Introduction
Subjects and methods
Study design
Study population
Exposure: timing of introduction of complementary foods
Breastfeeding status
Outcome measure: overweight throughout childhood
Confounders
Effect modifiers
Statistical analysis
Results
Participants versus non-participants
Baseline characteristics of the study population
Variablesa | Formula feeding (n = 415) | Ever breastfeeding (n = 2 196) | Breastfeeding < 4 months (n = 1 089) | Breastfeeding ≥ 4 months (n = 1 107) | ||||
---|---|---|---|---|---|---|---|---|
Intro CF in months | Intro CF in months | Intro CF in months | Intro CF in months | |||||
< 4 (n = 219) | ≥ 4 (n = 196) | < 4 (n = 857) | ≥ 4 (n = 1 339) | < 4 (n = 549) | ≥ 4 (n = 540) | < 4 (n = 308) | ≥ 4 (n = 799) | |
Intro CF in wks, median (IQR) | 15 (12–16) | 20 (18–22) | 15 (12–16) | 20 (18–24) | 14 (12–16) | 20 (18–22) | 15 (13–16) | 21 (18–24) |
Stopped breastfeeding, age in wks, median (IQR) | 0 (0) | 0 (0) | 12 (6–24) | 22 (10–26) | 7 (4–12) | 8 (4–12) | 28 (23–36) | 34 (25–43) |
Received no breastfeeding when introduced to CF | 100 (219) | 100 (196) | 67.2 (448) | 76.1 (624) | 81.6 (448) | 100 (540) | 0.0 (0) | 10.5 (84) |
First CF: fruit, fruit juice and/ or vegetables | 99.1 (217) | 99.0 (194) | 99.9 (856) | 99.4 (1 331) | 98.9 (543) | 98.3 (531) | 98.4 (303) | 98.1 (784) |
Maternal factors | ||||||||
Age at birth in years, mean (SD) | 29.7 (3.6) | 30.5 (3.8) | 30.1 (3.9) | 31.1 (3.6) | 29.8 (4.0) | 30.7 (3.6) | 30.6 (3.9) | 31.4 (3.6) |
Educational level, high | 10.6 (23) | 20.0 (39) | 31.3 (266) | 46.1 (613) | 26.6 (144) | 35.3 (189) | 40.0 (122) | 53.3 (424) |
Overweight before pregnancy | 32.5 (63) | 25.6 (45) | 20.6 (161) | 16.0 (202) | 22.0 (110) | 18.9 (95) | 18.2 (51) | 14.1 (107) |
Smoking during pregnancy | 24.2 (53) | 21.4 (41) | 17.0 (144) | 13.2 (176) | 19.5 (106) | 18.6 (100) | 12.6 (38) | 9.6 (76) |
Excessive weight gain during pregnancy | 32.3 (62) | 34.1 (59) | 35.5 (273) | 27.3 (338) | 35.3 (174) | 31.1 (154) | 35.6 (99) | 24.7 (184) |
Child factors | ||||||||
Girls | 46.3 (101) | 52.6 (103) | 48.1 (412) | 48.5 (650) | 47.8 (262) | 45.0 (243) | 48.7 (150) | 50.9 (407) |
Gestational age in wks, mean (SD) | 39.9 (1.3) | 39.8 (1.2) | 40.1 (1.2) | 40.1 (1.2) | 40.1 (1.2) | 40.1 (1.2) | 40.2 (1.2) | 40.2 (1.1) |
Birth weight in g, mean (SD) | 3534 (529) | 3548 (505) | 3570 (485) | 3577 (460) | 3562 (494) | 3554 (472) | 3582 (468) | 3593 (452) |
Birth weight > 4000 g | 17.8 (39) | 16.3 (32) | 18.1 (155) | 16.9 (226) | 18.7 (103) | 16.3 (88) | 16.9 (52) | 17.3 (138) |
Birth weight < 2500 g | 2.7 (6) | 3.1 (6) | 2.0 (17) | 1.3 (17) | 1.6 (9) | 1.8 (10) | 2.6 (8) | 0.9 (7) |
Delivered by Caesarean section | 7.8 (17) | 10.3 (20) | 8.9 (75) | 6.5 (86) | 8.5 (46) | 7.7 (41) | 9.5 (29) | 5.7 (45) |
Siblings present at birth | 57.7 (126) | 61.7 (121) | 43.3 (371) | 55.1 (738) | 41.3 (226) | 51.5 (278) | 47.1 (145) | 57.6 (460) |
Timing of introduction of complementary foods and overweight throughout childhood
All children (n = 2 611) | Formula feeding (n = 415) | Ever breastfeeding (n = 2 196) | Breastfeeding < 4 months (n = 1 089) | Breastfeeding ≥ 4 months (n = 1 107) | ||||||
---|---|---|---|---|---|---|---|---|---|---|
OR | 95% CI | OR | 95% CI | OR | 95% CI | OR | 95% CI | OR | 95% CI | |
Intro CF ≥ 4 mo | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) | |||||
Crude | ||||||||||
Intro CF < 4 mo | 1.31* | 1.19, 1.44 | 1.30* | 1.04, 1.61 | 1.31* | 1.19, 1.44 | 1.40* | 1.21, 1.63 | 1.11 | 0.94, 1.30 |
Adjusteda | ||||||||||
Intro CF < 4 mo | 1.32* | 1.19, 1.47 | 1.51* | 1.17, 1.94 | 1.32* | 1.19, 1.47 | 1.48* | 1.26, 1.73 | 1.02 | 0.86, 1.22 |