Child and maternal characteristics and their association with BF categories
| Not BF | EBF <4 MO with BF <6 MO | EBF <4 MO with BF ≥6 MO | EBF 4–5 MO with BF <6 MO | EBF 4–5 MO with BF ≥6 MO | EBF ≥6 MO | All included | Excluded | |
| % (n) | % (n) | % (n) | % (n) | % (n) | n | n | ||
| All | 1.6 (613) | 19 (7335) | 11 (3998) | 3.9 (1488) | 40 (15007) | 25 (9384) | 37 825 | 4000 |
| SGA | ||||||||
| Yes | 1.5 (8) | 27 (144) | 16 (86) | 4.1 (22) | 32 (170) | 20 (106) | 536 | 85 |
| No | 1.6 (605) | 19 (7191) | 11 (3912) | 3.9 (1466) | 40 (14837) | 25 (9278) | 37 289 | 3816 |
| LGA | ||||||||
| Yes | 2.5 (43) | 22 (385) | 11 (189) | 3.5 (62) | 35 (614) | 26 (457) | 1750 | 172 |
| No | 1.6 (570) | 19 (6950) | 11 (3809) | 4.0 (1426) | 40 (14393) | 25 (8927) | 36 075 | 3729 |
| Congenital malformation* | ||||||||
| Yes | 4.0 (32) | 25 (196) | 9.7 (77) | 3.6 (29) | 35 (277) | 23 (186) | 797 | 3891 |
| No | 1.6 (581) | 19 (7139) | 11 (3921) | 3.9 (1459) | 40 (14730) | 25 (9198) | 37 028 | 109 |
| Sex | ||||||||
| Male | 1.6 (319) | 20 (3926) | 11 (2077) | 4.1 (795) | 40 (7751) | 24 (4731) | 19 599 | 2088 |
| Female | 1.6 (294) | 19 (3409) | 11 (1921) | 3.8 (693) | 40 (7256) | 26 (4653) | 18 226 | 1912 |
| Maternal age | ||||||||
| ≤19 | 2.5 (10) | 47 (187) | 7.5 (30) | 8.2 (33) | 24 (98) | 11 (43) | 401 | 146 |
| 20-–24 | 1.6 (67) | 33 (1402) | 9.0 (378) | 6.7 x (282) | 32 (1362) | 17 (723) | 4214 | 607 |
| 25–29 | 1.7 (198) | 21 (2366) | 9.8 (1136) | 4.7 (545) | 40 (4582) | 24 (2727) | 11 554 | 1167 |
| 30–34 | 1.6 (222) | 15 (2108) | 11 (1482) | 3.4 (470) | 43 (5876) | 27 (3682) | 13 840 | 1305 |
| ≥35 | 1.5 (116) | 16 (1272) | 12 (972) | 2.0 (158) | 40 (3089) | 28 (2209) | 7816 | 775 |
| Parity | ||||||||
| 1 | 1.1 (185) | 22 (3510) | 12 (1878) | 3.9 (642) | 39 (6384) | 23 (3724) | 16 323 | 1821 |
| 2 | 1.9 (268) | 18 (2486) | 9.3 (1301) | 4.3 (603) | 41 (5738) | 26 (3584) | 13 980 | 1336 |
| 3 | 2.1 (110) | 17 (902) | 10 (541) | 3.1 (165) | 41 (2177) | 27 (1440) | 5335 | 535 |
| ≥4 | 2.3 (50) | 20 (437) | 13 (278) | 3.6 (78) | 32 (708) | 29 (636) | 2187 | 308 |
| Maternal smoking | ||||||||
| No smoking | 1.5 (521) | 18 (6136) | 11 (3744) | 3.8 (1337) | 41 (14362) | 26 (9061) | 35 161 | 2366 |
| Smoking | 3.5 (92) | 45 (1199) | 9.5 (254) | 5.7 (151) | 24 (645) | 12 (323) | 2664 | 255 |
| Maternal education† | ||||||||
| ≤9 | 2.9 (102) | 36 (1273) | 11 (406) | 5.4 (193) | 29 (1014) | 16 (561) | 3549 | 419 |
| 10–12 | 2.2 (338) | 25 (3942) | 10 (1590) | 5.4 (838) | 35 (5516) | 22 (3378) | 15 602 | 1217 |
| 13–14 | 1.1 (56) | 15 (725) | 10 (500) | 3.2 (161) | 42 (2071) | 30 (1472) | 4985 | 491 |
| ≥14 | 0.9 (117) | 10 (1395) | 11 (1502) | 2.2 (296) | 47 (6406) | 29 (3973) | 13 689 | 1217 |
| Maternal country of birth | ||||||||
| Sweden | 1.6 (526) | 19 (6231) | 9.9 (3168) | 4.1 (1313) | 40 (12853) | 25 (7977) | 32 068 | 2693 |
| Other Nordic | 0.8 (6) | 17 (134) | 8.8 (70) | 2.4 (19) | 41 (326) | 30 (238) | 793 | 128 |
| Other Europe and North America | 1.8 (27) | 20 (303) | 12 (185) | 3.2 (48) | 37 (564) | 25 (382) | 1509 | 339 |
| Asia | 1.3 (33) | 22 (538) | 16 (399) | 3.0 (75) | 36 (895) | 21 (528) | 2468 | 540 |
| Africa | 1.9 (12) | 11 (67) | 20 (126) | 3.1 (19) | 38 (233) | 26 (163) | 620 | 224 |
| Other | 2.5 (9) | 17 (62) | 14 (50) | 3.8 (14) | 37 (136) | 26 (96) | 367 | 73 |
Children with missing data on BF (n=2127) or covariates (n=1873) were excluded leaving 37 825 children.
*ICD-10 codes: Q00–Q99.
†Maternal education level at year of birth, categorised as 9 years or less, 10–12 years, 13–14 years or 15 years or more.
BF, breast feeding; EBF, exclusive BF; LGA, large for gestation age; MO, months; SGA, small for gestation age.