The mothers of all eligible study members were contacted: 4,435 mothers of cohort members were interviewed by the health visitor or school nurse.
| Provided information | 4,435 | ||||||
| Cumulative total of deaths | 236 | ||||||
| Cumulative permanent refusals | 1 | ||||||
| Temporarily living abroad | 40 | ||||||
| Cumulative emigrated | 259 | ||||||
| Failure to contact | 391 | ||||||
School nurses and health visitors interviewed mothers at home about the child’s health and development, school absences, play, the mother’s work, and the home and family circumstances. Teachers administered cognitive tests at school.
Instructions are given at the head of each form.