Table 4.
Crude and Adjusted Odds Ratios (ORadj) and 95% Confidence Intervals (CIs) for Autism Spectrum Disorders (ASD) Associated with Organ Specific Infections, Kaiser Permanente Northern California Childhood Autism Perinatal Study, 1995 – 1999
| Exposure* | ASD Cases (N=407) n (%) |
Controls (N=2075) n (%) |
Crude OR (95% CI) | ORadj** (95% CI) |
|---|---|---|---|---|
| Unexposed group*** | 199 (48.9) | 1080 (52.0) | reference | reference |
| Genitourinary infection | ||||
| 30 Days Pre Conception | 6 (1.5) | 31 (1.5) | 1.05 (0.43 – 2.55) | 1.07 (0.42 – 2.67) |
| Pregnancy period1 | 73 (17.9) | 299 (14.4) | 1.32 (0.98 – 1.78) | 1.39 (1.02 – 1.90) |
| 1st Trimester | 16 (3.9) | 94 (4.5) | 0.92 (0.53 – 1.60) | 0.98 (0.54 – 1.77) |
| 2nd Trimester | 23 (5.6) | 83 (4.0) | 1.50 (0.92 – 2.44) | 1.58 (0.95 – 2.63) |
| 3rd Trimester | 40 (9.8) | 156 (7.5) | 1.39 (0.95 – 2.03) | 1.47 (0.99 – 2.17) |
| Lower respiratory infection | ||||
| 30 Days Pre Conception | 3 (0.7) | 15 (0.7) | - | - |
| Pregnancy period1 | 35 (8.6) | 153 (7.4) | 1.24 (0.83 – 1.85) | 1.20 (0.80 – 1.81) |
| 1st Trimester | 10 (2.5) | 45 (2.2) | 1.21 (0.60 – 2.43) | 1.22 (0.60 – 2.51) |
| 2nd Trimester | 11 (2.7) | 55 (2.6) | 1.08 (0.56 – 2.11) | 1.05 (0.52 – 2.08) |
| 3rd Trimester | 14 (3.4) | 68 (3.3) | 1.12 (0.62 – 2.02) | 1.01 (0.54 – 1.87) |
| Upper respiratory infection | ||||
| 30 Days Pre Conception | 12 (2.9) | 58 (2.8) | 1.12 (0.59 – 2.13) | 1.03 (0.53 – 1.99) |
| Pregnancy period1 | 76 (18.7) | 386 (18.6) | 1.07 (0.80 – 1.43) | 1.05 (0.78 – 1.42) |
| 1st Trimester | 26 (6.4) | 129 (6.2) | 1.09 (0.70 – 1.71) | 1.09 (0.69 – 1.74) |
| 2nd Trimester | 31 (7.6) | 163 (7.8) | 1.03 (0.68 – 1.56) | 1.00 (0.65 – 1.53) |
| 3rd Trimester | 33 (8.1) | 150 (7.2) | 1.19 (0.79 – 1.79) | 1.15 (0.76 – 1.75) |
| Skin infection | ||||
| 30 Days Pre Conception | 6 (1.5) | 11 (0.5) | 2.96 (1.08 – 8.10) | 3.43 (1.21 – 9.70) |
| Pregnancy period1 | 13 (3.2) | 91 (4.4) | 0.77 (0.42 – 1.41) | 0.80 (0.43 – 1.47) |
| 1st Trimester | 4 (1.0) | 36 (1.7) | - | - |
| 2nd Trimester | 6 (1.5) | 39 (1.9) | 0.83 (0.35 – 2.0) | 0.83 (0.34 – 2.02) |
| 3rd Trimester | 7 (1.7) | 29 (1.4) | 1.31 (0.57 – 3.03) | 1.45 (0.60 – 3.48) |
| Unknown | ||||
| 30 Days Pre Conception | 2 (0.50) | 15 (0.7) | - | - |
| Pregnancy period1 | 88 (21.6) | 383 (18.5) | 1.25 (0.94 – 1.64) | 1.36 (1.01 – 1.83) |
| 1st Trimester | 32 (7.8) | 154 (7.4) | 1.13 (0.75 – 1.70) | 1.33 (0.83 – 2.11) |
| 2nd Trimester | 20 (4.9) | 69 (3.3) | 1.57 (0.93 – 2.65) | 1.80 (1.04 – 3.13) |
| 3rd Trimester | 43 (10.60) | 197 (9.50) | 1.185 (0.82 – 1.70) | 1.20 (0.82 – 1.75) |
*
Maternal infections diagnosed during an inpatient hospitalization or outpatient clinic visit during pregnancy.
**
All ORs were adjusted for the matching variables (child sex, year of birth and hospital of birth) in addition to maternal age and race/ethnicity.
***
The unexposed group had no diagnosed infections during the period from 30 days before pregnancy to delivery.
1
The pregnancy period is defined as the time between the LMP and the date of delivery.