From: Assessment of selection bias in a health survey of children and families – the IDEFICS Sweden-study
IDEFICS population | Reference population | p-value | ||
---|---|---|---|---|
n=1 431 | n= 1 825 | |||
Maternal characteristics | ||||
BMI | 23.8 (3.7) | 24.0 (3.9) | 0.479 | |
n = 1 158 | n = 1 305 | |||
Age (years) | 37.8 (4.5) | 37.0 (5.2) | <0.001 | |
n = 1 370 | n = 1 557 | |||
Smoking 3 months before pregnancy | Not smoking | 1 071 (86.9%) | 1 095 (80.1%) | |
1–9 cigarettes/day | 73 (5.9%) | 133 (9.7%) | ||
10 or more cigarettes/day | 88 (7.1%) | 139 (10.2%) | <0.001 | |
Family characteristics | ||||
Educational level | ISCED (1–2) Low | 18 (1.3%) | 49 (2.7%) | |
ISCED (3–4) Medium | 492 (34.4%) | 820 (45.0%) | ||
ISCED (5–6) High | 921 (64.4%) | 953 (52.3%) | <0.001 | |
Family type | Single parent | 112 (7.8%) | 269 (14.7%) | |
Married or co-habiting | 1 319 (92.2%) | 1 556 (85.3%) | <0.001 | |
Number of children | One child | 168 (11.7%) | 287 (15.7%) | |
Two or more children | 1 263 (88.3%) | 1 538 (84.3%) | <0.01 | |
Single or twin birth | Single birth | 1 327 (96.9%) | 1 510 (97%) | |
Twin birth | 43 (3.1%) | 47 (3.0%) | 0.934 | |
Parental origin | Swedish | 1 337 (93.4%) | 1 599 (87.6%) | |
Foreign | 94 (6.6%) | 226 (12.4%) | <0.001 | |
Family economy | Disposable income/familya | 4 943 (2 039) | 4 651 (2 527) | <0.001 |
n = 1 431 | n = 1 825 | |||
Parental personal incomea (one parent) | 2 827 (2 445) | 2 078 (1 814) | 0.004 | |
n = 112 | n = 269 | |||
Social welfare pension/family | 26 (1.8%) | 85 (4.7%) | <0.001 | |
Disability pension/family | 45 (3.1%) | 103 (5.6%) | <0.001 | |
Unemployment compensation/family | 141 (9.9%) | 243 (13.3%) | 0.003 | |
Financial study assistance/family | 106 (7.4%) | 194 (10.6%) | 0.002 |