Table 1.
Participant Characteristics by Breastfeeding History Among Postmenopausal Women
| Never Breastfed (n=33 492) % | Ever Breastfed (n=46 699) % | Breastfed 1 to 6 Months (n=23 666) % | Breastfed 7 to 12 Months (n=10 177) % | Breastfed 13 or More Months (n=12 575) % | |
|---|---|---|---|---|---|
| Race/ethnicitya , b | |||||
| Non‐Hispanic white | 84.8 | 82.8 | 82.3 | 83.3 | 83.9 |
| Non‐Hispanic black | 8.3 | 7.6 | 8.1 | 7.7 | 6.2 |
| Hispanic | 3.4 | 4.2 | 4.0 | 3.9 | 4.5 |
| Other race/ethnicity | 3.6 | 5.4 | 5.5 | 5.2 | 5.4 |
| Age at screening, mean (SD)a , b | 63.3 (7.1) | 63.9 (7.4) | 64.1 (7.3) | 63.7 (7.5) | 63.8 (7.4) |
| 50 to 59a , b | 32.4 | 30.1 | 28.9 | 32.4 | 30.8 |
| 60 to 69 | 46.0 | 44.1 | 44.9 | 42.2 | 44.2 |
| 70 to 79 | 21.6 | 25.8 | 26.2 | 25.4 | 25.1 |
| Educationa , b | |||||
| High school or less | 37.1 | 29.5 | 32.2 | 27.7 | 25.7 |
| Some college | 39.8 | 38.6 | 40.2 | 37.4 | 36.6 |
| Postcollege | 23.1 | 31.9 | 27.7 | 34.9 | 37.6 |
| Regiona , b | |||||
| Northeast | 28.4 | 18.8 | 19.4 | 18.5 | 18.0 |
| South | 25.8 | 25.9 | 26.9 | 26.2 | 23.5 |
| Midwest | 20.8 | 23.1 | 22.4 | 22.5 | 24.7 |
| West | 25.0 | 32.3 | 31.3 | 32.8 | 33.8 |
| Extension cohorta , b | 66.2 | 69.0 | 67.3 | 70.1 | 71.5 |
| Age at menarche, mean (SD)a , b | 12.6 (1.5) | 12.6 (1.5) | 12.6 (1.5) | 12.6 (1.5) | 12.7 (1.5) |
| Parity, mean (SD)a , b | 2.7 (1.2) | 3.1 (1.2) | 2.9 (1.2) | 3.0 (1.1) | 3.6 (1.1) |
| Body mass index at baseline, mean (SD)a , b | 27.5 (5.9) | 27.2 (5.8) | 27.3 (5.8) | 27.0 (5.7) | 27.2 (5.7) |
| Under/normal (≤24.9)a , b | 39.2 | 41.0 | 40.3 | 42.4 | 41.2 |
| Overweight (25‐29.9) | 34.5 | 34.2 | 34.4 | 34.3 | 33.6 |
| Obese (≥30) | 26.3 | 24.8 | 25.3 | 23.4 | 25.2 |
| Physical activity (metabolic equivalent task/wk), mean (SD)a , b | 13.3 (14.2) | 14.0 (14.4) | 13.6 (14.3) | 14.3 (14.3) | 14.6 (14.8) |
| Ever smokera , b | 52.6 | 46.6 | 49.7 | 45.9 | 41.5 |
| Multivitamin usea , b | 40.9 | 42.2 | 42.4 | 42.1 | 41.9 |
| Healthy eating index 2005 mean (SD) | 68.5 (10.7) | 69.8 (10.5) | 69.3 (10.5) | 70.1 (10.2) | 70.3 (10.2) |
| Hormone therapyWomen's Health Initiative baselinea , b | |||||
| Never | 31.3 | 29.2 | 27.9 | 28.1 | 32.1 |
| Past | 21.1 | 21.4 | 21.9 | 21.6 | 20.1 |
| Current | 47.6 | 49.5 | 50.1 | 50.3 | 47.8 |
| Aspirin use | 20.6 | 21.3 | 21.6 | 20.4 | 21.3 |
| Family history | |||||
| Diabetes mellitusa , b | |||||
| No | 62.4 | 64.9 | 63.7 | 66.0 | 66.1 |
| Yes | 33.0 | 30.7 | 31.5 | 29.7 | 30.1 |
| Unknownc | 4.6 | 4.5 | 4.8 | 4.3 | 3.8 |
| Strokea | |||||
| No | 59.3 | 58.2 | 58.0 | 58.1 | 58.6 |
| Yes | 35.9 | 36.9 | 37.2 | 36.8 | 36.5 |
| Unknownc | 4.9 | 4.9 | 4.9 | 5.1 | 4.9 |
| Myocardial Infarction a , b | 53.8 | 51.6 | 52.6 | 50.0 | 51.2 |
| Cardiovascular disease and risk factors at baseline | |||||
| Stroke | 1.5 | 1.6 | 1.6 | 1.6 | 1.4 |
| Transient ischemic attack | 2.4 | 2.5 | 2.6 | 2.3 | 2.6 |
| Myocardial infarction | 2.5 | 2.5 | 2.7 | 2.2 | 2.3 |
| Heart failure | 1.0 | 1.0 | 0.9 | 1.0 | 0.9 |
| Atrial fibrillationb | 4.7 | 4.9 | 5.2 | 4.6 | 4.4 |
| Anginab | 5.8 | 6.3 | 6.7 | 5.9 | 5.7 |
| Diabetes mellitus | 5.7 | 5.6 | 5.8 | 5.2 | 5.7 |
| Hypertension treatmenta , b | |||||
| Never | 65.6 | 66.8 | 65.8 | 67.5 | 68.1 |
| Untreatedd | 8.0 | 7.8 | 7.8 | 8.0 | 7.7 |
| On treatment | 26.4 | 25.4 | 26.4 | 24.5 | 24.2 |
| Hypercholesterolemia treatmenta , b | 16.1 | 14.4 | 15.2 | 13.7 | 13.2 |
Data are presented as n (%) or mean (SD).
a
Comparison between participant characteristics and (ever and never) breastfeeding chi‐squared test or t test, P<0.01.
b
Comparison between participant characteristics and breastfeeding duration chi‐squared test or ANOVA, F‐test P<0.01.
c
Unlike other listed variables, this variable includes “unknown” values.
d
Unlike other listed variables, this variable includes “untreated” values.