Table 5 Characteristics of the participants stratified according to age at introduction of complementary foods
Age at introduction of complementary foods (N = 3814) | ||||
|---|---|---|---|---|
≥ 6 months (n = 996) | < 6 months (n = 2818) | |||
Characteristics | na | na | ||
Maternal age at birth, years, mean (SD) | 994 | 31.2 (4.2) range: 18.0–43.8 | 2810 | 29.6 (4.5) range: 17.0–43.7 |
Maternal education, n (%) | 596 | 1409 | ||
< 12 years (less than high school) | 17 (2.9) | 106 (7.5) | ||
12–16 years (up to 4 years university) | 288 (48.3) | 749 (53.2) | ||
> 16 years (more than 4 years university) | 291 (48.8) | 554 (39.3) | ||
Mean incomeb, NOK, mean (SD, range) | 952 | 256,368 (28674) | 2699 | 254,101 (29284) |
Family history of allergyc, n (%) | 995 | 768 (77.2) | 2812 | 2147 (76.4) |
Older sibling, n (%) | 995 | 588 (59.1) | 2809 | 1570 (55.9) |
Maternal smoking, n (%) | ||||
During pregnancy | 538 | 10 (1.9) | 1126 | 91 (8.1) |
During child’s first 2 years | 994 | 107 (10.8) | 2807 | 597 (21.3) |
Paternal smoking, n (%) | 981 | 170 (17.3) | 2717 | 680 (25.0) |
Child exposed to smoke during first 2 yearsd, n (%) | 995 | 201 (20.2) | 2817 | 923 (32.8) |
Petse, n (%) | 996 | 239 (24.0) | 2818 | 633 (22.5) |
Birthweight, gram, mean (SD, range) | 992 | 3583 (576) range: 1100–5500 | 2808 | 3587 (577) range: 585–5370 |
Birthweight < 2500 g, n (%) | 992 | 31 (3.1) | 2808 | 106 (3.8) |
Sex, male, n (%) | 996 | 465 (46.7) | 2818 | 1418 (50.3) |
Lower respiratory tract infection within first yearf, n (%) | 992 | 101 (10.2) | 2809 | 307 (10.1) |
Antibiotic treatment within first year, n (%) | 995 | 203 (20.4) | 2812 | 689 (24.5) |
Introduced to formula < 6 months of age, n (%) | 992 | 127 (12.8) | 2810 | 897 (31.9) |
Start of day-care < 12 months of age, n (%) | 806 | 70 (8.7) | 2281 | 200 (8.8) |