Subgroup variable scores for low and high phenylalanine groups
| Group | Age (years) | Peak phenylalanine (μmol/l) | Start day | Social class (1–7) | cFSIQ | FSIQ |
| Low phenylalanine (n = 29) | 8.12 (0.3) | 2311 (1070) | 17.8 (11.3) | 4.41 (1.62) | 90.61-150 (12.2) | 95.071-160 (13.47) |
| High phenylalanine (n = 28) | 8.16 (0.3) | 2811 (977) | 16.5 (5.7) | 4.71 (1.51) | 80.81-150 (14.0) | 87.001-160 (13.58) |
Values are mean (SD).
The low phenylalanine group (individual indices of dietary control (IDCs) < 360 μmol/litre at age 2) and the high phenylalanine group (individual IDCs > 360 μmol/litre at age 2) were matched for age at test, peak pretreatment phenylalanine, day of treatment commencement, and social class, but differed significantly in both corrected full scale IQ (cFSIQ) and uncorrected FSIQ.
↵1-150 p < 0.01;
↵1-160 p < 0.05.