Table 1.
Covariates in relation to immigration status in controls and in relation to the risk of Asperger’s syndrome
| Immigration | Relationship between covariates and Asperger’s syndrome, p valuef |
|||||
|---|---|---|---|---|---|---|
| Covariates | Both parents Finnish n (%) |
Mother immigrant n (%) |
Father immigrant n (%) |
Both parents immigrants n (%) |
p valuef | |
| Maternal age (≥median, 29 years) | 3,729 (55.2) | 44 (50.0) | 73 (54.9) | 51 (38.4) | 0.001 | 0.07 |
| mean (SD) (years) | 29.4 (5.1) | 29.4 (4.8) | 29.6 (5.1) | 27.2 (4.9) | ||
| Paternal age (≥median, 31 years)a | 3,171 (47.0) | 49 (55.7) | 59 (44.3) | 73 (54.9) | 0.10 | 0.87 |
| mean (SD) (years) | 31.7 (5.8) | 34.7 (8.4) | 31.9 (7.3) | 32.4 (6.2) | ||
| Maternal smokingb | 1,047 (15.9) | 8 (9.4) | 20 (15.5) | 6 (4.8) | 0.003 | 0.04 |
| Previous births (≥2)c | 1,658 (24.6) | 16 (18.2) | 19 (14.3) | 48 (36.1) | <0.001 | <0.0001 |
| Preterm birth (<37 weeks)d | 332 (4.9) | 5 (5.7) | 10 (7.5) | 10 (7.5) | 0.29 | 0.08 |
| Low birth weight (<2,500 g)e | 185 (2.7) | 5 (5.7) | 7 (5.3) | 10 (7.5) | 0.001 | 0.38 |
| mean (SD) (g) | 3,614 (541) | 3,482 (524) | 3,482 (557) | 3,419 (602) | ||
a
frequency missing = 39 cases and 91 controls
b
frequency missing = 48 cases and 155 controls
c
frequency missing = 14 cases and 43 controls
d
frequency missing = 12 cases and 42 controls
e
frequency missing = 7 cases and 29 controls
f
Χ2 test