Women who ever breastfed (%) | 0 | 52 | 68 | 76 | 80 | 0 | 100 | 70 |
Duration breastfeeding | ||||||||
Total duration in months (mean (s.d.)) | 0 | 1.9 (3.5) | 4.3 (6.2) | 6.8 (8.7) | 10.5 (13.9) | 0 | 7.7 (8.8) | 4.7 (7.8) |
Duration per child in months (mean (s.d.)) | 0 | 1.9 (3.5) | 2.1 (2.9) | 2.3 (2.9) | 2.3 (3.0) | 0 | 3.1 (3.1) | 1.9 (2.9) |
In lower third of socioeconomic group (%) | 33 | 34 | 30 | 36 | 51 | 39 | 33 | 34 |
Current smokers (%) | 17 | 20 | 17 | 19 | 25 | 23 | 17 | 19 |
Strenuous physical activity less than once a week (%) | 26 | 30 | 27 | 28 | 34 | 34 | 26 | 28 |
