Table 2. Association Between Childhood Infection and IQ at Age 18 Years in a Sample of 647 515 Swedish Men.
| Age at Infection, y | Exposed to Infection | Unexposed to Infection | Unadjusted Analysis | Adjusted Analysisa | ||||
|---|---|---|---|---|---|---|---|---|
| Sample, No. (%) | IQ, Mean (SD) | Sample, No.b | IQ, Mean (SD)b | Mean Difference (95% CI) | P Value | Mean Difference (95% CI) | P Value | |
| All (0-13) | 153 460 (23.7) | 99.18 (15.02) | 494 055 | 100.26 (14.98) | −1.08 (−1.16 to −0.99) | <.001 | −0.98 (−1.07 to −0.90) | <.001 |
| 0-1 | 49 127 (7.6) | 98.20 (15.10) | 494 055 | 100.26 (14.98) | −1.82 (−1.96 to −1.68) | <.001 | −1.61 (−1.74 to −1.47) | <.001 |
| 2-4 | 84 020 (13.0) | 99.20 (15.02) | 494 055 | 100.26 (14.98) | −0.72 (−0.83 to −0.61) | <.001 | −0.70 (−0.81 to −0.60) | <.001 |
| 5-9 | 34 266 (5.3) | 99.49 (15.00) | 494 055 | 100.26 (14.98) | −0.36 (−0.52 to −0.20) | <.001 | −0.26 (−0.42 to −0.10) | <.01 |
| 10-13 | 14 979 (2.3) | 99.69 (14.90) | 494 055 | 100.26 (14.98) | −0.23 (−0.47 to 0.02) | .07 | −0.12 (−0.36 to 0.12) | .31 |
a
Regression models have been adjusted for household crowding, winter birth, parental socioeconomic status, migration status, and parental history of nonaffective psychoses.
b
The same control group was used for all analyses (ie, participants with no infection between birth and age 13 years).