TABLE 2—
Gender-Adjusted Associations (With 95% Confidence Intervals [CIs]) of Childhood Intelligence and Other Early Life Characteristics With at Least 1 Unintentional Injury Hospital Admission in Adulthood: Aberdeen Children of the 1950s Cohort, Aberdeen, Scotland
| No. of Accidents | Gender-Adjusted Hazard Ratio (95% CI) | P | |
| IQ score | |||
| Age 7 y (per SD) | 1043 | 0.75 (0.70, 0.80) | <.001 |
| Age 9 y (per SD) | 1043 | 0.76 (0.72, 0.81) | <.001 |
| Age 11 y (per SD) | 1043 | 0.72 (0.68, 0.77) | <.001 |
| Father’s occupational social class at time of birth | <.001 | ||
| I/II (highest) | 65 | 1.00 | |
| III nonmanual | 87 | 1.08 (0.78, 1.50) | |
| III manual | 458 | 1.45 (1.11, 1.89) | |
| IV | 212 | 2.06 (1.54, 2.75) | |
| V (lowest) | 221 | 1.83 (1.36, 2.46) | |
| Mother’s number of pregnancies | <.001 | ||
| 1 | 301 | 1.00 | |
| 2 | 300 | 1.15 (0.98, 1.35) | |
| 3 | 191 | 1.17 (0.98, 1.40) | |
| 4 | 109 | 1.21 (0.97, 1.51) | |
| ≥ 5 | 142 | 1.50 (1.22, 1.84) | |
| Mother’s age at delivery, y | .40 | ||
| 15–19 | 55 | 1.17 (0.89, 1.53) | |
| 20–34 | 857 | 1.00 | |
| ≥ 35 | 131 | 1.09 (0.90, 1.31) | |
| Born outside marriage | .30 | ||
| No | 991 | 1.00 | |
| Yes | 52 | 1.16 (0.88, 1.54) | |
| Mother’s height, in | .02 | ||
| ≤ 60a | 290 | 1.00 | |
| 61 | 174 | 0.96 (0.80, 1.17) | |
| 62 | 177 | 0.87 (0.72, 1.05) | |
| 63 | 159 | 0.96 (0.79, 1.17) | |
| 64 | 123 | 0.89 (0.72, 1.11) | |
| ≥ 65 | 120 | 0.76 (0.62, 0.94) | |
| Birthweight (per z score) | 1043 | 0.95 (0.88, 1.02) | .10 |
| Height at school entry (per z score) | 1043 | 0.86 (0.81, 0.92) | <.001 |
| Weight at school entry (per z score) | 1043 | 0.92 (0.84, 1.01) | .08 |
| Educational attainment | <.001 | ||
| None | 399 | 1.00 | |
| School leaving certificate | 26 | 0.67 (0.41, 1.12) | |
| Certificate of secondary education | 24 | 0.90 (0.55, 1.47) | |
| Ordinary-level qualifications | 251 | 0.76 (0.64, 0.91) | |
| Advanced-level qualifications | 82 | 0.46 (0.35, 0.58) | |
| Higher national certificate | 162 | 0.71 (0.57, 0.87) | |
| University degree | 99 | 0.43 (0.33, 0.57) | |
Note. Analyses were conducted with 10 multiple imputation data sets, which allows all 11 103 participants to contribute to the analyses. For the intelligence measures, hazard ratios refer to each 1-standard-deviation increase in score. The hazard ratio for birthweight was that for a 1-standard-deviation increase standardized for differences in birthweight owing to differences in gestational age and gender.
a152 cm or less.