Table 1.
Characteristics of Included Studies
| Study | Country | Year of baseline | No. of women | Mean age at study entry (y) | Mean parity | Mean age at first birth (y) | No. of women who had ever breastfed (%) | Mean lifetime duration of breastfeeding (mo) | CVD | CHD | Stroke | Fatal CVD | Median follow‐up duration (y) | NOS score |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 45&Up 7 | Australia | 2006–2009 | 100 864 | 60.2 | 2.7 | 25.0 | 88 347 (88) | 14.6 | ● | ○ | ○ | ● | 6.1* , † | 7 |
| CKB 8 | China | 2004–2008 | 285 603 | 50.5 | 2.0 | 23.4 | 277 818 (97) | 24.0 ‡ | ● | ● | ● | ● | 8.1 | 7 |
| EPIC 9 , 10 | Multinational | 1992–2000 | 266 607 | 50.3 § | 2.3 | 24.9 | 212 041 (80) | 9.6 | ● || | × || | ● || | ● | 12.9* | 7 |
| 8044 | 52.6 | 2.2 | NR | 7016 (87) | 9.7 | ○ | ● | ○ | ○ | 11.1 | 7 | |||
| Gallagher 11 | China | 1989–1991 | 254 116 | 43.0 ‡ | 2.1 | 25.7 | 214 614 (84) | 18.9 | ● || | ● || | ● || | ● | 9.6* | 5 |
| HUNT2 12 | Norway | 1995–1997 | 20 007 | 52.1 | 2.6 | 23.4 | 19 350 (97) | 16.5 | ● || | ○ | ○ | ● | 14.5 | 7 |
| JPHC 13 | Japan | 1990–1994 | 37 496 | 50.6 § | 2.7 | 25.1 | 32 622 (87) | NR | ● || | ● || | ● || | ● | 20.9* | 8 |
| NHS 14 | United States | 1986 | 89 326 | 40–65 ¶ | 2.5 | NR | 56 619 (63) | 8.4 | ○ | ● | ○ | ○ | 15.1* | 6 |
| WHI 15 , 16 , 17 | United States | 1993–1998 | 138 681 | 63.3 | 3.1 | NR | 81 155 (59) | 9.4 | ● | ○ | ○ | ○ | 7.9 | 7 |
| 80 191 | 63.7 | 2.9 | NR | 46 699 (58) | 7.4 | ○ | ○ | ● | ○ | 12.6 | 6 | |||
| 62 427 | 63.2 § | 3.1 | 24.3 | 36 884 (59) | NR | ○ | ● | ○ | ○ | 12.0 | 8 | |||
| Total | 1986–2009 | 1 192 700 | 51.3 | 2.3 | 24.6 | 982 566 (82) | 15.6 | 10.3 | 6.5 |
If different publications were analyzed for a study, the publication with the largest number of participants was used to compute overall estimates; alternatively, if this publication did not report a variable, the publication that provided this information was used. 45&Up indicates 45 and Up Study; ● = provided; ○ = not provided; × = provided but not used for analysis; CHD, coronary heart disease; CKB, China Kadoorie Biobank; CVD, cardiovascular disease; EPIC, European Prospective Investigation Into Cancer and Nutrition; HUNT2, Nord‐Trøndelag Health Survey 2; JPHC, Japan Public Health Center–based prospective study; NHS, Nurses' Health Study; NOS; Newcastle‐Ottawa Scale; NR, not reported; and WHI, Women’s Health Initiative.
Mean.
Mean of 6.1 for nonfatal CVD and 5.7 for fatal CVD.
Median.
Nulliparous women included.
Fatal only.
Minimum–maximum.