Table S2.
Sibling analysis: characteristics of ASD cases and same-sex siblings
| ASD cases N=531 (%) | Siblings N=601 (%) | Univariate OR (95% CI) | |
|---|---|---|---|
| Child characteristics | |||
| Year of birth | |||
| <1995 | 24 (4.5) | 62 (10.3) | 1.0 (reference) |
| 1995–1999 | 123 (23.2) | 133 (22.1) | 2.07 (1.37–3.13) |
| 2000–2004 | 220 (41.4) | 181 (30.1) | 3.48 (2.25–5.39) |
| 2005–2009 | 154 (29.0) | 185 (30.8) | 2.08 (1.29–3.34) |
| 2010–2011 | 10 (1.9) | 40 (6.7) | 0.74 (0.38–1.46) |
| Child sex | |||
| Female | 75 (14.1) | 82 (13.6) | Matched |
| Male | 456 (85.9) | 519 (86.4) | Matched |
| Birth order | |||
| First born | 233 (43.9) | 254 (42.3) | 1.0 (reference) |
| Second born | 245 (46.1) | 253 (42.1) | 1.03 (0.86–1.23) |
| Third born or higher | 53 (10.0) | 94 (15.6) | 0.79 (0.54–1.16) |
| Maternal characteristics | |||
| Age at delivery (years) | |||
| 13–19 | 18 (3.4) | 23 (3.8) | 0.98 (0.50–1.93) |
| 20–24 | 111 (20.9) | 149 (24.8) | 1.0 (reference) |
| 25–29 | 184 (34.7) | 169 (28.1) | 1.54 (1.08–2.18) |
| 30–34 | 128 (24.1) | 165 (27.5) | 1.13 (0.73–1.74) |
| 35–39 | 71 (13.4) | 77 (12.8) | 1.31 (0.76–2.25) |
| 40–45 | 19 (3.6) | 18 (3.0) | 1.64 (0.66–4.07) |
| BMI | |||
| <18.5 | 15 (2.8) | 20 (3.3) | 0.85 (0.34–2.12) |
| 18.5–24.9 | 156 (29.4) | 170 (28.3) | 1.0 (reference) |
| 25–29.9 | 69 (13.0) | 85 (14.1) | 0.80 (0.47–1.36) |
| ≥30 | 59 (11.1) | 67 (11.2) | 0.91 (0.47–1.76) |
| Unknown | 232 (43.7) | 259 (43.1) | 0.86 (0.58–1.27) |
| Smoking status | |||
| Nonsmoker | 233 (43.9) | 266 (44.3) | 1.0 (reference) |
| Smoker | 140 (26.4) | 129 (21.5) | 2.01 (1.16–3.47) |
| Ex-smoker | 50 (9.4) | 69 (1.5) | 0.98 (0.53–1.82) |
| Unknown | 108 (20.3) | 137 (22.8) | 0.95 (0.65–1.39) |
| Depression | 137 (25.8) | 134 (22.3) | 1.56 (1.03–2.36) |
| Suicidal behaviors | 25 (4.7) | 28 (4.7) | 2.52 (0.65–9.81) |
| Anxiety | 83 (15.6) | 101 (16.8) | 0.95 (0.53–1.67) |
| Other psychiatric disorders | 7 (1.3) | 9 (1.3) | 0.92 (0.23–3.71) |
Abbreviation: BMI, body mass index.