Table 1 Characteristics of the study population by occupational level
From: To what extent does IQ 'explain' socio-economic variations in function?
| Â | Â | Occupational level: | ||
|---|---|---|---|---|
| Â | Total | High | Intermediate | Low |
| Â | (n = 1211) | (n = 385) | (n = 422) | (n = 404) |
Women (%) | 48.6 | 34.5 | 57.3 | 41.8 * |
Age, mean (SD) | 50.3 (15.4) | 50.2 (14.7) | 48.5 (15.3) | 50.1 (15.1) |
Low intellectual abilities (%) | 31.6 | 10.4 | 27.7 | 48.8 * |
Early socioeconomic conditions | Â | Â | Â | Â |
   Deprivation (%) | 7.0 | 4.8 | 5.7 | 12.7 * |
   Low occupational level of father (%) | 36.0 | 26.6 | 33.4 | 47.0 * |
   Low educational level of father (%) | 54.9 | 44.7 | 53.7 | 63.5 * |
   Low educational level of mother (%) | 65.5 | 59.0 | 60.3 | 73.9 * |
Early developmental factors | Â | Â | Â | Â |
   Assisted birth (%) | 5.0 | 5.8 | 3.9 | 5.6 |
   Low birth weight (%) | 4.4 | 3.0 | 5.2 | 5.4 |
   Nuchal cord (%) | 2.4 | 2.3 | 1.9 | 3.4 |
   Delayed milestones (%) | 4.6 | 2.4 | 6.5 | 4.3 * |
   Severe disease in childhood (%) | 7.2 | 4.9 | 7.6 | 9.2 |